Crawcrook Quarry is a 28ha site situated between the villages of Wylam and Crawcrook, in Tyne and Wear. Nature After Minerals worked with the RSPB-CEMEX  biodiversity adviser input to a restoration plan for the site. Extraction ceased in 2012; the site had started to develop some significant biodiversity interest through natural regeneration. We recommended that the plan incorporate the interest features that had already developed, and add to these through ongoing natural regeneration, and appropriate management to maintain the open mosaic habitat. 

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Size

28ha

Location

Crawcrook Quarry, Tyne & Wear

Status

Post-extraction

Mineral Type

Sand and Gravel

Operator

N/A

Proposed restoration

Agriculture
Hedgerows
Ponds
Open mosaic habitat and acid grassland

Potential best practice

Natural regeneration
Retaining open mosaic habitat on previously developed land

Introduction

Crawcrook quarry is located to the west of the village of Crawcrook within the metropolitan county of Tyne and Wear in north-east England. A requirement was for an appropriate restoration scheme to be developed and implemented by the operator, CEMEX (UK) Ltd, with relevant stakeholders.

Opportunities identified by RESTORE

As time had lapsed since extraction works ceased, nature was already colonising the site. This then provides a case study of the value of natural regeneration in the development of the priority habitat: ‘open mosaic habitat on previously developed land’. The importance of this restoration method and habitat type is not always recognised by planners, so it is important to ensure that the current value of the site for nature was incorporated into plans, so safeguarding important features.

The value of restoring species-rich grassland and retaining open mosaic habitat on previously developed land is highlighted in the National Character Area profile (14) for Tyne and Wear Lowlands. The Statement of Environmental Opportunity (SEO1) states that NCA should ensure:

“restoring and creating a network of species-rich grasslands” and “protecting biodiverse brownfield land for its biodiversity interest, avoiding greening of these sites”.

Crawcrook quarry map

Why Crawcrook Quarry fitted RESTORE objectives:

The site has already developed significant biodiversity value through natural regeneration, but the requirement by the Mineral Planning Authority for a formal restoration plan could put these important features at risk unless they were embedded within the required plan. ‘Open mosaic habitat’ has the potential to support several rare species, particularly invertebrates, and it is important that this enhanced and managed appropriately in the long term.  The site is located between two inhabited areas, so could also provide important local community green open space.

Timetable

November 2012

CEMEX initially contacted the RSPB Regional Office with regard to inputting into a revised restoration plan for Crawcrook Quarry.

February 2014

Working with the RSPB-CEMEX Biodiversity advisor, we submitted pre-application comments to CEMEX on an updated revised proposed restoration plan.

Proposed restoration

The indicative restoration scheme incorporated a mixed end-use, with agriculture to the north of the site and nature conservation to the south.

The biodiversity interest proposed included a hedgerow, area of tree / scrub planting, open mosaic habitat, wetland features and acid grassland. The site also includes an area of un-worked land, which is improved grassland.

Our response and suggestions

The proposed restoration sought to protect and enhance what had already developed into a species-rich site.  However, additional measures could optimise the site even further for biodiversity. Also there is potential for introducing some public access into the site.

Our response included recommendations to enhance the restoration and aftercare, as detailed below:

Open Mosaic Habitat

Forming a south facing cliff exposure 1-2m high would provide a valuable feature for burrowing invertebrates.  Provision of sandy, bare ground within the dry acid grassland creates a fine-scale open mosaic supporting important invertebrate and plant populations. The existing varied topography and micro-topography can be augmented with additional topographic features (small depressions, low cliffs, small ponds / puddles) during land forming. The biodiversity interest already developing at the site is as a result of natural regeneration; this restoration approach should be maintained on the dry acid grassland area. Any additional seeding propugules can be sourced from already regenerated grassland, and green hay can be spread on sections of the restored areas.

not approved

Artificial Sand Martin Bank

During extraction the site supported a large colony of sand martin, however since extraction ceased the remaining faces degraded and collapsed such that there are now no suitable nest sites. To return this feature, as an option, an artificial sand martin bank could be created similar to that adopted at Langford Lowfields (Nottinghamshire) which has proven to be highly successful.

Diversifying Un-worked Grassland

The area of un-worked grassland within the east of the site has been agriculturally improved in the past. The floristic diversity of this grassland could be enhanced, by collecting and spreading seed rich donor material from the grassland that has naturally regenerated elsewhere on site. From a Flora Locale Advice sheet ground preparation may be needed first – including some disking or harrowing.

not approved

Ponds and Scrapes

A number of ponds already existed or were marked on the restoration plan. These and other ponds need to be protected and enhanced. Also, during land forming, it may be possible to enhance the wetland features further by scraping to create shallow wet depressions in existing low points, then leaving them to colonise naturally. These will be particularly beneficial for the population of European Protected Species great crested newt that is known to be present on site.

Public access

The site could provide valuable greenspace as an asset for the local community once restoration is completed. As such, the applicant could consider the feasibility of providing public access e.g. via a circular footpath), should this complement the operator’s long-term aspirations for the site.

not approved

Long-term Management

The long-term management of the site will be key to developing and retaining the habitat and species interest of site. Natural England has provided some guidance on management of open mosaic habitat which can be found here.

How this best practice is transferable

Natural regeneration or colonisation of vegetation at Crawcrook Quarry has allowed the site to develop its own biodiversity interest. This demonstrates how, in some situations, working with the grain of nature, and being less prescriptive produces a more biodiverse, and, by using less resources in restoration, more sustainable end result. A similar restoration is being used at Threshfield Quarry, where other restoration blasting for the landforming, the site is being left for nature to move in.

Lessons learned

This site demonstrates how in certain circumstance being less prescriptive in the restoration, and allowing nature time to develop through natural regeneration can result in a species-rich site at a much reduced cost. However, this is not just an excuse to just walk away post extraction, as the key to retaining the value of the site will be in its long term management, slowing succession and maintaining a balance of bare ground with more mature vegetation.