Effect of mammalian mesopredator exclusion on vertebrate scavenging communities

Carrion is a valuable resource used by facultative scavengers across the globe. Due to conflicts with humans, many vertebrate scavengers have experienced population declines due to direct persecution or indirect effects of human activities. However, little is known about the implications of altered scavenger community composition on the fate and efficiency of carrion removal within ecosystems. In particular, mammalian mesopredators are efficient scavengers that are often subjected to control, thus, it is important to understand how the reduction of this scavenger guild influences the fate of carrion resources and efficiency of carrion removal within ecosystems. We evaluated the influence of the absence of mammalian mesopredators on vertebrate scavenging dynamics by comparing the efficiency of carrion removal and species composition at carrion between sites where we experimentally manipulated mesopredator abundance and paired control sites. Overall scavenging rates were high, even within our mesopredator exclusion sites (79% of carcasses). Despite the exclusion of an entire guild of dominant scavengers, we saw little effect on scavenging dynamics due to the extensive acquisition of carrion by avian scavengers. However, we observed a slight reduction in vertebrate scavenging efficiency in sites where mesopredators were excluded. Our results suggest vertebrate communities are highly efficient at carrion removal, as we saw a functional response by avian scavengers to increased carrion availability. These data provide insights into the impact of mesopredator control on food web dynamics, and build upon the growing body of knowledge investigating the role of vertebrate scavengers on ecosystem services provided through carrion removal.