Richesse spécifique le long d'un gradient de production: Utilisation d'une approche multivariée

The specific shape and mechanisms underlying the relationship between plant diversity and productivity are still highly debated. Recent advances suggest that the relationship depends on several environmental variables and appears to change with the observational scale. In this study, a multivariate, multiscale approach is used to identify the variables influencing the most the relationship between species richness and annual production along a forest/old-field edge. Light availability stands as the major determinant of production. Richness is determined by production through different linear relationships. Under low light availability, richness increases faster than production which is more determined by soil resources than by light per se. At high light availability, production increases to the detriment of richness because of simplified vertical stratification by dominance. Combining these different relationships over the entire site gives the classic unimodal curve.