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Restoration of blanket bog vegetation for biodiversity, carbon storage and water regulation - BD5104

Description
UK peatlands represent large stores of carbon (C). During photosynthesis, peatland plants take up carbon dioxide (CO2) some of which is subsequently respired back to the atmosphere. The remaining C is converted into organic matter which, after the plants die, decays over time releasing the C back into the atmosphere as either CO2 or methane (CH4). Crucially, water logged conditions suppress decay leading to active peat formation as C inputs exceed C losses. In the UK this has been the case during many millennia, contributing to a net cooling effect on the global climate due to reduced atmospheric greenhouse gas (GHG) concentrations. However, the balance of CO2 versus CH4 is important as CH4 is a GHG with a global warming potential about 25 times higher than CO2.
In the UK, many blanket bogs are managed for grazing having been drained for this purpose, often combined with regular burning, which frequently leads to increased dominance of heather (Calluna vulgaris). Over dominance by heather tends to dry the peat further as well as causing underground erosion (peat pipes and suppressing active peat forming plants such as Sphagnum spp. mosses (Lindsay, 2010). Whilst the drains, (called grips) can be blocked to raise the water table and help restore active peat accumulation, there is still a widespread need to reverse the dominance of heather which impedes this process. Wetter conditions also tend to benefit bird populations feeding on soil animals (e.g. crane flies) that rely on wet peatlands. However, certain heather reduction strategies currently in use may have detrimental effects on, for example, peat C stocks and air quality (burning) or water quality (herbicides). Therefore, restoration schemes must also consider these environmental consequences, which are linked to fundamental ecosystem services provided by UK peatlands for many millions of people. Recent studies by Defra (and elsewhere) have highlighted these issues. Importantly, the consequences of changes in management practice are likely to be slow to emerge so that long-term monitoring is needed.
services.
Objective
The overarching aim of this study is to acquire experimental data to underpin the development of possible management techniques, applicable through Environmental Stewardship, to reduce the dominance of heather and facilitate the progression towards an „active‟ blanket bog (with peat-forming species, particularly Sphagnum spp). This requires screening for the most suitable management techniques and then including those restoration techniques as part of a long-term manipulative experiment to provide scientifically sounds data upon which to base policy advice and subsequently decisions. The project will address four main objectives:

1. Review potential techniques to reduce heather cover and restore appropriate „active‟ peatland vegetation on blanket peatlands, and identify practical management options for experimental testing.
2. Field test the identified options and evaluate their effect on:
a) plant species composition, including bryophytes, to indicate likely impact on peat formation,
b) water table and peat fluvial and gaseous carbon fluxes through measurements.
3. Provide a cost-benefit analysis to determine the cost of achieving a range of ecosystem services.
4. Evaluate the impact of treatments on vegetation dynamics, stream flow, water budgets, carbon stocks and fluxes (including GWP) based on measurements and model approaches.
Time-Scale and Cost
From: 2011

To: 2017

Cost: £979,326
Contractor / Funded Organisations
University of York
Keywords
Agriculture and Water Quality              
Habitats