Resumo

TORRICO-PAZ, Stephanie et al. Baccharis boliviensis (Asteraceae), a key species in Andean semiarid environments?. Ecología en Bolivia [online]. 2018, vol.53, n.2, pp.92-112. ISSN 1605-2528.

The importance of acquiring knowledge about the structure and dynamics of arid and semiarid environments in Bolivia is crucial, considering that these environments occupy a large part of Bolivian territory and are greatly degraded, with few patches in a good conservation state. The study of spatial patterns is considered appropriate to begin to understand ecosystems and their dynamics, allowing to make future plans for conservation and restoration afterwards. The present study was carried out in two sites within La Paz valley: Collana and Mecapaca, in order to understand the processes that structure these communities. Wooden individuals were recorded and measured in a single plot per locality, the pair correlation index g (r) was used for univariate and bivariate analyzes around the first 500 centimeters using three different null models. In total, 840 individuals in Mecapaca were measured, and 721 in Collana, recording five and six species, respectively. Most of the recorded species showed an aggregated pattern, this being stronger in Collana than in Mecapaca. In both sites, positive associations between most of the species and B. boliviensis were found making it likely that this species might be a keystone species that allows survival of other woody plants (biotic facilitation). Future studies about the relationship between woody and herbaceous species, and also the spatial relations between Prosopis alba (Mesquite tree) and B. boliviensis and other woody species may allow us to further gain insight into the structure and dynamics of these communities.

Palavras-chave : Aggregation; Facilitation; Interandean dry valleys; Plant community; Spatial patterns.

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