Niche versus chance and tree diversity in forest gaps

Studies that are unprecedented in scale, detail or approach show that niche partitioning contributes less, and chance events more, than expected to ma intaining tree species richness via gap dynamics in tropical and temperate forests, Some tree species are differentially adapted for regeneration in d ifferent gap microenvironments. However, the stochastic availability of gap s, and limited recruitment of juveniles, mean that gaps are filled mostly b y chance occupants rather than by best adapted species. This chance surviva l can slow competitive exclusion and maintain tree diversity. Gap dynamics do not explain the latitudinal gradient in tree richness.