Seasonal Selection Preferences for Woody Plants by Breeding Herds of African Elephants (Loxodonta africana) in a Woodland Savanna

To evaluate dynamics of elephant herbivory, we assessed seasonal preferences for woody plants by African elephant breeding herds in the southeastern part of Kruger National Park (KNP) between 2002 and 2005. Breeding herds had access to a variety of woody plants, and, of the 98 woody plant species that were recorded in the elephant's feeding areas, 63 species were utilized by observed animals. Data were recorded at 948 circular feeding sites (radius 5？m) during wet and dry seasons. Seasonal preference was measured by comparing selection of woody species in proportion to their estimated availability and then ranked according to the Manly alpha (α) index of preference. Animals demonstrated a selection preference in feeding on woody vegetation, and Grewia hexamita, Grewia bicolor, Grewia flavescens, and Grewia monticola were selected consistently more over all seasons. In addition, our results indicate that elephant herds have a low preference for at least some of the woody species prone to extirpation and that feeding preferences for woody plants do not account for the association of elephants and riparian fringe habitat. 1. Introduction The transformed and fragmented South African landscape has resulted in a lack of suitably sized protected areas for elephants, thus creating major challenges for managing elephant populations relative to their effects on ecosystem processes, vegetation structure, and species of plants and other animals [1]. Prolonged periods of locally high densities of elephants can alter vegetation structure, and the impact can intensify, especially when animals are confined to small or medium sized fenced reserves [2, 3]. This is especially challenging in fenced reserves smaller than 1000？km2 to which elephants have been reintroduced by 2001 in South Africa [4, 5]. Subsequent to the introduction of elephant in these small areas, these savannas are exposed to intensive management, and decision makers are increasingly challenged to choose options which can balance needs of locally high elephant numbers with the maintenance of vegetation and ecosystem diversity. Elephant feeding behaviour in combination with natural processes, for example, climate and fire, is the architects in different African landscapes and has been the focus of numerous studies describing elephant diet [6–11]. However, many of these studies failed to define selection preferences at the plant species level and only describe preferences at the broad level of growth forms [12, 13]. This gap resulted in incorrectly assigning certain responses in the environment to