Habitat suitability model for savanna large herbivores: identifying potential conservation area for Western Derby eland in the south-eastern Senegal

Bc. Moussa SEYDI

Master's thesis

Abstract:

The population of the Western Derby eland (WDE) is low the wild, estimated at 150 - 200 individuals at the only site, i.e. in the Niokolo Koba national park in south-east Senegal. Therefore, the WDE is considered critically endangered subspecies of Derby elands at the IUCN Red List. This research aimed to predict a suitable habitat for Western Derby eland in his current range within the Niokolo Koba national park using Habitat Suitability Model (HSM) tool. This tool uses species occurrence data and environmental variables to estimate species-habitat relationships and predict potentially suitable habitat. We employed the maximum entropy model, MaxEnt, to predict suitable habitat for Western Derby eland with limited occurrence records, i.e. a total of 33 presence locations. Environmental variables included type of land cover, digital elevation model, distance to rivers, distance to ranger camps, distance to national road, and distance to villages. Model performance was measured by area under the Receiver Operating Characteristics (ROC) curve (AUC). The AUC of 0.91 indicated that the model performed substantially better than a random prediction. The national road crossing the park and the distance to villages around the protected area were relatively the most important variables affecting the model. The proximity to the road is not indicated as suitable for the WDE and suitability increases with distance, while it decreases again at certain point, having the peak of suitability around 2500 m from the road. Similar pattern occurred with the distance to villages indicating the peak of suitability at the distance 20000 m. The MaxEnt output confirmed the affinity of this species for the area in the core (central part) of the protected area, southern as well as northern side of the national road, avoiding the borders of park, the proximity of the road in the center of the park and a large sector south-western part the park, on the left side of the Gambia river in the direction to the Koulountou river. Beyond the protected area border on the north-east of the park, there were some few patches of suitability close to the northern border. This model can be used for informed, science-based and effective conservation decision-making. Further, this model could be enhanced with more occurrence positions and altered environmental variables to produce variations in predictions, allowing for more conclusive results.

Keywords

Endangered antelope, Habitat Suitability Model, Maxent, Niokolo Koba national park, Senegal, Taurotragus derbianus, Western Derby eland, Wildlife conservation

Language used: English

Date on which the thesis was submitted / produced: 15. 5. 2020

Thesis defence

• Supervisor: prof. RNDr. Pavla Hejcmanová, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Zemědělská specializace / Tropical and Subtropical Agriculture