Rapid and unprecedented increases in temperature are expected for tropical forested ecosystems in the coming decades. Understanding how such temperature change will affect the function and integrity of lowland tropical forests is of global concern due to the large role that these forests play in the global carbon cycle and the regulation of Earth’s climate. Natural temperature gradients in the tropics offer great opportunities for understanding temperature effects on plant and ecosystem functioning; however, predicted temperature regimes are not present in the lowland tropics today and the warm ends of such gradients are likely to see further warming over the coming decades. Thus, the only way to achieve predicted temperature regimes for these systems is to manipulatively warm the warmest forests. Field-based warming experiments offer a powerful approach, yet such warming manipulations have remained missing in tropical ecosystems despite their widespread implementation in higher latitudes. Here, we present the experimental design and initial results from the first field warming experiment in a wet tropical forest in Puerto Rico (Tropical Responses to Altered Climate Experiment; TRACE).
Results/Conclusions
We utilized a hexagonal array of infrared heaters established 2-m above the vegetation to increase temperature +4 oC in three warmed plots relative to three controls. The controls received the same infrastructure, but no warming. Using the design presented here we were able to successfully acheive the desired warming with minimal effects on soil moisture. In addiiton to presenting the treatment effects, we will discuss the intial temperature responses of the most biogeochemically-active components of the system (leaves, roots, and soil microbes). By utilizing the mechanism-based approach presented here, we aim to improve Earth System Model parameterization of pools and fluxes of water, carbon, and nutrients.