Dieta da lontra longicaudis (Olfers, 1818) em ambientes antropicamente alterados: a predação de espécies invasoras em diferentes escalas

Abstract

Freshwater ecosystems are central for maintaining their dynamic balance and environmental health. Among their biggest threats are the degradation of environmental habitats, changes in their flows due to dams, besides the introduction of invasive species. These anthropogenic factors have altered many environments that nowadays can be called “Novel aquatic ecosystems”. Since climate change tends to increase the expansion of some aquatic invasive species, it is important to understand the aspects which restrict the action of predators such as Neotropical otters on these species in these new ecosystems. Once these mustelids possess ecophysiological and behavioral characteristics that drive them to optimal foraging and selection of their prey. Therefore, monitoring the trophic networks that contain these ecosystems and their changes is essential for understanding complex relationships, anticipating global changing scenarios and analyzing the potential for controlling invasive species by otters based on natural processes (e.g. predation). Firstly, a review and scientometrics on the predation of non-native species by Lontra longicaudis, investigated relevant aspects of the trophic ecology of the mustelid, such as the choice of groups of fish according to their mobility and whether the studies with these records were made in areas with human influences, such as urban environment, agropastoral landscapes and the presence of dams. The case study aimed to describe the composition of the Neotropical Otter diet during the severe ENSO drought (2015- 2016) and the beginning of the resumption of rain (predominance of floods), by investigating whether there is an influence of ENSO and which prey groups and species vary due to the pluviometric regime in a degraded landscape with potential occurrence of invasive aquatic species over five years. Among the conclusive aspects, it can be noticed that, in general, otters consume more invasive slow-movement species that are widely distributed in the Neotropics and have high invasive potential. Furthermore, there were the first records of invasive species in the species' diet, which are also proven to be harmful to aquatic ecosystems. Moreover, there was the first record of the presence of microplastics and percentages of complementary prey (Insects and amphibians) record for the species. These findings highlight major changes in prey communities and degradation of the local ecosystem.