ABSTRACT
Tropical diversity, defined as taxonomic richness, may be explained by historical or biotic/environmental factors. Changing community response to small-scale, relatively frequent environmental changes would suggest that the two ecosystem types are quasi-stable responses to a moderate level of climatic variability. The alternative view is that disturbances are required to maintain diversity. The rainforest may be viewed as a structural object within which such processes as regeneration, leaf fall and seed dispersal are taking place. In such an approach, the fixed elements, the trees, form a vertically differentiated, or stratified, canopy. There are three stages to the growth cycle; gap, building and mature phases. It is important to stress, however, that these phases are really abstractions and not separate entities. The ‘coarseness, or ‘openness’ of the vegetation mosaic depends upon the initial gap size.
