Running title: DETERMINANTS OF TENEBRIONIDAE IN PENÍNSULA VALDÉS Academy Section: ECOSYSTEMS

Arid lands provide several products and services to humankind, but human activities affect this environment, increasing the extinction risk of the native species. Thus, to successfully conserve the biodiversity of these ecosystems, it is necessary to identify which environmental factors infl uence the spatial distribution of the organisms that offer these benefi ts. Darkling beetles play a relevant role on the functioning of deserts. Although these insects are among the most abundant and diverse in these environments, there is no agreement on the relative importance that different environmental factors have as determinants of their spatial distribution. In this work, we assessed the role of climate, vegetation, and soil variables as factors that determine distribution patterns of darkling beetles within the Natural Protected Area Península Valdés (Northeastern Patagonia). Five groups of environmental units were identifi ed, each one with an exclusive tenebrionid species assemblage and different species diversity. The most infl uential environmental variables were temperature, precipitations, and soil texture. Results suggest that the magnitude of several ecosystem processes may vary among the groups of environmental units. We recommend prioritizing the conservation of the fi ve groups of environmental units and incorporating the darkling beetles-environment relationship in future conservation strategies for arid Patagonia.