An endangered species is a population of an organism which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters. An endangered species is usually a taxonomic species, but may be another evolutionary significant unit. The World Conservation Union (IUCN) has calculated the percentage of endangered species as 40 percent of all organisms based on the sample of species that have been evaluated through 2006. (Note: the IUCN groups all threatened species for their summary purposes.) Many nations have laws offering protection to these species: for example, forbidding hunting, restricting land development or creating preserves. Only a few of the many species at risk of extinction actually make it to the lists and obtain legal protection. Many more species become extinct, or potentially will become extinct, without gaining public notice.
The conservation status of a species is an indicator of the likelihood of that endangered species not living. Many factors are taken into account when assessing the conservation status of a species; not simply the number remaining, but the overall increase or decrease in the population over time, breeding success rates, known threats, and so on. The IUCN Red List is the best known conservation status listing.
Internationally, 190 countries have signed an accord agreeing to create Biodiversity Action Plans to protect endangered and other threatened species. In the United States this plan is usually called a species Recovery Plan.
IUCN Red List Endangered species
Endangered species under the IUCN Red List refers to a specific category of threatened species, and may include critically endangered species.
IUCN Red List of Threatened Species uses the term endangered species as a specific category of imperilment, rather than as a general term. Under the IUCN Categories and Criteria, endangered species is between critically endangered and vulnerable. Also critically endangered species may also be counted as endangered species and fill all the criteria
The more general term used by the IUCN for species at risk of extinction is threatened species, which also includes the less-at-risk category of vulnerable species together with endangered and critically endangered.
IUCN categories include:
* Extinct: the last remaining member of the species has died, or is presumed beyond reasonable doubt to have died. Examples: Thylacine, Dodo, Passenger Pigeon
* Extinct in the wild: captive individuals survive, but there is no free-living, natural population. Examples:South China Tiger, Alagoas Curassow
* Critically endangered: faces an extremely high risk of extinction in the immediate future. Examples: Arakan Forest Turtle, Javan Rhino, Brazilian Merganser
* Endangered: faces a very high risk of extinction in the near future. Examples: Blue Whale, Snow Leopard, African Wild Dog, Tiger, Albatross, Crowned Solitary Eagle
* Vulnerable: faces a high risk of extinction in the medium-term. Examples: Cheetah, Gaur, Lion, Wolverine
* Conservation Dependent: The following animal is not severely threatened, but the animal must depend on conservation programs. Examples: Spotted Hyena, Leopard Shark, Black Caiman
* Near Threatened: may be considered threatened in the near future. Examples: Blue-billed Duck, Solitary Eagle, Small-clawed Otter , Maned Wolf
* Least Concern: no immediate threat to the survival of the species. Examples: Brown Rat, Nootka Cypress, Wood Pigeon
United States
Under the Endangered Species Act in the United States, "endangered" is the more protected of the two categories. The Salt Creek tiger beetle (Cicindela nevadica lincolniana) is an example of an endangered subspecies protected under the ESA.
In the United States alone, the “number of known species threatened with extinction is ten times higher than the number protected under the Endangered Species Act” (Wilcove & Master, 2008, p. 414). The US Fish and Wildlife Service as well as the National Marine Fisheries Service are held responsible for classifying and protecting endangered species, yet, adding a particular species to the list is a long, controversial process and in reality it represents only a fraction of imperiled plant and animal life (Wilcove & Master, 2008, p. 414).
Some endangered species laws are controversial. Typical areas of controversy include: criteria for placing a species on the endangered species list, and criteria for removing a species from the list once its population has recovered; whether restrictions on land development constitute a "taking" of land by the government; the related question of whether private landowners should be compensated for the loss of uses of their lands; and obtaining reasonable exceptions to protection laws.
Being listed as an endangered species can have negative effect since it could make a species more desirable for collectors and poachers. This effect is potentially reducible, such as in China where commercially farmed turtles may be reducing some of the pressure to poach endangered species.
Another problem with listing species is its effect of inciting the use of the "shoot, shovel, and shut-up" method of clearing endangered species from an area of land. Some landowners currently may perceive a diminution in value for their land after finding an endangered animal on it. They have allegedly opted to silently kill and bury the animals or destroy habitat, thus removing the problem from their land, but at the same time further reducing the population of an endangered species. The effectiveness of the Endangered Species Act, which coined the term "endangered species", has been questioned by business advocacy groups and their publications, but is nevertheless widely recognized as an effective recovery tool by wildlife scientists who work with the species. Nineteen species have been delisted and recovered and 93% of listed species in the northeastern United States have a recovering or stable population.
Currently, 1,556 known species in the world have been identified as endangered, or near extinction, and are under protection by government law (Glenn, 2006, Webpage). This approximation, however, does not take into consideration the number of species threatened with endangerment that are not included under the protection of such laws as the Endangered Species Act. According to NatureServe’s global conservation status, approximately thirteen percent of vertebrates (excluding marine fish), seventeen percent of vascular plants, and six to eighteen percent of fungi are considered imperiled (Wilcove & Master, 2008, p. 415-416). Thus, in total, between seven and eighteen percent of the United States’ known animals, fungi, and plants are near extinction (Wilcove & Master, 2008, p. 416). This total is substantially more than the number of species protected under the Endangered Species Act in the United States, which means numerous species are inching closer and closer toward extinction.
Question of ethics
Even in the search to learn more about these species, many ecologists do not take into consideration the impact they leave on the environment and its inhabitants. It is apparent that the “quest for ecological knowledge, which is so critical for informing efforts to understand and conserve Earth’s biodiversity along with valued ecosystem goods and services, frequently raises complex ethical questions”, and there is no clear way to identify and resolve these issues. Environmentalists tend to focus on the whole ecological sphere instead of the welfare of individual animals. Focusing on such a broad view tends to diminish the value of each individual creature. “Biodiversity conservation is currently a principle goal for resource management of 11.5% of the world’s surface area.” Large portions of life occur outside these protected areas and must be taken into consideration if the conservation of endangered species is going to be effective.
Impact on biodiversity and endangered species
In order to conserve the biodiversity of the planet, one must take into consideration the reasons why so many species are becoming endangered. “Habitat loss is the most widespread cause of species endangerment in the U.S., affecting 85% of imperiled species” (Wilcove & Master, 2008, p. 416). When an animal’s ecosystem is not maintained, they lose their home and are either forced to adapt to new surroundings or perish. Pollution is another factor that causes many species to become endangered, especially a large proportion of aquatic life. Also, overexploitation, disease (Wilcove & Master, 2008, p. 416), and climate change (Kotiaho et al., 2005, p. 1963) have led to the endangerment of several species.
However, the most important factor leading to the endangerment of the majority of wildlife in the world is the human impact on the species and their environment. “As human use of resources, energy, and space intensified over the past few centuries, the diversity of life has been substantially diminished in most parts of the world” (Ishwaran & Erdelen, 2006, p.179). Basically, as the human impact on the environment increases, the diversity of life decreases. Humans are constantly using the resources and space of other species for themselves, negatively impacting the survival rate of many creatures.
Humans have also set standards for which species they think should be saved and which species they find unimportant. For example, the coqui frog in Hawaii is so common that its “nocturnal singing” reduces the value of homes and prevents hotels from using rooms near forests. Hawaiians have proposed eliminating the frog, and several wildlife managers want to release a pathogen to kill the frogs (Minteer & Collins, 2005, p. 333). This example of the coqui frog demonstrates how humans have no consideration for the life of another species, and are more concerned about their own contentment and personal gain. The frog decreased the value of homes and lost business for several hotels, so the Hawaiians figured it was acceptable to get rid of the group of coqui frog living near them, without taking into consideration the environmental impact of destroying the species.
Another example where the human impact affected the welfare of a species was in the instance of non-native mute swans establishing themselves at Arrowhead Lake in Vermont. When the population of swans grew to eight birds, the Vermont Fish and Wildlife Department decided to kill take action. Two swans were eventually killed, angering animal welfare organizations and people living near the lake (Minteer & Collins, 2005, p. 333). The case of the Arrowhead Lake swans demonstrates what one considers the natural environment based on human assumptions. Simply because the swans were not normally living there does not mean it is not part of their natural habitat, and there is certainly no reason for them to be destroyed because of human dissatisfaction. Yet another example of the human impact in the lives of endangered species is that of the Preble’s meadow jumping mouse.
Research has shown that the mouse is not taxonomically different from the Bear Lodge meadow jumping mouse and the US Fish and Wildlife Service has proposed removing the Preble’s mouse from the endangered species list based on this information (Minteer & Collins, 2005, p. 333). This example brings into consideration the role of science in determining the maintenance of a species. It brings into questions whether scientific evidence should be the only resource used to support conservation of biodiversity. A final example of the human impact on existing species is the issue of toe clipping in ecological research. While ecologists are doing research on different species to advance their knowledge of methods of conservation, they must take into consideration the impact they have on the wildlife they are studying.
Toe clipping “has been reported to result in a number of adverse effects on the animals, including inflammation and infection of the feet and limbs” (Minteer & Collins, 2005, p. 334). This example demonstrates how humans must take into consideration the wellbeing of the animal even before they perform research to help conserve the species. The human impact on species and their environments has many negative effects. It is important for humans to help maintain all species in the world and not deter their development.
Species maintaining importance
“Diversity of life and living systems are a necessary condition for human development” (Ishwaran & Erdelen, 2006, p.179). Many question the importance of maintaining biodiversity in today’s world, where conservation efforts prove costly and time consuming. The fact is that the preservation of all species is necessary for human survival. Species should be saved for “aesthetic and moral justifications; the importance of wild species as providers of products and services essential to human welfare; the value of particular species as indicators of environmental health or as keystone species crucial to the functioning of ecosystems; and the scientific breakthroughs that have come from the study of wild organisms” (Wilcove & Master, 2008, p. 418). In other words, species serve as a source of art and entertainment, provide products such as medicine for human wellbeing, indicate the welfare of the overall environment and ecosystem, and provided research that resulted in scientific discoveries. An example of an “aesthetic justification” in conserving endangered species is that of the introduction of the gray wolf into Yellowstone National Park. The gray wolf has brought numerous amounts of tourists to the park and added to the biodiversity in the protected region (Wilcove & Master, 2008, p. 418).
Another example, supporting the conservation of endangered species as providers of products for human wellbeing, is the scrub mint. It has been found that the scrub mint contains an antifungal agent and a natural insecticide (Wilcove & Master, 2008, p. 418). Also, the deterioration of the bald eagle and the peregrine falcon “alerted people to the potential health hazards associated with the widespread spraying of DDT and other persistent pesticides” (Wilcove & Master, 2008, p. 418).
This serves as an example of how certain species can serve as identifiers of environmental health and protect human life as well as other species. Finally, an example of species providing for scientific discoveries is the instance of the Pacific yew which “became the source of taxol, one of the most potent anticancer compounds ever discovered” (Wilcove & Master, 2008, p. 418-419). Endangered species could prove useful to human development, maintenance of biodiversity and preservation of ecosystems. Many endangered species serve to better humanity; therefore humanity should serve to better endangered species.Some of the negative behavior of annimals is caused by abuse
Helping preserve endangered species
It is the goal of conservationists to create and expand upon ways to preserve endangered species and maintain biodiversity. Everyone should be a conservationist in some way. There are several ways in which one can aid in preserving the world’s species who are nearing extinction. One such way is obtaining more information on different groups of species, especially invertebrates, fungi, and marine organisms, where sufficient data is lacking.
For example, to understand the causes of population declines and extinction an experiment was conducted on the butterfly population in Finland. In this analysis, the butterflies’ endangered list classification, distribution, density, larval specificity, dispersal ability, adult habitat breadth, flight period and body size were all recorded and examined to determine the threatened state of each species. It was found that the butterflies’ distribution has declined by fifty-one and a half percent, and they have a severely restricted habitat. One example of specific butterflies who have a declining distribution rate are the Frigga’s Fritillary and Grizzled Skipper, who have been affected by habitat loss due to extensive draining of the bogs where they live (Kotiaho et al., 2005, p. 1963-1967). This experiment proves that when we know the causes of endangerment, we can successfully create solutions for the management of biodiversity.
Another way to help preserve endangered species is to create a new professional society dedicated to ecological ethics. This could help ecologists make ethical decisions in their research and management of biodiversity. Also, creating more awareness on environmental ethics can help encourage species preservation. “Courses in ethics for students, and training programs for ecologists and biodiversity managers” all could create environmental awareness and prevent violations of ethics in research and management (Minteer & Collins, 2005, p. 336). One final way in which one can conserve endangered species is through federal agency investments and protection enacted by the federal government. “Ecologists have proposed biological corridors, biosphere reserves, ecosystem management, and ecoregional planning as approaches to integrate biodiversity conservation and socioeconomic development at increasingly larger spatial scales” (Ishwaran & Erdelen, 2006, p.179).
One example of a federal mandated conservation zone is the Northwest Hawaiian Islands Marine National Monument, the largest marine protected area in the world. The monument is essential to the preservation of underwater communities and overfished regions. Only researchers working in the area are permitted to fish, no corals may be removed, and the Department of Homeland Security will enforce restrictions on vessels passing through the waters via satellite imaging. The monument will serve as a home to an estimated seven thousand species, most of which cannot be found anywhere else in the world (Raloff, 2006, p. 92). This environmental monument demonstrates the fact that it is possible to create a safe environment for endangered species, as well as maintaining some of the world’s largest ecosystems.
Captive breeding programs
This technique has been used with great success for many species for some time, with probably the oldest known such instances of captive breeding being attributed to menageries of European and Asian rulers, a case in point being the Pere David's Deer. However, captive breeding techniques are usually difficult to implement for highly mobile species like some migratory birds (eg. cranes) and fishes (eg. Hilsa). Additionally, if the captive breeding population is too small, inbreeding may occur due to a reduced gene pool; this may lead to the population lacking immunity to diseases.
Legal private farming for profit
Whereas illegal poaching causes substantial reductions in endangered animal populations, legal private farming for profit has the opposite effect. Legal private farming has caused substantial increases in the populations of both the southern black rhinoceros and the southern white rhinoceros. Dr Richard Emslie, a scientific officer at the IUCN, said of such programs, "Effective law enforcement has become much easier now that the animals are largely privately owned... We have been able to bring local communities into the conservation programmes. There are increasingly strong economic incentives attached to looking after rhinos rather than simply poaching: from eco-tourism or selling them on for a profit. So many owners are keeping them secure. The private sector has been key to helping our work."
Sunday, December 28, 2008
Keystone species
A keystone species is a species that has a disproportionate effect on its environment relative to its abundance Such species affect many other organisms in an ecosystem and help to determine the types and numbers of various others species in a community.
Such an organism plays a role in its ecosystem that is analogous to the role of a keystone in an arch. Sea otters are a keystone species. While the keystone feels the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity. It has become a very popular concept in conservation biology.
A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.
Examples
Without a consensus on its exact definition, we are left to illustrate the concept of keystone species with a list of examples.
A classic keystone species is a small predator that prevents a particular herbivorous species from eliminating dominant plant species. Since the prey numbers are low, the keystone predator numbers can be even lower and still be effective. Yet without the predators, the herbivorous prey would explode in numbers, wipe out the dominant plants, and dramatically alter the character of the ecosystem. The exact scenario changes in each example, but the central idea remains that through a chain of interactions, a non-abundant species has an out-sized impact on ecosystem functions. One example is the weevil and its suggested keystone effects on aquatic plant species diversity by prey activities on nuisance Euransian Watermilfoil.
Predators
Some sea stars may perform this function by preying on sea urchins, mussels, and other shellfish that have no other natural predators. If the sea star is removed from the ecosystem, the mussel population explodes uncontrollably, driving out most other species, while the urchin population annihilates coral reefs. In his classic 1966 paper, Dr. Robert Paine described such a system in Mukkaw Bay in Washington State. This led to his 1969 paper where he proposed the keystone species concept.
Similarly, sea otters in kelp forests keep sea urchins in check. Kelp roots are merely anchors, and not the vast nutrient gathering networks of land plants. Thus the urchins only need to eat the roots of the kelp, a tiny fraction of the plant's biomass, to remove it from the ecosystem.
These creatures need not be apex predators. Sea stars are prey for sharks, rays, and sea anemones. Sea otters are prey for orca.
Engineers
In North America, the grizzly bear is a keystone species - not as a predator but as ecosystem engineers. They transfer nutrients from the oceanic ecosystem to the forest ecosystem. The first stage of the transfer is performed by salmon, rich in nitrogen, sulfur, carbon, and phosphorus, who swim up rivers, sometimes for hundreds of miles. The bears then capture the salmon and carry them onto dry land, dispersing nutrient-rich feces and partially-eaten carcasses. It has been estimated that the bears leave up to half of the salmon they harvest on the forest floor.
