Food limitation and demography of a migratory antelope, the white-eared kob

摘要: Although it is commonly presumed that many populations of large-herbivores are limited by food availability, supporting evidence scarce. This hypothesis was investigated in a population over 800,000 white-eared kob the Boma National Park region southern Sudan. Food body condition, and mortality rates adults calves were measured during dry seasons 1982 1983. Sampled age distributions from both live carcasses used to calculate age-specific mortality. In 1982, supplies season augmented substantial rainfall, which produced regrowth grass areas ordinarily had little green forage. As result, fat reserves declined little, adult showed no increasing trend. Total 5%. 1983, there rainfall intake insufficient meet estimated energy requirements kob. increased fourfold. 10% (equivalent recruitment rate yearling into population). Calf similar years (50%), based on field estimates calf/female ratios. Lactation throughout possibly provided buffer for against variations availability. The structure 1983 suggests drought 1980 reduced numbers 40%. These results suggest survival influenced strongly availability season. However, duration also plays an important role. During season, declining make proportion vulnerable even moderate droughts may lead changes numbers.