Higher forest cover and less contrasting matrices improve carrion removal service by scavenger insects in tropical landscapes.
Abstract
Understanding the links between biological communities and ecosystem service provision through the mechanisms driven by landscape structure is crucial to promote management strategies that safeguard both biodiversity and provision of these services. Here, we assess the impact of landscape structure and matrix contrast on carrion removal by scavenger insects, an often overlooked ecosystem service but of paramount importance for nutrient cycling and disease control. We first hypothesize that more forested landscapes and less contrasting matrices harbour richer communities of scavenger insects, mainly composed of forest species. We then posit that these richer communities of scavenger insects promote a higher provision of the carrion removal service. The scavenger insect community and carrion removal service was surveyed using 18 independent paired sampling sites (forest-agricultural matrix, composed either by coffee plantations or cattle pastures) in the Atlantic Brazilian Forest domain. We measured insect species richness, community composition and carrion removal amount using meat baits inside exclusion cages monitored along 6 days across a forest cover gradient (8%-89%) and distance gradient from forest edge (0-100 m to the interior of forest patches and adjacent matrix). Species richness of scavenger insects was higher in more fragmented landscapes, with more forested areas presenting communities composed of mainly forest-associated species. Carrion in coffee plantations attracted richer communities than in cattle pastures or forests. Coffee plantations also presented communities with more forest-associated species than cattle pastures. Carrion removal was higher in both forest and coffee plantations compared to cattle pastures. Even though forest communities had lower species richness, key forest-associated groups were the bulk of a higher service provision. Synthesis and applications. Forested landscapes with less contrasting matrices maintain a higher provision of carrion removal service by sustaining communities composed of scavenger insects with higher carrion removal capacity-mostly forest-associated species. Landscape management focusing on the conservation and reforestation of native forest patches, as well as reducing matrix contrast, could facilitate species spillover and thereby ensure the provision of carrion removal service.