GLOBAL CLIMATE-CHANGE AND TROPICAL FOREST GENETIC-RESOURCES

Global climate change may have a serious impact on genetic resources i n tropical forest trees. Genetic diversity plays a critical role in th e survival of populations in rapidly changing environments. Furthermor e, most tropical plant species are known to have unique ecological nic hes, and therefore changes in climate may directly affect the distribu tion of biomes, ecosystems, and constituent species. Climate change ma y also indirectly affect plant genetic resources through effects on ph enology, breeding systems, and plant-pollinator and plant seed dispers er interactions, and may reduce genetic diversity and reproductive out put. As a consequence, population densities may be reduced leading to reduction in genetic diversity through genetic drift and inbreeding. T ropical forest plants may respond to climate change through phenotypic plasticity, adaptive evolution, migration to suitable site, or extinc tion. However, the potential to respond is limited by a rapid pace of change and the non-availability of alternate habitats due to past and present trends of deforestation. Thus climate change may result in ext inction of many populations and species. Our ability to estimate the p recise response of tropical forest ecosystems to climate change is lim ited by lack of long-term data on parameters that might be affected by climate change. Collection of correlative data from long-term monitor ing of climate as well as population and community responses at select ed sites offer the most cost-effective way to understand the effects o f climate change on tropical tree populations. However, mitigation str ategies need to be implemented immediately. Because many effects of cl imate change may be similar to the effects of habitat alteration and f ragmentation, protected areas and buffer zones should be enlarged, wit h an emphasis on connectivity among conserved landscapes. Taxa that ar e likely to become extinct should be identified and protected through at situ conservation programs.