Negative impacts of discrete, short‐term disturbances to wildlife populations are well‐documented. The consequences of more gradual environmental change are less apparent and harder to study because they play out over longer periods and are often indirect in their action. Yet, they can drive the decline of wildlife populations even in seemingly pristine and currently well‐protected habitats. One such environmental change is a successional shift in a community's species composition as it regenerates from disturbance caused by past human land use. Early and middle successional tree species often provide key foods to folivores and frugivores, but the abundance of these resources drops as the forest matures, with adverse repercussions for these consumers. Our 44‐year record (1974–2018) of howler monkey (
Abstract in Spanish is available with online material.