La dieta de mamíferos como indicador de la modificación del paisaje

The modification of primary environments due to human activities imposes different challenges on animal species living in sympatry, which may respond with behavioral and ecological adjustments to survive. Omnivorous mammals, unlike carnivores or herbivores, require special attention due to their constant intake of diets based on vertebrates, invertebrates, and plants. Strategies to obtain food may vary among omnivore species according to the degree of habitat disturbance. For this reason, there is a need to understand how different omnivores respond, in terms of feeding ecology, when subjected to the same anthropogenic pressures within a shared habitat. In this study, we examined the diet of sympatric medium-sized mammals living in a coniferous forest in Veracruz, Mexico, which has been subject to anthropogenic pressures. We focused on ringtail (Bassariscus astutus), common opossum (Didelphis marsupialis) and gray fox (Urocyon cinereoargenteus). We predicted that dietary patterns would differ between habitat types (conserved vs disturbed) and seasons (dry and rainy), being the species with a more specialized diet more affected by landscape modification. We collected and examined scats of the three mammal species. Overall, the most common food item consumed was plants, followed by invertebrates and, to a lesser extent, vertebrates. Food intake frequency was similar between conserved and disturbed zones; however, we recorded a higher invertebrate intake during the rainy season. Bassariscus astutus and D. marsupialis showed a higher frequency of plant intake, followed by vertebrate and invertebrate items, whereas in U. cinereoargenteus, plant and vertebrate items showed equal frequency, followed by invertebrates. Considering each species, the type of consumed food item differed among species and between sampled areas, and an interaction between species and seasons was also found