Habitat Management at National Grid Electricity Transmission’s Margam Substation

Before work started on the site at Margam Substation

Before work started on the site at Margam Substation

After the site management

After the site management

In 2019, National Grid approached The Wildlife Trust of South and West Wales (WTSWW) to work with them on a sustainability project located on National Grid Electricity Transmission (NGET) non-operational land surrounding Margam Substation located in Margam near Port Talbot, South Wales. The land consists of approximately 14 ha of reedbed, marshy grassland, scrub and brownfield habitats.

Hannah Urquhart, a National Grid Electricity System Operator graduate working on the project, said:

“In February 2019, the project team began planning a sustainability project as part of National Grid’s annual Natural Grid project, contributing to National Grid’s corporate target of improving the environmental value of 50 of our sites by 2020. WTSWW have provided invaluable advice and support throughout the project, from how to best enhance the land from the early planning stages through to the current stage of implementation, by sharing knowledge on preferred habitats for onsite species to carrying out reedbed clearance.”

Historically, the land has not been managed in any way other than standard maintenance around the National Grid infrastructure. While it already offered very good potential for wildlife there were clear opportunities to enhance it for a number of species.

The expanse of dense reedbed provides home for a number of amphibians and breeding birds

These include Cetti’s warblers, harvest mice and potentially water voles. There is also potential for scarce species such as bitterns to hunt amongst the reeds. Predators like otters and grass snakes will no doubt hunt the amphibians which are likely to be breeding in areas of standing water; a freshly-sloughed grass snake skin was found on our first visit to the site as immediate proof!

In addition to supporting species such as these, the reedbed is also a dense monoculture with little open water, so it was suggested that a number of scallops were cut into the reeds by WTSWW (ably assisted by National Grid members of the project team!).

Instead of struggling beneath the reed canopy, these newly created open areas will allow fresh vegetation to flourish. The open water will also benefit invertebrates such as damselflies and dragonflies, whose larvae will hopefully appreciate the raised temperatures in the areas now exposed to direct sunlight. The fresh shoots will also provide egg-laying sites for newt species and the removal of the thatch of previous years’ reeds will improve the habitat for frogs and many invertebrate species.

Willow and birch scrub is present in a number of areas around the site and is an important resource for many species but it was cut back in a few places where it was starting to encroach into the reedbed and therefore starting to dry it out. The cuttings from the scrub clearance was stacked into dense habitat piles upon which the cut reeds were placed. As this vegetation slowly rots it will provide ideal egg-laying habitat for grass snakes and will also hopefully be used by small mammals and invertebrates.

Signs of harvest mice (old nests) were seen amongst the reeds but sadly no water vole evidence was found despite searches at various points around the site. Hopefully we will be able to go back in spring to look for them during the optimum survey period as well as monitoring how the newly-created scallops are developing.

Alongside reedbed management, areas of the wet meadow were cut by contractors with brushcutters with the cuttings again used to create habitat piles. Not all the area was cut and it is hoped that different patches can be cut on rotation ensuring that it doesn’t all become rank and that there is a range of flowering plants throughout.

During the initial visit to the site, kestrels were seen hunting over this area, no doubt taking advantage of the field vole population, of which there were frequent signs. It was suggested that a number of specialist kestrel boxes were placed at suitable locations around the site. These have been purchased and will hopefully be installed in time for the breeding season.

School visits to talk about sustainability

In addition to the habitat management work, WTSWW has been visiting schools around Margam with members of the National Grid project team to talk about sustainability and the small things that school children can do to contribute. As part of this a competition to design bug hotels was run with the aim of creating a large bug hotel on the Margam site. This will hopefully provide extra habitat for the invertebrates present on site. The land contains areas of brownfield-type habitat around the tracks and pylons 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.

Zaryab Suddle, a National Grid Electricity Construction graduate working on the project, said:

“We have delivered a significant amount of transformation on site that will bring great benefit to the local ecosystem and the environment. The project has met major milestones and is now 80% complete. A significant difference on site is already evident, which we hope will promote biodiversity and attract wider variety of species known to be present in the local area. It has been a pleasure to work with WTSWW on this sustainability project – their commitment to ensuring land in south and west Wales is well managed for the benefit of local species is clearly apparent.”

It has been very rewarding working on this lovely site with National Grid. The habitat improvements will benefit the local wildlife, while the education work will enthuse local children about the wildlife around them. We will build on our relationship with National Grid and follow up with surveys in the spring and potentially future habitat work to ensure that the site continues to support a diverse range of habitats and important species.

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