Next generation of warming experiments in tropical forests

Background/Question/Methods

Current literature suggests that the tropics are likely to experience rapid and unprecedented increases in temperature 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 percentage of the World’s biodiversity supported by these systems, as well as the significant role that these forests play in regulating Earth’s climate. Taking a multi-faceted scientific approach – for example, combining leaf-level measurements, soil incubations, environmental gradient studies, and modeling – is considered the ideal for generating meaningful predictions about ecosystem responses to global change. Field-based warming experiments offer a powerful complementary approach, yet such warming manipulations remain missing in tropical ecosystems despite their widespread implementation in higher latitudes. Here, we explore key considerations for establishing field-warming experiments in tropical forested ecosystems.

Results/Conclusions

We suggest that the priority should be a mechanistic focus on the temperature responses of the most biogeochemically-active components of the system: canopy leaves, roots, and soil microbes. A network of such experiments that span natural gradients (e.g., precipitation, soil fertility) and that offer a longer-term perspective (i.e., >5 yr) would provide valuable insight into temperature-moisture interactions and would additionally fit into a functional trait framework with respect to both plants and microbe communities. This approach could additionally address the complexities stemming from high biodiversity. Mechanism-based hypothesis testing would be paramount, as would the improvement of Earth System Model parameterization of pools and fluxes of water, carbon, and nutrients. This experimental framework would generate innumerable research opportunities for wide-ranging collaborative projects, including the effects of warming on: tree seedling demography, biogenic volatile organic carbon emissions, insects, roots and mycorrhizae, soil macro- and micro-fauna, and even reptiles and amphibians. As a scientific community, we possess the technology, expertise and motivation necessary to greatly expand our understanding of and capacity to predict fundamental responses of tropical forests to warming.