Extreme weather events threaten land mammal populations

December 14th, 2012 by Zoological Society of London

Mammals could be at a greater risk of extinction due to predicted increases in extreme weather conditions, states a paper published by the Zoological Society of London (ZSL).

Highlighted in red is the distribution of Primate species having portions of their ranges at least 25% exposed to droughts from 1980 to 2011 (click map to expand - map courtesy of the ZSL)

Scientists have mapped out land mammal populations, and overlapped this with information of where droughts and cyclones are most likely to occur.

Highlighted in red is the distribution of Primate species having at least 25% exposure to a high cyclone occurrence (period 1992 to 2005). Areas of greatest cyclone frequency marked in dark blue (click map to expand - map courtesy of the Zoological Society of London)

This allowed them to identify species at high risk of exposure to extreme weather.

The paper, ‘Assessing exposure to extreme climatic events for terrestrial mammals‘, published in the journal Conservation Letters, describes the results of assessing almost six thousand species of land mammals in this way.

Eric Ameca y Juárez of the ZSL and lead author of the paper said “approximately a third of the species assessed have at least a quarter of their range exposed to cyclones, droughts or a combination of both.”

“If these species are found to be highly susceptible to these conditions, it will lead to a substantial increase in the number of mammals classified as threatened by the IUCN under the category ‘climate change and severe weather’,” he said.

In particular, primates – already among the most endangered mammals in the world – are highlighted as being especially at risk.

Over 90% of black howler monkey (Alouatta pigra) and Yucatan spider monkey (Ateles geoffroyi yucatanensis) known

Yucatan black howler monkey, Alouatta pigra (click image to expand - ©Juan Carlos Serio-Silva - courtesy of ZSL)

habitats have been damaged by cyclones in the past, and studies have documented ways they are able to adapt to the detrimental effects of these natural disasters.

The Yucatan spider monkey, Ateles geoffroyi yucatanensis (click image to expand - ©Juan Carlos Serio-Silva - image courtesy of ZSL)

In contrast, very little is known about the impacts of these climatic extremes on other species.

In Madagascar, entire known distributions of the western woolly lemur (Avahi occidentalis) and the golden bamboo lemur (Hapalemur aureus) have been exposed to both cyclones and drought.

These endangered species are also amongst the world’s most evolutionary distinct, yet remain highly understudied.

Dr Nathalie Pettorelli, ZSL’s research fellow, said “this is the first study of its kind to look at which species are at risk from extreme climatic events.”

“There are a number of factors which influence how an animal copes with exposure to natural disasters. It is essential we identify species at greatest risk so that we can better inform conservation management in the face of global environmental change.” she said.


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