| Popis: |
Numerous species of ungulates are forced to face the effects of rising temperatures and anthropogenic influences. The most dramatic effects of these concerns have been documented in Southern Africa, where wildlife and livestock are often the main source of income. This research uses the Kalahari region of Botswana as a case study. Kalahari wildlife had historically relied on migratory routes that facilitated access to vital water sources during seasonal extremes. Under the 1975 Tribal Grazing Land Policy (TGLP) in Botswana, ungulates, such as the blue wildebeest (Connochaetes taurinus), have lost access to these resources due to the increase in fenced areas, resulting in rapid population declines and a transition towards a sedentary lifestyle. At one point, almost 80,000 wildebeest mortalities were reported annually. To gain more insight on wildebeest habitat selection, individual step-selection functions (SSFs) were fit for GPS locations (n = 117,297) from 10 female blue wildebeest. The wildebeest data were collected between August 2011 and July 2014 and collars were worn for an average of 12.6 months (range = 3 – 21 months). A total of 11 habitat variables that may influence wildebeest movement were identified and SSF models were fit to assess how selection differed by individual and time. The results suggest that wildebeest generally selected for areas closer to water and pan habitats and for lower Enhanced Vegetation Index (EVI) values (P < 0.05). Selection differed by time of day and season and individuals also displayed unique differences. Ultimately, these results highlight the importance of incorporating individual variation within movement studies and support the use of SSF’s as management tools to observe how changing habitat conditions affect movement |
