The commonly observed high diversity of trees in tropical rain forests and corals on tropical reefs is a nonequilibrium state which, if not disturbed further, will progress toward a low-diversity equilibrium community. This may not happen if gradual changes in climate favor different species. If equilibrium is reached, a lesser degree of diversity may be sustained by niche diversification or by a compensatory mortality that favors inferior competitors. However, tropical forests and reefs are subject to severe disturbances often enough that equilibrium may never be attained.

https://www.colby.edu/biology/BI358j/Readings/Diversity%20in%20rainforests%20and%20coral%20reefs.pdf

Diversity in tropical rain forests and coral reefs.

J+=j

widespread, usually transitional between semidesert or savanna and moist forest. About 40% of the earth's tropical and subtropical landmass is dominated by open or closed forest. Of this, 42% is dry forest, 33% is moist forest, and only 25% is wet and rain forest (sensu Holdridge, 42; 15). We will never know the true original or potential extent of dry forest because many savannas and scrub or thorn woodlands are thought to be derived from disturbed dry forest. Walter (110), for example, considers most or all of the grassland in India to have been derived from seasonal or dry forest. Some of the processes that cause this conversion are addressed later in this review. The largest proportion of dry forest ecosystems is in Africa and the world's tropical islands, where they account for 70-80% of the forested area. In South America they

Ecology of Tropical Dry Forest

The disturbance of forest ecosystems: the ecological basis for conservative management

Much research has been conducted in tropical rain forests since publication of P. W. Richards' (134) epic The Tropical Rainforest in 1952. Studies have emphasized the environmental relations of individual species in Southeast Asia and Africa, and biomass dynamics and coevolutionary interaction in the neotropics. However, relatively little work has been done on the physiological ecology of tropical succession in any region. Tropical ecologists have called attention to the paucity of data and exceptional research opportunities in tropical succession (53, 60, 63, 79, 110, 134-136, 156, 158). However, scattered information is available about response patterns of species in tropical forests. This review collates available literature, identifies trends, suggests research directions, and makes comparisons with temperate forest successions where possible. We were not always able to examine the original literature, and have sometimes relied on summaries. Furthermore, space limitations do not permit citation of literature on temperate successions when making comparisons between these and tropical successions; we rely heavily on a review of the ecology of temperate successions (20). Here we review successional environments in lowland and lower montane tropical rain forests and the physiological responses of various plants. We do not deal with upper montane or highly seasonal forests.

PHYSIOLOGICAL ECOLOGY OF TROPICAL SUCCESSION: A Comparative Review

On the other hand, it has often been stated that the tropical rain forests (tall evergreen forests in tropical warm and humid regions) around the world must be protected and conserved for the future generations (1). It has also been stated that it is most important that knowledge about the structure, diversity, and function of these ecosystems has priority in future biological research (2). Unfortunately, either these voices have not been heard or their arguments have not been convincing enough to promote action in this direction.

A. Gómez-Pompa

Papers

The tropical rain forest: a nonrenewable resource.

Tropical rain forests.

Response : Tropical Rain Forests