LONG-TERM CONSEQUENCES OF CHANGES IN TERRITORY QUALITY ON FEEDING ANDREPRODUCTIVE STRATEGIES OF VERVET MONKEYS

1. Food availability and quality are important determinants of mammali an reproductive success, and long-term changes in food availability we re assessed for their impact on diets and reproduction of three adjace nt groups of vervet monkeys in Amboseli, Kenya in two periods spanning an interval of 9 years. 2. Diets were largely restricted to the produ cts of two species of acacia trees (Acacia xanthophloea and Acacia tor tilis), with food selection primarily determined by availability (tree density, size and seasonal production of foods).3. Over this period t he overall abundance of major foods, measured through absolute species density, declined while territory size increased. 4. Despite signific ant changes in food plant densities, diets remained relatively stable, suggesting a component of consistency in diet choice. Limited options or high costs for incorporation of novel foods are suggested as facto rs maintaining this stability, with deleterious consequences in the fa ce of very long-term habitat changes. 5. This study suggests that the habitat deterioration, assessed by reduction in food densities, initia ted local group extinction. An increased energy expenditure in foragin g, high mortality and low reproductive rates ultimately led to a popul ation crash under conditions of reduced food availability.