On the diversity of tree species in tropical rain forest ecosystems

Numerous theories have been developed in the past on the species diversity of the tropical moist forest ecosystems. In this paper the theories were grouped in five categories according to their emphasis on:

• productivity of the ecosystem
• long undistributed evolution
• disturbances
• heterogeneity of site conditions
• the Jazen/ Connel/ Clark and Clark model

Some pro and contra evidence for each of these theories is briefly discussed. The Author arrives at the conclusion that none of the above theories offers a satisfactory explanation as the sole cause for the species richness of tropical moist forest ecosystems. The high species diversity of tropical forests is therefore probably the multi-causal result mainly of:

• an optimum combination of growth factors, that allows the co-existence of many species
• a long, not seriously disturbed evolution
• disturbances that create now opportunities foe evolution and migration without reducing the existing species diversity to zero the heterogeneity of site conditions in space and time.