Another ecosystem engineering keystone species is the beaver, which transforms its territory from a stream to a pond or swamp.
In the African savanna, the larger herbivores, especially the elephants, shape their environment. The elephants destroy trees, making room for the grass species. and since the African elephants population has tippled in the last year these animals have become much more efficient. Without these animals, much of the savanna would turn into woodland.
Such an organism plays a role in its ecosystem that is analogous to the role of a keystone in an arch. Sea otters are a keystone species. While the keystone feels the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity. It has become a very popular concept in conservation biology.
A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.
Examples
Without a consensus on its exact definition, we are left to illustrate the concept of keystone species with a list of examples.
A classic keystone species is a small predator that prevents a particular herbivorous species from eliminating dominant plant species. Since the prey numbers are low, the keystone predator numbers can be even lower and still be effective. Yet without the predators, the herbivorous prey would explode in numbers, wipe out the dominant plants, and dramatically alter the character of the ecosystem. The exact scenario changes in each example, but the central idea remains that through a chain of interactions, a non-abundant species has an out-sized impact on ecosystem functions. One example is the weevil and its suggested keystone effects on aquatic plant species diversity by prey activities on nuisance Euransian Watermilfoil.
Predators
Some sea stars may perform this function by preying on sea urchins, mussels, and other shellfish that have no other natural predators. If the sea star is removed from the ecosystem, the mussel population explodes uncontrollably, driving out most other species, while the urchin population annihilates coral reefs. In his classic 1966 paper, Dr. Robert Paine described such a system in Mukkaw Bay in Washington State. This led to his 1969 paper where he proposed the keystone species concept.
Similarly, sea otters in kelp forests keep sea urchins in check. Kelp roots are merely anchors, and not the vast nutrient gathering networks of land plants. Thus the urchins only need to eat the roots of the kelp, a tiny fraction of the plant's biomass, to remove it from the ecosystem.
These creatures need not be apex predators. Sea stars are prey for sharks, rays, and sea anemones. Sea otters are prey for orca.
Engineers
In North America, the grizzly bear is a keystone species - not as a predator but as ecosystem engineers. They transfer nutrients from the oceanic ecosystem to the forest ecosystem. The first stage of the transfer is performed by salmon, rich in nitrogen, sulfur, carbon, and phosphorus, who swim up rivers, sometimes for hundreds of miles. The bears then capture the salmon and carry them onto dry land, dispersing nutrient-rich feces and partially-eaten carcasses. It has been estimated that the bears leave up to half of the salmon they harvest on the forest floor.
Another ecosystem engineering keystone species is the beaver, which transforms its territory from a stream to a pond or swamp.
In the African savanna, the larger herbivores, especially the elephants, shape their environment. The elephants destroy trees, making room for the grass species. and since the African elephants population has tippled in the last year these animals have become much more efficient. Without these animals, much of the savanna would turn into woodland.
Kyoto Protocol,UNFCCC,UNCED
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), an international environmental treaty produced at the United Nations Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro, Brazil, from 3–14 June 1992. The treaty is intended to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system." The Kyoto Protocol establishes legally binding commitments for the reduction of four greenhouse gases (carbon dioxide, methane, nitrous oxide, sulfur hexafluoride), and two groups of gases (hydrofluorocarbons and perfluorocarbons) produced by "Annex I" (industrialized) nations, as well as general commitments for all member countries. As of 2008[update], 183 parties have ratified the protocol, which was initially adopted for use on 11 December 1997 in Kyoto, Japan and which entered into force on 16 February 2005. Under Kyoto, industrialized countries agreed to reduce their collective GHG emissions by 5.2% compared to the year 1990. National limitations range from 8% reductions for the European Union and some others to 7% for the United States, 6% for Japan, and 0% for Russia. The treaty permitted GHG emission increases of 8% for Australia and 10% for Iceland.
Kyoto includes defined "flexible mechanisms" such as Emissions Trading, the Clean Development Mechanism and Joint Implementation to allow Annex I economies to meet their greenhouse gas (GHG) emission limitations by purchasing GHG emission reductions credits from elsewhere, through financial exchanges, projects that reduce emissions in non-Annex I economies, from other Annex I countries, or from Annex I countries with excess allowances. In practice this means that Non-Annex I economies have no GHG emission restrictions, but have financial incentives to develop GHG emission reduction projects to receive "carbon credits" that can then be sold to Annex I buyers, encouraging sustainable development. In addition, the flexible mechanisms allow Annex I nations with efficient, low GHG-emitting industries, and high prevailing environmental standards to purchase carbon credits on the world market instead of reducing greenhouse gas emissions domestically. Annex I entities typically will want to acquire carbon credits as cheaply as possible, while Non-Annex I entities want to maximize the value of carbon credits generated from their domestic Greenhouse Gas Projects.
Among the Annex I signatories, all nations have established Designated National Authorities to manage their greenhouse gas portfolios; countries including Japan, Canada, Italy, the Netherlands, Germany, France, Spain and others are actively promoting government carbon funds, supporting multilateral carbon funds intent on purchasing Carbon Credits from Non-Annex I countries,[citation needed] and are working closely with their major utility, energy, oil & gas and chemicals conglomerates to acquire Greenhouse Gas Certificates as cheaply as possible.[citation needed] Virtually all of the non-Annex I countries have also established Designated National Authorities to manage the Kyoto process, specifically the "CDM process" that determines which GHG Projects they wish to propose for accreditation by the CDM Executive Board.
Objectives
The objective is to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."
The Intergovernmental Panel on Climate Change (IPCC) has predicted an average global rise in temperature of 1.4°C (2.5°F) to 5.8°C (10.4°F) between 1990 and 2100.
Proponents also note that Kyoto is a first step as requirements to meet the UNFCCC will be modified until the objective is met, as required by UNFCCC Article 4.2(d).
The treaty was negotiated in Kyoto, Japan in December 1997, opened for signature on 16 March 1998, and closed on 15 March 1999. The agreement came into force on 16 February 2005 following ratification by Russia on 18 November 2004. As of May 2008, a total of 181 countries and 1 regional economic integration organization (the EEC) have ratified the agreement (representing over 61.6% of emissions from Annex I countries).
According to article 25 of the protocol, it enters into force "on the ninetieth day after the date on which not less than 55 Parties to the Convention, incorporating Parties included in Annex I which accounted in total for at least 55% of the total carbon dioxide emissions for 1990 of the Parties included in Annex I, have deposited their instruments of ratification, acceptance, approval or accession." Of the two conditions, the "55 parties" clause was reached on 23 May 2002 when Iceland ratified. The ratification by Russia on 18 November 2004 satisfied the "55%" clause and brought the treaty into force, effective 16 February 2005. Australian Prime Minister Kevin Rudd ratified the Kyoto protocol on 3 December 2007. This came into effect after 90 days (the end of March 2008), as is stated in the guidelines set by the United Nations.
Please help improve this section by expanding it. Further information might be found on the talk page. (May 2007)
The five principal concepts of the Kyoto Protocol are:
* Commitments. The heart of the Protocol lies in establishing commitments for the reduction of greenhouse gases that are legally binding for Annex I countries, as well as general commitments for all member countries.
* Implementation. In order to meet the objectives of the Protocol, Annex I countries are required to prepare policies and measures for the reduction of greenhouse gases in their respective countries. In addition, they are required to increase the absorption of these gases and utilize all mechanisms available, such as joint implementation, the clean development mechanism and emissions trading, in order to be rewarded with credits that would allow more greenhouse gas emissions at home.
* Minimizing Impacts on Developing Countries by establishing an adaptation fund for climate change.
* Accounting, Reporting and Review in order to ensure the integrity of the Protocol.
* Compliance. Establishing a Compliance Committee to enforce compliance with the commitments under the Protocol.
Kyoto includes defined "flexible mechanisms" such as Emissions Trading, the Clean Development Mechanism and Joint Implementation to allow Annex I economies to meet their greenhouse gas (GHG) emission limitations by purchasing GHG emission reductions credits from elsewhere, through financial exchanges, projects that reduce emissions in non-Annex I economies, from other Annex I countries, or from Annex I countries with excess allowances. In practice this means that Non-Annex I economies have no GHG emission restrictions, but have financial incentives to develop GHG emission reduction projects to receive "carbon credits" that can then be sold to Annex I buyers, encouraging sustainable development. In addition, the flexible mechanisms allow Annex I nations with efficient, low GHG-emitting industries, and high prevailing environmental standards to purchase carbon credits on the world market instead of reducing greenhouse gas emissions domestically. Annex I entities typically will want to acquire carbon credits as cheaply as possible, while Non-Annex I entities want to maximize the value of carbon credits generated from their domestic Greenhouse Gas Projects.
Among the Annex I signatories, all nations have established Designated National Authorities to manage their greenhouse gas portfolios; countries including Japan, Canada, Italy, the Netherlands, Germany, France, Spain and others are actively promoting government carbon funds, supporting multilateral carbon funds intent on purchasing Carbon Credits from Non-Annex I countries,[citation needed] and are working closely with their major utility, energy, oil & gas and chemicals conglomerates to acquire Greenhouse Gas Certificates as cheaply as possible.[citation needed] Virtually all of the non-Annex I countries have also established Designated National Authorities to manage the Kyoto process, specifically the "CDM process" that determines which GHG Projects they wish to propose for accreditation by the CDM Executive Board.
Objectives
The objective is to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."
The Intergovernmental Panel on Climate Change (IPCC) has predicted an average global rise in temperature of 1.4°C (2.5°F) to 5.8°C (10.4°F) between 1990 and 2100.
Proponents also note that Kyoto is a first step as requirements to meet the UNFCCC will be modified until the objective is met, as required by UNFCCC Article 4.2(d).
The treaty was negotiated in Kyoto, Japan in December 1997, opened for signature on 16 March 1998, and closed on 15 March 1999. The agreement came into force on 16 February 2005 following ratification by Russia on 18 November 2004. As of May 2008, a total of 181 countries and 1 regional economic integration organization (the EEC) have ratified the agreement (representing over 61.6% of emissions from Annex I countries).
According to article 25 of the protocol, it enters into force "on the ninetieth day after the date on which not less than 55 Parties to the Convention, incorporating Parties included in Annex I which accounted in total for at least 55% of the total carbon dioxide emissions for 1990 of the Parties included in Annex I, have deposited their instruments of ratification, acceptance, approval or accession." Of the two conditions, the "55 parties" clause was reached on 23 May 2002 when Iceland ratified. The ratification by Russia on 18 November 2004 satisfied the "55%" clause and brought the treaty into force, effective 16 February 2005. Australian Prime Minister Kevin Rudd ratified the Kyoto protocol on 3 December 2007. This came into effect after 90 days (the end of March 2008), as is stated in the guidelines set by the United Nations.
Please help improve this section by expanding it. Further information might be found on the talk page. (May 2007)
The five principal concepts of the Kyoto Protocol are:
* Commitments. The heart of the Protocol lies in establishing commitments for the reduction of greenhouse gases that are legally binding for Annex I countries, as well as general commitments for all member countries.
* Implementation. In order to meet the objectives of the Protocol, Annex I countries are required to prepare policies and measures for the reduction of greenhouse gases in their respective countries. In addition, they are required to increase the absorption of these gases and utilize all mechanisms available, such as joint implementation, the clean development mechanism and emissions trading, in order to be rewarded with credits that would allow more greenhouse gas emissions at home.
* Minimizing Impacts on Developing Countries by establishing an adaptation fund for climate change.
* Accounting, Reporting and Review in order to ensure the integrity of the Protocol.
* Compliance. Establishing a Compliance Committee to enforce compliance with the commitments under the Protocol.
Monsanto,NYSE: MON)
The Monsanto Company (NYSE: MON) is an American multinational agricultural biotechnology corporation. It is the world's leading producer of the herbicide glyphosate, marketed as "Roundup". Monsanto is also by far the leading producer of genetically engineered (GE) seed, holding 70%–100% market share for various crops. Agracetus, owned by Monsanto, exclusively produces Roundup Ready soybean seed for the commercial market. In March 2005, it finalized the purchase of Seminis Inc, making it also the largest conventional seed company in the world. It has over 18,800 employees worldwide, and an annual revenue of USD$8.563 billion reported for 2007.
Monsanto's development and marketing of genetically engineered seed and bovine growth hormone, as well as its aggressive litigation and political lobbying practices, have made the company controversial around the world and a primary target of the anti-globalization movement and environmental activists.
History
Monsanto was founded in St. Louis, Missouri, in 1901, by John Francis Queeny, a 30-year veteran of the pharmaceutical industry. He funded the start-up with his own money and capital from a soft drink distributor, and gave the company his wife's maiden name. The company's first product was the artificial sweetener saccharin, which it sold to the Coca-Cola Company. It also introduced caffeine and vanillin to Coca-Cola, and became one of that company's main suppliers. In 1919, Monsanto established its presence in Europe by entering into a partnership with Graesser's Chemical Works at Cefn Mawr in Ruabon, Wales to produce vanillin, salicylic acid, aspirin and later rubber.
In its second decade, the 1920s, Monsanto expanded into basic industrial chemicals like sulfuric acid, and the decade ended with Queeny's son Edgar Monsanto Queeny taking over the company in 1928.
The 1940s saw Monsanto become a leading manufacturer of plastics, including polystyrene, and synthetic fibers. Since then, it has remained one of the top 10 US chemical companies. Other major products have included the herbicides 2,4,5-T, DDT, and Agent Orange used primarily during the Vietnam War as a deforestation agent (and later proven to be highly carcinogenic to any who come into contact with the solution), aspartame (NutraSweet), bovine somatotropin (bovine growth hormone (BST), and PCBs. Also in this decade, Monsanto operated the Dayton Project, and later Mound Laboratory in Miamisburg, Ohio, for the Manhattan Project, the development of the first nuclear weapons and, after 1947, the Atomic Energy Commission. Monsanto began manufacturing DDT in 1944, along with some 15 other companies. The use of DDT in the U.S. was banned by Congress in 1972, due in large efforts to environmentalists, who persisted in the challenge put forth by Rachel Carson and her book, Silent Spring in 1962, which sought to inform the public of the side effects associated with the insecticide. In 1947, an accidental explosion of ammonium nitrate fertilizer loaded on the French ship S.S. Grandcamp destroyed an adjacent Monsanto styrene manufacturing plant, along with much of the port at Galveston Bay. The explosion, known as the Texas City Disaster, is considered the largest industrial accident in US history, with the highest death toll. As the decade ended, Monsanto acquired American Viscose from England's Courtauld family in 1949.
In 1954, Monsanto partnered with German chemical giant Bayer to form Mobay and market polyurethanes in the US. In the 1960s and 1970s, Monsanto became the leading producer of Agent Orange for US Military operations in Vietnam.
In 1980, Monsanto established the Edgar Monsanto Queeny safety award in honor of its former CEO (1928–1960), to encourage accident prevention.
Monsanto scientists became the first to genetically modify a plant cell in 1982. Five years later, Monsanto conducted the first field tests of genetically engineered crops.
Through a process of mergers and spin-offs between 1997 and 2002, Monsanto has made a transition from chemical giant to biotech giant. Part of this process involved the 1999 sale by Monsanto of their phenylalanine facilities to Great Lakes Chemical Corporation (GLC) for $125 million. In 2000, GLC sued Monsanto because of a $71 million dollar shortfall in expected sales.
With the dawn of the new millennium in 2001, retired Monsanto chemist William S. Knowles was named a co-winner of the Nobel Prize in Chemistry for his research on catalytic asymmetric hydrogenation, which was carried out at Monsanto beginning in the 1960s until his 1986 retirement.
Throughout 2004 and 2005, Monsanto filed lawsuits against many farmers in Canada and the U.S. The lawsuits have been on the grounds of patent infringement, specifically the farmer's sale of seed containing Monsanto's patented genes–which require the farmer initial purchase of the seed and its technology–unknowingly sown by wind carrying the seeds from neighboring crops. These instances began in the mid to late 1990s, with one of the most significant cases being decided in Monsanto's favor by the Canadian Supreme Court. By a 5-4 vote in late May 2004, that court ruled that "by cultivating a plant containing the patented gene and composed of the patented cells without license, the appellants (canola farmer Percy Schmeiser) deprived the respondents of the full enjoyment of the patent." With this ruling, the Canadian courts followed the U.S. Supreme Court in its decision on patent issues involving plants and genes.
As of February 2005, Monsanto has patent claims on breeding techniques for pigs which would grant them ownership of any pigs born of such techniques and their related herds. Greenpeace claims Monsanto is trying to claim ownership on ordinary breeding techniques.[6] Monsanto claims that the patent is a defensive measure to track animals from its system. They furthermore claim their patented method uses a specialized insemination device that requires less sperm than is typical.
