Low Hedgeley is a former sand and gravel extraction site in north east England. The site had been formerly restored to a mixed nature conservation / agricultural afteruse, however the land owner wanted to explore opportunities for increasing the biodiversity value of features at the site, namely a steep sided island.  Nature After Minerals advised on best practice island design and scrape creation. Works have begun, and the re-profiled island is already attracting bird interest with oystercatcher and little grebe recorded breeding in 2014.

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Picture 2

Size

41ha

Location

Low Hedgeley, Northumberland, UK

Status

Restored

Mineral Type

Sand and gravel

Proposed restoration

Retrofitting island features

Potential best practice

Retrofitting features to a restored site to improve biodiversity value

Introduction

Low Hedgeley is a former sand and gravel quarry in Northumberland. Post extraction, the site was restored to a mix of nature conservation and agricultural after uses. The restored site is situated within the Hedgeley Estate, which extends to 1,640 Ha and is owned by the Carr-Ellison family.

Nature After Minerals was asked by the landowner to provide some specialist advice on how the existing restored gravel pits could be improved for wildlife.

Low Hedgeley Quarry map

Opportunities identified by RESTORE

Techniques on creating habitats have evolved considerably in recent years, hence the quality of mineral site restoration is continually improving. However, there is a legacy of older restorations that, while they offer some nature conservation benefit, do not now fulfil their full potential. Low Hedgeley restoration includes agricultural, and a lake with a steep sided island (Figure 1). This is a similar case to the now Lancashire Wildlife Trust nature reserve, Brockholes, where steep sided islands were also included in early restoration plans.

The relatively light touch ground works proposed for Low Hedgeley could greatly enhance the value of the island to in particular wetland birds including lapwing, ringed plovers, and little ringed plovers.

Why Low Hedgeley fitted RESTORE objectives:

Engaging at an early planning stage is important for ensuring high quality restoration and long-term management plans / funds are secured. The legacy of restoration schemes that don’t achieve their now full potential like at Low Hedgeley can be redressed by retro-fitting ecological features, like reprofiled islands design working directly with the post-restoration landowner.

Timetable

September 2012

The landowner requested advice on how the site could be improved.

March 2013

NAM assessed the existing restoration and the context in which the site sites compared to the surrounding landscape.

November 2013

Landowner initiated ground works to re-profile the island.

Spring 2014

Breeding oystercatcher and little grebe recorded on the island.

Autumn 2014

Second phase of ground works were completed.

Our response and suggestions

In consultation with the landowner, and using similar works at Lancashire Wildlife Trust’s Brockholes site, advice focussed on two enhancements: island re-profiling and scrape creation. These would increase the site’s potential to support wetland bird specialists.

Scrape creation

Scrapes are seasonally flooded shallow depressions, that support high densities of non-biting midge larvae, providing abundant feeding for waders. Scrape design should include gradually sloping sides providing a combination of shallow water and exposed mud (ideally at least 10-15% of the scrape), and very little emergent vegetation. To maintain the scrape’s effectiveness in the long term grazing the area with cattle would provide a varied sward structure – predominately short but with scattered rushes and tussocks.

During autumn 2013 contractors undertook ground works on the island, to decrease the height, reduce the batter on the slopes and to create more indentations / spits. These groundworks immediately showed success, with oystercatchers and two pairs of little grebe breeding on the island during spring 2014.Plans to create scrapes were put on hold as the landowner is in receipt of a RDP grant from the Rural Payment Agency (RPA) for the grazing land. Natural England advised the landowner that if scrapes retained water throughout the year, that the RPA may categorise them as ponds (not grazing land) and impose penalties.

Island re-profile

To improve the functionality of the island, the advice was to lower its height to just above the water level, and increase the shoreline length as far as possible with spits and bays, particularly on the sheltered side.

Also recommended was to top the central part of the island with washed gravel, a preferred nesting substrate for terns, and which will also slow down the rate of vegetation succession.

Willow scrub and other vegetation will colonise and compromise the value of the island, for water birds, so advice was that a scheme be devised to control the willows outside of the breeding season.

How this best practice is transferable

Extractions often result in large deep bodies of water, without features like islands. Low Hedgeley retro-fit gave rise to a set of guiding principles for island design, and options for including artificial tern rafts or floating islands for where water is too deep, or there is no suitable overburden to develop natural islands. This has already been used to guide work at Whitesands Quarry, and was shared with a local authority ecologist to inform the quality of other restorations.

Lessons learned

This case study demonstrates the importance of working with landowners to secure the long-term viability of biodiversity enhancements retrospectively. It also highlights a potential conflict between agri-environment grants and biodiversity outcomes. It presents a strong case for better understanding of the dual benefit of ephemeral shallow water areas providing grazing for cattle and the role of cattle in maintaining wetland habitats.