Print PageThe world’s soils are a major carbon pool. Continued increases in atmospheric greenhouse gas concentrations are predicted to increase average global surface temperatures by at least 1 - 6 ºC by 2100 and alter the distribution of precipitation across ecosystems. These changes will alter the distribution of plants as well as the soil microbial communities associated with them. Shifts in plant and microbial communities will alter the pool of terrestrial carbon by changing the input (uptake by plants) and release (decomposition rates of soil organic matter by microbes) of carbon from ecosystems. Soil microbial communities are directly responsible for the mineralization of soil carbon and are linked to plant processes such as root exudation and detrital input. Hence, understanding the links among plant and microbial community composition and function and soil processes is a major theme in ecosystem and global change ecology. Our inability to decouple plant and soil microbial responses decreases our ability to predict and model whether soils in terrestrial ecosystems will be a net source of carbon to, or sink of carbon from, the atmosphere. This talk will present results from three different climate change experiments, a multifactor experiment (CO2 × warming × precipitation) in a Tennessee old-field ecosystem, a warming experiment in a Colorado alpine meadow, and precipitation manipulation in a semi-arid New Mexico pinyon-juniper woodland and a meta analysis to explore how changes in plant and soil communities impact the functional response of ecosystems to global change.
Results/Conclusions
We find that both the direct (e.g., decreases in precipitation) and the indirect (influence on plant species distributions) effect of climate change can influence soil community composition and function across ecosystems. However, the interactions among the plant species and their individual and combined response to treatments often had a larger influence on the functional response of the soil community than the direct influence of the manipulations on those same communities. Soil moisture and plant identity were often the best predictor of soil microbial response and we predict that these microbial responses could feedback to regulate ecosystem production, especially in nutrient-limited ecosystems. In addition, we will present results that suggest that the way samples are collected from climate change experiments can, perhaps, lead to incorrect predictions of what soil microbial communities and their function will be in the future.
