Interactions among climate, biodiversity, and ecosystem services in tropical forest ecosystems

Background/Question/Methods

Despite a historical interest in the relationship between biodiversity and ecosystem functioning (BD-EF), many questions remain regarding the relationships and interactions among environmental drivers, biodiversity, and ecosystem function, particularly for tropical forest ecosystems. Our ability to predict and manage the effects of climate change and deforestation may depend on our understanding of the complex interplay among these factors. To address this issue, we analyzed a global data set of tropical tree and liana diversity from the Tropical Ecology Assessment & Monitoring (TEAM) Network. We calculated carbon storage and a variety of taxonomic and functional diversity metrics from the TEAM data and collected climate data from TEAM field stations.  We then used path analysis to examine the context dependency of the relationships between environmental drivers, biodiversity, and carbon storage.

Results/Conclusions

Our results imply a complicated interplay between the direct effects of the environment on biodiversity and carbon storage as well as its impact on the relationship between the two. As expected, we found strong positive relationships between precipitation and both biodiversity and carbon storage across sites.  We found a unimodal (hump-shaped) relationship between tree richness and carbon storage, suggesting that carbon sequestration (an important ecosystem function) is maximized in areas with intermediate levels of diversity.  However, we also found that the choice of diversity metric (e.g. taxonomic vs. functional) influenced the diversity/carbon relationship. This information will be useful to conservation managers tasked with selecting particular regions to protect in order to maximize both biodiversity and carbon storage in the context of efforts to reduce emissions due to deforestation (e.g. REDD+).