Partitioning of trophic resources in an assemblage of exotic and native herbivores in the Ischigualasto Provincial Park (San Juan, Argentina)

CAMPOS, C. M.; REUS, M. L.; DE LOS RÍOS, C.; PECO, B.

Belfast

Congreso; 11th International Mammalogical Congress; 2013

International Federation of Mammalogists

Trophic interactions among herbivorous mammals (exotics: European hare, donkey, and cow; natives: guanaco, mara, and viscacha rat) were studied considering a) digestive type (ruminant and non-ruminant species); b) body-size; c) origin (native or exotic); and d) seasonality in resource availability. We analyzed herbivore diets using microhistological analysis of faeces. Redundancy analyses (RDA) were performed to assess association among diets. Diet selection was evaluated using Bonferroni intervals; Shannon-Weaver index was estimated as an indicator of diet breadth; and Pianka's index as an indicator of dietary overlap. The best model included the relationship among diets considering seasonality. Herbivores consumed mainly shrubs, the most abundant functional plant group on offer across the year. Prosopis torquata and Zuccagnia punctata were the species selected by native species. Exotic herbivores showed the widest diet breadth and the smaller native herbivore (viscacha rat) had the narrowest diet breadth. In general, trophic overlap increased over the dry season.