14 research outputs found

    Spatial distribution and tree cover of hillside and ravine forests in Uruguay: the challenges of mapping patchy ecosystems

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    The mapping and monitoring of forest ecosystems on a national scale is key to their management and conservation. Native forests in Uruguay are considered given their importance for biodiversity and ecosystem services. Here we evaluate the spatial distribution of the land cover class ‘hillside and ravine forest’ —a subclass of native forest characterized by patches and transition zones with native grasslands— using Landsat images (30 x 30 m) from 2014 and 2015 and high-resolution images from Google Earth. To evaluate spatial heterogeneity within hillside forests, we then used highresolution SPOT images of 1 km2 from 1998-2012 to evaluate differences in the normalized difference vegetation index (NDVI) among canopy coverage categories. The hillside and ravine forest class were characterized as a composite cover class with an average canopy coverage of 69 ± 23%, variability of wich was reflected in NDVI values. The total area of this class in 2015 was estimated as 334,480 ha, somewhat less than an earlier 2008 estimate (384,240 ha). Among the potential errors in delineating hillside forests using Landsat images, there was the classification of «forest» in areas characterized by grassland and a tree canopy cover <25 %. This potential error in delimitation at broader scales led to the overestimation of hillside and ravine forest area in southeastern Uruguay, but an underestimation in northern Uruguay. Our study highlights the large discrepancies in the estimation of the distribution of hillside and ravine forest at different spatial scales, and also indicates the potential of NDVI to evaluate the heterogeneity of this forest within the same cover class

    Use of Cross-Taxon Congruence for Hotspot Identification at a Regional Scale

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    One of the most debated problems in conservation biology is the use of indicator (surrogate) taxa to predict spatial patterns in other taxa. Cross-taxon congruence in species richness patterns is of paramount importance at regional scales to disclose areas of high conservation value that are significant in a broader biogeographical context but yet placed in the finer, more practical, political context of decision making. We analysed spatial patterns of diversity in six arthropod taxa from the Turkish fauna as a regional case study relevant to global conservation of the Mediterranean basin. Although we found high congruence in cross-taxon comparisons of species richness (0.241<r<0.645), hotspots of different groups show limited overlap, generally less than 50 per cent. The ability of a given taxon to capture diversity of other taxa was usually modest (on average, 50 percent of diversity of non-target taxa), limiting the use of hotspots for effective conservation of non-target groups. Nevertheless, our study demonstrates that a given group may partially stand in for another with similar ecological needs and biogeographical histories. We therefore advocate the use of multiple sets of taxa, chosen so as to be representative of animals with different ecological needs and biogeographical histories

    IdentificaciĂłn de grupos genĂ©ticos y distribuciĂłn de la variabilidad de papas silvestres para su conservaciĂłn en colecciones nĂșcleo y uso en mejoramiento genĂ©tico. [Resumen]

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    En Uruguay, Argentina y el sur de Brasil se distribuyen parientes silvestres de la papa como Solanum commersonii, S. malmeanum y S. chacoense. Presentan resistencia a varios estreses biĂłticos y abiĂłticos, gran adaptabilidad a nuestros ambientes y amplia diversidad genĂ©tica. Este proyecto busca, en paralelo con un proyecto de Embrapa Clima Temperado en Brasil, caracterizar genĂ©tica y morfolĂłgicamente los parientes silvestres de la papa de Uruguay y sur de Brasil y construir colecciones nĂșcleo