Disentangling mechanisms of co-adaptation between trees and soil food webs in response to environmental perturbations

点击翻译按钮获取中文摘要

Trees interact with thousands of tiny animals and microorganisms living in soil beneath them. They do this indirectly and directly. Indirect interactions occur via production of dead litter, especially leaves. When litter is produced, soil animals and microorganisms break it down and recycle nutrients, and the composition of the community doing this breakdown process can be influenced by the nature of the litter itself, such as how much nitrogen it contains or how tough it is. Direct interactions occur because some microorganisms are intimately associated with tree roots and actually form mutually beneficial associations with trees. These organisms rely on trees for their energy in the form of sugars, and their activity fuels many processes essential for tree health and nutrition. A big question in ecology is how these interactions will be affected by components of global climate change, such as drought and elevated concentrations of carbon dioxide in the atmosphere? Our project will tackle this question. A further question concerns whether components of global change will affect these indirect and direct interactions in different ways, and our proposal will also address this issue.We will tackle these issues by undertaking experiments in the laboratory where we have lots of control of various important factors, but also by using two amazing field-based experiments. These experiments artificially manipulate concentrations of carbon dioxide and the incidence of drought frequency and severity in mature oak forests, where the trees are taller than most houses. The experiments are big, and we are fortunate to have the benefit of multi-million pound investment in infrastructure and support. The laboratory experiments will use state-of-the-art stable isotope tracer experiments, which enable us to trace the fate of carbon atoms from plants to soil to soil organisms. Our findings will generate new mechanistic insight into the way that plants interact and shape their own biotic environment in soil, and how this is modified by climate change. Understanding these interactions is important because in managing land for food, fuel, fibre, and other ecosystem services, we routinely disconnect co-adapted food webs deliberately or inadvertently. Broader societal impact will be enhanced by using this new knowledge to inform strategies for creating, conserving and managing oak woodland (see Pathways to Impact).