Ecological and anthropogenic influences on space use by spotted hyaenas

Abstract

Due to increasing human encroachment into the remaining habitat of many large carnivore species, there is an immediate need to understand the ecological and anthropogenic factors influencing carnivore space use decisions. In particular, knowledge of changes in space use in response to disturbance, and the costs associated with these changes, will be critical in guiding conservation efforts. To investigate the ecological factors influencing carnivore space use, we intensively radiotracked members of two large social groups (clans) of spotted hyaenas Crocuta crocuta in the Masai Mara National Reserve, Kenya. In addition, we studied the influence of livestock grazing by comparing space use between two study clans that differed dramatically in exposure to grazing. Logistic regression modeling indicated that space use in the absence of livestock was most influenced by the location of the clan's communal den. However, hyaenas were also found to select shrubland, areas of high prey density, and proximity to seasonal streams. Movements of hyaenas exposed to livestock grazing were most influenced by vegetation type, with a strong avoidance of open grass plains. Den location and prey density had less influence on space use decisions in the disturbed than the undisturbed clan. Livestock distribution did not directly influence hyaena movements either during daytime, when livestock were present, or at night. We suggest that direct livestock avoidance was unnecessary due to the observed increased use of vegetative cover by hyaenas exposed to grazing livestock. The greater distances from the den, and from areas of high prey density at which hyaenas were found in disturbed than undisturbed areas indicates potential energetic costs incurred by disturbed hyaenas. Our results therefore suggest that reduced vegetative cover, as is often found outside protected areas, may result in more dramatic modifications of hyaena movements in the presence of livestock.

Heterogeneity in the density of spotted hyaenas in Hluhluwe-iMfolozi Park, South Africa

“…Within ecosystems with large resident herbivore populations similar to HiP, hyaena distribution has been correlated with small scale variations in prey density even within relatively small clan territories (Boydston et al 2003b, Höner et al 2005, Kolowski and Holekamp 2009). Cromsigt (2006) indicated for the same annual period (August-October) as our survey, significant spatial heterogeneity in the densities of four of the main prey species of hyaena in HiP at an even smaller scale (2.5´2.5 km grid) than our survey.…”

Lifetime selection on a hypoallometric size trait in the spotted hyena

“…The females used in each analysis represent all females for which we had all necessary data. Although bias could possibly be introduced into the path analysis by inclusion of data from two clans, the ecological conditions experienced by both clans are very similar [41], and the results of the selection gradient analysis match the path analysis closely, so we believe it unlikely. The three composite size measures were included in a multiple regression along with the standardized social rank of each animal.…”

Spatiotemporal patterns of lion space use in a human-dominated landscape

“…A carnivore's response to people, however, may not be as simple as straightforward avoidance of human-occupied areas (Kolowski & Holekamp, 2009). Such areas may contain valuable resources (e.g.…”