Results from the Global Mammal Assessment
The Global Mammal Assessment , coordinated by the IUCN, produced conservation assessments for all 5,487 known marine and land mammal species (Schipper et al (2008) The status of the world’s land and marine mammals: diversity, threat, and knowledge. Science 322, 225-230).
© Ben Collen
© Nadia Richman
© Monika Böhm
© ZSL
© Ally Batchelor
© Monika Böhm
The conservation status of mammals was assessed in a 5-year, IUCN-led collaboration involving more than 1,700 experts throughout the world, resulting in an up-to-date assessment of the conservation status of mammals and the type of threats which put mammals at risk of extinction. The pygmy hippo Choeropsis liberiensis, for example, has been severely affected by habitat loss (mainly due to deforestation) and has been listed as Endangered in the IUCN Red List.
One quarter (1,139) of all species were threatened with extinction. Around 15% of all mammal species were data deficient and could not be assessed; actual threat levels are therefore unknown and might range from 21% to 36%.
Threat levels for marine mammals were even higher when assessed separately from land mammals, with 36% of marine mammals threatened with extinction compared to 25% of land mammals.
Species richness of terrestrial mammals is highest throughout the tropics, from South America through Africa to Southeast Asia (picture). The highest concentration of threatened land mammals was found in South and Southeast Asia - for example, 79% of primates in these regions are considered to be in serious danger of extinction.
For marine mammals, the threat was found to be greatest in the North Atlantic, North Pacific and in Southeast Asia, which are known areas of endemism and impacted by a range of anthropogenic factors. Numbers of the humpback whale Megaptera novaeangliae have been increasing since the end of whaling, so that the species is currently listed as Least Concern. However, the impact of any future hunting on humpback populations remains unclear.
Habitat loss and degradation (40%) and harvesting (17%) are by far the major threats affecting mammal populations.
Accidental mortality (78%) and pollution (60%) are the dominant threats for marine mammals. 25% of fatalities in adult Florida manatees are caused by watercraft collisions. Harvesting (52% of species) of marine mammals remains a major problem despite progress through international agreements.
These results paint quite a bleak future for mammals worldwide, with one in four species at risk of going extinct and one in two populations experiencing declines.
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