Journal Article

Bird Metacommunities in Temperate South American Forest: Vegetation Structure, Area, and Climate Effects

Meynard, Christine N., Quinn, J. F.

2008

Overview

Spatial structure in metacommunities and their relationships to environmental gradients have been linked to opposing theories of community assembly. In particular, while the species sorting hypothesis predicts strong environmental influences, the neutral theory, the mass effect, and the patch dynamics frameworks all predict differing degrees of spatial structure resulting from dispersal and competition limitations. Here we study the relative influence of environmental gradients and spatial structure in bird assemblages of the Chilean temperate forest. We carried out bird and vegetation surveys in South American temperate forests at 147 points located in nine different protected areas in central Chile, and collected meteorological and productivity data for these localities. Species composition dissimilarities between sites were calculated, as well as three indices of bird local diversity: observed species richness, Chao estimate of richness, and Shannon diversity. A stepwise multiple regression and partial regression analyses were used to select a small number of environmental factors that predicted bird species diversity. Although diversity indices were spatially autocorrelated, environmental factors were sufficient to account for this autocorrelation. Moreover, community dissimilarities were not significantly related to distance between sites. We then tested a multivariate hypothesis about climate, vegetation, and avian diversity interactions using a structural equation modeling (SEM) approach. The SEM showed that climate and area of fragments have important indirect effects on avian diversity, mediated through changes in vegetation structure. Given the scale of this study, the metacommunity framework provides useful insights into the mechanisms driving bird assemblages in this region. Taken together, the weak spatial structure of community composition and diversity, as well as the strong environmental effects on bird diversity, support the interpretation that species sorting has a predominant role in structuring avian assemblages in the region.

• Publisher: Ecological Society of America,Wiley
• Subject: Animal and plant ecology / Animal, plant and microbial ecology / Animals / area effect / Aves / Biodiversity / Biological and medical sciences / Birds / Birds - physiology / Chile / Climate / Climate effects / Climate models / climatic factors / Cluster Analysis / Community composition / community structure / Conservation biology / dissimilarity / diversity / Diversity indices / Ecosystem / Environmental effects / Environmental factors / Environmental gradient / Forest ecology / Fundamental and applied biological sciences. Psychology / General aspects / habitat fragmentation / Life Sciences / metacommunity / Old growth forests / Patagonia / physiology / Plants / Population Dynamics / Protected areas / Rainforests / richness / Species / Species composition / Species diversity / Species richness / species sorting / Studies / temperate forest / Temperate forests / Trees / turnover rates / Understory / Vegetation / Vegetation structure / Vegetation surveys / Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution / wild birds