Abstract 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 influence the spatial distribution of the organisms that offer these benefits. 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 identified, each one with an exclusive tenebrionid species assemblage and different species diversity. The most influential 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 five groups of environmental units and incorporating the darkling beetles-environment relationship in future conservation strategies for arid Patagonia.

Abstract The north of Neuquén province shares with the south of Mendoza province the subprovince Payunia of the biogeographical province of Patagonic steppe, which is characterized by the presence of approximately 800 volcanoes. Although we have conducted several samplings in volcanoes of Mendoza in past years to recognize the biodiversity of tenebrionids, it is still pending which is the role that these mountains have in the biota of tenebrionids in Neuquén. In this work we reported the results of two consecutive years of prospection in two volcanoes separated by 120 km between each other, Tromen and Auca Mahuida which have 3978 and 2215 meters above sea level respectively. We found that Auca Mahuida harbours a total diversity of 10 tenebrionid species and Tromen 9, but these communities were significantly different between them. From these prospections two new endemic species of Tenebrionidae are described: Scotobius aucamahuidensis Silvestro sp. nov. (Tenebrioninae: Scotobiini) from Auca Mahuida and Psectrascelis tromensis Flores sp. nov. (Pimeliinae: Nycteliini) from Tromen. Photographs for these two new species are included, with comparisons to other known species of these genera. Based on these results we discuss the role of different factors that influence tenebrionid diversity and their implications to conserve biodiversity.

The aim of this study was to survey the species of terrestrial mammals in the main islands of the Parque Interjurisdiccional Marino Costero Patagonia Austral (PIMCPA). This study was conducted in Leones, Tova, Tovita and surrounding smaller islands. Small mammals were surveyed with trapping; these and other species were documented with walking transects and analysis of raptor pellet. Seven species of land mammals were recorded in total. In Leones island three species were found: big hairy armadillo (Chaetophractus villosus), small big-eared brown bat (Histiotus montanus) and Norway rat (Rattus norvegicus), while in Tova and Tovita islands four species were identified: feral cat (Felis catus), southern mountain cavy (Microcavia australis), European rabbit (Oryctolagus cuniculus) and pichi (Zaedyus pichiy). The presence of introduced species could generate conflicts with marine birds nesting in these islands.

El objetivo de este trabajo fue relevar las especies de mamíferos terrestres presentes en las principales islas del Parque Interjurisdiccional Marino Costero Patagonia Austral (PIMCPA). Este estudio se desarrolló en las islas Leones, Tova, Tovita e islas menores aledañas. Los pequeños mamíferos fueron capturados con trampas; estos y otras especies fueron también registrados a partir de transectas de caminatas y análisis de egagrópilas de aves rapaces. Se registraron siete especies de mamíferos terrestres. En isla Leones se encontraron tres especies: peludo (Chaetophractus villosus), murciélago orejudo chico (Histiotus montanus) y rata noruega (Rattus norvegicus), mientras que en las islas Tova y Tovita se hallaron cuatro: gato (Felis catus), cuis chico (Microcavia australis), conejo (Oryctolagus cuniculus) y piche (Zaedyus pichiy). La presencia de especies introducidas podría generar conflictos con la avifauna marina que nidifica en estas islas.

The introduction of domestic livestock in the arid Patagonia produced changes in vegetation and soil that altered fundamental ecosystem processes, increasing desertification and biodiversity loss. In this region, it is common to observe gradients of decreasing animal activity from watering points where livestock impact is greatest near the watering sites, called piospheres, particularly suitable for assessing the efect of grazing on arid ecosystems. The aim of this study was to evaluate the efect of sheep-grazing intensity using piospheres on the structure of the vegetation and soil in shrubby steppes of Peninsula Valdes, Argentina. Variation of plant cover, vertical complexity of the vegetation, number and area of vegetated patches, micro-topography and soil compaction in relation to piosphere gradients were studied using Generalized Linear Mixed Models (GLMM) and multivariate analyses. Grazing intensity decreased according to increasing distance to the watering point. This fact, explaining more than 50% of the overall environmental variability, confirmed the existence of a piosphere gradient on each studied site. Such environmental changes were characterized by a gradual increase in grass and litter cover, vertical complexity of vegetation and soil microtopography at increasing distances from the watering point. Percentages of bare soil and gravel, cover of annual grasses and soil compaction showed the opposite pattern. This study demonstrates, for the first time, the existence of sheep piospheres in the shrubby steppes of Peninsula Valdes. Our results indicate that sheep-grazing intensity is associated with changes in the structure and composition of the vegetation and the soil characteristics that are compatible with degradation processes in the study region. Taking into account the importance of Peninsula Valdes in the context of biodiversity conservation, more studies of this type are required to implement efective management actions integrating livestock and conservation eforts on the terrestrial ecosystems of the region.

