Environmental parameters and anthropogenic effects predicting the spatial distribution of wild ungulates in the Akagera savannah ecosystem

Abstract

Savannah areas affected by human activities such as livestock keeping and agriculture are often characterized by shifts in landscape structuring, with a predominance of few(er) habitat types. This is typically accompanied by pronounced changes in the communities of ungulates. The aim of this study was to find out whether shifts in ungulate communities in Lake Mburo National Park (LMNP) are primarily predicted by an alteration in the composition of the preferred habitat types or if more complex interactions between habitat changes and the prevalence of ungulates occur. Monthly road counts were used to establish the number of eleven ungulate species in LMNP and adjacent unprotected Ankole Ranching Scheme. The common duiker (Sylvicapra grimmia campbelliae Gray, 1843) was found in more abundance in disturbed areas, while showing a significant change in habitat use. Common duiker tended to use the vegetation type otherwise used by the bushbuck (Tragelaphus scriptus dama Neumann, 1902). Our results support the claim that the occurrence of ungulates is not only directly affected by the availability of ‘suitable’ habitats, but behavioural plasticity and competitive exclusion also need to be considered.

Do ecotypes of bushbuck differ in grouping patterns?

“…The study lasted for 3 years (April 1999 to February 2002), including a total of 3,864 bushbuck sightings (Table 1). Data from LMNP and the ARS (Uganda, Victoria Basin, dama ecotype) were collected during road transect counts (Averbeck et al 2009b) along four transects (two in LMNP, two on ARS). Each transect had a total track length of 150 km and was patrolled twice a month between May 1998 and December 1999.…”

Hunting differentially affects mixed‐sex and bachelor‐herds in a gregarious ungulate, the impala (Aepyceros melampus: Bovidae)

“…In other species like the impala ( Aepyceros melampus ), sighting rates and population density estimates were slightly higher outside than inside the park (Rannestad et al. , 2006; Averbeck et al. , in press).…”

“…A situation as outline above is found in some ungulate species inhabiting Lake Mburo National Park (LMNP) and the adjacent unprotected farmland [the Ankole ranching scheme (ARS)] in western Uganda. Some ungulate species like topi ( Damaliscus lunatus ) experienced a dramatic decline in population densities outside LMNP (estimated from sighting rates: Averbeck et al. , in press).…”

Co‐occurrence modelling highlights conservation implications for two competing spiral‐horned antelope

“…Schmidt () showed that that bushbuck exist in densities ranging between 2 and 4 individuals per km 2 in Eucalyptus plantations (however, Odendaal & Bigalke () found that bushbuck avoided Eucalyptus plantations). Averbeck et al () found plasticity in habitat associations between PA versus non‐PA sites for bushbuck, indicating tolerance to anthropogenic disturbance. Therefore, the association between bushbuck and anthropogenic habitats such as plantations might be context‐specific and may be influenced by population density, competition and predation factors.…”