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Monitoring of Moorland Grazing Units in Exmoor ESA - MA01020

Background and Introduction

The Environmentally Sensitive Areas Scheme was established by MAFF in 1987 with the aim of providing an incentive to land managers to protect land from intensification in defined areas of significant wildlife, landscape and historic interest. The Exmoor ESA was launched in 1993. In each ESA, management is tailored to meet specific objectives through entering land into tiers within which management is constrained by prescriptions designed to deliver environmental benefits through maintenance or enhancement of habitats. The payment received by the landowner reflects the income forgone and costs of implementing the prescribed management.

Each ESA has been the subject of a programme of monitoring since inception, which included botanical monitoring of moorland in six ESAs (Dartmoor, Exmoor, the Lake District, North Peak, Shropshire Hills and South West Peak). The methods used and results are described in ADAS monitoring reports which are available on the Defra website. The last (re)surveys were done between 1995 and 1997 with the exception of Dartmoor which was resurveyed in 2003 by ADAS (Project MA01016).


A resurvey of Exmoor grazing units will be undertaken involving all 13 of those last surveyed in 1996 (of which 11 were previously surveyed in the 1993 baseline). In these, sampling points were located on five transects between random points in each GU. Thus, whilst the whole GU was available for sampling, in practice the samples were clustered along random transects. The transects were re-randomised on resurvey in 1996; this appeared to introduce significant (but random) sampling error in the comparison between years. The number of samples per site varied between 50 and 200 depending on the size of site. The sample sizes for the resurvey are likely to be similar to the previous surveys, though there may be some scope for adjusting the samples on some sites based on analysis of the variation in GI and other variables recorded in previous surveys.

The project will also involve an element of development work on moorland monitoring methods building on recent reviews. From both contributory elements, analysis will be carried out to quantify and interpret any changes in vegetation composition, condition and structure from previous surveys and to describe the current condition of sites/features. As well as allowing comparison with baseline surveys, the project will involve field-testing the revised methodologies and, in the light of this, reviewing their potential use for future AES moorland monitoring.

The policy customer for the project is Conservation Management Division (CMD) of Defra.

Field methods

The contractor will undertake botanical recording involving a range of variables to be agreed with RDS based on those to be used in the revised overgrazing surveillance method being developed by RDS. These are not likely to be finalised until February–March 2004, but are likely to include condition assessment attributes and heather GI (see earlier). This is likely to result in some previously recorded variables being dropped (e.g. slope, distance to tracks, linear features and palatable grasses etc.).

Where available, condition assessment results will be obtained from English Nature (via RDS) for SSSI Site Units which fall within the monitoring sites for comparison with the data collected.

Data handling and analysis

The method used to express the results of grazing on Heather shoots will be agreed with RDS. It will comprise the percentage of shoots grazed (GI) and will not involve the conversion to Biomass Utilisation or percentage of samples suppressed as used in the previous analysis. This reflects concern regarding methodological issues on which RDS will provide documentation. Otherwise the analysis of change from previous surveys should be based on that used in previous reports, though there is scope for alternative approaches. Data on new variables added in 2004 will be summarised, including an assessment of whether the site, site units and/or features were in favourable condition.

The analyses may need to group particular sites; in particular on Exmoor, sites 1–10 comprise a random sample, site 11 a Tier 2 case study and sites 12 and 13 further case studies added in the 1996 resurvey. The results should be interpreted in the context of the agreement status of sites (tier/supplement and length of time under agreement); EN condition assessment results, where available; and the results of other relevant AES and other moorland monitoring nationally.

Time-Scale and Cost
From: 2004

To: 2005

Cost: £108,930
Contractor / Funded Organisations
Centre for Ecology and Hydrology, ADAS UK Ltd.
Environmental monitoring              
Environmental Protection              
Environmentally Sensitive Areas (ESA)              
Fields of Study
Environmental Protection - Agriculture