Dietary studies provide a partial picture of the feeding ecology of grey wolves across different environments

Jacopo Cerri , Rudy Brogi, Carmela Musto, Elena Bassi, Giordano Ventura, Alessandro Bianchi, Massimo Scandura, Marco Apollonio

The recent and ongoing expansion of grey wolves (Canis lupus) in Europe has led them into new ecological contexts, including areas characterized by poor prey communities and higher levels of landscape anthropization. While dietary studies are essential for predicting wolf’s ecological functions/role and impacts, it remains unclear whether research on wolf diet has kept pace with this expansion, potentially leaving knowledge gaps in newly occupied landscapes.
By using Italy, a country where wolves recovered most of their historical range, as a case study, we mapped the current distribution of wolves and then distinguished between areas with different food resources: domestic or wild ungulates, the coypu (Myocastor coypus), and resources associated with landscape anthropization, such as food wast and domestic pets. Finally, we checked the coverage of these areas by dietary studies (n = 36).
The distribution range of wolves in Italy includes areas with nine different food resource assemblages. However, most studies on wolf diet have focused on remote areas of the Alps, where northern chamois and red deer are abundant, and on the Northern and Central Apennines with a rich assemblage of wild ungulates. The feeding ecology of wolves remain largely unexplored in highly anthropized landscapes and in areas of Southern Italy with poorer ungulate assemblages, despite these environments together accounting for most areas of ongoing wolf expansion.
Knowledge gaps about highly anthropized landscapes hinder the role played by rodents, animal byproducts, domestic pets and food waste as resources. And their influence over the fitness of wolves, mediated by their energetic content and predictability, as well as by their capacity to expose wolves to toxic compounds or pathogens. Similarly, knowledge gaps about Mediterranean environments, where wolves rely almost exclusively on wild boar, hinders our ability to predict the potential impact of African Swine Fever on wolf ecology and behaviour.
Carefully evaluating dietary studies about wolves, in their coverage of the different environmental conditions where they live, is crucial to better understand their feeding ecology and role as predators and scavengers, as well as to guide research to address knowledge gaps and predict future changes in their ecology.