Predicting the effect of climate change on a scavenging community using community science data

Courtney Marneweck and David S. Jachowski, Forestry and Environmental Conservation, Clemson University, Clemson, SC, Todd E. Katzner, Forest and Rangeland Ecosystem Science Center, U.S. Geological Survey, Boise, ID

Background/Question/Methods
Scavenging is an important function within ecosystems where scavengers remove organic matter, reduce disease, stabilize food webs, and generally make ecosystems more resilient to environmental changes. Global change (i.e. changing climate and increasing human impact) is currently influencing scavenger communities. Thus, understanding what promotes species richness in scavenger communities and how that informs management should be a conservation priority. Using a long-term dataset from camera traps deployed by community scientists with animal carcasses as bait along a 1,881 km latitudinal gradient in the Appalachian Mountains of eastern USA, we investigated the relative impact of climate and humans on species richness and diversity of scavengers.
Results/Conclusions
Our most supported models for both mammalian and avian scavengers preliminarily included climatic, but not human, variables. The richness of mammalian and avian scavengers was highest during relatively warm (5 – 10 °C) and dry (100 – 150 mm precipitation) winters, when food was likely limited and reliance on carrion was high. The diversity of mammalian and avian scavengers was highest under drier conditions. We used these results to project the future species richness of scavengers under the climate scenario of 2070 (emissions level RCP8.5), which suggests up to 80% and 67% reductions in avian and mammalian scavenger species richness, respectively. Climate-induced shifts in behavior (i.e. reduction in scavenging even if present) at this scale could have cascading negative implications for ecosystem function, resilience, and human health. Further, our study highlights the importance of conducting studies of scavenger community dynamics within ecosystems across wide spatial gradients within temperate environments. More broadly, these findings build upon our understanding of the impacts of climate-induced adjustments in behavior that can likely have substantial impacts on systems at a large scale.