Abstract. Elevational gradients are an empirical tool to assess long-term forest responses to environmental change. We studied whether functional composition of tropical forest along elevational gradients in South America and in Africa showed similar shifts. We assessed community-weighted functional canopy traits and indicative δ15N shifts along two new altitudinal transects in the tropical forest biome of both South-America and Africa. We found that the functional forest composition response along both transects was parallel, with a species shift towards more nitrogen conservative species at higher elevations. Moreover, canopy and topsoil δ15N signals decreased with increasing altitude, suggesting a more conservative N cycle at higher elevations. This cross-continental study provides two empirical indications that both South-American and African tropical forest show a parallel response along altitude, driven by nitrogen availability along the altitudinal gradients, inducing a parallel shift in the functional forest composition. This highlights the importance of nutrient availability for tropical forest in a changing world. More standardized research, and more research on other elevational gradients is needed to confirm our observations.
Effect of Post-Logging Silvicultural Treatment on Growth Rates of Residual Stand in a Tropical Forest