In 2006, the Public Patent Foundation filed requests with the U.S. Patent Office to revoke four patents that Monsanto has used in patent lawsuits against farmers. In the first round of reexamination, claims in all four patents were rejected by the Patent Office in four separate rulings dating from February through July 2007. Monsanto has since filed responses in the reexaminations.
Spin-offs and mergers
Through a series of transactions, the Monsanto that existed from 1901–2000 and the current Monsanto are legally two different corporations. Although they share the same name, corporate headquarters, many of the same executives and other employees, and responsibility for liabilities arising out of its former activities in the industrial chemical business, the agricultural chemicals business is the only segment carried forward from the pre-1997 Monsanto Company to the current Monsanto Company. A timeline follows:
1985: Monsanto purchases G. D. Searle & Company. In this merger, Searle's aspartame business became a separate Monsanto subsidiary, the NutraSweet Company. CEO of NutraSweet, Robert B. Shapiro, goes on to become CEO of Monsanto from 1995 to 2000.
1997: Monsanto spins off its industrial chemical and fiber divisions into Solutia Inc. This transfers the financial liability related to the production and contamination with PCBs at the Illinois and Alabama plants. In January, Monsanto announced the purchase of Holden's Foundations Seeds, a privately-held seed business owned by the Holden family along with its sister sales organization, Corn States Hybrid Service, of Williamsburg and Des Moines, Iowa, respectively. The combined purchase price totaled $925M. Also, in April, Monsanto purchases the remaining shares of Calgene.
1999: Monsanto sells Nutrasweet Co. and two other companies.
2000: Monsanto merges with Pharmacia and Upjohn. Later in the year, Pharmacia forms a new subsidiary, also named Monsanto, for the agricultural divisions, and retains the medical research divisions, which includes products such as Celebrex.
2002: Pharmacia spins off its remaining interest in Monsanto, which has since existed as a separate company: the "new Monsanto." As part of the deal, Monsanto agrees to indemnify Pharmacia against any liabilities that might be incurred from judgments against Solutia. As a result, the new Monsanto continues to be a party to numerous lawsuits that relate to operations of the old Monsanto.
2005: Monsanto purchases Seminis, the largest seed company not producing corn or soybeans in the world.
2008: Monsanto purchases the Dutch seed company De Ruiter Seeds for about 855 million dollars.
Sponsorships
Monsanto has been the corporate sponsor of many attractions at Disneyland and Walt Disney World.
At Disneyland they include:
* Hall of Chemistry
* Fashions and Fabrics through the Years
* House of The Future
* Adventure Thru Innerspace
And at Walt Disney World they included:
* Magic Eye Theatre
* Circle Vision 360
All attractions that the company has ever sponsored were located in Tomorrowland.
Monsanto's development and marketing of genetically engineered seed and bovine growth hormone, as well as its aggressive litigation and political lobbying practices, have made the company controversial around the world and a primary target of the anti-globalization movement and environmental activists.
History
Monsanto was founded in St. Louis, Missouri, in 1901, by John Francis Queeny, a 30-year veteran of the pharmaceutical industry. He funded the start-up with his own money and capital from a soft drink distributor, and gave the company his wife's maiden name. The company's first product was the artificial sweetener saccharin, which it sold to the Coca-Cola Company. It also introduced caffeine and vanillin to Coca-Cola, and became one of that company's main suppliers. In 1919, Monsanto established its presence in Europe by entering into a partnership with Graesser's Chemical Works at Cefn Mawr in Ruabon, Wales to produce vanillin, salicylic acid, aspirin and later rubber.
In its second decade, the 1920s, Monsanto expanded into basic industrial chemicals like sulfuric acid, and the decade ended with Queeny's son Edgar Monsanto Queeny taking over the company in 1928.
The 1940s saw Monsanto become a leading manufacturer of plastics, including polystyrene, and synthetic fibers. Since then, it has remained one of the top 10 US chemical companies. Other major products have included the herbicides 2,4,5-T, DDT, and Agent Orange used primarily during the Vietnam War as a deforestation agent (and later proven to be highly carcinogenic to any who come into contact with the solution), aspartame (NutraSweet), bovine somatotropin (bovine growth hormone (BST), and PCBs. Also in this decade, Monsanto operated the Dayton Project, and later Mound Laboratory in Miamisburg, Ohio, for the Manhattan Project, the development of the first nuclear weapons and, after 1947, the Atomic Energy Commission. Monsanto began manufacturing DDT in 1944, along with some 15 other companies. The use of DDT in the U.S. was banned by Congress in 1972, due in large efforts to environmentalists, who persisted in the challenge put forth by Rachel Carson and her book, Silent Spring in 1962, which sought to inform the public of the side effects associated with the insecticide. In 1947, an accidental explosion of ammonium nitrate fertilizer loaded on the French ship S.S. Grandcamp destroyed an adjacent Monsanto styrene manufacturing plant, along with much of the port at Galveston Bay. The explosion, known as the Texas City Disaster, is considered the largest industrial accident in US history, with the highest death toll. As the decade ended, Monsanto acquired American Viscose from England's Courtauld family in 1949.
In 1954, Monsanto partnered with German chemical giant Bayer to form Mobay and market polyurethanes in the US. In the 1960s and 1970s, Monsanto became the leading producer of Agent Orange for US Military operations in Vietnam.
In 1980, Monsanto established the Edgar Monsanto Queeny safety award in honor of its former CEO (1928–1960), to encourage accident prevention.
Monsanto scientists became the first to genetically modify a plant cell in 1982. Five years later, Monsanto conducted the first field tests of genetically engineered crops.
Through a process of mergers and spin-offs between 1997 and 2002, Monsanto has made a transition from chemical giant to biotech giant. Part of this process involved the 1999 sale by Monsanto of their phenylalanine facilities to Great Lakes Chemical Corporation (GLC) for $125 million. In 2000, GLC sued Monsanto because of a $71 million dollar shortfall in expected sales.
With the dawn of the new millennium in 2001, retired Monsanto chemist William S. Knowles was named a co-winner of the Nobel Prize in Chemistry for his research on catalytic asymmetric hydrogenation, which was carried out at Monsanto beginning in the 1960s until his 1986 retirement.
Throughout 2004 and 2005, Monsanto filed lawsuits against many farmers in Canada and the U.S. The lawsuits have been on the grounds of patent infringement, specifically the farmer's sale of seed containing Monsanto's patented genes–which require the farmer initial purchase of the seed and its technology–unknowingly sown by wind carrying the seeds from neighboring crops. These instances began in the mid to late 1990s, with one of the most significant cases being decided in Monsanto's favor by the Canadian Supreme Court. By a 5-4 vote in late May 2004, that court ruled that "by cultivating a plant containing the patented gene and composed of the patented cells without license, the appellants (canola farmer Percy Schmeiser) deprived the respondents of the full enjoyment of the patent." With this ruling, the Canadian courts followed the U.S. Supreme Court in its decision on patent issues involving plants and genes.
As of February 2005, Monsanto has patent claims on breeding techniques for pigs which would grant them ownership of any pigs born of such techniques and their related herds. Greenpeace claims Monsanto is trying to claim ownership on ordinary breeding techniques.[6] Monsanto claims that the patent is a defensive measure to track animals from its system. They furthermore claim their patented method uses a specialized insemination device that requires less sperm than is typical.
In 2006, the Public Patent Foundation filed requests with the U.S. Patent Office to revoke four patents that Monsanto has used in patent lawsuits against farmers. In the first round of reexamination, claims in all four patents were rejected by the Patent Office in four separate rulings dating from February through July 2007. Monsanto has since filed responses in the reexaminations.
Spin-offs and mergers
Through a series of transactions, the Monsanto that existed from 1901–2000 and the current Monsanto are legally two different corporations. Although they share the same name, corporate headquarters, many of the same executives and other employees, and responsibility for liabilities arising out of its former activities in the industrial chemical business, the agricultural chemicals business is the only segment carried forward from the pre-1997 Monsanto Company to the current Monsanto Company. A timeline follows:
1985: Monsanto purchases G. D. Searle & Company. In this merger, Searle's aspartame business became a separate Monsanto subsidiary, the NutraSweet Company. CEO of NutraSweet, Robert B. Shapiro, goes on to become CEO of Monsanto from 1995 to 2000.
1997: Monsanto spins off its industrial chemical and fiber divisions into Solutia Inc. This transfers the financial liability related to the production and contamination with PCBs at the Illinois and Alabama plants. In January, Monsanto announced the purchase of Holden's Foundations Seeds, a privately-held seed business owned by the Holden family along with its sister sales organization, Corn States Hybrid Service, of Williamsburg and Des Moines, Iowa, respectively. The combined purchase price totaled $925M. Also, in April, Monsanto purchases the remaining shares of Calgene.
1999: Monsanto sells Nutrasweet Co. and two other companies.
2000: Monsanto merges with Pharmacia and Upjohn. Later in the year, Pharmacia forms a new subsidiary, also named Monsanto, for the agricultural divisions, and retains the medical research divisions, which includes products such as Celebrex.
2002: Pharmacia spins off its remaining interest in Monsanto, which has since existed as a separate company: the "new Monsanto." As part of the deal, Monsanto agrees to indemnify Pharmacia against any liabilities that might be incurred from judgments against Solutia. As a result, the new Monsanto continues to be a party to numerous lawsuits that relate to operations of the old Monsanto.
2005: Monsanto purchases Seminis, the largest seed company not producing corn or soybeans in the world.
2008: Monsanto purchases the Dutch seed company De Ruiter Seeds for about 855 million dollars.
Sponsorships
Monsanto has been the corporate sponsor of many attractions at Disneyland and Walt Disney World.
At Disneyland they include:
* Hall of Chemistry
* Fashions and Fabrics through the Years
* House of The Future
* Adventure Thru Innerspace
And at Walt Disney World they included:
* Magic Eye Theatre
* Circle Vision 360
All attractions that the company has ever sponsored were located in Tomorrowland.
Medieval hunting,The hound,The hawk
Throughout Western Europe in the Middle Ages, men hunted wild animals. While game was at times an important source of food, it was rarely the principal source of nutrition. Hunting was engaged by all classes, but by the High Middle Ages, the necessity of hunting was transformed into a stylized pastime of the aristocracy. More than a pastime, it was an important arena for social interaction, essential training for war, and a privilege and measurement of nobility.
As with heraldry, too, the conventions and vocabulary of hunting were originally French in origin, via the transmission of Roman property laws through Frankish monarchs.
There exists a rich corpus of Medieval poetry and literature, manuals, art and ceremonies surrounding the hunt, increasingly elaborated in the 14th and 15th centuries as part of the vocabulary of aristocratic bearing.
History
Hieratic formalized recreational hunting has been taking place since Assyrian kings hunted lions from chariots in a demonstration of their royal nature. In Roman law, property included the right to hunt, a concept which continued under the Frankish Merovingian and Carolingian monarchs who considered the entire kingdom to be their property, but who also controlled enormous royal domains as hunting reserves (forestes). The biography of the Merovingian noble Saint Hubert (died 727/728) recounts how hunting could become an obsession. Carolingian Charlemagne loved to hunt and did so up until his death at age seventy-two.
With the breakup of the Carolingian Empire, local lords strove to maintain and monopolize the reserves and the taking of big game in forest reserves, and small game in warrens. They were most successful in England after the Norman Conquest, and in Gascony from the 12th century. These large sanctuaries of woodland—the royal forest—where populations of game animals were kept and watched over by gamekeepers. Here the peasantry could not hunt, poaching being subject to severe punishment: the injustice of such "emparked" preserves was a common cause of complaint in populist vernacular literature. The lower classes mostly had to content themselves with snaring birds and smaller game outside of forest reserves and warrens.
Equipment
The weapons used for hunting would mostly be the same as those used for war: bow and arrow or crossbow, lance or spear, and sword. Shortbows and longbows were the most commonly used weapon; the crossbow was introduced around the time of the First Crusade (1100), but was not generally used for hunting until the second half of the 15th century. Cudgels (clubs) were used for clubbing small game in particular by women who joined the hunt; "boar spears" were also used. With the introduction of handheld firearms to hunting in the 16th century, traditional medieval hunt was transformed.
The hunter would also need a horn for communication with the other hunters. In addition to this the hunter depended on the assistance of certain domesticated animals. Three animals in particular were essential tools for the medieval hunter: the horse, the hound and the hawk (or falcon).
The horse
The horse was the most important animal of the great medieval household. The stables, also called the "marshalsea," would be separate from the rest of the household, and its head officer—the marshal—would be one of the household's senior officers. The marshal would have pages and grooms serving under him to care for the horses.
A large household would have a wide array of horses for different purposes. There were cart- and packhorses employed in the day-to-day work of the household, palfreys used for human transport, and destriers, or warhorses, a powerful and expensive animal that in late medieval England could obtain prices of up to £80. Although it had the necessary qualities, the destrier would not be used for hunting, due to its value. Instead, a special breed called a courser would be used. The courser, though inferior to the destrier and much smaller than today’s horses, still had to be both powerful enough to carry the rider at high speeds over large distances, agile, so it could maneuver difficult terrain without difficulty, and fearless enough not to be scared when encountering wild beasts
The hound
The dog was essential for several purposes. Its good sense of smell made it invaluable in finding the quarry. It would then assist in driving the hunted animal and, when the animal was finally at bay, the dog would either be the instrument of attack, or distract the quarry while the hunter moved in for the kill. Different breeds would be used for different tasks, and for different sorts of game, and while some of these breeds are recognizable to us today, the dogs were nevertheless somewhat different from modern breeds
Foremost among the hunting breeds was the greyhound. This breed was valued first and foremost for its speed, but also for its ability to attack and take down the game. Since the greyhound did not have much stamina, it was essential that it be not released before the quarry was in sight, toward the end of the hunt. Furthermore, greyhounds, though aggressive hunters, were valued for their docile temper at home, and often allowed inside as pets.
The alaunt, or alant, was a somewhat more robust animal than the greyhound, and therefore used against larger game, such as bears or boars. The alaunt was considered a reckless animal, and had been known to attack domestic animals, or even its owner. The mastiff was an even more rugged breed, and though also used on the larger game, was mostly considered useful as a guard-dog.
What all these dogs lacked was the ability to follow the scent of the quarry, and run it down. For this purpose the running-dog was used. The running-dog was somewhat similar to today’s foxhound. This dog had, as the name indicates, excellent stamina, as well as a good nose. Another dog valued for its scenting skills was the lymer, a forerunner of today’s bloodhound. The lymer would be used to find the lay of the game before the hunt even started, and it was therefore important that, in addition to a good nose, it remained quiet. Silence in the lymer was achieved through a combination of breeding and training. Other dogs used for hunting were the kenet, the terrier, the harrier and the spaniel.
The hounds were kept in a kennel, inside or separate from the main domicile. Here the dogs would have oak beds to sleep on, and often also a second level where the dogs could go when the ground level became too hot or too cold. Outside the kennel there would be grass for the dogs to eat whenever they had digestive problems. To care for the dogs would be a hierarchy of servants such as pages, varlets, aides and veneurs; the page being the lowest, often a young boy. Pages would often sleep in the kennels with the dogs, to keep them from fighting and care for them if they got sick. Though this might seem harsh by modern standards, the warm dog house could often be much more comfortable than the sleeping quarters of other medieval servants.
The hawk
Medieval terminology spoke of hawks of the tower and hawks of the fist, which roughly corresponds to falcons and hawks, respectively. The female hawk was preferred, since it was both larger than the male and easier to train. Hawks were captured all over Europe, but birds from Norway or Iceland were considered of particularly good quality.
Training a hawk was a painstaking process. It was normal at first to "seel" the bird’s eyelids—sew them shut—so that it would not be scared or distracted. The trainer would then carry the hawk on his arm for several days, to get it accustomed to human presence. The eyes would gradually be unsealed, and the training would begin. The bird would be encouraged to fly from its perch to the falconer’s hand over a gradually longer distance. Hunting game would be encouraged first by the use of meat, then a lure, and eventually live prey. Such prey included herons, sometime with their legs broken to facilitate the kill.
Hawks would be housed in mews, a special edifice found in most large medieval households, mostly a certain distance from the main domicile, so that the hawks would not be disturbed. The mews could be rather elaborate structures. There should be windows in the wall, and the ground should be kept clean so that the bird’s regurgitations could be found and analyzed.
As with heraldry, too, the conventions and vocabulary of hunting were originally French in origin, via the transmission of Roman property laws through Frankish monarchs.
There exists a rich corpus of Medieval poetry and literature, manuals, art and ceremonies surrounding the hunt, increasingly elaborated in the 14th and 15th centuries as part of the vocabulary of aristocratic bearing.
