Direct and indirect effects of fragmentation on nest web

Direct and indirect effects of fragmentation on nest web. - The understanding of factors that influence or maintain community structure is essential for biodiversity conservation. There is an increasing interest in fragmentation effects in community structure due to the interference in species interaction, habitat structure, and ecosystem processes. In this study, we evaluated the potential of three hypothesis on the relationship of patch size of the web of cavity nests using "structural equation modeling." From 2007 to 2008 birds nesting in cavities were sampled and the density of snags and cavity nests of nine Atlantic forest remnants were measured. The path analysis supported the hypothesis that patch size affected the secondary cavity nesters (Dendrocolaptidae) directly and indirectly. The indirect effect is mediated through changes in cavity availability. Contrary to the expectations, there was no significant relationship between primary cavity nesters (Picidae) and secondary nesters through the cavity nest. These results highlight the interference of patch size on web nest mainly of secondary cavity nesters that were more vulnerable in fragmented landscape.