Spatial Marked Point Patterns for Herd Dispersion in a Savanna Wildlife Herbivore Community in Kenya

Abstract

Quantitative descriptions of animal species’ distributions at the ecosystem level are rare. In this study we used marked spatial point pattern analysis to characterize herd spatial distributions of several species comprising a savanna large herbivore community in Laikipia, central Kenya. Points are the herd centres, marks are the herd sizes. Previous research [15] identified possible discrepancies between prey and non-prey species on the basis of the nearest neighbour distance function. In this paper we make a similar distinction and analyse possible consequences. Analysis concentrated on Ripley’s K-function on several data subsets. A digitised boundary of the area has been included. The herd patterns of Thomson gazelle and of the plains zebra were modelled with a Strauss marked point process. The pattern of the Thomson gazelle showed a single mode, whereas that of the plains zebra showed multiple modes. This can be well explained by the ecosystem behavior (habitat specialist versus habitat generalist) of the two species.