History
Hieratic formalized recreational hunting has been taking place since Assyrian kings hunted lions from chariots in a demonstration of their royal nature. In Roman law, property included the right to hunt, a concept which continued under the Frankish Merovingian and Carolingian monarchs who considered the entire kingdom to be their property, but who also controlled enormous royal domains as hunting reserves (forestes). The biography of the Merovingian noble Saint Hubert (died 727/728) recounts how hunting could become an obsession. Carolingian Charlemagne loved to hunt and did so up until his death at age seventy-two.
With the breakup of the Carolingian Empire, local lords strove to maintain and monopolize the reserves and the taking of big game in forest reserves, and small game in warrens. They were most successful in England after the Norman Conquest, and in Gascony from the 12th century. These large sanctuaries of woodland—the royal forest—where populations of game animals were kept and watched over by gamekeepers. Here the peasantry could not hunt, poaching being subject to severe punishment: the injustice of such "emparked" preserves was a common cause of complaint in populist vernacular literature. The lower classes mostly had to content themselves with snaring birds and smaller game outside of forest reserves and warrens.
Equipment
The weapons used for hunting would mostly be the same as those used for war: bow and arrow or crossbow, lance or spear, and sword. Shortbows and longbows were the most commonly used weapon; the crossbow was introduced around the time of the First Crusade (1100), but was not generally used for hunting until the second half of the 15th century. Cudgels (clubs) were used for clubbing small game in particular by women who joined the hunt; "boar spears" were also used. With the introduction of handheld firearms to hunting in the 16th century, traditional medieval hunt was transformed.
The hunter would also need a horn for communication with the other hunters. In addition to this the hunter depended on the assistance of certain domesticated animals. Three animals in particular were essential tools for the medieval hunter: the horse, the hound and the hawk (or falcon).
The horse
The horse was the most important animal of the great medieval household. The stables, also called the "marshalsea," would be separate from the rest of the household, and its head officer—the marshal—would be one of the household's senior officers. The marshal would have pages and grooms serving under him to care for the horses.
A large household would have a wide array of horses for different purposes. There were cart- and packhorses employed in the day-to-day work of the household, palfreys used for human transport, and destriers, or warhorses, a powerful and expensive animal that in late medieval England could obtain prices of up to £80. Although it had the necessary qualities, the destrier would not be used for hunting, due to its value. Instead, a special breed called a courser would be used. The courser, though inferior to the destrier and much smaller than today’s horses, still had to be both powerful enough to carry the rider at high speeds over large distances, agile, so it could maneuver difficult terrain without difficulty, and fearless enough not to be scared when encountering wild beasts
The hound
The dog was essential for several purposes. Its good sense of smell made it invaluable in finding the quarry. It would then assist in driving the hunted animal and, when the animal was finally at bay, the dog would either be the instrument of attack, or distract the quarry while the hunter moved in for the kill. Different breeds would be used for different tasks, and for different sorts of game, and while some of these breeds are recognizable to us today, the dogs were nevertheless somewhat different from modern breeds
Foremost among the hunting breeds was the greyhound. This breed was valued first and foremost for its speed, but also for its ability to attack and take down the game. Since the greyhound did not have much stamina, it was essential that it be not released before the quarry was in sight, toward the end of the hunt. Furthermore, greyhounds, though aggressive hunters, were valued for their docile temper at home, and often allowed inside as pets.
The alaunt, or alant, was a somewhat more robust animal than the greyhound, and therefore used against larger game, such as bears or boars. The alaunt was considered a reckless animal, and had been known to attack domestic animals, or even its owner. The mastiff was an even more rugged breed, and though also used on the larger game, was mostly considered useful as a guard-dog.
What all these dogs lacked was the ability to follow the scent of the quarry, and run it down. For this purpose the running-dog was used. The running-dog was somewhat similar to today’s foxhound. This dog had, as the name indicates, excellent stamina, as well as a good nose. Another dog valued for its scenting skills was the lymer, a forerunner of today’s bloodhound. The lymer would be used to find the lay of the game before the hunt even started, and it was therefore important that, in addition to a good nose, it remained quiet. Silence in the lymer was achieved through a combination of breeding and training. Other dogs used for hunting were the kenet, the terrier, the harrier and the spaniel.
The hounds were kept in a kennel, inside or separate from the main domicile. Here the dogs would have oak beds to sleep on, and often also a second level where the dogs could go when the ground level became too hot or too cold. Outside the kennel there would be grass for the dogs to eat whenever they had digestive problems. To care for the dogs would be a hierarchy of servants such as pages, varlets, aides and veneurs; the page being the lowest, often a young boy. Pages would often sleep in the kennels with the dogs, to keep them from fighting and care for them if they got sick. Though this might seem harsh by modern standards, the warm dog house could often be much more comfortable than the sleeping quarters of other medieval servants.
The hawk
Medieval terminology spoke of hawks of the tower and hawks of the fist, which roughly corresponds to falcons and hawks, respectively. The female hawk was preferred, since it was both larger than the male and easier to train. Hawks were captured all over Europe, but birds from Norway or Iceland were considered of particularly good quality.
Training a hawk was a painstaking process. It was normal at first to "seel" the bird’s eyelids—sew them shut—so that it would not be scared or distracted. The trainer would then carry the hawk on his arm for several days, to get it accustomed to human presence. The eyes would gradually be unsealed, and the training would begin. The bird would be encouraged to fly from its perch to the falconer’s hand over a gradually longer distance. Hunting game would be encouraged first by the use of meat, then a lure, and eventually live prey. Such prey included herons, sometime with their legs broken to facilitate the kill.
Hawks would be housed in mews, a special edifice found in most large medieval households, mostly a certain distance from the main domicile, so that the hawks would not be disturbed. The mews could be rather elaborate structures. There should be windows in the wall, and the ground should be kept clean so that the bird’s regurgitations could be found and analyzed.
Marine pollution,Plastic debris,Toxins,Eutrophication,Acidification,NOAA ,chemicals, particles, industrial, agricultural and residential waste
Marine pollution occurs when harmful effects, or potentially harmful effects, can result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, or the spread of invasive organisms.
Most sources of marine pollution are land based. The pollution often comes from nonpoint sources such as agricultural runoff and wind blown debris.
Many potentially toxic chemicals adhere to tiny particles which are then taken up by plankton and benthos animals, most of which are either deposit or filter feeders. In this way, the toxins are concentrated upward within ocean food chains. Many particles combine chemically in a manner highly depletive of oxygen, causing estuaries to become anoxic.
When pesticides are incorporated into the marine ecosystem, they quickly become absorbed into marine food webs. Once in the food webs, these pesticides can cause mutations, as well as diseases, which can be harmful to humans as well as the entire food web.
Toxic metals can also be introduced into marine food webs. These can cause a change tissue matter, biochemistry, behaviour, reproduction, and suppress growth in marine life. Also, many animal feeds have a high fish meal or fish hydrolysate content. In this way, marine toxins can be transferred to land animals, and appear later in meat and dairy products.
History
Although marine pollution has a long history, significant international laws to counter it were enacted in the twentieth century. Marine pollution was a concern during several United Nations Conferences on the Law of the Sea beginning in the 1950s. Most scientists believed that the oceans were so vast that they had unlimited ability to dilute, and thus render harmless, pollution.. In the late 1950s and early 1960s, there were several controversies about dumping radioactive waste off the coasts of the United States by companies licensed by the Atomic Energy Commission, into the Irish Sea from the British reprocessing facility at Windscale, and into the Mediterranean Sea by the French Commissariat à l'Energie Atomique. After the Mediterranean Sea controversy, for example, Jacques Cousteau became a worldwide figure in the campaign to stop marine pollution. Marine pollution made further international headlines after the 1967 crash of the oil tanker Torrey Canyon, and after the 1969 Santa Barbara oil spill off the coast of California. Marine pollution was a major area of discussion during the 1972 United Nations Conference on the Human Environment, held in Stockholm. That year also saw the signing of the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, sometimes called the London Convention. The London Convention did not ban marine pollution, but it established black and gray lists for substances to be banned (black) or regulated by national authorities (gray). Cyanide and high-level radioactive waste, for example, were put on the black list. The London Convention applied only to waste dumped from ships, and thus did nothing to regulate waste discharged as liquids from pipelines.
Pathways of pollution
Bjorn Jenssen (2003) notes in his article, “Anthropogenic pollution may reduce biodiversity and productivity of marine ecosystems, resulting in reduction and depletion of human marine food resources” (p. A198). There are many different ways to categorize, and examine the inputs of pollution into our marine ecosystems. Patin (n.d.) notes that generally there are three main types of inputs of pollution into the ocean: direct discharge of waste into the oceans, runoff into the waters due to rain, and pollutants that are released from the atmosphere.
One common path of entry by contaminants to the sea are rivers. The Hudson in New York State and the Raritan in New Jersey, which empty at the northern and southern ends of Staten Island, are a source of mercury contamination of zooplankton (copepods) in the open ocean. The highest concentration in the filter-feeding copepods is not at the mouths of these rivers but 70 miles south, nearer Atlantic City, because water flows close to the coast. It takes a few days before toxins are taken up by the plankton.
Pollution is often classed as point source or nonpoint source pollution. Point source pollution occurs when there is a single, identifiable, and localized source of the pollution. An example is directly discharging sewage and industrial waste into the ocean. Pollution such as this occurs particularly in developing nations. Nonpoint source pollution occurs when the pollution comes from ill-defined and diffuse sources. These can be difficult to regulate. Agricultural runoff and wind blown debris are prime examples.
Pollution from ships
Ships can pollute waterways and oceans in many ways. Oil spills can have devastating effects. While being toxic to marine life, polycyclic aromatic hydrocarbons (PAHs), the components in crude oil, are very difficult to clean up, and last for years in the sediment and marine environment.
Discharge of cargo residues from bulk carriers can pollute ports, waterways and oceans. In many instances vessels intentionally discharge illegal wastes despite foreign and domestic regulation prohibiting such actions. Ships create noise pollution that disturbs natural wildlife, and water from ballast tanks can spread harmful algae and other invasive species.
Meinesz believes that one of the worst cases of a single invasive species causing harm to an ecosystem can be attributed to a seemingly harmless jellyfish. Mnemiopsis leidyi, a species of comb jellyfish that spread so it now inhabits estuaries in many parts of the world. It was first introduced in 1982, and thought to have been transported to the Black Sea in a ship’s ballast water. The population of the jellyfish shot up exponentially and, by 1988, it was wreaking havoc upon the local fishing industry. “The anchovy catch fell from 204,000 tons in 1984 to 200 tons in 1993; sprat from 24,600 tons in 1984 to 12,000 tons in 1993; horse mackerel from 4,000 tons in 1984 to zero in 1993.”[3] Now that the jellyfish have exhausted the zooplankton, including fish larvae, their numbers have fallen dramatically, yet they continue to maintain a stranglehold on the ecosystem.
Invasive species can take over once occupied areas, facilitate the spread of new diseases, introduce new genetic material, alter underwater seascapes and jeopardize the ability of native species to obtain food. Invasive species are responsible for about $138 billion annually in lost revenue and management costs in the US alone.
Plastic debris
Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Eighty percent of marine debris is plastic - a component that has been rapidly accumulating since the end of World War II. The mass of plastic in the oceans may be as high as one hundred million tonnes.
Discarded plastic bags, six pack rings and other forms of plastic waste which finish up in the ocean present dangers to wildlife and fisheries.[7] Aquatic life can be threatened through entanglement, suffocation, and ingestion.Fishing nets, usually made of plastic, can be left or lost in the ocean by fishermen. Known as ghost nets, these entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation.
Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection.
Plastics accumulate because they don't biodegrade in the way many other substances do. They will photodegrade on exposure to the sun, but they do so properly only under dry conditions, and water inhibits this process. In marine environments, photodegraded plastic disintegrates into ever smaller pieces while remaining polymers, even down to the molecular level. When floating plastic particles photodegrade down to zooplankton sizes, jellyfish attempt to consume them, and in this way the plastic enters the ocean food chain.Many of these long-lasting pieces end up in the stomachs of marine birds and animals, including sea turtles, and black-footed albatross.
Plastic debris tends to accumulate at the centre of ocean gyres. In particular, the Great Pacific Garbage Patch has a very high level of plastic particulate suspended in the upper water column. In samples taken in 1999, the mass of plastic exceeded that of zooplankton (the dominant animal life in the area) by a factor of six.
Toxic additives used in the manufacture of plastic materials can leech out into their surroundings when exposed to water. Waterborne hydrophobic pollutants collect and magnify on the surface of plastic debris, thus making plastic far more deadly in the ocean than it would be on land. Hydrophobic contaminants are also known to bioaccumulate in fatty tissues, biomagnifying up the food chain and putting pressure on apex predators. Some plastic additives are known to disrupt the endocrine system when consumed, others can suppress the immune system or decrease reproductive rates. Floating debris can also absorb persistent organic pollutants from seawater, including PCBs, DDT and PAHs. Aside from toxic effects, when ingested some of these are mistaken by the animal brain for estradiol, causing hormone disruption in the affected wildlife.
Toxins
Apart from plastics, there are particular problems with other toxins that do not disintegrate rapidly in the marine environment. Examples of persistent toxins are PCBs, DDT, pesticides, furans, dioxins and phenols. Heavy metals are metallic chemical elements that have a relatively high density and are toxic or poisonous at low concentrations. Examples are mercury, lead, nickel, arsenic and cadmium.
Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation. They are also known to accumulate in benthic environments, such as estuaries and bay muds: a geological record of human activities of the last century.
Eutrophication
Polluted lagoon.
Eutrophication is an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem. It can result in an increase in the ecosystem's primary productivity (excessive plant growth and decay), and further effects including lack of oxygen and severe reductions in water quality, fish, and other animal populations.
The biggest culprit are rivers that empty into the ocean, and with it the many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. An excess of oxygen depleting chemicals in the water can lead to hypoxia and the creation of a dead zone.
Estuaries tend to be naturally eutrophic because land-derived nutrients are concentrated where runoff enters the marine environment in a confined channel. The World Resources Institute has identified 375 hypoxic coastal zones around the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia, particularly in Japan. In the ocean, there are frequent red tide algae blooms that kill fish and marine mammals and cause respiratory problems in humans and some domestic animals when the blooms reach close to shore.
In addition to land runoff, atmospheric anthropogenic fixed nitrogen can enter the open ocean. A study in 2008 found that this could account for around one third of the ocean’s external (non-recycled) nitrogen supply and up to three per cent of the annual new marine biological production. It has been been suggested that accumulating reactive nitrogen in the environment may have consequences as serious as putting carbon dioxide in the atmosphere.
Acidification
The oceans are normally a natural carbon sink, absorbing carbon dioxide from the atmosphere. Because the levels of atmospheric carbon dioxide are increasing, the oceans are becoming more acidic. The potential consequences of ocean acidification are not fully understood, but there are concerns that structures made of calcium carbonate may become vulnerable to dissolution, affecting corals and the ability of shellfish to form shells.
A report from NOAA scientists published in the journal Science in May 2008 found that large amounts of relatively acidified water are upwelling to within four miles of the Pacific continental shelf area of North America. This area is a critical zone where most local marine life lives or is born. While the paper dealt only with areas from Vancouver to northern California, other continental shelf areas may be experiencing similar effects.
Most sources of marine pollution are land based. The pollution often comes from nonpoint sources such as agricultural runoff and wind blown debris.
Many potentially toxic chemicals adhere to tiny particles which are then taken up by plankton and benthos animals, most of which are either deposit or filter feeders. In this way, the toxins are concentrated upward within ocean food chains. Many particles combine chemically in a manner highly depletive of oxygen, causing estuaries to become anoxic.
When pesticides are incorporated into the marine ecosystem, they quickly become absorbed into marine food webs. Once in the food webs, these pesticides can cause mutations, as well as diseases, which can be harmful to humans as well as the entire food web.
Toxic metals can also be introduced into marine food webs. These can cause a change tissue matter, biochemistry, behaviour, reproduction, and suppress growth in marine life. Also, many animal feeds have a high fish meal or fish hydrolysate content. In this way, marine toxins can be transferred to land animals, and appear later in meat and dairy products.
