275 Amphibians at risk

Definition

Mapped here is data from the IUCN Red List of Threatened Species. "The IUCN Red List Categories and Criteria are intended to be an easily and widely understood system for classifying species at high risk of global extinction."

The map shows amphibian species that are at risk of extinction. In the Red List they are assessed as Critically Endangered (CR), Endangered (EN) or Vulnerable (VR). The very precise criteria are largely based on population size or geographic range, and how fast these are falling within a timescale of 3 generations or 10 years, whichever is the longer. "The categorization process is only applied to wild populations inside their natural range, and to populations resulting from benign introductions (attempts to establish a species, for the purpose of conservation, outside its recorded distribution, but within an appropriate habitat and eco-geographical area)." "Extinction is a chance process. A listing in a higher extinction risk category implies a higher expectation of extinction."

Vertebrates (animals with backbones) are divided into mammals, birds, reptiles, amphibians and fishes. Amphibians are cold bloodied, hatch from eggs into tadpoles that can only breathe in water through gills, but most have lungs as adults and can then live in and out of water. 5,918 species have been described and all now assessed by Red List criteria. By 2006 1,811 species were categorised as Threatened Species (CR, EN or VR). However "It should be noted that for certain species endemic to Brazil, there was not time to reach agreement on the Red List Categories between the Global Amphibian Assessment (GAA) Coordinating Team, and the experts on the species in Brazil. The 2004 and 2006 figures for Amphibians displayed here are those that were agreed at the GAA Brazil workshop in April 2003. However, in the subsequent consistency check conducted by the GAA Coordinating Team, many of the assessments were found to be inconsistent with the approach adopted elsewhere in the world." In 2004, 24 species and in 2006 28 species of amphibian were classified as Threatened Species in Brazil.

Amphibians include Frogs and Toads (4,380 species) and Newts and Salamanders (470 species) and 170 Caecilian species (limbless, worm-like animals).

Double counting in our regional and total figures suggest that amphibians assessed as Threatened Species exist on average in 1.2 territories. With 100% of amphibian species assessed, 31% of all amphibian species known will qualify as Threatened Species.

Data sources

The source of this data is the International Union for Conservation of Nature and Natural Resources, 2006, Red List of threatened species 2004. Tables 5, 6a and 6b.

For more source and data information, see the technical notes for 267, Species Extinct.

Click here to view detailed data source references

The quotation used to accompany this map was sourced form Amphibia Web. The quotation comes from the answer to this question: ‘Worldwide Amphibian Declines: How big is the problem, what are the causes and what can be done?’. The date of this text is 15 th June 2006 . The quotation was sourced from the webpage below, in December 2006:

http://amphibiaweb.org/declines/declines.html

Extra information about the Greek roots and meaning of the word ‘amphibian’ which was used in the text that accompanies the map, was sourced from the Smithsonian National Zoological Park website. This was available at the webpage below in December 2006:

http://nationalzoo.si.edu/Animals/ReptilesAmphibians/

Other information that was used in the descriptive note that accompanies the map was sourced from Amphibia Web, from the site below, in December 2006:

http://amphibiaweb.org

Excel sheet

Below is an explanation of each of the columns in the excel file:

Column A = Unique numerical territory (see 001).

Column B = Region and territory names (see 001).

Column C = Region code (see 001).

Column D = The ISO 3 code, or ISO ALPHA-3 (see 001).

Column E = Number of amphibian species assessed as threatened species by 2004. From Source Data (Column H).

Column F = amphibian species assessed as threatened per 1000 local species assessed for that territory by 2004. This is calculated by dividing the number of amphibians at risk in 2004 (Column H) by the count of all species in that territory (Column G) multiplied by 1000 so that the rate per 1000 is given. (F = 1000 * H / G).

Column G = Number of local plant and animal species assessed by 2004. This is calculated by adding the count of animal species and plant species together. The data for this can be found on the source data sheet.

Column H = Number of amphibian species assessed as threatened species, 2004. This is taken from the source data sheet.