Resumo

LOPEZ, Ramiro Pablo. Prepuna shrubs and their effect on herb composition in terms of spatial scale. Ecología en Bolivia [online]. 2009, vol.44, n.1, pp.5-16. ISSN 1605-2528.

Shrubs in arid regions create more favorable microclimatic conditions beneath their crowns than open, inter-shrub areas. Several studies have documented the importance of these belowshrub spaces for the increase in plant diversity, but few have explicitly studied the influence of shrubs on herb species composition in a given region. Even worse, no studies have addressed this influence in terms of the spatial scale. In this study I compare prepuna herb communities between both microhabitats (below and away from shrubs) at eight localities in the rainy season of 2008. Moreover, I assess the influence of spatial scale on the similarity of herb communities of both microhabitats. I found differences in the species composition established beneath shrubs and in the open. Several species were found exclusively associated to shrubs. In some localities (especially those located at the lowest altitudes), under-shrub communities tended to resemble more the open-space communities of their own locality than under-shrub communities of other localities. In the highest-altitude localities I found a more complex pattern. Spatial scale did not modify the similarity relations between sites associated with shrubs and those in the open, which suggests similar beta diversities for both microhabitats. Prepuna shrubs seem to be very important for many herb species. This has implications in terms of biodiversity conservation in this Andean region.

Palavras-chave : Shrubs; Facilitation; Herbs; Prepuna; Species richness.

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