History
Although marine pollution has a long history, significant international laws to counter it were enacted in the twentieth century. Marine pollution was a concern during several United Nations Conferences on the Law of the Sea beginning in the 1950s. Most scientists believed that the oceans were so vast that they had unlimited ability to dilute, and thus render harmless, pollution.. In the late 1950s and early 1960s, there were several controversies about dumping radioactive waste off the coasts of the United States by companies licensed by the Atomic Energy Commission, into the Irish Sea from the British reprocessing facility at Windscale, and into the Mediterranean Sea by the French Commissariat à l'Energie Atomique. After the Mediterranean Sea controversy, for example, Jacques Cousteau became a worldwide figure in the campaign to stop marine pollution. Marine pollution made further international headlines after the 1967 crash of the oil tanker Torrey Canyon, and after the 1969 Santa Barbara oil spill off the coast of California. Marine pollution was a major area of discussion during the 1972 United Nations Conference on the Human Environment, held in Stockholm. That year also saw the signing of the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, sometimes called the London Convention. The London Convention did not ban marine pollution, but it established black and gray lists for substances to be banned (black) or regulated by national authorities (gray). Cyanide and high-level radioactive waste, for example, were put on the black list. The London Convention applied only to waste dumped from ships, and thus did nothing to regulate waste discharged as liquids from pipelines.
Pathways of pollution
Bjorn Jenssen (2003) notes in his article, “Anthropogenic pollution may reduce biodiversity and productivity of marine ecosystems, resulting in reduction and depletion of human marine food resources” (p. A198). There are many different ways to categorize, and examine the inputs of pollution into our marine ecosystems. Patin (n.d.) notes that generally there are three main types of inputs of pollution into the ocean: direct discharge of waste into the oceans, runoff into the waters due to rain, and pollutants that are released from the atmosphere.
One common path of entry by contaminants to the sea are rivers. The Hudson in New York State and the Raritan in New Jersey, which empty at the northern and southern ends of Staten Island, are a source of mercury contamination of zooplankton (copepods) in the open ocean. The highest concentration in the filter-feeding copepods is not at the mouths of these rivers but 70 miles south, nearer Atlantic City, because water flows close to the coast. It takes a few days before toxins are taken up by the plankton.
Pollution is often classed as point source or nonpoint source pollution. Point source pollution occurs when there is a single, identifiable, and localized source of the pollution. An example is directly discharging sewage and industrial waste into the ocean. Pollution such as this occurs particularly in developing nations. Nonpoint source pollution occurs when the pollution comes from ill-defined and diffuse sources. These can be difficult to regulate. Agricultural runoff and wind blown debris are prime examples.
Pollution from ships
Ships can pollute waterways and oceans in many ways. Oil spills can have devastating effects. While being toxic to marine life, polycyclic aromatic hydrocarbons (PAHs), the components in crude oil, are very difficult to clean up, and last for years in the sediment and marine environment.
Discharge of cargo residues from bulk carriers can pollute ports, waterways and oceans. In many instances vessels intentionally discharge illegal wastes despite foreign and domestic regulation prohibiting such actions. Ships create noise pollution that disturbs natural wildlife, and water from ballast tanks can spread harmful algae and other invasive species.
Meinesz believes that one of the worst cases of a single invasive species causing harm to an ecosystem can be attributed to a seemingly harmless jellyfish. Mnemiopsis leidyi, a species of comb jellyfish that spread so it now inhabits estuaries in many parts of the world. It was first introduced in 1982, and thought to have been transported to the Black Sea in a ship’s ballast water. The population of the jellyfish shot up exponentially and, by 1988, it was wreaking havoc upon the local fishing industry. “The anchovy catch fell from 204,000 tons in 1984 to 200 tons in 1993; sprat from 24,600 tons in 1984 to 12,000 tons in 1993; horse mackerel from 4,000 tons in 1984 to zero in 1993.”[3] Now that the jellyfish have exhausted the zooplankton, including fish larvae, their numbers have fallen dramatically, yet they continue to maintain a stranglehold on the ecosystem.
Invasive species can take over once occupied areas, facilitate the spread of new diseases, introduce new genetic material, alter underwater seascapes and jeopardize the ability of native species to obtain food. Invasive species are responsible for about $138 billion annually in lost revenue and management costs in the US alone.
Plastic debris
Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Eighty percent of marine debris is plastic - a component that has been rapidly accumulating since the end of World War II. The mass of plastic in the oceans may be as high as one hundred million tonnes.
Discarded plastic bags, six pack rings and other forms of plastic waste which finish up in the ocean present dangers to wildlife and fisheries.[7] Aquatic life can be threatened through entanglement, suffocation, and ingestion.Fishing nets, usually made of plastic, can be left or lost in the ocean by fishermen. Known as ghost nets, these entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation.
Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey. Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection.
Plastics accumulate because they don't biodegrade in the way many other substances do. They will photodegrade on exposure to the sun, but they do so properly only under dry conditions, and water inhibits this process. In marine environments, photodegraded plastic disintegrates into ever smaller pieces while remaining polymers, even down to the molecular level. When floating plastic particles photodegrade down to zooplankton sizes, jellyfish attempt to consume them, and in this way the plastic enters the ocean food chain.Many of these long-lasting pieces end up in the stomachs of marine birds and animals, including sea turtles, and black-footed albatross.
Plastic debris tends to accumulate at the centre of ocean gyres. In particular, the Great Pacific Garbage Patch has a very high level of plastic particulate suspended in the upper water column. In samples taken in 1999, the mass of plastic exceeded that of zooplankton (the dominant animal life in the area) by a factor of six.
Toxic additives used in the manufacture of plastic materials can leech out into their surroundings when exposed to water. Waterborne hydrophobic pollutants collect and magnify on the surface of plastic debris, thus making plastic far more deadly in the ocean than it would be on land. Hydrophobic contaminants are also known to bioaccumulate in fatty tissues, biomagnifying up the food chain and putting pressure on apex predators. Some plastic additives are known to disrupt the endocrine system when consumed, others can suppress the immune system or decrease reproductive rates. Floating debris can also absorb persistent organic pollutants from seawater, including PCBs, DDT and PAHs. Aside from toxic effects, when ingested some of these are mistaken by the animal brain for estradiol, causing hormone disruption in the affected wildlife.
Toxins
Apart from plastics, there are particular problems with other toxins that do not disintegrate rapidly in the marine environment. Examples of persistent toxins are PCBs, DDT, pesticides, furans, dioxins and phenols. Heavy metals are metallic chemical elements that have a relatively high density and are toxic or poisonous at low concentrations. Examples are mercury, lead, nickel, arsenic and cadmium.
Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation. They are also known to accumulate in benthic environments, such as estuaries and bay muds: a geological record of human activities of the last century.
Eutrophication
Polluted lagoon.
Eutrophication is an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem. It can result in an increase in the ecosystem's primary productivity (excessive plant growth and decay), and further effects including lack of oxygen and severe reductions in water quality, fish, and other animal populations.
The biggest culprit are rivers that empty into the ocean, and with it the many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. An excess of oxygen depleting chemicals in the water can lead to hypoxia and the creation of a dead zone.
Estuaries tend to be naturally eutrophic because land-derived nutrients are concentrated where runoff enters the marine environment in a confined channel. The World Resources Institute has identified 375 hypoxic coastal zones around the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia, particularly in Japan. In the ocean, there are frequent red tide algae blooms that kill fish and marine mammals and cause respiratory problems in humans and some domestic animals when the blooms reach close to shore.
In addition to land runoff, atmospheric anthropogenic fixed nitrogen can enter the open ocean. A study in 2008 found that this could account for around one third of the ocean’s external (non-recycled) nitrogen supply and up to three per cent of the annual new marine biological production. It has been been suggested that accumulating reactive nitrogen in the environment may have consequences as serious as putting carbon dioxide in the atmosphere.
Acidification
The oceans are normally a natural carbon sink, absorbing carbon dioxide from the atmosphere. Because the levels of atmospheric carbon dioxide are increasing, the oceans are becoming more acidic. The potential consequences of ocean acidification are not fully understood, but there are concerns that structures made of calcium carbonate may become vulnerable to dissolution, affecting corals and the ability of shellfish to form shells.
A report from NOAA scientists published in the journal Science in May 2008 found that large amounts of relatively acidified water are upwelling to within four miles of the Pacific continental shelf area of North America. This area is a critical zone where most local marine life lives or is born. While the paper dealt only with areas from Vancouver to northern California, other continental shelf areas may be experiencing similar effects.
Thursday, December 25, 2008
Historical ecology,Human-mediated disturbance,Anthropogenic fire,Biological invasions,Epidemic disease,Soil management
Historical ecology is a research program that focuses on the intermingling of people and the environments in which they live. Rather than just looking at a quick snapshot, historical ecology involves studying and understanding this relationship in both time and space in order to gain a full picture of all of its accumulated effects. Through this interaction humans manipulate the environment and further the transformation of landscapes.
William Balée, Professor of Anthropology at Tulane University has proposed four hard-core postulates which are interdependent and set historical ecology apart from other more traditional research programs, as evident in its intellectual background. Basically summarized, these are:
1. Humans have had an effect on nearly all environments of Earth
2. Humans are seen as morally neutral: they are not inherently bad and programmed to destroy the land and biodiversity in their environments nor are they inherently good
3. Different types of societies influence their landscapes in different ways
4. The relationship between people and the landscape can be comprehended holistically
An important aspect of historical ecology is that human culture and the environment are in a dialogue. They influence and respond to one another in continuous cycles. This is different from saying that throughout time, as the environment has changed, the human species has adapted to these changes. Instead, humans have brought their cultures to new lands, impacted these landscapes, and then made the necessary changes to adjust their culture or lifestyle to the now altered landscape. In fact, as the first postulate holds, it is very difficult to find a landscape anywhere on the planet that has not somehow been changed as a result of humans. These alterations can be referred to as human-mediated disturbance.
As the second and third postulates imply, it is important that we do not overgeneralize humans and society. Humans impact nearly every environment but this can create an increase in biodiversity of certain landscapes at certain times. When indigenous people use broadcast fires they often consequently create more niches for new species. However, the changes some humans make to the landscape are not always beneficial to all humans and all biota. Just as human cultures and languages vary, different societies and political systems have distinct impacts on the landscape.
Finally, people and the landscape can be studied as a connected trend because when one looks at the landscape, people and the environment coexist. They each are so dependent on one another that it is more efficient and accurate to study them together as a single entity. The landscape is visual evidence of the totality, or interaction, of culture and the environment.
(R) William Balée, Anthropology professor at Tulane University, with (L) indigenous consultant on landscape transformation in Brazil
Intellectual background
While historical ecology is an interdisciplinary research program, it borrows heavily from the rich intellectual history of environmental anthropology. Western scholars have known since the time of Plato that the history of environmental changes, induced by natural catastrophes and human activities, is an integral part of human history. Greek and Roman philosophers developed several ideas to describe human-environmental interactions, many of which have been retained or reflected in contemporary environmental theories. The first of these ideas is the concept of the Great Chain of Being, or inherent design in nature. In this, all species on earth are arranged in an ascending hierarchical scale, with humanity topping the scale. Humanity, as the highest being, has the knowledge and ability to modify nature. These two ideas lend to a third, the concept of "another," or manmade nature. The first nature is the design inherent in nature, and second nature has been modified by humanity.
Interest in environmental transformation increased in the 18th, 19th, and 20th centuries, and a series of new intellectual approaches emerged. One of these approaches was environmental determinism, developed by human geographer Friedrich Ratzel. This view held that it was environmental conditions, not social conditions, which determined the culture of a population. Proponents of environmental determinism held that humans are restricted by nature, in a teleological sense, to certain levels in the great chain of being. A later approach was the historical viewpoint of Franz Boas. Boas refuted environmental determinism by saying that culture, not nature, is the primary molder of human cultures. While the environment produces limitations on societies, the form and meaning of the modification the environment can provide depends on the culture itself. The cultural ecology of Julian Steward is thought to be a fusion of environmental determinism and the historical approach of Franz Boas. Steward felt it was neither nature nor culture that had the most impact on a population, but it was the mode of subsistence used by the people.
Anthropologist Roy Rappaport introduced the field of ecological anthropology. Rappaport coined the new term in a deliberate attempt to move away from cultural ecology. He was explicitly interested in the role of religion in society, and felt that in order to fully understand religion and ritual, the researcher has to look beyond humans. Studies in ecological anthropology borrow heavily from the natural sciences, in particular the concept of the ecosystem. Under this approach, which is also called systems theory, human populations are seen as one of many aspects in a self-regulating ecosystem. Systems theorists gave increased attention to time and change in populations and the individual actors in them. Systems theory treated communities as static populations in harmonious equilibrium with the local environment.
All these intellectual approaches are important because they provide the framework for historical ecology. These viewpoints have been critiqued, expanded, and improved to create the current approaches in environmental anthropology; one approach is historical ecology. Eric Wolf, a student of Julian Steward, was prominent in the critique of late twentieth century anthropology. The revisions of Wolf and others are especially pertinent to the development of historical ecology. Most of these theories do not take a long view of history. In other words, they view a population as static, as a slice in time. This, according to historical ecology, does not provide a deep enough understanding of a culture or landscape because it ignores the events that helped create it. Other problems arose when many of these theories were applied to complex societies. Cultural ecology can be useful in understanding classless or simple societies, where factors such as indigenous technology, low population size, and less political organization directly correlate to the modes of subsistence. However, it is more difficult to explain the complex factors in peasantries and urban societies only in terms of their modes of production. wiki wiki pedia Some of the main tenets of historical ecology have specific influences as well. One of them, the cultural landscape, is directly attributed to American geographer Carl Sauer. Sauer’s theories developed as a critique of environmental determinism, which was a popular theory in the early twentieth century. Sauer’s pioneering 1925 paper “The Morphology of Landscape” is now fundamental to many disciplines and defines the domain. In this, the term landscape is used in a geographical sense to mean an arbitrarily selected section of reality; morphology means the conceptual and methodological processes for altering it. Hence to Sauer wherever humans lived and impacted the environment, landscapes with determinate histories resulted.
Landscapes in historical ecology
In historical ecology, the landscape is defined as an area of interaction. The landscape provides the story of the place, it is a realistic place that changes throughout time. Historical ecology dispenses the notion of an ecosystem and replaces this notion with the concept of a landscape. While the ecosystem is perpetual and cyclic, a landscape is historical, cultural, and evolutionary.
Historical ecologists have received influence on their idea of landscapes from various time periods and individuals. The idea that humans are long-term agents of change to the land goes back to the classical, distant past. A recent influence is from cultural and historical geographers. These geographers believe that humans and the environment are inseparable. They received this idea from nineteenth-century German architects, gardeners, and landscape painters in Europe, Australia, and North America.
The perception of the landscape in historical ecology differs from other disciplines, such as landscape ecology. Landscape ecologists often criticize wildlife preserves for the depletion of biodiversity. Historical ecologists recognize that this is not always true. These changes are due to multiple factors that contribute to the ever-changing landscape. Landscape ecology still focuses on areas defined as ecosystems. In this, the ecosystem perpetually returns to an equilibrium state. Also, landscape ecologists view noncyclical human events and natural disasters as disturbances, while historical ecologists view this as part of the landscape’s history. Historical ecologists recognize that landscapes undergo continuous alteration over time and these modifications are part of that landscape’s history.
Historical ecology recognizes that there is a primary and a secondary succession that occurs in the landscape. These successions should be understood without discrimination towards human nature. Primary succession occurs when an area that once had no life on it is colonized. An example of this is colonization on newly formed volcanic atolls. Over a long timescale of millions of years, primary succession is the replacement of one phyla with a totally new phyla. Secondary succession is the replacement of organisms with completely new organisms. This occurs when the area has been disturbed by things such as hurricanes and extensive agriculture. Landscapes can undergo mulitple stages of transformation. These stages demonstrate the history of the landscape. Also, these stages can be brought on by humans or natural causes.
Historical ecology challenges the implication of a pristine landscape, such as virgin rainforests. The belief of historical ecology is that most landscapes are untouched and unaltered. This notion was configured from several precursors in the fields of history, ecology, and anthropology. Combining concepts from these fields provided for an interdisciplinary view of the changes of landscapes prior to western civilizations. Historical ecologists have recognized that all landscapes have been altered by various organisms and mechanisms. These organisms altered the land prior to human existence on Earth. The alteration of these landscapes provides evidence as to the cultural history of the land. The history of the landscape can be seen through traces of the various mechanisms that have altered it, such as epidemic disease and anthropogenic fire.
The landscape is a concrete replacement to the idea of an ecosystem. Historical proceedings unfurl in tangible places which leads to changes in the landscapes. These changes have been studied through the archeological record of modern humans and their history. The evidence that classless societies, like foragers and trekkers, were able to change a landscape was a breakthrough in historical ecology. Understanding the concept of the individuality of every landscape, in addition to relations among landscapes and the forms which comprise the landscape, is key to understanding historical ecology.
Human-mediated disturbance
Throughout their history Homo sapiens have interacted with their environments, and in most cases their interactions have had lasting effects. Humans have, at times, taken active conscious roles in changing their landscapes, while at other times changes have come about as secondary effects of human action. These changes in landscapes are called human-mediated disturbances of landscapes, and act through various mechanisms. Mechanisms of human-mediated disturbances vary in the effect they have on the landscape in that they may be detrimental in some cases, and advantageous in others. Some of the main mechanisms of human-mediated disturbances include anthropogenic fire, biological invasion, spread of disease, and soil and water management.
