Efeitos da fragmentação florestal sobre a diversidade de lagartos da região metropolitana de Manaus

Abstract

The changes in land cover resulting from human activities have the potential to transform natural landscapes into disturbed environments, exerting a significant impact on lizard communities. According to the habitat amount hypothesis (Fahrig, 2013), preserving or restoring a substantial amount of habitat in the local landscape is crucial to maintaining the ecological functions of these species in urbanized environments. Thus, lizards, sensitive to urbanization processes, stand out as a valuable model for investigating the effects of landscape modifications due to urbanization, emphasizing the importance of considering not only changes in landscape configuration but also the total amount of habitat. Our assessment focused on lizard assembly responses in 38 forest sites located along rural-urban gradients in the Central Amazon. We tested how lizard richness, abundance, and assembly composition vary in relation to local variables describing microenvironments, as well as variables describing landscape composition and configuration. We used generalized linear models to generate different combinations of predictor variables for response variables and employed non-metric multidimensional scaling to characterize the similarity of lizard assembly composition among sites. Our analyses revealed that among the predictor variables, edge density significantly influences lizard richness. Forests with higher edge influence tend to exhibit lower lizard richness. Furthermore, according to our models, lizard abundance tends to increase with rising air temperature. However, it is important to note that this increase may be associated with opportunistic species less sensitive to urbanization. Regarding composition, we observed less pronounced variation along the rural-urban gradient. While Amazonian endemic species occur in urban forest fragments, most species found in urban forest remnants are associated with more preserved environments. Our results underscore the importance of considering not only the effects of urbanization on landscape configuration but also the amount of preserved habitat to maintain the ecological diversity of lizard communities in urbanized environments. Lastly, the lizard assembly in the Metropolitan Region of Manaus is more influenced by large-scale landscape metrics than by specific local conditions, urban forest remnants harbor endemic species, and larger cities tend to have more generalist species. Long-term monitoring is crucial for understanding and conserving lizard diversity in the Amazon, with the aim of reducing fragmentation and population isolation.