Microclimates slow and alter the direction of climate velocities in tropical forests

Abstract Climate velocity—the speed and direction species must move to track climate change—is often estimated without accounting for vegetation-driven microclimatic variation. Using mechanistic microclimate models parameterized with three-dimensional maps of topography and vegetation structure, here we show that microclimate heterogeneity reduces the magnitude and alters the direction of climate velocity for maximum and minimum temperatures. For understory-dwelling organisms, the magnitude of maximum temperature velocity was halved and generally oriented towards areas with dense vegetation. For canopy-dwelling organisms, the magnitude of maximum temperature velocity was nearly zero, with vectors oriented vertically downward. These results demonstrate that vegetation complexity produces localized microrefugia, enabling short-term persistence of species under warming conditions. Our findings emphasize the need to integrate fine-scale habitat heterogeneity into predictions of climate resilience and highlight the value of structurally complex forests in providing microclimatic refugia.