Tropical rainforests and the need for cross-continental comparisons.

Ecologists have tended to overemphasize the common features of tropical rainforests on different continents. In reality, the five major tropical rainforest regions (tropical America, Africa, Southeast Asia, Madagascar and New Guinea) are distinct ecological and biogeographical entities. Although it is easy to find examples of at least superficial convergence between unrelated organisms in these different regions, there are many other cases where convergence is incomplete or there are no obvious ecological equivalents. Pantropical comparisons with standardized methods are needed for the insights that they can provide into rainforest ecology and the help that they can offer in identifying conservation strategies that are appropriate to regional conditions. Here, we suggest ways in which the practical difficulties of such pantropical comparisons can be minimized.