Food niche segregation between sympatric golden jackals and red foxes in central Bulgaria

Abstract

In Europe, the range of the golden jackal (Canis aureus) has expanded since the mid‐twentieth century, but little is known about how it interacts with other sympatric carnivores. Among European countries, Bulgaria has the largest population of golden jackals and jackal numbers have increased around two‐fold during the past two decades, particularly in lowland habitats. Larger canids often competitively exclude, or even kill, smaller sympatric ones, especially when guild dynamics are in flux due to population re‐establishment. We therefore investigate whether trophic niche segregation occurs between golden jackals and red foxes (Vulpes vulpes) in central Bulgaria, where both species are sympatric. Because jackals are more abundant in lowland than in upland Bulgaria, we further investigate whether habitat elevation affects the strength of trophic competition. From the analysis of stomach contents of both species, collected from lowland and upland areas during hunting seasons between 1997 and 2009, we found no significant food niche overlap, and no effect of elevation on trophic interactions. In lowland habitat, golden jackals mainly scavenged carcasses of domestic animals, whereas in upland habitat they consumed mostly carcasses of wild ungulates. In contrast, red foxes predominantly and consistently predated rodents in both habitats. This suggests that trophic segregation facilitates the coexistence of these canids under these prevailing population conditions. Nevertheless, we stress that as golden jackals colonize Eastern Europe, impacts on red foxes, and consequences for ecological communities, should be monitored carefully, especially in regions with less carrion available to support jackals.

Niche partitioning between sympatric wild canids: the case of the golden jackal (Canis aureus) and the red fox (Vulpes vulpes) in north-eastern Italy

“…The consumption of medium-sized mammals, the third shared food category, was of secondary importance for both canids. Generally, the food habits of both species were similar to those reported by previous researches, in particular those carried out in more natural and heterogeneous landscapes [ 88 , 89 ]. Conversely in human-modified landscapes, e.g.…”

Human disturbance has contrasting effects on niche partitioning within carnivore communities

“…This effect, however, was only reported once in our literature search by a study comparing mesopredator diet overlap between two study areas with a large difference in grey wolf, Canis lupus , density due to a wolf‐control program (Sivy et al ., 2017). Additionally, this effect can be partially mitigated by provisioning carcasses resulting from hunting activities, as we found in two studies (Barrull et al ., 2014; Tsunoda et al ., 2017), or livestock practices (Cortés‐Avizanda, Carrete & Donázar, 2010). However, artificial disposal of carrion may inadvertently affect non‐target species (e.g.…”

Variations in the trophic niches of the golden jackal Canis aureus across the Eurasian continent associated with biogeographic and anthropogenic factors

“…Golden jackals have expanded northward in Europe (Arnold et al 2012), as evidenced by their establishment and potential reproduction in the Baltic region (Kowalczyk et al 2020), which has raised concerns for their management in newly colonised countries (Trouwborst et al 2015). Our finding that jackals consume small mammals to a greater extent at higher latitudes indicates potential food resource competition with other rodentivorous carnivores, such as the red fox Vulpes vulpes; previous studies have demonstrated food competition between these two canids in southern European and Mediterranean regions (Scheinin et al 2006, Farkas et al 2017, Tsunoda et al 2017. Furthermore, disruption to the availability of the staple food of jackals (i.e.…”