Of all the mechanisms of human-mediated disturbances, anthropogenic fire is the one that is most immediately visible, both destructive and at times constructive, and its absence may prove to be catastrophic. Humans have practiced controlled burns of forests on all continents for thousands of years, shaping landscapes in order to better suit their needs. They burned off fuel creating space for their crops, and in many cases allowed for greater biodiversity. Controlled burns also aided in prevention of natural wildfires which spread uncontrollably and cause severe damage, and in the absence of indigenous populations (most notably in North America and Australia) who once practiced controlled burns we have seen an increase in the frequency of naturally ignited wildfires. Along with an increase of natural wild fires there has been destabilization of "ecosystem after ecosystem, and there is good documentation to suggest fire exclusion by Europeans has led to floral and faunal extinctions."
Biological invasions and the spread of pathogens and disease are two mechanisms that spread both inadvertently and purposefully, although they often have different effects. They can be spread by castaways on ships in the form of rodents, with the intention of adding a useful new species to a landscape, or even as weapons in warfare. Biological invasions are introductions of foreign species or biota into an already existing environment. The effects of such an introduction can be positive or negative; in some cases a new species may wreak havoc on a landscape, causing the loss of native species and destruction of the landscape. In other cases, the new species may fill a previously empty niche, and play a positive role. Conversely, the spread of new pathogens, viruses, and diseases may happen in the same way as biological invasions, but rarely if ever have any positive effects. New pathogens and viruses often cause the destruction of populations of native species or populations lacking immunities to those diseases. Some pathogens have the ability to transfer between species, and may be spread as a secondary effect of a biological invasion. This also acts as an example of a secondary effect of a mechanism of human-mediated disturbance in that one mechanism serves as a catalyst for another to work.
Other mechanisms of human-mediated disturbances include water management and soil management. These have been recognized as ways of landscape alteration since the time of the Roman Empire. Cicero noted that through fertilization, irrigation, and other activities humans had essentially created a second world. While Cicero may have been able to witness the effects of ancient fertilization and irrigation techniques, he had no way of knowing how destructive they would become. At present, fertilization serves as a means of creating larger more productive crop yields, but has had adverse effects on the landscapes. Fertilizers also decrease biodiversity of plant species and add harmful pollutants to the soil that often seep down to the water table and contaminate rivers, streams, and lakes.
The mechanisms of human-mediated disturbances are numerous and have various effects. They may be beneficial to landscapes in that they allow for an increase in biodiversity or protect them from catastrophic fires. In other cases, like those of certain biological invasions or the spread of pathogens and disease, they can prove to be extremely detrimental to landscapes and the biodiversity within them. Mechanisms of human-mediated disturbances may also have unforeseen secondary effects that can lead to further damage of landscapes.
Anthropogenic fire
Anthropogenic fire is a mechanism of human-mediated disturbance, defined within historical ecology as a means of altering the landscape in a way that better suits human needs. Humans have met their needs by employing anthropogenic fire in its most common forms of controlled burns, or broadcast burning. Though the words burn, fire, and forests usually have negative connotations when they are paired together, the controlled burns humans have used for thousands if not hundreds of thousands of years have proven to have more favorable than adverse effects on landscape biodiversity, formation, and even protection.
When looking at the effects of broadcast burning upon the biota of a landscape we can see a gradual change from detriment to prosperity. The immediate effect of a forest fire is a decrease in biodiversity. However, after a few cycles of burning depending on the intensity, frequency, timing, and size of the fires there is an increase in biodiversity and adaptation to fire regimes. It is the adaptation to fire that has shaped most of the Earth's landscapes.
A swidden fire, an example of a controlled burn
In addition to creating biodiversity controlled burns have helped shape and change landscapes. These changes can range from grass to woods, from prairies or forest-steppes, to scrub to forest. Whichever may be the case the transformations increase biodiversity and create landscapes more suitable to human needs creating patches rich in utilitarian and natural resources.
While broadcast burning has led to increases in biodiversity and landscapes better suited to human needs they have also become a source of protection. Humans had essentially fireproofed landscapes by burning off undergrowth and using up potential fuel, leaving little or no chance for a wild fire to be sparked by lightning. In a stark contrast to its benefits, the absence of controlled burns can have immensely destructive effects because there are no checks being placed on undergrowth and fuel allowing for wildfires to start with greater ease.
Of all of the mechanisms of human-mediated disturbances, anthropogenic fire has become one of great interest to ecologists and anthropologists alike. For anthropologists studying the effects of anthropogenic fire has been a way to measure cultural identities and landscape needs of past cultures. In the wake of the industrial revolution and the migration of populations from rural areas to urban areas there has been an increase in the frequency and strength of wildfires because there have been no means to curb or prevent them. For this reason the study of anthropogenic fires has become of great interest as ecologists look to the methods used in past anthropogenic fires in order to revive and put them into use again. The interest of historical ecology is essentially a fusing of the interests of ecologists and anthropologists with an added interest in the effects on the landscapes.
Biological invasions
Biological invasions are exotic biota, including invasive species and diseases, that enter a landscape and replace species that resemble the same structure. Much like weeds, they multiply and grow quickly, causing the destruction of existing flora and fauna by different mechanisms such as direct competitive exclusion. Invasive species typically spread at a faster rate when they have no natural enemies or when they fill an empty niche. Often these invasions occur in a context of human history and are known as a type of human-mediated disturbance called human-mediated invasions.
Invasive species can be transported intentionally or accidentally. Often invasive species are located near shipping areas where they are unintentionally transported to their new location. This method allowed red tides to become invasive after 1500. Sometimes populations intentionally introduce species into new landscapes for various purposes that range from being ornamentals to aiding in erosion control. These species can later become invasive and totally modify the landscape, like the Kentucky Coffee Tree, chestnut blight and Butternut in North America and the Walnut and Sweet Chestnut in the British Isles. It is important to note that not all exotic species are invasive; in fact, the majority of newly introduced species never become invasive.
In the Mississippi River Delta, the introduction of the nutria has caused a change in the ecology of the wetlands. They outcompeted and perhaps aided in the rapid decline of the indigenous muskrat population. They also exceeded the carrying capacity and destroyed large portions of the marsh by eating nearly all of the vegetation, especially roots. The destruction is long-term and leads to erosion and habitat loss. This invasion is an example of a human-mediated disturbance as people introduced the nutria to its new environment and also caused a number of factors that have allowed for the explosion of nutria. During a hurricane in 1941 the nutria escaped from their pens off the coast at Avery Island, where they had been imported to help control the spread of water hyacinth. Overhunting of the American Alligator and preference for muskrat fur rather than nutria fur in the market were major reasons for the huge growth of the nutria population.
Regardless of the way they were introduced, biological invasions have an effect on the landscape. The goal of eliminating invasive species is not new; Plato wrote about the benefits of biodiversity centuries ago. However, eliminating invasive species is a difficult notion because there is no set rule on how long a species must be in a specific environment until it is no longer classified as invasive. European forestry defines plants as being archaeotypes if they existed in Europe before 1500 and neophytes if they arrived after 1500. This classification is still arbitrary and some species have unknown origins while others have become such a key component of their landscape that they are a keystone species. As a result, their removal would have an enormous impact on the landscape, but not necessarily cause a return to the state that existed before the invasion.
Epidemic disease
A clear relationship between nature and people is expressed through human disease. Human diseases emerge from interactions among parasites, hosts, and their environment. All three of these factors are intertwined; if there were no humans, there would be fewer hosts, and a different amount of infectious disease. In this way, infectious disease is another method of human-mediated disturbance. The study of infectious disease requires a holistic approach, using knowledge from the fields of history, biology, geography, population dynamics and anthropology.
Studies of human disease have shown the reciprocal relationship between humans and parasites. The variety of parasites found within the human body, especially the small intestine, often reflects the diverse environment where that person lives. For example, Bushmen and Australian Aborigines have half as many intestinal parasites as African and Malaysian hunter-gatherers living in a species-rich tropic rainforest. Human activity can either increase or decrease species diversity in a landscape, causing a corresponding decrease in pathogenic diversity.
Infectious diseases are categorized as either chronic or acute, and can be either epidemic or endemic. Chronic diseases occur over long periods of time, change very little, and confer no immunity to the host. Chronic diseases include herpes simplex and tuberculosis. In contrast, acute diseases like measles, rubella, and smallpox have short periods of infection with high mortality rates. Acute infection survivors usually acquire immunity. Chronic infections often turn endemic, taking a regular toll on a population. Acute infections often become epidemic, and the effects are especially important to historical ecologists. Invasive species are often the ones that turn epidemic. Bacterial, protozoan, viral, and prion infections can take on epidemic characteristics when interacting with previously unexposed native flora and fauna, including human. Historically, evidence of epidemic diseases is associated with the beginnings of agriculture and sedentary communities. Prior to that, human populations were too small and mobile for most infections to become established chronic human diseases. Diseases often faded out if they could not be transferred from one community to another. The permanent settlements with more inter-community interaction as a result of agriculture allowed infections to develop as specifically human pathogens.
Transformation of waterways
Historical ecologists postulate that landscape transformations have occurred throughout history, even before the dawn of western civilization. Human-mediated disturbances are predated by soil erosion and animals damming waterways which contributed to waterway transformations. Landscapes, in turn, were altered by waterway transformation. Historical ecology, views the effects of human-mediated disturbances on waterway transformation as both subtle and drastic occurrences. Waterways have been modified by humans through the building of irrigation canals, expanding or narrowing waterways, and multiple other adjustments done for agricultural or transportation usage.
The evidence for past and present agricultural use of wetlands in Mesoamerica suggests an evolutionary sequence of landscape and waterway alteration. Pre-Columbian, indigenous agriculturalists developed capabilities with which to raise crops under a wide range of ecological conditions, giving rise to a multiplicity of altered, cultivated landscapes. The effects of waterway transformation were particularly evident in Mesoamerica, where agricultural practices ranged from swiddening to multicropped hydraulically transformed wetlands.
Historical ecologists view the Amazonian landscape as cultural and embodying social labor. The Amazon River has been altered by the local population for crop growth and water transportation. Previous research failed to account for human interaction with the Amazonian landscape. Recent research, however, has demonstrated that the landscape has been manipulated by its indigenous population over time. The continual, natural shifting of rivers, however, often masked the human disturbances in the course of rivers. As a result, the indigenous populations in the Amazon are often overlooked for their ability to alter the land and the river.
However, waterway transformation has been successfully identified in the Amazonian landscape. Clark Erickson observes that prehispanic savanna peoples of the Bolivian Amazon built an anthropogenic landscape through the construction of raised fields, large settlement mounds, and earthen causeways. Erickson, on the basis of location, form, patterning, associations and ethnographic analogy, identified a particular form of earthwork, the zigzag structure, as fish weirs in the savanna of Baures, Bolivia. The artificial zigzag structures were raised from the adjacent savanna and served as a means to harvest the fish who used them to migrate and spawn.
Further evidence of waterway transformation is found in Igarapé Guariba in Brazil. It is an area in Amazonia where people have intervened in nature to change rivers and streams with dramatic results. Researcher Hugh Raffles notes that British naturalists Henry Walter Bates and Alfred Russel Wallace noted waterway transformation as they sailed through a canal close to the town of Igarapé-Miri in 1848. Archival materials identifies that it had been dug out by slaves. In his studies he notes an abundance of documentary and anecdotal evidence which supports landscape transformation by the manipulation of waterways. Transformation continues in more recent times as noted when in 1961, a group of villagers from Igarapé Guariba cut a canal about two miles (3 km) long across fields thick with tall papyrus grass and into dense tropical rain forest. The narrow canal and the stream that flowed into it have since formed a full-fledged river more than six hundred yards wide at its mouth, and the landscape in this part of the northern Brazilian state of Amapá was dramatically transformed..
In general, with an increase in global population growth, comes an increase in the anthropogenic transformation of waterways. The Sumerians had created extensive irrigations by 4000 BC. As the population increased in the 3,000 years of agriculture, the ditches and canals increased in number. By the early 1900s, ditching, dredging, and diking had become common practice. This led to an increase in erosion which impacted the landscapes. Human activities have affected the natural role of rivers and its communal value. These changes in waterways have impacted the floodplains, natural tidal patterns, and the surrounding land.
The importance of understanding such transformation is it provides a more accurate understanding to long-standing popular and academic insights of Amazonia, as well as other ecological settings, as places where indigenous populations have dealt with the forces of nature. Ecological landscapes have been portrayed as an environment, not a society. Recent studies supported by historical ecologists, however, understand that ecological landscape like the Amazon are biocultural, rather than simply natural and provide for a greater understanding of anthropogenic transformation of both waterways and landscapes.
Soil management
Soil management, or direct human interaction with the soil, is another mechanism of anthropogenic change studied by historical ecologists. Soil management can take place through rearranging soils, altering drainage patterns, and building large earthen formations. Consistent with the basic premises of historical ecology, it is recognized that anthropogenic soil management practices can have both positive and negative effects on local biodiversity. Some agricultural practices have led to organically and chemically impoverished soils. In the North American Midwest, industrial agriculture has led to a loss in topsoil. Salinization of the Euphrates River has occurred due to ancient Mesopotamian irrigation, and detrimental amounts of zinc have been deposited in the New Caliber River of Nigeria. Elsewhere, soil management practices may not have any effect on soil fertility. The iconic mounds of the Hopewell Indians built in the Ohio River valley likely served a religious or ceremonial purpose, and show little evidence of changing soil fertility in the landscape.
Terra preta
The case of soil management in the Neotropics (including Amazonia) is a classic example of beneficial results of human-mediated disturbance. In this area, prehistoric peoples altered the texture and chemical composition of natural soils. The altered black and brown earths, known as Amazon Dark Earths, or Terra preta, are actually much more fertile than unaltered surrounding soils.. Furthermore, the increased soil fertility improves the results of agriculture. Terra preta is characterized by the presence of charcoal in high concentrations, along with pottery shards and organic residues from plants, animal bones, and feces. It is also shows increased levels of nutrients such as nitrogen, phosphorus, calcium, zinc, and manganese; along with high levels of microorganic activity. It is now accepted that these soils are a product of a labor intensive technique termed slash-and-char. In contrast to the commonly known slash-and-burn technique, this uses a lower temperature burn that produces more charcoal than ashes. Research shows these soils were created by human activity between 9000 and 2500 years ago. Contemporary local farmers actively seek out and sell this dark earth, which covers around 10% of Amazonia. Harvesting Terra preta does not deplete it however, for it has the ability to regenerate at the rate of one centimeter per year by sequestering more carbon.
Scorched land resulting from slash-and-burn agriculture
Interest in and the study of Amazon dark earths was advanced with the work of Wim Sombroek. Sombroek's interest in soil fertility came from his childhood. He was born in the Netherlands and lived through the Dutch famine of 1944. His family subsided on a small plot of land that had been maintained and improved for generations. Sombroek's father, in turn, improved the land by sowing it with the ash and cinders from their home. Sombroek came across Terra preta in the 1950s and it reminded him of the soil from his childhood, inspiring him to study it further. Soil biologist from the University of Kansas William W. Woods is also a major figure in Terra preta research. Woods has made several key discoveries and his comprehensive bibliography on the subject doubles in size every decade.
Globally, forests are well-known for having greater biodiversity than nearby savannas or grasslands. Thus, the creation of ‘forest islands’ in multiple locations can be considered a positive result of human activity. This is evident in the otherwise uniform savannas of Guinea and central Brazil that are punctured by scattered clumps of trees. These clumps are the result of generations of intense resource management. Earth works and mounds formed by humans, such as the Ibibate mound complex in the Llanos de Mojos in Bolivia, are examples of built environments that have undergone landscape transformation and provide habitats for a greater number of species than the surrounding wetland areas. The forest islands in the Bolivian Amazon not only increase the local plant species diversity, but also enhance subsistence possibilities for the local people.
William Balée, Professor of Anthropology at Tulane University has proposed four hard-core postulates which are interdependent and set historical ecology apart from other more traditional research programs, as evident in its intellectual background. Basically summarized, these are:
1. Humans have had an effect on nearly all environments of Earth
2. Humans are seen as morally neutral: they are not inherently bad and programmed to destroy the land and biodiversity in their environments nor are they inherently good
3. Different types of societies influence their landscapes in different ways
4. The relationship between people and the landscape can be comprehended holistically
An important aspect of historical ecology is that human culture and the environment are in a dialogue. They influence and respond to one another in continuous cycles. This is different from saying that throughout time, as the environment has changed, the human species has adapted to these changes. Instead, humans have brought their cultures to new lands, impacted these landscapes, and then made the necessary changes to adjust their culture or lifestyle to the now altered landscape. In fact, as the first postulate holds, it is very difficult to find a landscape anywhere on the planet that has not somehow been changed as a result of humans. These alterations can be referred to as human-mediated disturbance.
