Land use legacies in tropical dry forests: Linking above- and belowground dynamics.
详细信息
文摘
Land change can affect the release and residence time of one of the largest global terrestrial pools of carbon (C) stored above- and belowground in tropical ecosystems. For this dissertation,I investigated the consequences of land change on C stocks and the influence of historical land use on above- and belowground C stocks and the associated mechanisms that regulate ecosystem C. I first conducted a pan-tropical meta-analysis on the consequences of land change on soil C stocks by testing the importance of site history and environmental controls on regulating changes in soil C stocks across the tropics. For the remaining parts of this dissertation,I focused on tropical dry forests,which have experienced significant rates of land change and are the most perturbed,fragmented,heavily used,and threatened tropical forests. I measured the effects of the legacy of historical land use on aboveground C stocks in tree biomass and changes in tree species composition. Next,I investigated the factors that mediate and regulate belowground soil C storage in these tropical dry forests with a study on soil biogeochemistry and soil microbial community composition and function. Finally,to understand controls on C decomposition,I conducted a leaf litter and root transplant decomposition experiment. Taken together,the results of these studies suggest that land change can significantly alter C storage both above- and belowground but that the factors controlling aboveground C storage may follow different patterns in comparison to belowground. Understanding links between above- and belowground controls on C stocks will improve predictions of the fate of ecosystem C as tropical areas continue to experience significant land change,particularly tropical dry forests.