Predation on artificial caterpillars following understorey fires in human-modified Amazonian forests

Tropical forests are facing several impacts from anthropogenic
disturbances, climate change and extreme climate events, with potentially
severe consequences for ecological functions, such as predation on
folivorous invertebrates. Folivory has a major influence on tropical
forests by affecting plant fitness and overall seedling performance.
However, we do not know whether predation of folivorous arthropods by
birds, mammals, reptiles and other arthropods is affected by anthropogenic
disturbances such as selective logging and forest fires. We investigated
the impacts of both pre-El Niño human disturbances and the 2015-2016 El
Niño understorey fires on the predation of 4,500 artificial caterpillars
across 30 Amazonian forest plots. Plots were distributed in four pre-El
Niño forest classes: undisturbed, logged, logged-and-burned and secondary
forests, of which 14 burned in 2015-16. We found a higher predation
incidence in forests that burned during the El Niño in comparison to
unburned ones. Moreover, logged-and-burned forests that burned again in
2015-16 were found to have significantly higher predation incidence by
vertebrates than other forest classes. However, overall predation
incidence in pre-El Niño forest disturbance classes was similar to
undisturbed forests. Arthropods were the dominant predators of artificial
caterpillars, accounting for 91.5% of total predation attempts. Our
results highlight the resilience of predation incidence in human-modified
forests, although the mechanisms underpinning this resilience remain
unclear.