Abstract
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.https://doi.org/10.25260/EA.20.30.1.0.867
Highlights
Área de estudioLa región de Los Llanos, en la provincia de La Rioja, pertenece a la zona más árida de la región fitogeográfica del Chaco árido, particularmente a la región chaqueña occidental (Ragonese and Castiglioni 1970; Morello et al 1973)
Of arthropods and plants: Arthropod fauna diversity in a vegetation gradient in Los Llanos of La Rioja province (Argentina)
Por sus importantes funciones ecosistémicas y por su sensibilidad a cambios ambientales, se destacan como grupos indicadores, ya sea del tipo de hábitat, de la calidad del ecosistema o de los cambios ambientales, por lo que fueron incluidos en planes de manejo y monitoreo (Gerlach et al 2013)
Summary
La región de Los Llanos, en la provincia de La Rioja, pertenece a la zona más árida de la región fitogeográfica del Chaco árido, particularmente a la región chaqueña occidental (Ragonese and Castiglioni 1970; Morello et al 1973). El ambiente de Salinas (Figura 1b) presenta una alta temperatura media y un suelo arcilloso pobre en materia orgánica, con escaso desarrollo de vegetación (Ruiz Posse et al 2007; Coirini et al 2010). Un abundante estrato arbustivo de cardones y jarillas (Larrea divaricata Cav.) y un estrato más bajo de plumerillo (Trichloris crinita (Lag.) Parodi) y avenilla (Gouinia paraguayensis (Kuntze) Parodi var.), presenta una mayor estructuración vertical que el ambiente Salinas, pero menor que el Monte, ya que no tiene especies leñosas de gran envergadura. El ambiente Monte (Figura 1d) presenta mayor cantidad de materia orgánica, menor temperatura media y la mayor complejidad en la estructura vegetal de los tres ambientes, con una cobertura foliar densa. El estrato más bajo está formado por escasos plumerillo y avenilla, sin presencia de especies halófitas (Morello et al 1973; Biurrun et al 2012; Karlin et al 2013; Oyarzabal et al 2018)
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