Mapping Potential Distribution for the Endangered Wild Asses of Asia, Equus hemionus

Abstract

Abstract:

Predicting Potential Distribution for the Endangered Wild Asses of Asia, Equus hemionus, in a Changing World


Aim: The Asian wild ass (Equus hemionus) is a globally Endangered large mammal inhabiting arid plains of Asia. Despite several on-going conservation measures, its potential suitable habitat is unknown. This study provides a range-wide suitability map for the ungulate across time in response to climate change and human impact.

Location: South and Central Asia (4°-53° N latitude and 30°-120° E longitude).

Method: I used MAXENT to build distribution model considering both environmental and anthropogenic factors. Nine different combinations of climate change emission scenarios and global circulation models are implied here to predict future potential distribution. These models are used for evaluating the efficiency of existing network of protected areas and the appropriateness of conservation measures for the Asian wild ass.

Results: The suitability map portraits a relatively large area (ca. 3,565,000 km²) of potential distribution of which only 11.18% is currently occupied by the species. Temperature seasonality, precipitation seasonality, Human influence and elevation contributed the most to the model. Existing protected areas maintain 12.5% of the Asian wild ass potential range. The most conservative model predicts ca. 244,662 km² of potential distribution for 2050s from currently suitable areas (only 7%); there are some areas within the range becoming suitable, however.

Main conclusions: Relocation of species –as a conservation strategy- necessitates the identification of its potential geographic range. In the future some areas will lose their suitability while others becoming suitable in response to changes in the environment. Therefore, conservation measures should focus on areas which are suitable; not only in current time but also under future predicted changes. By addressing sources of over-predictions, this study can be served as a baseline for conservationists and decision makers prior to releasing the wild ass individuals. Also, protected areas should be redrawn for better protection of wild ass habitat. Since the predicted distribution seems fragmented, the long term survival of the populations relies on facilitating their dispersal by protecting the corridors.

Abstract

Popular science summary:

Potential Distribution for the Endangered Asian Wild Ass

Over the past century, large mammals have been globally under increasing pressure of humanized landscapes. Since extirpations of large herbivores are likely to have complicated consequences for the entire ecosystem, their conservation is a priority. With almost 81% threatened species, Perissodactyla (odd-toad ungulates) is the most endangered terrestrial mammalian order. The Asian wild ass (Equus hemionus), in this order, is a globally Endangered large mammal inhabiting arid plains of Asia. Despite several on-going conservation measures, its potential suitable habitat is unknown. The species distribution map is needed to prioritize areas for protection and investigate potential threat to those areas. This also helps to more effectively assess the impact of climate change on species distribution. My study provides a range-wide distribution map for the Asian wild ass across time in response to climate change and human impact.

I used maximum entropy modeling approach to build the species distribution map. For this aim, environmental conditions are linked to species known presence locations. These maps were used for evaluating the efficiency of existing protected areas regarding conservation of the Asian wild ass.

The distribution map portraited a large area (ca. 3,565,000 km²) of potentially appropriate for the wild ass. Only 11.18% is currently occupied by the species, however. Existing protected areas maintain 12.5% of the Asian wild ass potential range. The most conservative model predicted ca. 244,662 km² of potential distribution for 2050s from currently suitable areas (only 7%).

Implications for conservation
While habitat is changing, the conservation management should be adaptive regarding requirements of populations. Such efforts should focus on areas which are appropriate; not only in current time but also under future predicted changes. By addressing sources of uncertainties, this study can be served as a baseline for conservationists and decision makers prior to relocating the wild ass individuals. Also, protected areas should be redrawn for better protection of wild ass habitat. There is still suitable habitat for Asian wild ass, even with the most extreme forecast in future time, but the species is susceptible to hunting and land use change. Therefore its long term survival necessitates sufficient protection.

Advisor: Ola Olsson, Torben Wittwer
Master´s Degree Project 45 credits in Animal Ecology, 2013
Department of Biology, Lund University

• author: Tourani, Mahdieh
• supervisor: Ola Olsson; Torben Wittwer
• organization: Degree Projects in Biology
• course: BION32 20121
• year: 2013
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• language: English
• id: 4053876
• date added to LUP: 2013-09-19 09:50:43
• date last changed: 2013-09-19 09:50:43