Resilience and regime shifts in peatland microbial communities: implications for soil functioning

Humans rely on soils in many ways. They provide nutrients, water and anchorage for most of the crops that we eat, they filter and hold onto rainfall, and they store vast amounts of carbon, which helps to mitigate climate change. Soils also are home to a vast diversity of soil organisms, which play major roles in driving the biogeochemical cycles on which the functioning of Earth depends. Despite these important roles, a range of pressures, including changes in land management, land contamination, and climate change are threatening soils and the populations of microbes and animals that live in them. These pressures not only pose immediate threats to soil functioning, but also they could have longer-term impacts, for instance making soils more vulnerable to extreme climatic events, which are becoming more common worldwide as a result of climate change and can have devastating consequences for ecosystems. Evidence from studies of oceans, lakes and forests shows that extreme events, such as heat waves and drought, can trigger sudden and dramatic transitions, or regime shifts, from one ecosystem state to another. For example, reef communities off the western coast of Australia revealed a sudden and dramatic transition from extensive kelp forest to turf-forming seaweeds triggered by marine heatwaves. These regime shifts can have major consequences for the functions that these ecosystems provide. However, whether such regime shifts occur in soils is not really known.

In this small grant, we would like to tackle three so far untested questions of high relevance for Soil Security. First, we want to know if long term climate warming makes soils and their microbial communities more vulnerable to, and less able to recover from, extreme climate events, namely drought, which is increasing in frequency. Second, we want to test if long-term effects of climate on soils and their microbial communities make them more vulnerable to transitions, or regime shifts from one state to another, and whether these regimes shifts degrade the functions that soils perform, for example their ability to store carbon. Last, we want to see if these effects of climate change on soil functioning can be dampened, for instance through changing the management of vegetation.

We plan to make use of a unique warming and vegetation manipulation experiment that we set up several years ago on blanket peat at Moor House National Nature Reserve, northern England, funded by NERC. This experiment is ideally suited to this study because it has been running continuously since 2008, which puts us in a unique position to detect how long-term warming (9 years in 2017) has altered the resilience of soils and their microbial communities to drought, but also their susceptibility to regime shifts. The experiment also includes a vegetation manipulation treatment, which allows us to test if vegetation change, especially the presence of ericaceous dwarf-shrubs, can dampen effects of climate change on soils and their functioning. And finally, the experiment is on carbon-rich peatlands, which are not only of high relevance for UK Soil Security because they cover a large area of the UK land surface and store vast amounts of carbon, but also they add a distinct and highly complementary dimension to the NERC Soil Security Programme.

These questions are at the heart of the NERC Soil Security programme which seeks to resolve what controls the ability of soils and their functions to resist, recover and ultimately adapt, to perturbations, such as those caused by extreme climatic events. Also, by testing our questions, we will gain new, transformative understanding of the dynamics of microbial communities and their functioning in relation to on-going and rapid environment change, and produce knowledge that could help in the design of sustainable management strategies for maintaining resilience in peatlands.

Who will benefit from our research?

The main beneficiaries of our project will be the soil science, ecological, and wider scientific research community interested in understanding how soils and their functioning respond to climate change, including extreme events. A unique interest of our research will be new insights in to the impact of long term, gradual climate change on soil resilience to extreme climatic events, which is rarely considered. We expect certain stakeholders, including landowners, local and national government departments (Defra) and agencies (e.g., Natural England) to also benefit from our research, especially via providing scientific evidence to underpin management strategies for mitigation of climate change effects on peatland carbon loss via vegetation management. Our project will also benefit the general public with interests in understanding how climate change will impact soils and their functioning under climate change, which is a topic that is gaining public attention. The peatland site we use is an area of high conservation and amenity interest, and is within the Moor House National Nature Reserve and close to an Environmental Change Network site; hence, increasing public awareness of our research will be an important goal of our project.

How will these benefits be realised?

Dissemination of research findings to international audience: This will be achieved through the publication of our research findings in leading international journals, and via presentations by PDRAs and PIs at international conferences and workshops. Given the novel and timely nature of our proposed research, and our track record of publishing work in top journals, we expect to publish at least two high impact publications in this work. The PDRA will be encouraged to present at international conferences and workshops, and to be actively involved in research networks, such as the BES Plants, Soils, and Ecosystems Special Interest Group and the to disseminate research findings.

To engage with and promote knowledge transfer to stakeholders: We will directly engage with stakeholders, including policymakers, land managers, farmers and landowners, and other interested parties. This will be done via two routes. First, we will integrate the policy relevant goals and findings of this project into our existing Soil Security (NE/M017028/1) engagement and knowledge transfer activities, and specifically a workshop planned for late 2017 aimed at exploring mechanisms of integrating research knowledge on climate change into sustainable soil management for maintaining resilience. Second, we propose to take is the making of a short film by a student intern filmmaker from the University, on threats of climate and vegetation change on peatland ecosystems and potential solutions or mitigation strategies.

To raise public awareness of our research: The lead PI and Co-I have a strong track record of being actively involved in outreach activities, promoting public awareness of our science through local and national media interviews, and by presenting our results at science communication events, and we will continue to use these knowledge exchange outlets (see CV's). For this project, we will raise public awareness via the above film, which will also be available to the general public, but also via our involvement in specific educational events at The University of Manchester and public engagement activities at Manchester Museum.

Transferable skills training: An important outcome of this project will be the delivery of highly trained staff with training in multi-disciplinary approaches to the study of soil. The PDRAs will also undertake public engagement training via NERC and the University.