Examples of Brownfield Sites
What are some typical examples of brownfield sites?
Brownfield sites encompass a variety of land types, often those with a history of industrial, agricultural, or urban use that has led to their current vacant or derelict state. Examples include abandoned industrial areas like oil refineries, vacant demolition sites, including those from historical events such as wartime bombing, quarries, abandoned industrial areas and spoil tips, railway embankments, canals, and road verges. Areas of waste ground and even managed landscapes like amenity grassland (mown lawns) can also be classified as brownfield.
The Phase 1 Habitat Survey uses specific classifications for vegetation found on brownfield sites. Short, patchy plant associations typical of derelict urban sites, quarries, and railway ballast are classified as "Ephemeral/short perennial". A broader category associated with brownfield habitats is "Cultivated and disturbed land," which includes "Arable", "Amenity grassland", and "Ephemeral/short perennial". If railway cuttings and embankments are wide enough and dominated by trees or scrub, they can be mapped as woodland or scrub, or as appropriate grassland habitat if grass-dominated. Narrow herb-rich verges can also be included.
Yes, despite their modified nature, the best examples of brownfield sites can be remarkably rich in species. Their varied characteristics, often due to past use, create diverse microhabitats. Some brownfield sites have been found to support as many invertebrates as ancient woodland, highlighting their potential ecological value. For example, an abandoned oil refinery on Canvey Island, Essex, was declared a Site of Special Scientific Interest (SSSI) due to its richness in insect species.
"Ephemeral/short perennial" is a vegetation type classified in the Phase 1 Handbook. It describes short, patchy plant associations that are characteristic of disturbed environments. These are typically found on derelict urban sites, quarries, and railway ballast, which are often classified as brownfield sites.
Historical events, such as wartime bombing, can directly lead to the creation of brownfield sites. Bomb sites and derelict buildings resulting from these events become vacant demolition sites. These sites were notably colonised by certain species, such as Black Redstarts, after the Second World War, demonstrating their potential to develop ecological value over time.
While many brownfield sites are derelict or abandoned, the classification also includes areas that are actively managed but still considered to have a history of development or disturbance. For instance, amenity grassland, such as mown lawns in parks and playing fields, is classified as a brownfield site. The Byes in Sidmouth, for example, was partly designated brownfield due to its extensive area of mown lawn classified as amenity grass.
The legacy of past industrial or agricultural use significantly influences the characteristics of brownfield sites. This can result in variation in the chemical content and pH of the soil, which is often thin and skeletal. The vegetation can therefore vary greatly, ranging from simple forms like lichens and mosses to more complex communities including tall ruderal herbs, pools, open turf, flower-rich grassland, and scrub.
Yes, brownfield sites are not necessarily static in their classification. Some sites may be undergoing restoration efforts. These restoration processes can lead to a gradual return to a more natural habitat, potentially resulting in eventual reclassification. The Lockyer Observatory site in Sidmouth is given as an example of a brownfield site that is gradually returning to heath habitat through restoration.