BNG Partnership

Case Study:

Culm Moor Nature Reserve

Location: Devon, UK
Area: 2.3 hectares
Habitat: Pond, wetland mosaic, woodland
Number of Trees: 19,399

Project Focus: Biodiversity Net Gain
Restoration of rare culm pasture
Reconnecting fragmented woodland
Pond and eco-scrapes
Reedbed and aquatic marginal plants
Hedgerow restoration

BNG UPLIFT – 45%

BNG Partnership

Site History

The site was intensively used as grazing pasture and heavily fertilised and resown regularly with grass, although it is a naturally wet area and had patches of rush growing. The site falls within the UNESCO North Devon Biosphere Reserve and is just north of Dartmoor National Park. The biosphere reserve designation is due to the unique ecological and geological features of the region, which is on the Culm Measures rock formation. The site would naturally be rare culm pasture, which is a wet, rushy habitat characterised by purple moor grass. There are also veteran trees and broadleaved woodland fragments in the area, rich in lichens and mosses.

BNG Partnership

Project Design

The project design was informed by our understanding of the site topography and context. We chose to capitalise on the damp nature of one of the fields by digging a pond and a series of eco-scrapes, filtering run-off from the grassed area through reeds down to the ditch. The meadow area will be allowed to revert to culm pasture, with a minimal intervention method and no reseeding. The addition of patches of nectar- and pollen-rich fruit-bearing trees will assist in reducing excess nutrients from the soil and woodland planting in the other field will link up fragmented patches of broadleaved woodland and create a contiguous woodland complex. Click image to expand.

BNG Partnership

Project Implementation

Our eDNA baseline survey confirmed that the soil had a heavy nutrient load, with 155 fungi records which were mostly associated with intensive fertilisation, and only 14 invertebrate species. The groundworks onsite were completed in 2022 and included digging and shaping a pond, creating eco scrapes, and mounding the tree plantation area. Trees were planted in the wetland area using the Miyawaki Method and using standard spacing in the plantation area. The pond is surrounded by aquatic marginal planting including reeds.

BNG Partnership

Project Results

The estimated BNG uplift at Culm Moor Nature Reserve is 2.5 units (45%). Downstream eDNA sampling will assess the impact of works on soil biodiversity, and sampling of water will assess the impact of new freshwater sources on aquatic biodiversity and water quality. Wildflowers have been appearing in the grassland area and swallows and frogs have been using the pond. Woodcock have been seen foraging on the site. The hedgerows have shown significant growth following the introduction of a less intensive management regime.