Abstract

BAUDINO, Florencia; CECCHETTO, Nicolás R; BUFFA, Liliana M  and  VISINTIN, Andrés M. Of arthropods and plants: Arthropod fauna diversity in a vegetation gradient in Los Llanos of La Rioja province (Argentina). Ecol. austral [online]. 2020, vol.30, n.1, pp.63-76. ISSN 1667-782X.

Given the fundamental role of arthropods and insects in the functioning of arid ecosystems, it is of key importance to understand their relationships with the environment, particularly for the development of future conservation efforts. Within the phytogeographic region of Chaco, in Los Llanos (La Rioja province, Argentina), great changes in vegetation occur within short distances, determining a pronounced gradient of plant heterogeneity. The aim of this study was to analyse the response of epigaeic arthropods to these changes. In this gradient, three environments were selected (Salinas, Interface and Monte), in which we collected arthropods and insects using fall traps during seven days during the warm season. Total abundance of arthropods and insects, and richness of insect species/morpho-species were determined. The association between the environments and the abundance and richness of species was evaluated by repeated measurements ANOVA. Nonparametric richness estimators (Chao₁, Jackniffe₁ and Bootstrap) and their species accumulation curves were used to test sampling completeness. To assess the structure of the insect community we used range-abundance curves and multivariate analysis. A total 8380 arthropods was collected, of which 5902 were insects grouped into 14 orders, 31 superfamilies, 35 families and 114 species/morphospecies. The environment with the greatest plant heterogeneity (Monte) presented the greatest abundance of arthropods and the greatest abundance and richness of insects. The most abundant and richest insect families were Formicidae (Hymenoptera) and Tenebrionidae (Coleoptera). Chao₁ and Bootstrap were the best richness estimators. In this study, we found that the abundance, richness and composition of arthropod species, particularly insects, were associated to a vegetation gradient.

Keywords : Variability; Epigaeic entomofauna; Indicators; Soil; Chaco ecoregion; La Rioja.

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