Top scavengers in a wilder Europe

Abstract

The concept of rewilding should not only be applied to recovering habitat and vertebrate populations but also to the restoration of complex ecological processes. Large avian scavengers are the target of restoration programs including conservation measures linked to the manipulation of food resources but we lack of a general approach to understanding how scavengers and the ecosystem services they provide will fit into a rewilded Europe. Carcasses play an important role in ecosystem functioning and in the energy flux within food webs. Large ungulates carcases availability, in particular, has, through the course of evolution, given way to the appearance of “true” scavenger strategies, displayed by large body-sized avian organisms (vultures) whose guilds are structured by complex interspecific relationships. Yet, livestock raised in traditional agro-grazing systems have historically replaced wild ungulates as the main food source for vultures. More recently, modern farm intensification, stricter European Union legislation that banned the abandonment of carcasses, and increasing human-vulture conflicts contributed to plunging vulture populations, leading to an unprecedented crisis. Consequently, supplementary feeding became a management tool used worldwide to aid in the recovery of their decimated populations. These so-called vulture restaurants, however, alter the spatial-temporal nature of trophic resources with strong consequences at individual, population, community and ecosystem levels. The conservation of these charismatic species in rewilded European landscapes should rely on wild ungulate expansion, the recovery of large carnivore populations and, in more humanized areas, the promotion of traditional extensive agro-grazing systems limiting artificial feeding activities. In this way, it may be possible to combine both the historically recognized ecosystem services provided by vultures (elimination of undesirable remains, nutrient cycling) with new recreational services (conferring aesthetical value to the environment) while providing economic benefits to rural societies. Vultures and other scavengers, because they exploit space at a huge scale, are singular actors within a rewilded Europe. Their conservation, and that of the ecological processes in which they are involved, requires large-scale approaches surpassing those limits imposed by administrations, habitats and even biomes.