Sapos na metrópole: como os anuros diurnos respondem às mudanças da paisagem causadas pela urbanização na Região Metropolitana de Manaus

Abstract

Urbanization is one of the main causes of the loss and reduction of global biodiversity. Changes in landscape cover and fragmentation of native vegetation due to human activities in urban areas destroy habitats and microhabitats used by native species and generate negative impacts on the balance and maintenance of ecosystems and natural environments. Amphibian anurans are among the most affected groups due to the close relationship between their reproductive processes and aquatic and humid environments, highly affected by urbanization processes. In our study, we evaluated the responses of the diurnal anuran community to changes in the landscape caused by the urbanization process in the Metropolitan Region of Manaus. We first assessed which scale best explains the effects of landscape metrics on the assemblage and then determined which landscape metrics and local environmental variables exert greater influence on anuran community richness and composition. We collected local variables and landscape metrics in 41 sites, distributed in six cities located in the Metropolitan Region of Manaus. At these sites, we performed audio recordings using autonomous recorders to assess the richness of diurnal anurans and analyzed the effects of local environmental variables and the characteristics of the surrounding landscape on the richness of diurnal anuran assemblages. We used generalized linear models (GLM) to assess the influence of predictor variables on anuran richness and non-metric multidimensional scaling to compare species composition (presence and absence) across sample sites. We found that landscape metrics at smaller scales responded better to data distribution. Both local environmental variables and landscape metrics explained variations in richness across sample sites. Although not expected, forest cover had a negative influence on frog richness, indicating that more urbanized areas with less forest cover also contribute to the diversity of diurnal frogs in cities. We observed an overlap between the composition of assemblages from more conserved sites and more anthropized sites. Possibly the anuran assemblages of sites with reduced forest cover include both sensitive and resilient species to urbanization, which would explain the similarity with sites with less forest cover. It is necessary to develop more studies in urbanized landscapes in the Amazon in order to better understand the response of frogs to other local and landscape metrics, but we emphasize here the importance of the quality of urban forest fragments for the maintenance of biodiversity