Resumo

TORRES ROBLES, Silvia S et al. Variaciones geográficas de la estructura y composición de la vegetación leñosa en el límite entre el espinal y el monte en el Noreste de la Patagonia (Argentina). Bol. Soc. Argent. Bot. [online]. 2015, vol.50, n.2, pp.209-215. ISSN 1851-2372.

The definition of ecoregions has implications on land use, because these classifications are the basis for the formulation of management and conservation policies. Disturbances promote variations among neighboring sites, and difficult the establishment of boundaries between ecoregions. With the aim of analyzing a geographical gradient in a transitional area between Espinal and Monte regions, we characterized the structure and composition of woody vegetation in the northeastern Patagonia, and we evaluated how neighboring sites with structural differences presented compositional differences assigned to each ecoregion. Variation in floristic composition presented more important changes in E-W direction than in N-S direction, reflecting a broad transitional gradient between Espinal and Monte. The most remarkable structural changes were the decrease in height and cover of trees in opposition to shrub cover. These changes were less associated with geographical variation than compositional changes, exhibiting a more evident trend of variation in N-S direction than in E-W direction. Disturbances promote more notable changes in structure than in floristic composition, then it is less probable that they may cause a disruption in the geographical boundaries between Espinal and Monte ecoregions.

Palavras-chave : Phytogeographical boundaries; Conservation; Ecoregion; NE Rio Negro province; SW Buenos Aires province.

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