About This Project

Grevy’s zebra are one of Africa’s most threatened large mammals. My project focuses on the largest extant Grevy's populations in Kenya, where animals face increasing environmental stress. The project goals are to understand how genetic diversity and environmental stress combine to affect disease risk. Results will inform efforts of Kenyan wildlife officials to mitigate the risk of disease, which they have identified as a major threat to the species' survival.

Ask the Scientists

What is the context of this research?

Since the 1980s, Grevy’s zebra populations have declined by as much as 68%. Such dramatic population declines often result in significant loss of genetic diversity, which in turn is frequently linked to increased risk of disease. At the same time, Grevy’s inhabit an environment characterized by rapid habitat loss and degradation. We know that environmental stress disproportionately affects species with low genetic diversity. In fact, studies have shown that low genetic diversity and environmental stress can act synergistically to reduce time to extinction by up to 28%. This project will test whether the loss of genetic diversity in Grevy’s zebra, in combination with high levels of environmental stress, may put them at increased risk for disease.

What is the significance of this project?

The Grevy’s zebra is in serious danger of extinction in the wild. The Kenya Wildlife Service has listed disease as a primary threat, yet we have very little information to inform disease mitigation efforts. Our data show that Grevy’s living in environments with more human disturbance have greater parasite burdens (specifically, two types of gastrointestinal parasites – strongyle nematodes and lungworms) than those in officially protected areas, but these areas cover less than 0.5% of the species’ range in Kenya. Additionally, we do not have information on how past population declines have impacted levels of genetic diversity. We have been working in collaboration with Kenyan wildlife officials since 2012 and will use our results to understand how disease risks can be mitigated.

What are the goals of the project?

The goal for this project is to establish information on genetic diversity for 500 unique Grevy’s zebra using fecal samples collected non-invasively across the Kenyan Grevy’s zebra range. Samples were taken from areas with high levels of environmental stress and from protected areas in 2014 and 2015. We have established that we can obtain high quality DNA from these samples. We will use microsatellite molecular markers amplified via polymerase chain reaction (PCR) to obtain genetic information for each individual. This will provide us with data to understand: 1) if genetic diversity impacts disease risk in Grevy’s zebra and 2) how environmental context impacts the relationship between genetic diversity and disease risk.