Interactions between wildlife, humans and cattle: activity patterns of a remnant population of impala on the degraded Mutara Rangelands, Rwanda

摘要

Large-to medium-sized African ungulates are often studied in conservation areas, ignoring the fact that most African landscapes are nowadays heavily impacted by agricultural and pastoralist practices. The present study emphasises the wealth of information obtained from studying a remnant population of a medium-sized ungulate, the impala (Aepyceros melampus), on degraded rangelands in Rwanda. Compared with impala occurring under similar climatic conditions in Serengeti National Park in Tanzania, the study population showed a marked reduction in daytime activity, absence of a mid-day resting phase, and a slight increase in activity towards the late afternoon. This pattern was not directly correlated with daily variation in human activity. It is argued that hunting/poaching leads impala to seek shelter to such a degree that any daytime rhythmicity in activity patterns is lost and that increased afternoon activity reflects a shifted cost-benefit ratio of hiding versus foraging, as hungry individuals are more likely to take risks. Indeed, impala were more likely to encounter cattle herds and their herdsmen towards the afternoon. The study augments understanding of behavioural flexibility, potential for habituation and adaptation to human-induced habitat alterations in impala and highlights a possible function of rangelands as dispersal corridors for African wildlife populations.