Post by Jeff on Feb 7, 2006 18:27:51 GMT -5
You see the term "endangered” on Web sites and in magazines, books, and newspapers, and you hear it on TV. In our glossary here, we define it as "in danger of becoming extinct.” But where does that information come from, and how is it determined?
When people talk about the status of animal species—the current state they are in, or how well they are doing in the world—they rely mostly on three sources: the International Union for the Conservation of Nature (IUCN), also called the World Conservation Union; the Convention on International Trade in Endangered Species (CITES); and the United States Fish and Wildlife Service.
All three of these organizations conduct field studies and population surveys and gather information on animal populations from local sources. By coordinating with many other groups, they determine how many individual animals of a certain species there are in the world. This is usually an approximation, not an exact number, because it would be hard to be absolutely sure that every single animal was counted.
Once the number of the population has been determined, then that species is given a term to describe its status, such as "endangered” or "threatened,” although the different agencies may use different terms.
The IUCN Red List uses these terms:
Extinct— No reasonable doubt that the last individual has died.
Extinct in the wild— Known only to survive in captivity or in an introduced population well outside the natural range.
Critically endangered— Facing an extremely high risk of extinction in the wild; based on a population reduction of 80 percent or more, a range reduced to 100 square kilometers (38.6 square miles) or less, or a 50 percent probability of extinction within 10 years (among other criteria).
Endangered— Facing a very high risk of extinction in the wild; based on a population reduction of 50 percent or more, a range reduced to 5,000 square kilometers (1,930 square miles) or less, or a 20 percent probability of extinction within 20 years (among other criteria).
Vulnerable— Facing a high risk of extinction in the wild; based on a population reduction of 30 percent or more, a range reduced to 20,000 square kilometers (7,722 square miles) or less, or a 10 percent probability of extinction within 100 years (among other criteria).
Threatened— Any of the three categories above.
Near threatened— Does not qualify for one of the other categories now, but is close to qualifying or is likely to qualify for one of them in the near future.
Least concern— Does not qualify for any of the other categories, and is currently widespread or abundant.
CITES uses these terms:
CITES Appendix I— Species threatened with extinction that are or may be affected by trade.
CITES Appendix II— Species that are not necessarily now threatened with extinction, but may become so unless trade is strictly controlled.
CITES Appendix III— Species that a country feels needs protection, regulating, and controlling trade to prevent exploitation.
The U.S. Fish and Wildlife Service’s List of Endangered and Threatened Wildlife uses these terms:
Endangered— A species in danger of extinction throughout all or a significant portion of its range, as a result of any of the following: habitat change, reduction or destruction, overhunting or excessive capture, disease or predation, lack of regulation or management, or other natural or man-made factors.
Threatened— A species that is likely to become endangered in the foreseeable future.
When people talk about the status of animal species—the current state they are in, or how well they are doing in the world—they rely mostly on three sources: the International Union for the Conservation of Nature (IUCN), also called the World Conservation Union; the Convention on International Trade in Endangered Species (CITES); and the United States Fish and Wildlife Service.
All three of these organizations conduct field studies and population surveys and gather information on animal populations from local sources. By coordinating with many other groups, they determine how many individual animals of a certain species there are in the world. This is usually an approximation, not an exact number, because it would be hard to be absolutely sure that every single animal was counted.
Once the number of the population has been determined, then that species is given a term to describe its status, such as "endangered” or "threatened,” although the different agencies may use different terms.
The IUCN Red List uses these terms:
Extinct— No reasonable doubt that the last individual has died.
Extinct in the wild— Known only to survive in captivity or in an introduced population well outside the natural range.
Critically endangered— Facing an extremely high risk of extinction in the wild; based on a population reduction of 80 percent or more, a range reduced to 100 square kilometers (38.6 square miles) or less, or a 50 percent probability of extinction within 10 years (among other criteria).
Endangered— Facing a very high risk of extinction in the wild; based on a population reduction of 50 percent or more, a range reduced to 5,000 square kilometers (1,930 square miles) or less, or a 20 percent probability of extinction within 20 years (among other criteria).
Vulnerable— Facing a high risk of extinction in the wild; based on a population reduction of 30 percent or more, a range reduced to 20,000 square kilometers (7,722 square miles) or less, or a 10 percent probability of extinction within 100 years (among other criteria).
Threatened— Any of the three categories above.
Near threatened— Does not qualify for one of the other categories now, but is close to qualifying or is likely to qualify for one of them in the near future.
Least concern— Does not qualify for any of the other categories, and is currently widespread or abundant.
CITES uses these terms:
CITES Appendix I— Species threatened with extinction that are or may be affected by trade.
CITES Appendix II— Species that are not necessarily now threatened with extinction, but may become so unless trade is strictly controlled.
CITES Appendix III— Species that a country feels needs protection, regulating, and controlling trade to prevent exploitation.
The U.S. Fish and Wildlife Service’s List of Endangered and Threatened Wildlife uses these terms:
Endangered— A species in danger of extinction throughout all or a significant portion of its range, as a result of any of the following: habitat change, reduction or destruction, overhunting or excessive capture, disease or predation, lack of regulation or management, or other natural or man-made factors.
Threatened— A species that is likely to become endangered in the foreseeable future.