The biological diversity (or biodiversity) value of urban greenspace is immensely variable, but all greenspace by definition contains some biodiversity. The biodiversity present will often depend on the functions of a particular site, as well as its history and location. Nearly all greenspace sites can increase their biodiversity, often quite simply.
‘Biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.’ Convention on Biological Diversity
Particular species or groups of species can sometimes be managed together.
Greenspace benefits biodiversity, increasing species populations and offering routes through otherwise inhospitable urban land use.
The benefits of biodiversity for people are varied, but may be difficult to quantify. Educational and recreational opportunities are apparent, but the extent to which contact with a wide range of species and habitats benefits human well-being are not currently well understood. However, for many people there is a moral imperative to preserve species and their local populations.
There are a number of mechanisms by which biodiversity is protected within the UK. These include European designations, for example under the EC Habitats Directive, and UK-wide protected areas, such as Sites of Special Scientific Interest both of which are overseen by Natural England, Scottish Natural Heritage and Countryside Council for Wales.
Local authorities also have Biodiversity Action Plans that detail the priority species and habitats for their areas. Greenspace should be designed to be sympathetic to these plans and aim to work with them to encourage desirable species or habitats specific to the region.
Planning Policy Statement 9: Biodiversity and Geological Conservation sets out the Government’s policy on protecting and enhancing the UK’s biodiversity within the context of planning.
Biodiversity management can range from the simplest measures to the most complex plan. This largely depends on the site itself, the functions of the site, and the resources available. It is helpful to decide from the outset what the target is for a given site, and what habitats you would like to include. Deciding this will depend on the condition of the site, its location and soil type, as well as surrounding habitats. There may be records of what habitat was on the site before it was first developed (the local library should be able to assist here).
Sites may be managed for a particular species or group of species. But managing for one group may conflict with another. As a general rule, increasing biodiversity can be achieved by diversifying the range of habitats or vegetation structures available at a site. This can be achieved by, for example, varying mowing regimes, planting or seeding with native tree and shrub species, or occasional soil disturbance. Animal diversity may be increased by providing a range of fruit sources, for example by not clipping berry-bearing shrubs until January, and by allowing wildflowers to flower for nectar provision and to bear seed as food for birds. Site drainage can also have an important impact.
Some urban sites have problems with eutrophication - having too many nutrients available. Such sites can be dominated by rank vegetation such as nettles and dock leaves. In this case, it may be helpful to identify where nutrients are entering the site, or to mow, strim or clip the vegetation and remove clippings to a local composting scheme.
Some sites may already contain species listed under protective legislation such as the Wildlife and Countryside Act or the EC Habitats Directive. The manager of the site will be required by law to protect these species from harm, often being prohibited from carrying out certain management actions. We recommend that if you have such species, or think you may have them, you seek specialist advice.
Forest Research can provide specialist advice and consultancy services on woodland management, including the restoration of woodland planted with non-native species. We also have specialists in open habitat management particularly heath and bog.
Forest Research can provide advice on the range of protected species that may be found on your site, and management advice on a range of species, particularly those linked to woodland.
- UK Biodiversity Action Plan
- Planning Policy Statement 9: Biodiversity and Geological Conservation
- Natural England
- Scottish Natural Heritage
- Countryside Council for Wales
Forest Research Best Practice Guidance
Sinnett, D. (2006). Maximising Biodiversity (PDF-289K). Best Practice Guidance for Land Regeneration, BPG Note 9. Forest Research, Farnham.