ANT-MEDIATED PREDATION IS MORE SENSITIVE TO LAND-USE CHANGE THAN SEED DISPERSAL IN THE BRAZILIAN AMAZON
Seed dispersal · Insect predation · Seed cleaning · Foraging behavior · Land-
use change
Land-use changes in the Amazon, primarily driven by agricultural expansion and cattle ranching, have altered biodiversity and compromised key ecological functions, such as seed dispersal and insect predation. In this context, ants play a key role in these processes and respond differently to environmental changes. Here, we investigated the effects of different land-use types on ant-mediated seed dispersal and insect predation in forest, pasture, shifting cultivation, and agroforestry systems in the Brazilian Amazon. We evaluated the richness, composition, behavior, and foraging strategies of ants associated with these ecological functions. We found higher richness of seed-interacting ants in forest environments, associated with a distinct species composition compared to anthropogenic environments. In contrast, the richness of predatory ants remained similar across land- use types, although species composition also varied along the environmental gradient. Seed removal rates did not differ among environments, suggesting functional stability despite changes in ant assemblage composition. Conversely, insect predation was higher in anthropogenic environments, particularly in shifting cultivation and SAFs. Solitary foraging predominated across all functions and environments evaluated, whereas seed-cleaning behavior was the most frequent interaction observed between ants and seeds. Our results indicate that ant-mediated ecological functions respond differently to land-use change, with seed dispersal remaining relatively stable while insect predation was more sensitive to environmental alterations. These findings reinforce the importance of considering not only assemblage composition, but also behavioral traits, to better understand the effects of anthropogenic disturbance on Amazonian ecosystems.