A defaunação interfere negativamente no comportamento e funções ecológicas de mamíferos e aves terrestres na Amazônia

Abstract

Defaunation leads to the alteration of ecological functions essential for natural ecosystems, such as predation, seed dispersal, and nutrient cycling. In recent decades, exclusion experiments have become a useful approach to investigate the impacts of wildlife loss on seedlings species diversity, but are seldom used to assess the impact of defaunation on ecological functions. In this context, we aimed to evaluate how ecological functions in a neotropical forest may be altered due to changes in the occurrence and frequency of behaviors exhibited by terrestrial vertebrates in areas simulating different levels of experimental defaunation: non-defaunated (control), intermediate (partial exclosure), and severe (total exclosure). Additionally, we questioned whether behaviors change more seasonally in non-defaunated areas than in defaunated experimental treatments. We recorded and quantified vertebrate behaviors within different treatments using camera traps, grouping species into functional groups. Behaviors were categorized as feeding, excretion or defecation, bioturbation, and trampling and weighted by species body size. We revealed that the weighted frequency of all behaviors was drastically reduced (> 95% reduction for trampling, feeding and bioturbation, and defecation) under severe defaunation conditions. During the dry season, there was an increase in the number of behavior records, mainly defecation or scent marking, with an emphasis on large rodents and small mammals in defaunated treatments. In the rainy season, bird records stood out, particularly in bioturbation and feeding behaviors. The removal of medium and large terrestrial mammals and birds led to a significant loss of behaviors, potentially reducing the services provided by tropical forests as a whole.