Most predictions of climate change effects in the tropics are based on anticipated alterations to ecosystem productivity, resulting from bottom-up changes in biogeochemistry or growth responses to greenhouse gases. However, the future functioning of ecosystems may be more strongly impacted by shifts in species composition and abundance that are determined in large part by species interactions. Four talks will highlight critical classes of interaction that influence tropical biota and their sensitivities to climate change: (i) mycorrhizal mutualisms interactions associated with nutrient uptake; (ii) plant-pollinator interactions; (iii) seed dispersal mutualisms; (iv) density-dependent population regulation resulting from herbivores and pathogens. Our discussion will focus on how to develop a framework to incorporate species interactions into climate change projections, guidance for researchers interested in documenting and detecting change phenomena, and potential case studies/systems that can be investigated across multiple sites.