Tropical tree diversity enhances light capture through crown plasticity and spatial and temporal niche differences

Jurgis Sapijanskas , Alain Paquette , Catherine Potvin , Norbert Kunert , Michel Loreau (1)

1 SEEM - Station d’Ecologie Expérimentale du CNRS à Moulis

Light partitioning is often invoked as a mechanism for positive plant diversity effects on ecosystem functioning. Yet evidence for an improved distribution of foliage in space or time in diverse plant communities remains scarce, and restricted mostly to temperate grasslands. Here we identify the mechanisms through which tree species diversity affects community‐level light capture in a biodiversity experiment with tropical trees that displays overyielding, i.e., enhanced biomass production in mixtures. Using a combination of empirical data, mechanistic models, and statistical tools, we develop innovative methods to test for the isolated and combined effects of architectural and temporal niche differences among species as well as plastic changes in crown shape within species. We show that all three mechanisms enhanced light capture in mixtures and that temporal niche differences were the most important driver of this result in our seasonal tropical system. Our study mechanistically demonstrates that niche differences and phenotypic plasticity can generate significant biodiversity effects on ecosystem functioning in tropical forests.

Mots clés: biodiversity; crown; ecosystem functioning; intraspecific diversity; light competition; niche differences; overyielding; phenology; phenotypic plasticity; Panama; plantation Sardinilla project; tree; plantation; Sardinilla project

Domaines: Biodiversité et Ecologie

Jurgis Sapijanskas, Alain Paquette, Catherine Potvin, Norbert Kunert, Michel Loreau. Tropical tree diversity enhances light capture through crown plasticity and spatial and temporal niche differences. Ecology, 2014, 95 (9), pp.2479-2492. ⟨10.1890/13-1366.1⟩. ⟨hal-02964493⟩