Hand held behind a green leaf - National Grid's environmental performance

Case Study – Margam Substation

Habitat Management at National Grid Electricity Transmission’s

In 2019, National Grid approached The Wildlife Trust of South and West Wales (WTSWW) to work with them on a sustainability project at Margam Substation near Port Talbot, South Wales.

The land consists of approximately 14 hectares of reedbed, marshy grassland, scrub and brownfield habitats. The dense reedbed provides home for several amphibians and breeding birds, including Cetti’s warblers, harvest mice and potentially water voles. There is also the potential for scarce species such as bitterns to hunt amongst the reeds. Predators such as otters and grass snakes will hunt amphibians which breed in areas of standing water.

The reedbed was a dense monoculture with little open water, so it was suggested that several scallops were cut into the reeds by WTSWW (assisted by the National Grid project team). The open water will benefit invertebrates such as damselflies and dragonflies, whose larvae will hopefully appreciate the raised temperatures in the areas now exposed to direct sunlight.

Scrub that was also cut back and stacked into dense habitat piles providing ideal egg-laying habitat for grass snakes and will also hopefully be used by small mammals and invertebrates.

The land contains areas of brownfield-type habitat where flowering plants and the exposed gravelly soil supports solitary bees and wasps.

There are also records of two rare bumble bees there: shrill carder bees and brown-banded carder bees. The management of these important habitats is incorporated into the future management plans.

During the initial visit to the site, kestrels were seen hunting over this area, therefore several specialist kestrel boxes were placed at suitable locations around the site in preparation for the breeding season.

Natural Capital Assessment

Using the National Grid Natural Capital tool, a site baseline showed that the site was important and valuable in terms of carbon, air quality, biodiversity and flood management. Our evaluation tool was used to model different management scenarios to increase ecosystem service provision whilst also protect the valuable habitats on site.