As the second and third postulates imply, it is important that we do not overgeneralize humans and society. Humans impact nearly every environment but this can create an increase in biodiversity of certain landscapes at certain times. When indigenous people use broadcast fires they often consequently create more niches for new species. However, the changes some humans make to the landscape are not always beneficial to all humans and all biota. Just as human cultures and languages vary, different societies and political systems have distinct impacts on the landscape.
Finally, people and the landscape can be studied as a connected trend because when one looks at the landscape, people and the environment coexist. They each are so dependent on one another that it is more efficient and accurate to study them together as a single entity. The landscape is visual evidence of the totality, or interaction, of culture and the environment.
(R) William Balée, Anthropology professor at Tulane University, with (L) indigenous consultant on landscape transformation in Brazil
Intellectual background
While historical ecology is an interdisciplinary research program, it borrows heavily from the rich intellectual history of environmental anthropology. Western scholars have known since the time of Plato that the history of environmental changes, induced by natural catastrophes and human activities, is an integral part of human history. Greek and Roman philosophers developed several ideas to describe human-environmental interactions, many of which have been retained or reflected in contemporary environmental theories. The first of these ideas is the concept of the Great Chain of Being, or inherent design in nature. In this, all species on earth are arranged in an ascending hierarchical scale, with humanity topping the scale. Humanity, as the highest being, has the knowledge and ability to modify nature. These two ideas lend to a third, the concept of "another," or manmade nature. The first nature is the design inherent in nature, and second nature has been modified by humanity.
Interest in environmental transformation increased in the 18th, 19th, and 20th centuries, and a series of new intellectual approaches emerged. One of these approaches was environmental determinism, developed by human geographer Friedrich Ratzel. This view held that it was environmental conditions, not social conditions, which determined the culture of a population. Proponents of environmental determinism held that humans are restricted by nature, in a teleological sense, to certain levels in the great chain of being. A later approach was the historical viewpoint of Franz Boas. Boas refuted environmental determinism by saying that culture, not nature, is the primary molder of human cultures. While the environment produces limitations on societies, the form and meaning of the modification the environment can provide depends on the culture itself. The cultural ecology of Julian Steward is thought to be a fusion of environmental determinism and the historical approach of Franz Boas. Steward felt it was neither nature nor culture that had the most impact on a population, but it was the mode of subsistence used by the people.
Anthropologist Roy Rappaport introduced the field of ecological anthropology. Rappaport coined the new term in a deliberate attempt to move away from cultural ecology. He was explicitly interested in the role of religion in society, and felt that in order to fully understand religion and ritual, the researcher has to look beyond humans. Studies in ecological anthropology borrow heavily from the natural sciences, in particular the concept of the ecosystem. Under this approach, which is also called systems theory, human populations are seen as one of many aspects in a self-regulating ecosystem. Systems theorists gave increased attention to time and change in populations and the individual actors in them. Systems theory treated communities as static populations in harmonious equilibrium with the local environment.
All these intellectual approaches are important because they provide the framework for historical ecology. These viewpoints have been critiqued, expanded, and improved to create the current approaches in environmental anthropology; one approach is historical ecology. Eric Wolf, a student of Julian Steward, was prominent in the critique of late twentieth century anthropology. The revisions of Wolf and others are especially pertinent to the development of historical ecology. Most of these theories do not take a long view of history. In other words, they view a population as static, as a slice in time. This, according to historical ecology, does not provide a deep enough understanding of a culture or landscape because it ignores the events that helped create it. Other problems arose when many of these theories were applied to complex societies. Cultural ecology can be useful in understanding classless or simple societies, where factors such as indigenous technology, low population size, and less political organization directly correlate to the modes of subsistence. However, it is more difficult to explain the complex factors in peasantries and urban societies only in terms of their modes of production. wiki wiki pedia Some of the main tenets of historical ecology have specific influences as well. One of them, the cultural landscape, is directly attributed to American geographer Carl Sauer. Sauer’s theories developed as a critique of environmental determinism, which was a popular theory in the early twentieth century. Sauer’s pioneering 1925 paper “The Morphology of Landscape” is now fundamental to many disciplines and defines the domain. In this, the term landscape is used in a geographical sense to mean an arbitrarily selected section of reality; morphology means the conceptual and methodological processes for altering it. Hence to Sauer wherever humans lived and impacted the environment, landscapes with determinate histories resulted.
Landscapes in historical ecology
In historical ecology, the landscape is defined as an area of interaction. The landscape provides the story of the place, it is a realistic place that changes throughout time. Historical ecology dispenses the notion of an ecosystem and replaces this notion with the concept of a landscape. While the ecosystem is perpetual and cyclic, a landscape is historical, cultural, and evolutionary.
Historical ecologists have received influence on their idea of landscapes from various time periods and individuals. The idea that humans are long-term agents of change to the land goes back to the classical, distant past. A recent influence is from cultural and historical geographers. These geographers believe that humans and the environment are inseparable. They received this idea from nineteenth-century German architects, gardeners, and landscape painters in Europe, Australia, and North America.
The perception of the landscape in historical ecology differs from other disciplines, such as landscape ecology. Landscape ecologists often criticize wildlife preserves for the depletion of biodiversity. Historical ecologists recognize that this is not always true. These changes are due to multiple factors that contribute to the ever-changing landscape. Landscape ecology still focuses on areas defined as ecosystems. In this, the ecosystem perpetually returns to an equilibrium state. Also, landscape ecologists view noncyclical human events and natural disasters as disturbances, while historical ecologists view this as part of the landscape’s history. Historical ecologists recognize that landscapes undergo continuous alteration over time and these modifications are part of that landscape’s history.
Historical ecology recognizes that there is a primary and a secondary succession that occurs in the landscape. These successions should be understood without discrimination towards human nature. Primary succession occurs when an area that once had no life on it is colonized. An example of this is colonization on newly formed volcanic atolls. Over a long timescale of millions of years, primary succession is the replacement of one phyla with a totally new phyla. Secondary succession is the replacement of organisms with completely new organisms. This occurs when the area has been disturbed by things such as hurricanes and extensive agriculture. Landscapes can undergo mulitple stages of transformation. These stages demonstrate the history of the landscape. Also, these stages can be brought on by humans or natural causes.
Historical ecology challenges the implication of a pristine landscape, such as virgin rainforests. The belief of historical ecology is that most landscapes are untouched and unaltered. This notion was configured from several precursors in the fields of history, ecology, and anthropology. Combining concepts from these fields provided for an interdisciplinary view of the changes of landscapes prior to western civilizations. Historical ecologists have recognized that all landscapes have been altered by various organisms and mechanisms. These organisms altered the land prior to human existence on Earth. The alteration of these landscapes provides evidence as to the cultural history of the land. The history of the landscape can be seen through traces of the various mechanisms that have altered it, such as epidemic disease and anthropogenic fire.
The landscape is a concrete replacement to the idea of an ecosystem. Historical proceedings unfurl in tangible places which leads to changes in the landscapes. These changes have been studied through the archeological record of modern humans and their history. The evidence that classless societies, like foragers and trekkers, were able to change a landscape was a breakthrough in historical ecology. Understanding the concept of the individuality of every landscape, in addition to relations among landscapes and the forms which comprise the landscape, is key to understanding historical ecology.
Human-mediated disturbance
Throughout their history Homo sapiens have interacted with their environments, and in most cases their interactions have had lasting effects. Humans have, at times, taken active conscious roles in changing their landscapes, while at other times changes have come about as secondary effects of human action. These changes in landscapes are called human-mediated disturbances of landscapes, and act through various mechanisms. Mechanisms of human-mediated disturbances vary in the effect they have on the landscape in that they may be detrimental in some cases, and advantageous in others. Some of the main mechanisms of human-mediated disturbances include anthropogenic fire, biological invasion, spread of disease, and soil and water management.
Of all the mechanisms of human-mediated disturbances, anthropogenic fire is the one that is most immediately visible, both destructive and at times constructive, and its absence may prove to be catastrophic. Humans have practiced controlled burns of forests on all continents for thousands of years, shaping landscapes in order to better suit their needs. They burned off fuel creating space for their crops, and in many cases allowed for greater biodiversity. Controlled burns also aided in prevention of natural wildfires which spread uncontrollably and cause severe damage, and in the absence of indigenous populations (most notably in North America and Australia) who once practiced controlled burns we have seen an increase in the frequency of naturally ignited wildfires. Along with an increase of natural wild fires there has been destabilization of "ecosystem after ecosystem, and there is good documentation to suggest fire exclusion by Europeans has led to floral and faunal extinctions."
Biological invasions and the spread of pathogens and disease are two mechanisms that spread both inadvertently and purposefully, although they often have different effects. They can be spread by castaways on ships in the form of rodents, with the intention of adding a useful new species to a landscape, or even as weapons in warfare. Biological invasions are introductions of foreign species or biota into an already existing environment. The effects of such an introduction can be positive or negative; in some cases a new species may wreak havoc on a landscape, causing the loss of native species and destruction of the landscape. In other cases, the new species may fill a previously empty niche, and play a positive role. Conversely, the spread of new pathogens, viruses, and diseases may happen in the same way as biological invasions, but rarely if ever have any positive effects. New pathogens and viruses often cause the destruction of populations of native species or populations lacking immunities to those diseases. Some pathogens have the ability to transfer between species, and may be spread as a secondary effect of a biological invasion. This also acts as an example of a secondary effect of a mechanism of human-mediated disturbance in that one mechanism serves as a catalyst for another to work.
Other mechanisms of human-mediated disturbances include water management and soil management. These have been recognized as ways of landscape alteration since the time of the Roman Empire. Cicero noted that through fertilization, irrigation, and other activities humans had essentially created a second world. While Cicero may have been able to witness the effects of ancient fertilization and irrigation techniques, he had no way of knowing how destructive they would become. At present, fertilization serves as a means of creating larger more productive crop yields, but has had adverse effects on the landscapes. Fertilizers also decrease biodiversity of plant species and add harmful pollutants to the soil that often seep down to the water table and contaminate rivers, streams, and lakes.
The mechanisms of human-mediated disturbances are numerous and have various effects. They may be beneficial to landscapes in that they allow for an increase in biodiversity or protect them from catastrophic fires. In other cases, like those of certain biological invasions or the spread of pathogens and disease, they can prove to be extremely detrimental to landscapes and the biodiversity within them. Mechanisms of human-mediated disturbances may also have unforeseen secondary effects that can lead to further damage of landscapes.
Anthropogenic fire
Anthropogenic fire is a mechanism of human-mediated disturbance, defined within historical ecology as a means of altering the landscape in a way that better suits human needs. Humans have met their needs by employing anthropogenic fire in its most common forms of controlled burns, or broadcast burning. Though the words burn, fire, and forests usually have negative connotations when they are paired together, the controlled burns humans have used for thousands if not hundreds of thousands of years have proven to have more favorable than adverse effects on landscape biodiversity, formation, and even protection.
When looking at the effects of broadcast burning upon the biota of a landscape we can see a gradual change from detriment to prosperity. The immediate effect of a forest fire is a decrease in biodiversity. However, after a few cycles of burning depending on the intensity, frequency, timing, and size of the fires there is an increase in biodiversity and adaptation to fire regimes. It is the adaptation to fire that has shaped most of the Earth's landscapes.
A swidden fire, an example of a controlled burn
In addition to creating biodiversity controlled burns have helped shape and change landscapes. These changes can range from grass to woods, from prairies or forest-steppes, to scrub to forest. Whichever may be the case the transformations increase biodiversity and create landscapes more suitable to human needs creating patches rich in utilitarian and natural resources.
While broadcast burning has led to increases in biodiversity and landscapes better suited to human needs they have also become a source of protection. Humans had essentially fireproofed landscapes by burning off undergrowth and using up potential fuel, leaving little or no chance for a wild fire to be sparked by lightning. In a stark contrast to its benefits, the absence of controlled burns can have immensely destructive effects because there are no checks being placed on undergrowth and fuel allowing for wildfires to start with greater ease.
Of all of the mechanisms of human-mediated disturbances, anthropogenic fire has become one of great interest to ecologists and anthropologists alike. For anthropologists studying the effects of anthropogenic fire has been a way to measure cultural identities and landscape needs of past cultures. In the wake of the industrial revolution and the migration of populations from rural areas to urban areas there has been an increase in the frequency and strength of wildfires because there have been no means to curb or prevent them. For this reason the study of anthropogenic fires has become of great interest as ecologists look to the methods used in past anthropogenic fires in order to revive and put them into use again. The interest of historical ecology is essentially a fusing of the interests of ecologists and anthropologists with an added interest in the effects on the landscapes.
Biological invasions
Biological invasions are exotic biota, including invasive species and diseases, that enter a landscape and replace species that resemble the same structure. Much like weeds, they multiply and grow quickly, causing the destruction of existing flora and fauna by different mechanisms such as direct competitive exclusion. Invasive species typically spread at a faster rate when they have no natural enemies or when they fill an empty niche. Often these invasions occur in a context of human history and are known as a type of human-mediated disturbance called human-mediated invasions.
Invasive species can be transported intentionally or accidentally. Often invasive species are located near shipping areas where they are unintentionally transported to their new location. This method allowed red tides to become invasive after 1500. Sometimes populations intentionally introduce species into new landscapes for various purposes that range from being ornamentals to aiding in erosion control. These species can later become invasive and totally modify the landscape, like the Kentucky Coffee Tree, chestnut blight and Butternut in North America and the Walnut and Sweet Chestnut in the British Isles. It is important to note that not all exotic species are invasive; in fact, the majority of newly introduced species never become invasive.
In the Mississippi River Delta, the introduction of the nutria has caused a change in the ecology of the wetlands. They outcompeted and perhaps aided in the rapid decline of the indigenous muskrat population. They also exceeded the carrying capacity and destroyed large portions of the marsh by eating nearly all of the vegetation, especially roots. The destruction is long-term and leads to erosion and habitat loss. This invasion is an example of a human-mediated disturbance as people introduced the nutria to its new environment and also caused a number of factors that have allowed for the explosion of nutria. During a hurricane in 1941 the nutria escaped from their pens off the coast at Avery Island, where they had been imported to help control the spread of water hyacinth. Overhunting of the American Alligator and preference for muskrat fur rather than nutria fur in the market were major reasons for the huge growth of the nutria population.
Regardless of the way they were introduced, biological invasions have an effect on the landscape. The goal of eliminating invasive species is not new; Plato wrote about the benefits of biodiversity centuries ago. However, eliminating invasive species is a difficult notion because there is no set rule on how long a species must be in a specific environment until it is no longer classified as invasive. European forestry defines plants as being archaeotypes if they existed in Europe before 1500 and neophytes if they arrived after 1500. This classification is still arbitrary and some species have unknown origins while others have become such a key component of their landscape that they are a keystone species. As a result, their removal would have an enormous impact on the landscape, but not necessarily cause a return to the state that existed before the invasion.
Epidemic disease
A clear relationship between nature and people is expressed through human disease. Human diseases emerge from interactions among parasites, hosts, and their environment. All three of these factors are intertwined; if there were no humans, there would be fewer hosts, and a different amount of infectious disease. In this way, infectious disease is another method of human-mediated disturbance. The study of infectious disease requires a holistic approach, using knowledge from the fields of history, biology, geography, population dynamics and anthropology.
Studies of human disease have shown the reciprocal relationship between humans and parasites. The variety of parasites found within the human body, especially the small intestine, often reflects the diverse environment where that person lives. For example, Bushmen and Australian Aborigines have half as many intestinal parasites as African and Malaysian hunter-gatherers living in a species-rich tropic rainforest. Human activity can either increase or decrease species diversity in a landscape, causing a corresponding decrease in pathogenic diversity.
Infectious diseases are categorized as either chronic or acute, and can be either epidemic or endemic. Chronic diseases occur over long periods of time, change very little, and confer no immunity to the host. Chronic diseases include herpes simplex and tuberculosis. In contrast, acute diseases like measles, rubella, and smallpox have short periods of infection with high mortality rates. Acute infection survivors usually acquire immunity. Chronic infections often turn endemic, taking a regular toll on a population. Acute infections often become epidemic, and the effects are especially important to historical ecologists. Invasive species are often the ones that turn epidemic. Bacterial, protozoan, viral, and prion infections can take on epidemic characteristics when interacting with previously unexposed native flora and fauna, including human. Historically, evidence of epidemic diseases is associated with the beginnings of agriculture and sedentary communities. Prior to that, human populations were too small and mobile for most infections to become established chronic human diseases. Diseases often faded out if they could not be transferred from one community to another. The permanent settlements with more inter-community interaction as a result of agriculture allowed infections to develop as specifically human pathogens.
