Influência da urbanização no risco de predação de lagartas artificiais: há como prosperar numa selva de concreto?

Abstract

An undeniable consequence of urban growth is the loss of biodiversity, especially in urban green areas. These areas, be them squares, parks or even gardens, are of great importance for the conservation of biodiversity within cities. In this context, local characteristics of green areas, as well as the landscape structure in their surroundings, are related to the maintenance of biodiversity. In addition, following the conservation of biodiversity, ecological processes and services are also maintained, which in turn provide a better quality of life within cities. Therefore, the understanding of how ecological processes are affected by urbanization can help the conservation of the urban ecosystems. However, studies aimed at understanding the effects of urbanization on ecological processes are scarce, especially in tropical cities. Therefore, the present study aims to fill this gap, analyzing the influence that urbanization has on predatorprey relationships, using artificial caterpillars. In ten urban green areas located in the city of Manaus, we studied the effect of local characteristics of green areas and the level of urbanization in which they are inserted (considering structural characteristics of the landscape present in the surroundings of these areas) on the predation pressure of artificial prey, to investigate the variation of the abundance and the different types of predators among the green areas. In each location, we distributed 100 artificial caterpillars, made with green plasticine, among five plots within each green area, and the models were left in each location for 4 days. We observed a clear influence of structural features of the landscape on the abundance of predators, with the amount of surrounding forest cover being the most important factor in our results. This study emphasizes the importance of maintaining green areas in cities in a green urban context to maintain certain relevant ecological processes, such as interactions between predators and prey, which may have important regulatory functions in cities.