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Restoration of wet grasslands through re-instatement of surface grips - BD1322

Description

The extent and quality of the lowland wet grassland resource has much diminished over the last century, and the surviving areas within grazing marshes are frequently degraded. DEFRA has sought to rehabilitate and re-create such habitats both through its agri-environment schemes (e.g. ESA and CSS) and in response to the UK Biodiversity Action Plan. To achieve this objective, various techniques have been used, and others proposed, including the creation or restoration of shallow, seasonally wet channels (“grips”). The value of such actions has not yet been thoroughly researched.

Hence, the core objective of the planned research is to test the efficacy of installing such grips in achieving improved biodiversity of degraded lowland wet grasslands, especially within grazing marshes and related habitats. In particular, this study will focus on the success of grip installation in effecting changes in in-field conditions likely to be favourable to wetland birds. To that end, it is proposed to conduct a controlled field experiment to investigate the impact of grip installation and spacing on: the in-field water regime, soil physical properties, soil-dwelling invertebrate populations and various attributes of the vegetation. All of these will be of relevance in determining how useful grips prove in enhancing habitat suitability for wetland birds. This investigation will be conducted on sites with mineral soils. Such soils are considered to be the least amenable to alteration of in-field hydrological conditions by simple ditch water-level management prescriptions and hence the most likely to require engineering of micro-topography to achieve desired biodiversity gains.

Within those DEFRA agri-environment schemes that are particularly relevant to the conservation, enhancement and re-creation of wet grasslands, there has been concern as to whether raised ditch water-level prescriptions are sufficient to meet the schemes’ goals. The proposed research will furnish DEFRA with quantitative information on the efficacy of grips and the influence of their spacing in altering key physical and biological parameters and guidelines for the use of seasonally wet channels in restoration.

Objective
1) To identify one or more clay sites on which to conduct a controlled experimental study of grip installation. (CEH, OU)
2) To design and install a network of surface-grips at the site. (CEH, OU)
3) To install all necessary hydrological monitoring equipment within the experimental areas. (CEH)
4) To conduct regular hydrological monitoring on experimental areas. (CEH)
5) To conduct regular monitoring of other relevant environmental parameters on experimental areas. (CEH)
6) To conduct botanical assessments in the first and final years of the project
7) To conduct four surveys per annum of the soil-dwelling invertebrate populations on experimental areas. (CEH)
8) To quantify the impact of grip installation and spacing on the spatial and temporal variation in the in-field water-table and surface wetness. (CEH)
9) To quantify the impact of grip installation and spacing on the physical attributes of the soil and vegetation, abundance and availability of soil-dwelling invertebrates and hence suitability of conditions for wetland birds. (CEH/OU)
10) To draw up guidelines for the installation of grip systems in lowland wet grasslands on clay (CEH/OU)

Project Documents
• Final Report : Restoration of wet grasslands through re-instatement of surface grips   (4768k)
• Final Report : Restoration of wet grasslands through re-instatement of surface grips   (6724k)
Time-Scale and Cost
From: 2003

To: 2007

Cost: £390,780
Contractor / Funded Organisations
Natural Environment Research Council, Centre for Ecology and Hydrology
Keywords
Agri-Environment              
Biodiversity              
Environmental Protection              
Habitat conservation              
Nature conservation              
Wetland