Transformation of waterways
Historical ecologists postulate that landscape transformations have occurred throughout history, even before the dawn of western civilization. Human-mediated disturbances are predated by soil erosion and animals damming waterways which contributed to waterway transformations. Landscapes, in turn, were altered by waterway transformation. Historical ecology, views the effects of human-mediated disturbances on waterway transformation as both subtle and drastic occurrences. Waterways have been modified by humans through the building of irrigation canals, expanding or narrowing waterways, and multiple other adjustments done for agricultural or transportation usage.
The evidence for past and present agricultural use of wetlands in Mesoamerica suggests an evolutionary sequence of landscape and waterway alteration. Pre-Columbian, indigenous agriculturalists developed capabilities with which to raise crops under a wide range of ecological conditions, giving rise to a multiplicity of altered, cultivated landscapes. The effects of waterway transformation were particularly evident in Mesoamerica, where agricultural practices ranged from swiddening to multicropped hydraulically transformed wetlands.
Historical ecologists view the Amazonian landscape as cultural and embodying social labor. The Amazon River has been altered by the local population for crop growth and water transportation. Previous research failed to account for human interaction with the Amazonian landscape. Recent research, however, has demonstrated that the landscape has been manipulated by its indigenous population over time. The continual, natural shifting of rivers, however, often masked the human disturbances in the course of rivers. As a result, the indigenous populations in the Amazon are often overlooked for their ability to alter the land and the river.
However, waterway transformation has been successfully identified in the Amazonian landscape. Clark Erickson observes that prehispanic savanna peoples of the Bolivian Amazon built an anthropogenic landscape through the construction of raised fields, large settlement mounds, and earthen causeways. Erickson, on the basis of location, form, patterning, associations and ethnographic analogy, identified a particular form of earthwork, the zigzag structure, as fish weirs in the savanna of Baures, Bolivia. The artificial zigzag structures were raised from the adjacent savanna and served as a means to harvest the fish who used them to migrate and spawn.
Further evidence of waterway transformation is found in Igarapé Guariba in Brazil. It is an area in Amazonia where people have intervened in nature to change rivers and streams with dramatic results. Researcher Hugh Raffles notes that British naturalists Henry Walter Bates and Alfred Russel Wallace noted waterway transformation as they sailed through a canal close to the town of Igarapé-Miri in 1848. Archival materials identifies that it had been dug out by slaves. In his studies he notes an abundance of documentary and anecdotal evidence which supports landscape transformation by the manipulation of waterways. Transformation continues in more recent times as noted when in 1961, a group of villagers from Igarapé Guariba cut a canal about two miles (3 km) long across fields thick with tall papyrus grass and into dense tropical rain forest. The narrow canal and the stream that flowed into it have since formed a full-fledged river more than six hundred yards wide at its mouth, and the landscape in this part of the northern Brazilian state of Amapá was dramatically transformed..
In general, with an increase in global population growth, comes an increase in the anthropogenic transformation of waterways. The Sumerians had created extensive irrigations by 4000 BC. As the population increased in the 3,000 years of agriculture, the ditches and canals increased in number. By the early 1900s, ditching, dredging, and diking had become common practice. This led to an increase in erosion which impacted the landscapes. Human activities have affected the natural role of rivers and its communal value. These changes in waterways have impacted the floodplains, natural tidal patterns, and the surrounding land.
The importance of understanding such transformation is it provides a more accurate understanding to long-standing popular and academic insights of Amazonia, as well as other ecological settings, as places where indigenous populations have dealt with the forces of nature. Ecological landscapes have been portrayed as an environment, not a society. Recent studies supported by historical ecologists, however, understand that ecological landscape like the Amazon are biocultural, rather than simply natural and provide for a greater understanding of anthropogenic transformation of both waterways and landscapes.
Soil management
Soil management, or direct human interaction with the soil, is another mechanism of anthropogenic change studied by historical ecologists. Soil management can take place through rearranging soils, altering drainage patterns, and building large earthen formations. Consistent with the basic premises of historical ecology, it is recognized that anthropogenic soil management practices can have both positive and negative effects on local biodiversity. Some agricultural practices have led to organically and chemically impoverished soils. In the North American Midwest, industrial agriculture has led to a loss in topsoil. Salinization of the Euphrates River has occurred due to ancient Mesopotamian irrigation, and detrimental amounts of zinc have been deposited in the New Caliber River of Nigeria. Elsewhere, soil management practices may not have any effect on soil fertility. The iconic mounds of the Hopewell Indians built in the Ohio River valley likely served a religious or ceremonial purpose, and show little evidence of changing soil fertility in the landscape.
Terra preta
The case of soil management in the Neotropics (including Amazonia) is a classic example of beneficial results of human-mediated disturbance. In this area, prehistoric peoples altered the texture and chemical composition of natural soils. The altered black and brown earths, known as Amazon Dark Earths, or Terra preta, are actually much more fertile than unaltered surrounding soils.. Furthermore, the increased soil fertility improves the results of agriculture. Terra preta is characterized by the presence of charcoal in high concentrations, along with pottery shards and organic residues from plants, animal bones, and feces. It is also shows increased levels of nutrients such as nitrogen, phosphorus, calcium, zinc, and manganese; along with high levels of microorganic activity. It is now accepted that these soils are a product of a labor intensive technique termed slash-and-char. In contrast to the commonly known slash-and-burn technique, this uses a lower temperature burn that produces more charcoal than ashes. Research shows these soils were created by human activity between 9000 and 2500 years ago. Contemporary local farmers actively seek out and sell this dark earth, which covers around 10% of Amazonia. Harvesting Terra preta does not deplete it however, for it has the ability to regenerate at the rate of one centimeter per year by sequestering more carbon.
Scorched land resulting from slash-and-burn agriculture
Interest in and the study of Amazon dark earths was advanced with the work of Wim Sombroek. Sombroek's interest in soil fertility came from his childhood. He was born in the Netherlands and lived through the Dutch famine of 1944. His family subsided on a small plot of land that had been maintained and improved for generations. Sombroek's father, in turn, improved the land by sowing it with the ash and cinders from their home. Sombroek came across Terra preta in the 1950s and it reminded him of the soil from his childhood, inspiring him to study it further. Soil biologist from the University of Kansas William W. Woods is also a major figure in Terra preta research. Woods has made several key discoveries and his comprehensive bibliography on the subject doubles in size every decade.
Globally, forests are well-known for having greater biodiversity than nearby savannas or grasslands. Thus, the creation of ‘forest islands’ in multiple locations can be considered a positive result of human activity. This is evident in the otherwise uniform savannas of Guinea and central Brazil that are punctured by scattered clumps of trees. These clumps are the result of generations of intense resource management. Earth works and mounds formed by humans, such as the Ibibate mound complex in the Llanos de Mojos in Bolivia, are examples of built environments that have undergone landscape transformation and provide habitats for a greater number of species than the surrounding wetland areas. The forest islands in the Bolivian Amazon not only increase the local plant species diversity, but also enhance subsistence possibilities for the local people.
Gillnet, Anchored Sink Gillnet,Drift Floating Gillnet,Drift Sink Gillnet, Anchored Floating Gillnet
Gillnetting is a common fishing method used by commercial fishermen of all the oceans and in some freshwater and estuary areas. Because gillnets can be so effective their use is closely monitored and regulated by fisheries management and enforcement agencies. Mesh size, twine strength, as well as net length and depth are all closely regulated to reduce bycatch of non-target species. Most salmon fisheries in particular have an extremely low incidence of catching non-target species.
External media A bottom set gillnet
Gillnet, the name of the net employed, illustrates the method used to snare target fish. They try to swim through deliberately sized mesh openings but are unable to squeeze through swimming forward. Once in this position, they are prevented from backing out due to the tendency for their gills to become caught. This effectively traps them.
History
Gillnetting began with First Nations fishermen using canoes and cedar fiber nets. They would attach stones to the bottom of the nets as weights, and pieces of wood to the top, to use as floats. This allowed the net to suspend straight up and down in the water. Each net would be suspended either from shore or between two boats. Native fishers in the Pacific Northwest, Canada, and Alaska still commonly use gillnets in their fisheries for salmon and steelhead.
By around 1864, gillnetting had expanded to European, Japanese, and other international fisheries. The boats used by these fisherman were typically around 25 feet (8 m) long and powered by oars. Many of these boats also had small sails and were called "row-sail" boats. At the beginning of the 1900s, steam powered ships would haul these smaller boats to their fishing grounds and retrieve them at the end of each day. However, at this time gas powered boats were beginning to make their appearance, and by the 1930s, the row-sail boat had virtually disappeared.
In 1931, the first powered drum was created by Laurie Jarelainen. The drum is a circular device that is set to the side of the boat and draws in the nets. The powered drum allowed the nets to be drawn in much faster and along with the faster gas powered boats, fisherman were able to fish in areas they had previously been unable to go into, thereby revolutionizing the fishing industry.
During World War II, navigation and communication devices, as well as many other forms of maritime equipment (ex. depth-sounding and radar) were improved and made more compact. These devices became much more accessible to the average fisherman, thus making their range and mobility increasingly larger. It also served to make the industry much more competitive, as the fisherman were forced to invest more into their boats and equipment in order to stay up to date with the current technology.
The introduction of fine synthetic fibres such as nylon in the construction of fishing gear during the 1960s marked an expansion in the commercial use of gillnets. The new materials were cheaper and easier to handle, lasted longer and required less maintenance than natural fibres. In addition, fibres such as nylon monofilaments become almost invisible in water, so nets made with synthetic twines generally caught greater numbers of fish than natural fibre nets used in comparable situations.
Nylon is highly resistant to abrasion, hence the netting has the potential to last for many years if it is not recovered. This ghost fishing is of environmental concern, however it is difficult to generalize about the longevity of ghost-fishing gillnets due to the varying environments in which they are used. Some researchers have found gill-nets to be still catching fish and crustaceans for over a year after loss, while others have found lost nets to be destroyed by wave action within one month or overgrown with seaweeds, increasing their visibility and reducing their catching potential to such an extent that they became a microhabitat used by small fishes.
This type of net was heavily used by many Japanese, South Korean, and Taiwanese fishing fleets on the high seas in the 1980s to target tunas. Although highly selective with respect to size class of animals captured, gill nets are associated with high numbers of incidental captures of cetaceans, (whales and dolphins). In the Sri Lankan gill net fishery, one dolphin is caught for every 1.7-4.0 tonnes of tuna landed. This compares poorly with the rate of one dolphin per 70 tonnes of tuna landed in the eastern Pacific purse seine tuna fishery. Gillnets were banned by the United Nations in 1993 in international waters, although their use is still permitted within 200 nautical miles (400 km) of a coast.
Selectivity
Gill nets are basically a series of panels of meshes with a weighted "foot rope" along the bottom, and a "headline", to which floats are attached. They can therefore be set to fish at any height in the water column. The meshes of a gill net are uniform in size and shape, hence highly selective for a particular size of fish. Fish which are smaller than the mesh of the net are able to pass through unhindered, while those which are too large to push their heads through the meshes as far as their gills are not retained. This gives a selectivity ogive which is skewed towards medium sized fishes, unlike active gears such as trawling, in which the proportion of fish entering the net which are retained increases with length.
Commercial gillnet fisheries are still an important method of harvesting salmon in Alaska, British Columbia, Washington, and Oregon. In the Columbia River, non-Indian commercial salmon fisheries for spring chinook have developed methods of selectively harvesting adipose fin clipped hatchery salmon using small mesh gillnets. Non-fin clipped (primarily natural origin salmon are required to be released. Fishery management agencies estimate a relatively low release mortality rate on salmon and steelhead released from these small mesh gillnets.
Gillnets are sometimes a controversial gear type especially among sport fishers who sometimes argue they are inappropriate especially for salmon fisheries. Most salmon fisheries are strictly managed to minimize total impacts to specific populations and salmon fishery managers continue to allow their use.
Types of Gillnets
* Anchored Sink Gillnet -
* Drift Floating Gillnet -
* Drift Sink Gillnet -
* Anchored Floating Gillnet -
External media A bottom set gillnet
Gillnet, the name of the net employed, illustrates the method used to snare target fish. They try to swim through deliberately sized mesh openings but are unable to squeeze through swimming forward. Once in this position, they are prevented from backing out due to the tendency for their gills to become caught. This effectively traps them.
History
Gillnetting began with First Nations fishermen using canoes and cedar fiber nets. They would attach stones to the bottom of the nets as weights, and pieces of wood to the top, to use as floats. This allowed the net to suspend straight up and down in the water. Each net would be suspended either from shore or between two boats. Native fishers in the Pacific Northwest, Canada, and Alaska still commonly use gillnets in their fisheries for salmon and steelhead.
By around 1864, gillnetting had expanded to European, Japanese, and other international fisheries. The boats used by these fisherman were typically around 25 feet (8 m) long and powered by oars. Many of these boats also had small sails and were called "row-sail" boats. At the beginning of the 1900s, steam powered ships would haul these smaller boats to their fishing grounds and retrieve them at the end of each day. However, at this time gas powered boats were beginning to make their appearance, and by the 1930s, the row-sail boat had virtually disappeared.
In 1931, the first powered drum was created by Laurie Jarelainen. The drum is a circular device that is set to the side of the boat and draws in the nets. The powered drum allowed the nets to be drawn in much faster and along with the faster gas powered boats, fisherman were able to fish in areas they had previously been unable to go into, thereby revolutionizing the fishing industry.
During World War II, navigation and communication devices, as well as many other forms of maritime equipment (ex. depth-sounding and radar) were improved and made more compact. These devices became much more accessible to the average fisherman, thus making their range and mobility increasingly larger. It also served to make the industry much more competitive, as the fisherman were forced to invest more into their boats and equipment in order to stay up to date with the current technology.
The introduction of fine synthetic fibres such as nylon in the construction of fishing gear during the 1960s marked an expansion in the commercial use of gillnets. The new materials were cheaper and easier to handle, lasted longer and required less maintenance than natural fibres. In addition, fibres such as nylon monofilaments become almost invisible in water, so nets made with synthetic twines generally caught greater numbers of fish than natural fibre nets used in comparable situations.
Nylon is highly resistant to abrasion, hence the netting has the potential to last for many years if it is not recovered. This ghost fishing is of environmental concern, however it is difficult to generalize about the longevity of ghost-fishing gillnets due to the varying environments in which they are used. Some researchers have found gill-nets to be still catching fish and crustaceans for over a year after loss, while others have found lost nets to be destroyed by wave action within one month or overgrown with seaweeds, increasing their visibility and reducing their catching potential to such an extent that they became a microhabitat used by small fishes.
This type of net was heavily used by many Japanese, South Korean, and Taiwanese fishing fleets on the high seas in the 1980s to target tunas. Although highly selective with respect to size class of animals captured, gill nets are associated with high numbers of incidental captures of cetaceans, (whales and dolphins). In the Sri Lankan gill net fishery, one dolphin is caught for every 1.7-4.0 tonnes of tuna landed. This compares poorly with the rate of one dolphin per 70 tonnes of tuna landed in the eastern Pacific purse seine tuna fishery. Gillnets were banned by the United Nations in 1993 in international waters, although their use is still permitted within 200 nautical miles (400 km) of a coast.
Selectivity
Gill nets are basically a series of panels of meshes with a weighted "foot rope" along the bottom, and a "headline", to which floats are attached. They can therefore be set to fish at any height in the water column. The meshes of a gill net are uniform in size and shape, hence highly selective for a particular size of fish. Fish which are smaller than the mesh of the net are able to pass through unhindered, while those which are too large to push their heads through the meshes as far as their gills are not retained. This gives a selectivity ogive which is skewed towards medium sized fishes, unlike active gears such as trawling, in which the proportion of fish entering the net which are retained increases with length.
Commercial gillnet fisheries are still an important method of harvesting salmon in Alaska, British Columbia, Washington, and Oregon. In the Columbia River, non-Indian commercial salmon fisheries for spring chinook have developed methods of selectively harvesting adipose fin clipped hatchery salmon using small mesh gillnets. Non-fin clipped (primarily natural origin salmon are required to be released. Fishery management agencies estimate a relatively low release mortality rate on salmon and steelhead released from these small mesh gillnets.
Gillnets are sometimes a controversial gear type especially among sport fishers who sometimes argue they are inappropriate especially for salmon fisheries. Most salmon fisheries are strictly managed to minimize total impacts to specific populations and salmon fishery managers continue to allow their use.
Types of Gillnets
* Anchored Sink Gillnet -
* Drift Floating Gillnet -
* Drift Sink Gillnet -
* Anchored Floating Gillnet -
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