Habitat selection of Oryx dammah in the Ouadi RiméOuadi Achim Faunal Reserve in Chad

The aim of this study was to determine the main factors influencing the habitat selection of Oryx dammah in the Ouadi Rimé-Ouadi Achim Faunal Reserve in Chad. More precisely, we used the spatial positions and movements of Oryx dammah acquired by GPS collars between 2016 and 2024 and sought correlations with some environmental factors in the observed habitat selection, using integrated step-selection functions. The final goal of this operation is to contribute to the conservation of this threatened species, by extending our knowledge of its ecology and increasing the probability of success of the current and potential future reintroduction projects.
We used step-selection functions to determine how vegetation density, wildfires, topography and human presence affect the habitat selection of Oryx dammah. We conducted this study in a seasonal framework, examining the particular features of each season. Our work shows that vegetation density is the main driver of Oryx dammah’s habitat selection. An indicator of woody vegetation density, in addition to overall vegetation density, increases the explanatory performance of a model. Oryx dammah is particularly sensitive to changes in vegetation during the hot dry season. Its presence is also positively correlated with places that suffered wildfires during previous cool dry seasons. Finally, the species is generally attracted by areas with a low Topographic Convergence Index (TCI) and a low human presence.

This Master's thesis was carried out as part of the doctoral research project entitled "Plant-herbivores interactions and their influence on the distribution of sub-Saharan antelopes" under the supervision of doctoral student Ngaba Waye Taroum Caleb and Prof. Clara Zemp.