CONICET | Buscador de Institutos y Recursos Humanos

Tropical forest destruction and fragmentation of habitat patches may reduce population persistence atthe landscape level. Given the complex nature of simultaneously evaluating the effects of these factors onbiotic populations, statistical presence/absencemodelling has become an important tool in conservationbiology. This study uses logistic regression to evaluate the independent effects of tropical forest coverand fragmentation on bird occurrence in easternGuatemala. Logistic regressionmodelswere constructedfor 10 species with varying response to habitat alteration. Predictive variables quantiﬁed forest cover,fragmentation and their interaction at three different radii (200, 500 and 1000m scales) of 112 pointswhere presence of target species was determined. Most species elicited a response to the 1000m scale,whichwas greater thanmost species reported territory size. Thus, their presence at the landscape scale isprobably regulated by extra-territorial phenomena, such as dispersal. Although proportion of forest coverwas the most important predictor of species presence, there was strong evidence of area-independentand -dependent fragmentation effects on species presence, results that contrast with other studies fromnorthernmost latitudes. Species habitat breadth was positively correlated with AIC model values, indi-cating a better ﬁt for species more restricted to tropical forest. Species with a narrower habitat breadthalso elicited stronger negative responses to forest loss. Habitat breadth is thus a simple measure thatcan be directly related to species vulnerability to landscapemodiﬁcation.Model predictive accuracywasacceptable for 4 of 10 species, which were in turn those with narrower habitat breadths.