CONICET | Buscador de Institutos y Recursos Humanos

The comprehensive assessment of environmental gradients influence over the species assemblage is important for implementing new conservation strategies under climate change and conservation. This study aims to determine the multi-scale effect of altitudinal and longitudinal gradients as drivers of richness and plant community assemblages in mountain landscapes of Isla de los Estados (Argentina) to identify areas with greater conservation value at Southern Patagonia. We chose three fjords across the island that extend from West to East direction and we categorize landscapes into four ecosystem types according to their vegetation type (forests and open-lands) and elevation in lower lands (0-100 m.a.s.l.) and upper lands (300-400 m.a.s.l.). Forest structure, soil cover (woody debris, rocky outcrop and bare soil) and vegetation cover (vascular and non-vascular), including richness and growth-forms (trees, shrubs, prostrate and erect herbs, tussock and rhizomatous grasses, ferns and inferior plants) were measured in 60 sampling areas (3 fjords x 2 vegetation types x 2 elevations x 5 replicas). ANOVAs and multivariate methods were used to analyse the heterogeneity of the forest structure, plant richness, and life-form. Plus, species richness and Simpson?s diversity index were analysed to understand the plant assemblage at multiple-scale (α, β and γ). Our results showed that environmental gradients (altitudinal and longitudinal) are important drivers of change of ecosystem type plant assembles rather that forest spatial structuring. Main results showed that forest structure significantly varied with altitudinal and longitudinal gradients affecting most of the studied variables. A greater similarity (richness and cover) between open-lands of lower and higher elevations were detected, as well as between forests. Fjords showed a West-East gradient, where West and Center fjords were closely related between them than the East fjord. Multi-scale diversity approach may play a central role in improving the understanding of main environmental drivers of richness and plant community assemblage in these forests, both theoretical and empirical, and make possible to identify the spatial scale at which ecosystems type greater conservation value. This study indicates that for southern forest conservation at regional level efforts must include all environmental gradients, including the different vegetation types to assure the fully conservation of all the species assemblage.