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Urban tardigrades are studied little worldwide. In Salta (Argentina), two studies have evaluated their diversity in an urban–native gradient. Vehicular traffic in Salta city has increased over the last decade, increasing environmental pollution. Our aim is to determine whether biotic homogenization occurs in this city. Sampling sites were selected considering different vehicular traffic intensities (high, medium and low). Tardigrades were sampled from bryophytes growing on tree trunks. Specimens were treated according to the usual study methodology. Different biotic and environmental abiotic variables of the microhabitat were considered. A total of 3049 specimens of 16 species of heterotardigrades and eutardigrades were reported. The low vehicular transit habitat was more diverse than the others. Ordination analyses evidenced a nested pattern in the studied urban habitats. Milnesium sp. nov. 3 and Minibiotus sp. nov. 1 were reported as detector species for habitats with medium vehicular traffic. The partition of the β diversity showed that the species turnover was higher among low and high vehicular traffic communities than medium, whereas a loss of species was evidenced between high and medium habitats. The high diversity of tardigrades in Salta city and their assemblages are partly dependent on several factors, including vehicular traffic.

Argentine tardigrades are relatively unknown and, in many cases, unstudied; in the province of Salta in north-western Argentina the lone record of tardigrade dates to the 1980s. Here, we evaluate and compare tardigrade diversity in natural habitats (N), urban environments (U) and rural communities (R) of Yungas. This work seeks to verify the existence of a reduction in tardigrade diversity outside their native habitats and if there is a biotic homogenization in the urban communities. Tardigrade community assemblages were compared between habitats using non-metric multidimensional scaling and a multi-response permutation procedure. Beta diversity was analysed in its component parts, species turnover and nesting, using a modified Raup–Crick test. Gamma diversity was divided into alpha and several beta levels. In total, 2080 eutardigrade and heterotardigrade specimens were registered and showed differences in tardigrade assemblages between habitats; the most diverse habitat was R. The beta diversity partition showed a nesting pattern in the U communities, highlighting faunal homogenization, while species turnover was key in the R and N communities. There was species loss from N to U communities, most markedly between R and U; various forces (both stochastic and deterministic) influence the structure of these communities. Fil: Rocha, Alejandra Mariana. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina Fil: González Reyes, Andrea. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina Fil: Corronca, Jose Antonio. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Rodriguez Artigas, Sandra Mónica. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Doma, Irene Luisa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Repp, Elma Yanina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Acosta, Ximena Gisela del Milagro. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina

El incremento de la degradación de los hábitats naturales ha fortalecido la necesidad de conocer y evaluar lospatrones de biodiversidad; siendo los inventarios biológicos y la suficiencia taxonómica herramientas que permitendescribir y monitorear la diversidad en cortos períodos de tiempo. El estudio de la araneofauna en el norte Argentinoes escaso en particular en ecorregiones donde se considera prioritario conservar sus ambientes. Las arañas son utilizadas como taxón indicador para comparar patrones de biodiversidad, donde el estudio de las familias y de los gremios puede potencialmente servir como sustitutos ecológicos de las especies dando indicación del uso del hábitat y de las estrategias de forrajeo. En este estudio, analizamos la diversidad alfa y beta de las comunidades de arañas epigeas en diferentes ecorregiones de la provincia de Salta (Chaco Serrano, Monte de Sierras y Bolsones, y Puna) utilizando trampas de caída y muestreos en las cuatro estaciones del año; y testeamos si el nivel taxonómico familia, en el caso de las arañas, puede actuar como potencial sustituto del nivel especie en las evaluaciones rápidas de biodiversidad. Para ello, en cada ecorregión seleccionamos tres sitiosampliamente separados que fueron muestreados durante el otoño, invierno, primavera y verano del 2005-2007. En cada sitio se colocaron 10 trampas de caída separadas por 10 m a lo largo de una transecta lineal y con una actividad de 7 días por estación. Se recolectaron 886 arañas de 100 especies/morfoespecies correspondientes a 19 familias.La ecorregión Chaco (S = 56, N = 495) reportó la mayor riqueza de especies y abundancia comparada con el Monte (S = 44, N = 262) y la Puna (S = 23, N = 129). La completitud del inventario obtenido para cada ecorregión fue completa, superando el 70 %. La diversidad alfa y beta evidenciaron que las comunidades ecorregionales de arañas fueron diferentes. Las estaciones más frías (otoñoe invierno) demostraron ser claves a la hora de evaluar la diversidad de arañas en las ecorregiones, aportando a la diversidad regional conjuntamente con la diversidad de las estaciones cálidas (primavera y verano). Además, el nivel taxonómico de familia evidenció reflejar, de igual manera que el nivel especie, los cambios en la diversidad alfa y beta. El uso de trampas de caída en todas las estaciones del año y el reconocimiento de las familias de arañas para la fauna epigea son de gran utilidad para realizar futuras evaluaciones rápidas de biodiversidad en el área en estudio; permitiendo así incorporar este grupo taxonómico en los estudios de monitoreo de biodiversidad que se lleven a cabo en estas ecorregiones. The increased degradation of natural habitats has strengthened the need to know and assess biodiversity patterns. Particularly, the study of the spider fauna in the North of Argentina is scarce in ecoregions with priority interests of conservation. Generally, spiders are used as indicators to compare biodiversity patterns, and here we tested whether the spider family-level can act as a substitute of the species-level in biodiversity rapid assessments. For this, we analyzed the alpha and beta diversity of the epigeal spider communities in three separate sites of three ecoregions of Salta province (Chaco Serrano, Monte de Sierras and Bolsones, and Puna), during the fall, winter, spring and summer of 2005-2007. In each site, 10 pitfall traps, located along a linear transect and 10 meters apart, were placed for seven days per season of continuous activity. A total of 886 spiders were collected from 100 species/morphospecies of 19 families. The completeness of the inventory obtained for each ecoregion surpassed 70 %. The Chaco ecoregion (S = 56, N = 495) reported the highest species richness and abundance compared to Monte (S = 44, N = 262) and Puna (S = 23, N = 129). Alpha and beta diversity showed that ecoregional spider communities were different, sharing few species (0.7 %). The Chaco reported a high dissimilarity of its assemblage with respect to the other ecoregions. The colder seasons (autumn and winter) are important in assessing the diversity of spiders, contributing to regional diversity in conjunction with the diversity of warm seasons (spring and summer). Four guilds were reported (ground hunters, specialists, other hunters and ambush hunters), but the latter was absent in Monte, and the specialists dominated Chaco. Zodariidae was dominant in Chaco Serrano, where Leprolochus birabeni is an indicator of native environments. On the other hand, Lycosidae, Philodromidae, Anyphaenidae and Oonopidae were important for Monte and Puna. Year-round pitfall traps and identification of epigeal spider families are useful for biodiversity rapid assessments in this area. Like the species-level, the taxonomic family-level evidenced changes in alpha and beta diversity. This allows the inclusion of this taxonomic group for future biodiversity monitoring. Fil: Cruz, Ivanna Gabriela. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Torres, Victor Manuel. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: González Reyes, Andrea Ximena. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina Fil: Corronca, Jose Antonio. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

