Dietary flexibility promotes range expansion: The case of golden jackals in Eurasia

AIM: Ongoing global changes can lead to the expansion of species' geographical range. Exploring the drivers of the successful ongoing expansion of the golden jackal across Europe is essential to understand the species' trophic ecology. We analysed which climatic and environmental factors affected the dietary composition of golden jackals and compared these drivers in the species' historic and recently colonized distribution ranges. LOCATION: Eurasia. TAXON: Golden jackal (Canis aureus). METHODS: Using 40 published datasets, we modelled jackal diet composition using 13 food categories based on the relative frequency of occurrence of food items and trophic niche breadth (BA) against climatic and environmental factors from throughout the jackals' recently colonized (22 studies) and historic range (18 studies) using general additive models. RESULTS: The proportion of small mammals in golden jackal diet decreased with annual mean temperature, whereas the consumption of wild ungulates increased with environmental productivity. Increasing temperature and environmental productivity positively influenced niche breadth, while increasing precipitation negatively affected it. The recently colonized distribution range of golden jackals in Europe had a lower mean temperature but higher environmental productivity compared to the species' historic range in Eurasia. In the recently colonized range, jackals consumed small mammals and/or wild ungulates (mostly from scavenging) more frequently, and fewer plants and/or domestic animals (again, mostly from scavenging). MAIN CONCLUSIONS: The golden jackal is an opportunistic, omnivorous carnivore with high dietary flexibility and biogeographical variation. Climatic and environmental factors shape the species' diet composition, which, in a changing environment, greatly enhances the opportunities for golden jackals to colonize new areas successfully. Golden jackals will likely continue to expand their range in the foreseeable future. The species' trophic niche is expected to broaden with predictions of overall increasing temperatures and reduced precipitation.