Endangered Species - biology.
Publié le 11/05/2013
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Red List database assesses the status of, and threats to, animal species worldwide.
To add to this and other biodiversity databases, nongovernmental organizationssuch as Conservation International and World Wildlife Fund conduct periodic rapid assessments (focused, intensive evaluations) of biodiversity in varioushotspots— regions like Madagascar that are both rich in endemic species and environmentally threatened.
This information is used in the administration of international agreements such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora(CITES), signed by 125 nations in 1973 and put into effect in 1975.
The purpose of CITES is to restrict exploitation of endangered plants and wildlife by regulating andrestricting their trade.
Despite legal protection, however, the future of many species, such as the African black rhinoceros, is in doubt because of poor law enforcementand the activities of poachers and dealers who supply the lucrative trade in endangered animals and animal parts.
Similarly, the International Whaling Commission ischarged with protecting global whale populations, but lacks the authority to enforce its rulings.
Several private and governmental efforts in the United States have been mobilized to save endangered species.
One immediate approach is to protect a species bylegislation.
The Lacey Act of 1900 was enacted to protect wildlife from commercial trade and overhunting.
The Marine Mammal Protection Act of 1972 banned the killingand importing of whales and nearly all marine mammals.
In addition to promoting species and habitat protection in the United States, the Endangered Species Act (ESA)discouraged the exploitation of endangered species in other countries by banning the importation and trade of any products, such as elephant-tusk ivory, obtained fromsuch species.
Although the ESA is one of the most progressive national wildlife protection laws ever enacted, it is constantly threatened by development industriesunhappy with the government restrictions.
Pressure from developers and from logging and mining interests also led to government efforts to roll back or circumventESA restrictions during the early 2000s.
The United States also has various agreements with other nations like Canada and Mexico for the legal protection of migratory birds.
These include the Migratory BirdTreaty Act of 1918, the Migratory Bird Conservation Act of 1929, and the North American Waterfowl Management Plan of 1986.
Canadian laws designed to protectendangered species include the Migratory Birds Convention Act of 1917, the Canadian Endangered Species Protection Act of 1996, and the Wild Animal and PlantProtection and Regulation of International and Interprovincial Trade Act of 1996.
Efforts to save endangered species also include captive breeding of severely endangered species later released in the wild to restore or add to a breeding population (apopulation of individuals capable of reproducing).
Due to breeding in captivity (such as in zoos and specialized animal clinics), the number of known California condors,whooping cranes, and peregrine falcons has increased over the last 20 years.
Genetic cloning techniques may one day help forestall extinction for endangered speciesthat reproduce poorly on their own.
Captive breeding and cloning programs are considered a last resort, however, because such breeding may reduce the genetic diversity of the species and its ability tosurvive in the wild.
For example, Pacific salmon raised in hatcheries may be less capable of surviving in adverse conditions than wild salmon, and if they interbreed withthe wild fish, they may dilute the natural survival ability of wild salmon.
Extremely difficult to successfully reintroduce to the wild, captive-bred animals are also morelikely to carry disease, which they may transmit to the wild population.
These programs are also extremely costly, sometimes reaching $500,000 per year per species.Moreover, captive breeding and cloning programs are a short-term repair that may divert attention from finding solutions to the original causes of the species decline,such as habitat destruction or toxic pollution.
For some species, however, such as the California condor and the peregrine falcon, captive breeding has made thedifference between survival and extinction.
IV CONSERVATION BIOLOGY
The scientific field of conservation biology evolved to study the complex problems surrounding habitat destruction and species protection.
The objectives of conservationbiologists are to understand how humans affect biodiversity and to provide potential solutions that benefit both humans and nonhuman species.
One of the approaches that conservation biologists study and implement is the development of habitat reserves and wildlife corridors.
All species require a minimumamount of habitat for survival.
Wildife habitat reserves are established to meet these requirements for as many species as possible.
Some national parks, wildernessareas, and other protected habitats are suitable for the survival of a wide range of species.
Unfortunately, the minimum area required by large carnivores such asgrizzly bears or cougars may be larger than the area protected in a reserve.
In order to effectively enlarge the area available to the species, protected wildlife corridorsthat interlace or connect separate reserves may be developed.
These areas are narrower than the actual reserve but ideally allow for unimpeded travel betweenreserves.
Conservation biologists recommend that both reserves and corridors be surrounded by a wide belt, or buffer zone, of similar landscape to maintain theeffectiveness of the reserve.
Conservation biologists also study and promote habitat restoration and extensive public education, and work with ecologists andtaxonomists (scientists who study the scientific classification of organisms) to identify and describe the millions of imperiled species not yet known to science.
The current global extinction crisis is one of the greatest challenges posed by the rapid growth and expansion of human populations.
The protection of endangeredspecies and habitats should be a top priority for international organizations, governmental agencies, industry, and individuals if there is hope for preserving the earth’svaluable biodiversity for future generations.
A United Nations Environment Program (UNEP) report on the global environment published in 2002 concluded that over 11,000 species (including almost a quarter of allmammals) face extinction within 30 years.
In total more than 5,000 plants, 1,000 mammals, and 5,000 other animals (including one in eight birds) are endangered,mostly due to habitat destruction and invasion by nonnative species.
The report states that factors that caused previous extinctions are operating with “ever-increasingintensity,” although it suggests that these problems could be eased if pacts such as the Convention on Biological Diversity and the Kyoto Protocol were implementedglobally.
The 1992 Convention on Biological Diversity seeks to maintain biodiversity, while the 1997 Kyoto Protocol seeks to curb emissions of greenhouse gases ( see Greenhouse Effect) that contribute to global warming.
Reviewed By:Reed F.
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Liens utiles
- SPECIES PLANTARUM (Résumé et analyse)
- Ant. Class Insecta Order Hymenoptera Family Formicidae Conservation Concerns 45 species are at risk
- Bear. Class: Mammalia Order: Carnivora Family: Ursidae Genus/Species: Ailuropoda melanoleuca (giant panda) Tremarctos oratus (spectacled
- Lion. Class Mammalia Order Carnivora Family Felidae Genus Panthera Species leo Names male: lion female: lioness young: cub group
- Mink. Class Mammalia Order Carnivora Family Mustelidae Genus Mustela Species lutreola (European) vison (American) Conservation Concerns The