Acquisitive traits improve seedling survival with drought at the edges of a fragmented tropical forest

Climate change and habitat fragmentation threaten biodiversity, but their interactive effects remain poorly understood. In closed-canopy forests, altered rainfall patterns may induce drought conditions that are exacerbated at forest edges due to warmer, drier microclimates. Plant responses to water limitation can be mediated by functional traits related to resource acquisition and stress tolerance. We examined how drought and edge conditions jointly affect seedling survival, and whether species’ responses are explained by their traits. In a human-modified forest in the central Western Ghats, India, we transplanted ~ 1-year-old seedlings in a factorial combination of habitat (forest edge vs. interior) and drought (throughfall exclusion vs. control). We monitored survival through one year and estimated drought response (survival in drought relative to control), which was related to six traits. Throughfall exclusion reduced soil moisture more at edges, particularly during dry months. At the edge, three species showed significantly lower survival under drought, whereas survival in the interior did not differ with water treatment. Acquisitive traits (high leaf area, low stem specific density, low leaf dry matter content, and low leaf mass per area) improved survival with drought at edges. Trait-mediated responses were not evident in the interior, likely due to buffered microclimates. Multi-trait combinations were better predictors of drought response than individual traits, suggesting trait coordination. Our results suggest that droughts may favour acquisitive species at forest edges, potentially altering community composition, which has implications for management and restoration of fragmented forests in a changing climate.