Seedling growth of savanna tree species from three continents under grass competition and nutrient limitation in a greenhouse experiment

1. Changes in savanna tree species composition, both within landscapes and across climatic gradients, suggest that species differ in their ability to utilise resources and cope with grass competition. Linking trait variation among species to their relative performance under resource limitation and competition treatments could provide mechanistic understanding of species’ turnover across environmental gradients in savannas. We investigated how tree species differ in response to competition from grasses and nutrient supply, and whether these responses can be related to plant traits. As humid savannas are often associated with low fertility, species of humid savannas may grow more efficiently under nutrient suppression than species from semi-arid savannas. In heterogeneous grass swards, fast-growing, resource-wasteful species may be found in short-grass patches and slow-growing, resource-conservative species in tall-grass patches. 2. We compared seedlings of 40 tree species sampled from hu...