Space use in lions, Panthera leo, in the Selous Game Reserve: social and ecological factors

Abstract. Habitat qualities, such as food supply or access to refuges, often influence home-range size. Furthermore, such qualitative differences usually lead to conspecific competition over space, which can be an important factor in determining the distribution of individuals within populations. In carnivores, patterns of resource dispersion are hypothesized to determine home range-size and group size. But in contests over space (or other resources), larger groups usually dominate smaller ones, and group size should therefore also affect home-range size. Here I describe the space use of lions, Panthera leo, in the Selous Game Reserve, Tanzania, and ask whether space use is related to pride size, habitat, or relatedness. Home ranges varied in size, but size showed no correlation to number of adult females in the pride or to habitat type. Lions exhibited a significant preference for riverine and short-grass habitat, and a significant avoidance of acacia woodland. Habitat preference ratios largely reflected prey availability in each habitat. Outer areas, as well as core areas of home ranges, were often used by two or more prides. Overlaps showed no correlation to relatedness among prides or habitat type. Thus, whereas home-range sizes and overlaps were determined by factors that could not be revealed by demographic factors or analyses of habitat composition or genetic structure, lion space use within each home range seemed driven mostly by prey availability, which mainly varies with habitat type.