Spatially explicit poisoning risk affects survival rates of an obligate scavenger

Authored by A Monadjem, A Kane, A Botha, C Kelly, C Murn

Date Published: 2018

DOI: 10.1038/s41598-018-22632-y

Sponsors: Irish Research Council

Platforms: NetLogo

Model Documentation: Other Narrative Mathematical description

Model Code URLs: https://raw.githubusercontent.com/kanead/white-backed-vulture-population-dynamics/master/vulture%20poison%20model.nlogo

Abstract

Obligate scavengers such as vultures provide critical ecosystem services and their populations have undergone severe declines in Asia and Africa. Intentional poisoning is a major threat to vultures in Africa, yet the impact on vulture populations of where poisoned carcasses are positioned is not known. We used re-sightings of 183 African white-backed vultures captured and tagged in two regions of South Africa, some 200 km apart, to estimate spatial differences in relative survival rates across life stages. Juvenile survival rates were similar in the two regions, whilst subadult and adult survival rates differed significantly. Using agent-based modelling, we show that this pattern of relative survival rates is consistent between regions that differ in intensity of poisoning, despite the proximity of the two regions. This may have important consequences for vulture conservation and the targeting of conservation efforts, particularly with regard to the efficacy of ``vulture safe zones{''} around vulture breeding populations.

Tags

Viability Land-use Demography health Africa Impacts Consequences Recovery Avian scavengers Marked animals Vulture population declines White-backed vultures Cape vultures Avian scavengers Gyps-coprotheres