Effect of agricultural activity on diet in an assemblage of lizards from Monte, Argentina

Abstract

Even though the encroachment of agriculture is the main cause for biodiversity loss, studies have focused in tropical and temperate environment, mainly in birds, mammals and beneficial and/or pests´ invertebrates. However, little is known about the impact in poor environment or lizards communities. Our aim was to compare food use and availability in trophic resources in two assemblages of seven lizard (Liolaemus darwinii, L. riojanus, L. cuyanus, L. wiegmannii, Aurivela longicauda, Homonota underwoodi and Teius teyou) at a cultivated and a non-cultivated site in a desert area of San Juan, Argentina. We analysed lizard food preferences, taxonomic and functional diversity, dissimilarity and the relationship between morphological variables and prey item frequency. We found that the diet of six species, at both sites, was focused on Hymenoptera (< 80%), whereas secondary and accessory items varied widely between species and sites, with 40% dissimilarity. Prey at the cultivated site were more abundant, rich and diverse than in the non-cultivated site, with 20% dissimilarity in species composition. Functional diversity showed redundancy when comparing morphological and dietary traits. Results suggest that the greater variation in the diet of species at the cultivated site is likely due to a higher diversity of prey available. We determined that diet could be a limiting factor for L. cuyanus, because there are no native plants at the cultivated site, whereas the remaining species opted for increasing their intake of Hymenoptera.