The effects of landscape - scale habitat modification on tropical bird community structure in eastern Guatemala

Habitat structure and composition affect the distribution and abundance of organisms. The landscape perspective extends the study of the determinants of species distribution from the territory and patch scale to the landscape mosaic. Furthermore, not all species are affected equally by landscape structure. Some species may benefit by changes in landscape heterogeneity, while others are negatively affected, through habitat loss and fragmentation, and this effect depends on their life-history characteristics. In this study, we evaluated the effects of landscape-scale habitat modification on the richness, abundance, and species composition of a tropical bird community in Eastern Guatemala. In general terms, we hypothesized that: 1) a reduction in habitat amount has its effects on species mainly through a decrease in population size, and consequently this direct effect is stronger than those of landscape composition and configuration; 2) bird community responses to habitat modification depend on their habitat affinity. We thus predicted that interior-forest species would be more vulnerable than forest-edge species, since the latter have adaptations to disturbed habitat that allow them to tolerate greater habitat modification. We sampled bird communities using point counts in 123 1-km radius landscapes. For each landscape, we quantified the proportional cover of native forest (the sum of primary and secondary tropical forest), forest landscape division index (as a measure of habitat fragmentation), total forest edge and the proportion of primary forest (of the total amount of native forest). Using generalized linear models, we found that: 1) habitat loss and fragmentation effects on species richness were much stronger for interior-forest species than for edge species; 2) bird abundance was insensitive to landscape configuration and composition (proportion of primary forest), and only responded to habitat loss; 3) bird species composition was affected by all landscape metrics, i.e., habitat loss, configuration (fragmentation and edge) and composition. We concluded that: 1) compared to habitat loss, landscape fragmentation effects on bird community parameters were greater in our study than in similar studies in temperate forests; 2) bird community response depended on species affinities: habitat modification effects were much greater for interior-forest species than for edge species; 3) the effects of landscape-level habitat modification vary greatly with respect to the community parameter being evaluated: effects were stronger and more varied on bird community composition and richness, but abundance was affected only by forest cover.

Bibliographic Details

Main Authors:	Cerezo, Alexis, Perelman, Susana Beatríz, Robbins, Chandler S.
Format:	Texto biblioteca
Language:	eng
Online Access:	http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=46339 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=
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