Process of biological invasion of fishes in Neotropical reservoirs: in search of general patterns that determine the success of invasive alien species in these systems.

Abstract

Knowledge of the controlling mechanisms of the invasion process is a current challenge in ecology. This knowledge becomes extremely important since the introduction of alien species has become widespread and has important implications for the wildlife conservation. Currently, studies have shown that alien species can cause several environmental impacts, such as biotic homogenization and destabilization of the native community, being considered one of the main threats to biodiversity and loss of ecosystem services. To investigate the process of fish invasion in reservoirs in the neotropical region, 29 reservoirs that have different environmental and biological invasion scenarios were used. In the first approach, we evaluated the importance of three hypotheses’ concept clusters of biological invasions in the studied reservoirs. Among all the hypotheses tested for biological invasion, the results corroborated the increased resource availability and biotic acceptance hypothesis. In the second approach, we assess whether the functional indices that represent niche overlap/complementarity between native species are predictors of the dominance of alien species in the environment. The results indicate that the dominance of alien species is greater when the uniformity of available resources is greater and the probability of competition between native species is less. It was also possible to observe that the smaller the niche complementarity of the more abundant native species, the lower the dominance of alien species. The results generated by the two approaches provide important information about the mechanisms that lead to the increase of alien species in the studied reservoirs. This information is extremely important for programs for the management of invasive species.