Scavengers and habitats shape nutrient input to the soil via wild ungulate carcass decomposition

Abstract

The soil is a dynamic matrix providing essential functions and services for ecosystems worldwide. Its formation involves complex interactions driven by both abiotic and biotic factors, including the decomposition of organic matter. While research has traditionally focused on plantderived organic matter, animal remains also contribute nutrients to the soil, influencing biogeochemical cycles locally. Wild ungulate carcasses, though unpredictable in time and space, serve as a key resource for a highly structured scavenger community. We aim to understand how scavenger consumption of carcasses mediates nutrient deposition in the soil and how landscape factors shape this process. Nineteen aoudad (Ammotragus lervia) carcasses were placed and monitored using camera traps in the Sierra Espuña Regional Park (Murcia, Spain) in areas with open and semi-closed vegetation cover. Using the pictures from the cameras, we identified the scavenger community in each carcass and the carcass consumption patterns (i.e., carcass detection and consumption times). Soil samples were also collected at each carcass site both before carcass placement and five months later, and analyzed for physical, chemical, biochemical, and biological properties. Facultative scavengers played the primary role in carcass consumption, with their activity and function shaped by vegetation cover. Parallelly, carrion decomposition impacted several soil properties, highlighting the microbial community structure, key enzymatic activities, and the concentration of elements essential for primary production. The availability of carrion to scavengers, influenced by habitat configuration, modulates the nutrient input through decomposition and its effects on the soil. These findings emphasize the important role of animal organic matter in soil nutrient cycles and the keystone role of scavengers in ecosystem nutrient pathways.