The role of terrestrial vertebrate scavengers in the utilization of waterfowl hunting carcasses in a Mediterranean wetland

Abstract

Vertebrate scavengers play a crucial role in ecosystems by stabilizing food webs, accelerating nutrient recycling, and eliminating potential disease sources. In El Hondo Natural Park (SE Spain), a wetland of international importance for birds, periodic mortality events occur, such as the hunting of waterfowl. Uncollected hunting remains create predictable pulses of carrion utilized by different scavenger species. This study describes the community of terrestrial vertebrate scavengers and their patterns of consumption of carrion that simulates hunting in El Hondo. Thirty-nine waterfowl carcasses were placed after hunting events in three areas adjacent to the hunting reserves, and their consumption was monitored with camera traps. We recorded seven species of vertebrate scavengers, highlighting the role of the red fox (Vulpes vulpes) and the brown rat (Rattus norvegicus) as the main carrion consumers, although the latter showed lower efficiency, increasing the persistence time of carrion in the ecosystem. We also identified other vertebrate species, such as insectivorous birds, that consumed invertebrates attracted by the carrion. The results demonstrated that waterfowl hunting remains are used by a diverse community of vertebrates in wetlands. Additionally, our results suggest that hunting in protected areas can favour the presence of invasive species, such as the brown rat. This highlights the need to adequately manage the interactions between human activities and scavenger communities for the effective conservation of threatened ecosystems that are essential for biodiversity, such as wetlands.