La introducción de ganado doméstico provocó modificaciones en la vegetación y en el suelo de la Patagonia extra-andina. Estos cambios alteraron procesos ecosistémicos, aumentaron la desertificación y causaron pérdida de biodiversidad. Es frecuente encontrar gradientes decrecientes de actividad animal partiendo de las aguadas (piósferas), que resultan adecuados para determinar el impacto del pastoreo sobre los ecosistemas. El objetivo de este estudio fue evaluar el efecto de la intensidad de pastoreo ovino a partir de gradientes de piósfera sobre la estructura de la vegetación y el suelo en estepas arbustivas representativas de Península Valdés, Argentina. Mediante modelos lineales generalizados mixtos (GLMM) y técnicas multivariadas se estudiaron las variaciones en la cobertura vegetal, complejidad vertical de la vegetación, número y área de parches vegetados, microtopografía del suelo y su compactación en relación con el gradiente de pastoreo. La intensidad del pastoreo disminuyó con la distancia a la aguada y explicó más de 50% de la variabilidad ambiental. Esto demuestra la existencia de efecto piósfera. La cobertura de herbáceas, mantillo, complejidad vertical de la vegetación y la microtopografía aumentaron al disminuir la presión de pastoreo en los sitios más alejados de la aguada, mientras que el porcentaje de suelo desnudo, gravas, cobertura de anuales y la compactación del suelo presentaron un patrón opuesto. Este estudio evidencia, por primera vez, la existencia de piósferas ovinas en Península Valdés e indica que la intensidad de pastoreo en la región se asocia con alteraciones ambientales compatibles con procesos importantes de degradación ecosistémica. Dada la importancia que reviste la península en el contexto de la conservación biológica de la región, se requieren más estudios de este tipo para una implementación efectiva de medidas de manejo que integren la ganadería y la conservación de los recursos naturales.

We conducted a study of the biogeographic patterns of epigean tenebrionids (Coleoptera: Tenebrionidae) that inhabit the Protected Natural Area Península Valdés (Chubut, Argentina), based on data obtained from collections and collecting trips. We present a comprehensive species list, where we detail the degree of adaptation to aridity shown by each species, an analysis of the quality of the inventory, an estimation of total species richness, and an evaluation of distribution and richness patterns, with the identification of areas of significantly greater richness or "hotspots". The results indicated that 25 species with different degrees of adaptation to aridity inhabit the peninsula, although it was estimated that the total richness of the area should be 27 species. In addition, it was recognized that the species range sizes follow a log-normal distribution and that only three species are endemic. The spatial distribution of richness was aggregate within the peninsula and we can identify 10 "hotspots". Finally, considering that in the Península Valdés are allowed productive activities that cause significant habitat degradation, we discuss the implicances that have these findings for epigean tenebrionids conservation.

Se realizó un estudio sobre los patrones biogeográficos de los tenebriónidos epigeos (Coleoptera: Tenebrionidae) que habitan el Área Natural Protegida Península Valdés (Chubut, Argentina), basado en datos de colecciones y material recolectado en viajes a la zona. Se presenta una lista exhaustiva de las especies en la que se consigna el grado de adaptación a la aridez de cada una de ellas; un análisis de la calidad del inventario y la estimación de la riqueza total de especies; una evaluación de los patrones de distribución y riqueza, y la identificación de áreas de significativa mayor riqueza o hotspots. Los resultados indicaron que 25 especies con diferente grado de adaptación a la aridez habitan la península, aunque se estima que la riqueza total del área debería ser de 27. Además, se reconoció que los rangos de distribución de los tenebriónidos siguen una distribución log-normal y que sólo 3 especies son endémicas. Espacialmente, la riqueza se distribuyó de forma agregada en la península y se determinaron 10 hotspots. Finalmente, considerando que en la península Valdés están permitidas actividades productivas que originan una importante degradación del hábitat, se examina la implicancia de los resultados para la conservación de los tenebriónidos epigeos.

Pitfall trapping is probably the most frequently used method for sampling grounddwelling arthropods. While the capture of specimens in pitfall traps largely depends on the number of individuals in the sampled area, trap design and trapping effort for a given environment, can also affect sampling success. The aim of this study was to determine the best pitfall trapping design for collecting ground-dwelling arthropods in the wind-blown and cold arid steppe areas of Patagonia. We tested four designs of traps, six types of preservative and different times of activation as well as the quantity of traps. Both preservation attributes and sampling efficiency differed between different trap designs and fluids compared. We conclude that in order to obtain reliable data on the structure of a community of ground-dwelling arthropods in Patagonia, at least three pitfall traps per experimental unit are required. In addition, traps should be opened for a minimum of 10 days filled with 300 ml of 30% ethylene glycol. We also suggested the use of a simple trap design (i. e. without funnel or roof). We believe these findings will contribute to more appropriate sampling of the ground dwelling fauna of Patagonia as well as other arid areas, leading to more reliable diversity studies.