Functional habitat heterogeneity and large herbivore seasonal habitat selection in northern Botswana

摘要

This study aimed to determine the functional seasonal attributes for herbivores of the major habitats and landscapes of the Savuti-Mababe-Linyanti ecosystem (SMLE) of northern Botswana and how various herbivore species responded to this heterogeneity. Floodplain grasslands and dambo grasslands provided the only significant green forage and biomass during the late dry season, whereas short grasslands of the Mababe Depression provided the highest forage quality of all habitats during the wet season. The ability to provide reliable forage and drinking water in floodplain, swampand dambo grasslands attracted large concentrations of zebra and buffalo during the dry season, which was mediated by fire. Large concentrations of zebra were observed in mineral-rich grasslands of the Mababe Depression during the wet season, whereas buffalo were not observed in these open grassland landscapes in this season. Other herbivore species appeared to use the same landscapes year-round where lechwe were observed mainly in floodplain and swamp landscapes on the western edge of the Linyanti Swamps, while wildebeest and impala were observed in floodplains and adjacent woodlands near permanent water suggesting that these species had access to sufficient resources at a landscape scale. Thus various herbivore species responded differently to functional heterogeneity across seasons and scales.