<p>Forests provide several ecosystem services that support the livelihoods of millions of forest-dependent people in lower- and middle-income countries. Provisioning of ecosystem services is directly linked to the maintenance of forest biodiversity, which in turn is influenced by human activities. We leveraged a unique dataset of plot-level tree species data from 322 tropical community forests to analyse the joint effects of demographic, socioeconomic and institutional factors on forest biodiversity, as such impacts have been rarely assessed simultaneously. We find that percentage of poor households and community reliance on fuelwood are associated with lower richness. Over time, forests in areas with higher population density and increasing numbers of poor households experienced declines in local species richness, with dominant species being the most affected. In contrast, forests in areas where households have increased their reliance on subsistence crops are associated with positive changes in species richness and these changes took place across rare, common and dominant species. Social and institutional factors (livestock presence and governance arrangements) showed no association with species richness losses or gains over time. Our analyses suggest that interventions aimed at reducing poverty may create positive effects on community forest diversity and thus on the ecosystem services these forests provide.</p>