Vultures function as natural recyclers of the environment, which is an essential ecosystem service. As the only vertebrate obligate scavengers, their diet is completely reliant on the carcasses of dead animals. With the global reduction in extensive farming, the impact of a decline in domestic ungulate biomass on scavenger populations is largely unknown. The Indian subcontinent has already seen an unprecedented vulture population decline, attributed to the use of diclofenac; a veterinary drug that was banned shortly after the threat was determined and it is still slowly being weaned out of the pharmaceutical market. As rehabilitation and conservation efforts focus on South Asian vulture populations, we examine the population dynamics of obligate scavengers under existing food availability scenarios considering domestic and wild ungulates. Using a computation modeling technique for population dynamics, P-Systems, we model the population trends of the scavenging ecosystem of Nepal’s Annapurna Conservation Area to determine the effects of current estimated food availability scenarios on the population of five vulture species (Gypaetus barbatus, Gyps himalayensis, Neophron percnopterus, Gyps fulvus and Aegypius monachus). We collected life-history parameters for the vulture species and thirteen wild and domestic ungulate species that provide a food source for the scavenger community.
Results/Conclusions
In our model of the scavenger ecosystem in the Annapurna Conservation Area, we simulate the population trends of each species under existing conditions of food availability. We find that the current wild and domestic ungulate biomass is insufficient to sustain the current populations in the Annapurna Conservation Area, resulting in a predicted loss of individuals for the five vulture species. The model assumes an isolated area, in which the individuals cannot obtain resources from outside the study area. The prediction of the species’ current and future carrying capacities is integral to increasing our knowledge of scavenger ecology and their dependence on wild and domestic ungulate biomass. This viable population estimate is of significance as it is based off of current available biomass in the ecosystem and creates a new baseline for the vulture populations of the Annapurna Conservation AreaThe resulting population trends may provide information on the predicted populations for obligate scavengers in other areas of the world, where extensive agriculture is also decreasing and indicates that food availability can act as a limiting factor for the current populations.