Ground beetles (Coleoptera: Carabidae) inhabiting anthropogenic habitats in the lower delta of the Paraná river, Argentina: geographic distribution and ecological characteristics

Abstract

The primary aim of this paper was to provide the first inventory of carabid beetles monthly collected in five different anthropogenic habitat types of the Lower Delta of the Paraná River, and to describe the main ecological characteristics, and to provide information on their distribution range in ecoregions, subregions and ecosystem complexes of Argentina and across the Neotropical region. Species were grouped considering six classes of distributions in relation to their presence in the Delta of the Paraná River. In addition, rarefaction curves were built in order to compare the seasonal species richness. We collected 1486 individuals belonging to 48 species. The southernmost distribution limit of 50% of the species is located south of the Delta region. Moreover, 21% of the species are confined to the Delta and Islands of the Parana and Uruguay Rivers ecoregion and to localities within the neighboring ecoregions of Espinal and Pampa. 63% of species were zoophagous and 25% were either omnivorous or seed eaters; 52% were hydrophilous, 44% mesophilous and one was xerophilous. The important number of species found in these ecoregion emphasizing its importance as a biodiversity hotspot of South American carabids. Human activities led to changes in the landscape of the Delta Islands which could favor the establishment of mesophilous and xerophilous species from other ecoregions. Seasonal carabid richness is higher in the warm seasons (spring and summer) respect to the cold (autumn and winter). Although, the highest absolute richness was found in the most anthropized habitat types, secondary forests had exclusive species, showing the importance of preserving the ecological mosaic of the landscape.