El estudio de la araneofauna en las Yungas argentinas es escaso. Sin embargo, es relevante debido a la alta diversidad ambiental y biológica que posee esta ecorregión, principalmente en los sistemas forestales amenazados por el avance de la frontera agropecuaria. El objetivo de este trabajo es comparar la diversidad y la composición de los ensambles de arañas epigeas en la Selva Pedemontana (SP), Selva Montana (SM) y Bosque Montano (BM) de las Yungas de la provincia de Salta. Se tomaron muestras mediante trampas de caída durante el otoño, la primavera 2006 y el verano 2007 en tres sitios de la SP, cinco en la SM, y tres en el BM. Se recolectaron 643 arañas pertenecientes a 75 especies/morfoespecies. Los ensambles de SP reportaron la mayor riqueza de especies sumado a una composición de especies muy disímil en relación con las de SM y BM. Las tejedoras espaciales, otras cazadoras y cazadoras de suelo representaron más del 95 % de la abundancia en cada comunidad. Ellas mostraron patrones semejantes de abundancia en la SM y BM, mientras que en la SP las tejedoras espaciales redujeron marcadamente su abundancia. El cambio en la configuración del paisaje debido al uso del suelo es la principal fuerza que estaría estructurando los ensambles locales de la SP. Este estudio constituye el primero en analizar la diversidad de arañas epigeas y sus gremios en las Yungas del norte argentino siendo un punto de partida para futuros monitoreos de biodiversidad en la región. The study of the arachnofauna in the argentinean Yungas is scarce. However, it is relevant due to the high environmental and biological diversity, mainly in the forest systems threatened by the advance of the agricultural frontier. The aim of this work is to compare the diversity and composition of epigeal spider assemblages in the Piedmont Forest (SP), Mountain Jungle (SM) and Mountain Forest (BM) of the Yungas in the province of Salta. Three sites of the SP and BM, and five of the SM were considered. Sampling was carried out during autumn, spring (2006) and summer (2007) with pitfall traps. A total of 643 spiders of 75 species/morphospecies were collected. The SP sites showed the highest species richness and species composition very dissimilar compared to the SM and BM. The space web weavers, other hunters and ground hunters accounted for more than 95 % of the abundance in each community considered. They showed similar patterns of abundance in SM and BM, while in SP the space web weavers markedly reduced their abundance. The change in the landscape configuration due to the land use is the main forces that would be structuring the local assemblages of the SP. This study is the first to analyze the epigeal spiders diversity and their guilds in the Yungas of the argentine north, being a starting point for future monitoring of biodiversity in the region. Fil: Torres, Victor Manuel. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Gonzalez Reyes, Andrea. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Corronca, Jose Antonio. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina

This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500-4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation-extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation. Fil: Gonzalez Reyes, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto Geonorte; Argentina Fil: Corronca, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto Geonorte; Argentina Fil: Rodriguez Artigas, Sandra Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto Geonorte; Argentina