Positive but un-sustained wildlife community responses to reserve expansion and mammal reintroductions in South Africa

Abstract

The creation and expansion of protected areas, coupled with wildlife reintroductions, are increasingly used as conservation measures to combat wildlife declines worldwide. Although these types of restoration efforts are expected be beneficial to wildlife populations, variable species management and interactions among species within complex food webs have the potential to lead to unintended species-specific responses to reserve expansion which can counteract the anticipated positive effects. We used a multi-season camera trap study to investigate community-wide responses of wildlife to a reserve expansion and associated wildlife releases in South Africa. We analyzed the camera trap data using community occupancy and N-mixture models to assess how the occupancy and intensity of use of individual species changed in the four seasons following reserve expansion. We found species-specific responses to reserve expansion, although responses were generally positive in occupancy and intensity of use but un-sustained. The apex predator, the lion ( Panthera leo ) and the majority of managed herbivores exhibited sustained or delayed positive responses, whereas most subordinate predators and unmanaged herbivores had short-lived, fluctuating, or neutral responses. Interactive effects of top-down suppression, competitive pressure, and increased space and food resources likely resulted in the temporally-variable responses of most species. Although no species responded negatively to reserve expansion and mammal reintroductions, the lack of sustained positive responses for most species indicates the complexities of implementing conservation actions to benefit multiple wildlife species. Our results highlight the importance of monitoring the entire wildlife community following management actions such as reserve expansion or wildlife reintroductions.