Functioning of soil food webs in response to woodland expansion

The myriad organisms that lives in soil interact to form complex food webs. These webs of life comprise microorganisms such as bacteria and fungi, and a wealth of larger bodied organisms such as springtails and mites. Soil food webs regulate several key ecosystem processes including biogeochemical (carbon, nitrogen, phorpsphorus) cycles, carbon storage and greenhouse gas emissions, but our ability to predict how the composition and diversity of soil food webs drive these processes is poor. Moreover, the relationship between food web composition and ecosystem processes - which ultimately contribute to ecosystem services - is likely to be significantly affected by major recent changes in land use policy, namely woodland expansion.

The UK has committed to planting many more trees - 30000 hectares per year in England alone, but this means we have to plant the right tree in the right place. Soil properties, including the biological diversity in soil are major factors related to the "right place" argument. To ensure woodland expansion has net positive impacts on ecosystem processes and services, a more complete understanding of the mechanisms that drive soil food web composition and function is urgently needed. Here, we build on past NERC funded research and undertake a series of novel field and laboratory experiments to determine the mechanisms that regulate food web activity and diversity in grassland - woodland transitions.

We test the hypotheses that food diversity regulates ecosystem processes but that the maintenance of such functions is dependent on adaptation of food webs to carbon inputs
from plants originating from their 'home' environment. We will also generate valuable information on the temporal dynamics of such adaptations using a chronosequence of woodland. Our findings will pave the way for developing predictive understanding of the critical role of soil food webs in driving ecosystem processes in response to woodland expansion.