Abstract

Tropical vegetation plays an important role in the terrestrial carbon stocks, and Mexico has a considerable amount of this vegetation that may store a large amount of carbon. However, an important variable of vegetation is its floristic diversity. Floristic diversity influences in a great extent the biomass of an ecosystem and hence carbon stocks. The purpose of this study was to determine whether there is a relationship between floristic diversity and carbon stocks in the case of tropical vegetation in Mexico. Floristic species richness, Shannon´s index and above-ground biomass were estimated for eight localities with arboreal and herbaceous vegetation. The biomass in the humid and sub-humid tropical forests was estimated using two specific allometric formulas for trees. In the case of grassland, it was estimated by harvesting the vegetation. A positive relationship was observed by a straight line (r² = 0.82, P = 0.001) and a significant relationship was observed in the inverse U polynomial model (r² = 0.84, P = 0.002) between species richness and carbon stocks. The diversity estimated by Shannon´s index also presented a significant relationship (r² = 0.65, P = 0.05). This proves what was expected and indicates that there is a relationship between floristic diversity and carbon stock in these ecosystems. The conservation of floristic diversity may represent an important factor in the mitigation of global warming, through the storage of large amounts of carbon.

Key words: Biomass, carbon budget, diversity index, global warming, species richness, sub-humid forest, tropical rain forest.