What do we know about seed dispersal by Carnivorans in Brazil?

Abstract

Seed dispersal plays a key role in resource provision and climate regulation, yet this interaction is threatened by habitat fragmentation, species loss and population declines. Carnivoran mammals contribute substantially to ecosystem functioning through various roles such as predators, but their role as seed dispersers is not well-understood. We assessed the state-of-knowledge and identified gaps regarding seed dispersal by omnivorous Carnivora that occur in Brazil. A systematic literature review was conducted to examine Carnivora–fruit interactions across four stages of the dispersal loop, namely: 1) frugivory and diet; 2) seed passage through the digestive tract; 3) patterns of seed deposition; and 4) their impact on seedling establishment. Based on 53 papers we found that three species (Cerdocyon thous, Nasua nasua and Potos flavus) concentrated more than 60 % of the studies, with the remaining eight species received less attention. Studies were largely concentrated in the Atlantic Forest, in most populated urban areas, with no studies conducted in the Pantanal biome. Still, large areas remained unexplored. Despite increasing interest in Carnivora–fruit interactions in the last years, only one study addressed the four stages of the dispersal loop, preventing us to compare seed dispersal effectiveness across species. Carnivorans interacted with 132 plant species, dispersing seeds from 0.35 to 340 m, with average seed germination of 48 %. We discussed potential explanations for the identified knowledge gaps and propose ways to fill this biodiversity shortfall, emphasizing the need for more comprehensive studies to establish a robust foundation of the role played by Carnivora in seed dispersal ecology.