Man-made field boundaries including linear woody features (hedgerows, windbreaks, and shelterbelts) are common rural features in many countries around the world. The number of fields and the field density (the number of fields per km2) has decreased throughout the UK due to the removal of field boundaries. The Countryside Survey mapping shows that between 1984 and 2007 nearly 110,000 km of hedgerows were destroyed and there are now only 402,000 km of managed hedgerow in England. The removal of hedgerows creates larger fields which encourage the propagation of runoff, due to longer flow pathways. This can lead to increased runoff velocities and greater soil erosion. However, the impact that individual hedgerows may have in terms of storing water, slowing the flow, breaking up flow paths is largely unknown, due to a lack of monitoring data. Environmental policy is now encouraging hedgerow planting, and these schemes funded the creation and restoration of 27,000 km of hedgerows from 1991-2012 (Barr et al., 2010).
Hedgerows provide multiple ecosystem services to society, such as through cultural value, biodiversity and providing a barrier to sediment and water. However, some of these impacts have been researched more than others, with multiple studies on the ecological value, but far fewer on the benefits on the water system.
This project will focus on quantifying both the impact of hedgerows on the different ecosystem services through field experimentation and the value of hedgerows through using the Natural Capital accounting frameworks.
The UK Government’s 25 Year Environment Plan (www.gov.uk/government/publications/25-year-environment-plan) uses the framework of Natural Capital, which is defined as “the elements of nature e.g freshwater, land, soils and air, which directly or indirectly bring value to people”. This builds upon the Ecosystem Services approach, which can be classified as provisioning (water supply), regulating (climate resilience), supporting (nutrient cycling), and cultural (recreation).
The specific objectives of this project are:
1) Develop a conceptual model of the ecosystem services provided by hedgerows
2) Map hedgerows at the national scale through time using OS historical maps and open source remote sensing imagery.
3) Quantify the benefits of hedgerows on ecosystem services which have seen less attention i.e. flood mitigation, soil erosion, at the individual and network scales.
4) Value the benefits of hedgerows for society through Natural Capital accounting tools.
5) Determine whether different types of hedgerows provide different benefits and values.