Spatial and trophic niche utilization by an assemblage of native and non native herbivores in arid lands of Argentina

S. Y. BOBADILLA; M.A. DACAR; F.M. JAKSIC; R.A. OJEDA ; CUEVAS, M. F.

Virtual meeting

Congreso; 100th Annual Meeting of the American Society of Mammalogists; 2021

The American Society of Mammalogists ASM

The coexistence of ecologically similar species is facilitated by differential use of niche axes (i.e. habitat, diet, and temporal gradients). We compare the utilization of spatial and trophic resources of native (plains viscacha, Lagostomus maximus) and nonnative herbivores (rabbit, Oryctolagus cuniculus; hare, Lepus europaeus; goat, Capra hircus) in the Monte ? Patagonia arid land of central western Argentina. We expected herbivores to show different responses in the use of the niche axes associated with seasonal changes in resource availability and according to the origin of the species (native, nonnative). We evaluated habitat microhabitat use through Chi-squared goodness of fit tests, Bonferroni confidence intervals and GLM models. We analyzed seasonal compositions of the diets, breadth of the trophic niches, and dietary overlaps. Our findings show that resources were not markedly segregated at habitat scale. The hares and goats were more flexible than rabbits and plains viscacha in the utilization of different habitats. Native and nonnative herbivores overlapped in the trophic niche dimension but segregated to some degree in the use of space at microhabitat scale. Diet composition was dominated by grasses during wet season. Under conditions of resource limitation (dry season), native herbivores differed in feeding strategy from the remaining nonnative herbivores. These results deepen our understanding of possible underlying mechanisms that allow coexistence of wild native-nonnative and domesticated herbivores in arid ecosystems.