Abstract All animals, through their behaviours, modify their habitats. However, except for ecosystem engineers, for most species we know little about these modifications and their ecological consequences. Here, we assessed whether mantled howler monkeys in Mexico, through group defecations under sleeping trees, create microhabitats in the understory through increased dung beetle and rodent activity. In defecation and control sites, we sampled dung beetles with pitfall traps and rodents with camera traps. We also used experimental stations to measure dung removal and secondary seed dispersal by dung beetles and seed predation/removal by rodents. Supporting our hypothesis, we found that defecation sites had higher abundance of beetles and prolonged rodent visitation after one day and higher seed predation/removal after seven days. However, we found no differences in dung removal or secondary seed dispersal by dung beetles between defecation and control sites. Finally, contrary to our prediction, defecation sites had fewer photo records of rodents than control sites. Overall, our study shows that monkey group defecations under sleeping trees can create short-term microhabitat heterogeneity, although not necessarily in the expected direction. The next step will be to determine whether such effects can have longer-term consequences for forest ecology, such as promoting plant species coexistence.
Andresen et al. (Thu,) studied this question.