Biodiversity Net Gain (BNG)

Biodiversity Net Gain (BNG) is an approach that leaves the environment in a better state than previously following development. BNG is to be a mandatory element of the planning system, but its principals are already being applied by developers.

One way to achieve BNG is the creation or enhancement of habitat for wading birds. Wading birds, or waders for short, are an order of birds that include around 350 species worldwide. Approximately 15 species are present in Britain in internationally important numbers. The creation of shallow freshwater or brackish pools, known as ‘wader scrapes’, can provide waders with important foraging habitat. If the pools are situated next to intertidal areas, they may also provide high tide roosting opportunities.

Wader scrapes should be situated towards the middle of large fields, in lower lying areas and away from woodland. They can be created in a number of ways, for example by blocking drainage or by scraping top soil from existing damp areas. The edges of scrapes are important. The margins should be irregularly shaped, shallow and relatively vegetation free. The land immediately surrounding scrapes is also important, ideally it should be flat and open. Once created, on-going management of scrapes is necessary. Ideally, water levels should be controllable and the land immediately surrounding the scrapes should be lightly grazed.

Wader scrapes can transform land that was previously poor for birds into magnets for foraging and roosting waders. Species such as Lapwing can be attracted to breed on scrapes, while Redshank pushed off a nearby estuary at high tide may use them for roosting. Passage waders such as Green Sandpiper and Ruff both regularly use wader scrapes, particularly in late-summer and autumn. Waders are an important group of birds, and yet suitable wader habitat is scarce. Wader scrapes are a relatively simple method to increase biodiversity.

Spotted Redshank and Black-tailed Godwit feeding in deeper water in a wader scrape.

Ruff, Black-tailed Godwit and Lapwing feeding at margins of a wader scrape.