Bird-habitat associations in coastal rangelands of southern Brazil

Nearly all remnants of temperate grasslands in southeastern South America are used for livestock ranching and are subject to habitat degradation resulting from this activity. Exploring how habitat features affect the composition of grassland avifaunal communities is a first step to understand how current cattle-ranching management practices impact avian diversity. We used canonical ordination to test for relationships between five habitat variables and the composition of the bird community in coastal grasslands in southern Brazil. We sampled pastures with different heights, from overgrazed short-grass to tall herbaceous vegetation. We recorded 1,535 individuals and 27 species of birds. The first ordination axis indicated a strong contribution of mean vegetation height on the composition of the bird community, whereas the second axis revealed the influence of herbaceous vegetation patchiness and woody vegetation cover. Three groups of species were revealed by the ordination: one more diffuse associated with intermediate and tall herbaceous vegetation, another with short grass, and a third with vegetation patchiness and woody vegetation. Species restricted to tall herbaceous vegetation are negatively impacted from habitat degradation resulting from overgrazing and trampling by livestock, and mowing and burning of tall plants. Occurrence of these species in our study area is related with the presence of swales immediately behind the dune system and where remnants of tall vegetation persist. Birds of pastures with ample cover of short herbaceous plants, including one globally threatened species and six other restricted to short-grass habitat, apparently benefit from local livestock management practices. Woody vegetation possibly functions as a keystone structure, enabling the occurrence in grasslands of avian species that rely on shrubby habitat. Although livestock ranching promotes the diversity of habitats by creating distinct patches of vegetation height in grasslands, current management practices directed to the maintenance of short grass pastures may eliminate an entire subset of species, including regionally threatened taxa, and reduce avian diversity. The maintenance of large patches of tall herbaceous plants is needed to ensure the survival of species reliant on this type of grassland structure in our study area

Willet (Tringa semipalmata) status update in southeastern South America

Se reevaluó el estatus del Playero Ala Blanca (Tringa semipalmata) en el sudeste de Sudamérica, sobre la base de nuevas observaciones, revisiones de literatura y de bases de datos ornitológicos en línea. Pese a los escasos reportes previos, nueva información sugiere que el Playero Ala Blanca es de presencia regular, si bien en bajos números, en la región. En el área se registraron tanto la subespecie oriental (T. s. semipalmata) como la occidental (T. s. inornata), lo cual extiende hacia el sur el rango conocido de distribución no reproductiva del Playero Ala Blanca Occidental: reportando nuevos registros para la Provincia de Buenos Aires en Argentina, los Departamentos de Montevideo y Maldonado en Uruguay y el Estado de Rio Grande do Sul en Brasil. Confirmamos la presencia del Playero Ala Blanca Oriental por primera vez en Uruguay y proporcionamos nuevos registros de esta subespecie para Argentina y Brasil. Finalmente, aportamos los primeros registros de sobre-veraneantes de las razas Oriental y Occidental para el cono sur.We reevaluated the status of Willets (Tringa semipalmata) in southeastern South America on the basis of new observations and reviews of literature and on-line ornithological databases. Despite relatively few previous reports, our new data indicate that Willets are regularly present in low numbers in the region. Both Eastern (T. s. semipalmata) and Western (T. s. inornata) Willet subspecies were recorded in our study area. We extended the Western Willet’s known wintering range southward reporting new records from Buenos Aires province in Argentina, Maldonado and Montevideo departments in Uruguay, and Santa Catarina and Rio Grande do Sul states in Brazil. We confirmed the presence of Eastern Willet for the first time in Uruguay and added new reports for Argentina and Brazil. Finally, we provided the first records of over-summering Western and Eastern Willets remaining in southeastern South America during the Austral winter.Fil: Martínez Curci, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Azpiroz, Alejandra Elizabeth. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Gianuca, Andros T.. Katholikie Universiteit Leuven; BélgicaFil: Gianuca, Dimas. Projeto Albatroz; BrasilFil: Simpson, Rick E.. Wader Quest; Reino UnidoFil: Dias, Rafael A.. Universidade Federal de Pelotas; Brasi

Urbanization drives cross‐taxon declines in abundance and diversity at multiple spatial scales

Abstract The increasing urbanization process is hypothesized to drastically alter (semi‐)natural environments with a concomitant major decline in species abundance and diversity. Yet, studies on this effect of urbanization, and the spatial scale at which it acts, are at present inconclusive due to the large heterogeneity in taxonomic groups and spatial scales at which this relationship has been investigated among studies. Comprehensive studies analysing this relationship across multiple animal groups and at multiple spatial scales are rare, hampering the assessment of how biodiversity generally responds to urbanization. We studied aquatic (cladocerans), limno‐terrestrial (bdelloid rotifers) and terrestrial (butterflies, ground beetles, ground‐ and web spiders, macro‐moths, orthopterans and snails) invertebrate groups using a hierarchical spatial design wherein three local‐scale (200 m × 200 m) urbanization levels were repeatedly sampled across three landscape‐scale (3 km × 3 km) urbanization levels. We tested for local and landscape urbanization effects on abundance and species richness of each group, whereby total richness was partitioned into the average richness of local communities and the richness due to variation among local communities. Abundances of the terrestrial active dispersers declined in response to local urbanization, with reductions up to 85% for butterflies, while passive dispersers did not show any clear trend. Species richness also declined with increasing levels of urbanization, but responses were highly heterogeneous among the different groups with respect to the richness component and the spatial scale at which urbanization impacts richness. Depending on the group, species richness declined due to biotic homogenization and/or local species loss. This resulted in an overall decrease in total richness across groups in urban areas. These results provide strong support to the general negative impact of urbanization on abundance and species richness within habitat patches and highlight the importance of considering multiple spatial scales and taxa to assess the impacts of urbanization