October 2015, Volume 13-5


The highlands of Ethiopia are inhabited by the culturally and economically significant mountain nyala Tragelaphus buxtoni, an endemic spiral horned antelope. The natural range of this species has become highly fragmented with increasing anthropogenic pressures; driving land conversion in areas previously considered critical mountain nyala habitat. Therefore, baseline demographic data on this species throughout its existing range are needed. Previous studies on mountain nyala demographics have primarily focused on a confined portion of its known range where trophy hunting is not practiced. Our objectives were to estimate group size, proportion of females, age class proportions, and calf and juvenile productivity for a sub-population of mountain nyala where trophy hunting is permitted and compare our results to recent and historical observations. We collected four years of demographic data using direct point counts in a controlled hunting area and summarized the data using the R statistical software.

Our results show that estimated proportion of females (0.63; 0.56 – 0.69) was similar to recent studies of non-hunted populations, but group size (3.74; 3.34 – 4.13), juvenile productivity (0.47; 0.35 – 0.62) and age class proportions (calves: 0.17 juveniles: 0.19 adults: 0.64) were considerably different. Our results are more similar to historical accounts than those in a national park. We demonstrate that the mountain nyala’s population structure and health varies across its range and may relate to the different management strategies and policies. We recommend using similar methods for remaining under surveyed sub-populations of mountain nyala to inform conservation actions at the landscape scale.

Evangelista and his co-authors conclude their paper saying

“The status of the Abasheba-Demaro population is likely due to the intensive hunting policies and regulations in place for mountain nyala and the management strategies of the concession owners. Although this area is outside the national park, it is still patrolled and managed year round under the direction of the concession owner. This appears to help protect the area from sprawling land conversion and increasing presence of humans and livestock; both implicated for declines in mountain nyala densities and range. There is an economic incentive for the concession owners to protect and promote the health of the mountain nyala population in this area. If the population falls and can be detected through bi-annual surveys conducted by the EWCA, the concession will be allocated a lower harvest quota reducing the number of available hunts and ultimately the concession owner’s revenue. Without the full quota, the concession owner may not be able to sustain the business and may have to abandon their year round presence. Without their direct and continual oversight, the area would likely be quickly settled, grazed and over-harvested for resources by nearby communities with potential cascading negative impacts on the mountain nyala status in the area. … As the mountain nyala population continues to become fragmented, all populations within their geographic range need to be monitored and evaluated. Understanding and managing sub-populations can improve conservation at broad-scales.“

Based out of the Colorado State University’s Warner College of Natural Resource Ecology Laboratory, the WCNR-Ethiopia Strategic Alliance is a consortium of U.S. and Ethiopian partners that are working to protect Ethiopia’s natural resources through education, research and engagement. The alliance includes academic institutions, government agencies, non-government organizations, local communities, and individuals. For decades, WCNR faculty, researchers, students and alum have had a distinguished presence in Ethiopia; ultimately leading to the creation of the Alliance.

Evangelista P, N Young, D Swift, A Wolde (2015) Demographic Observations of Mountain Nyala Tragelaphus buxtoni in a Controlled Hunting Area, Ethiopia. J Biodivers Endanger Species 3: 145. doi:10.4172/2332-2543.10.4172/2332-2543.1000145 (Download the complete pdf HERE)