Ecosystems are linked and maintained by water. Water enables plant growth and provides a permanent habitat for many species, including many species of fish, and is a breeding ground or temporary home for others, such as for many species of amphibians and reptiles. These ecosystems offer environmental security to humans by providing goods and services, such as food, medicines and timber products, and flood protection and water quality improvement.
The positive impacts that urban green infrastructure can have on air, water and soil quality provide benefits for ecology. Freshwater ecosystems, in the form of rivers, canals, lakes, reservoirs and ponds, are especially an important component of urban greenspaces. Almost half of the greenspace in the City of London is associated with freshwater elements and is therefore an important resource. In some areas ponds have been found to hold a greater diversity of species than nearby lakes or river systems; many of which have been heavily polluted, canalised or over managed. Amphibians and dragonflies move between several ponds and the network or “pondscape” has higher ecological value than a single pond.
However, garden ponds they may still make a substantial contribution to local species richness, especially for mobile invertebrates or amphibians by acting as temporary habitats. In such a way garden ponds have the potential to form stepping stones between other ponds in the wider landscape. Low density developments would seem to favour the protection of pond networks, both in public spaces and by providing a greater garden resource. However, growing pressure to increase urban infill development is likely to see a rise in building density and make the retention and management of urban blue and green spaces ever more challenging.
The habitats provided in urban green infrastructure can be particularly important for a range of species. This influence is caused by the flow of water between components of the wider landscape and can provide the following benefits:
- Increased habitat area
- Increased species movement
- Increased populations of protected species.
The inclusion of SUDS in new development plans is an option for increasing the area of freshwater habitat in an urban area. The use of wetlands, ponds, swales and trenches for water storage can encourage the biodiversity of aquatic organisms by providing a safe haven in the urban environment. These SUDS features can help to provide ‘green’ or ‘blue’ corridors for the movement of species, and provide a safe haven for populations of protected species.
There is an important role for planting woodland along urban river corridors to reduce thermal stress to fish and freshwater life. Water features will help adaptation to climate change due to reduction in surface runoff to reduce flooding. Water features also act as a focus for visitors and may attract people for recreation and leisure.
Conservation and planning must consider the broader aquatic landscape and the maintenance of biodiversity within it. Insight could be gained from longitudinal studies in newly developed areas to assess the long term impact of changes on ecology in the surrounding landscape.
The incorporation of SUDS into development planning to provide water features can improve ecological levels and encourage wildlife, and for this to be successful it is necessary to:
- Use appropriate ecological design
- Construct SUDS in accordance with that design
- Carry out management to ensure the SUDS are functioning correctly
- Monitor the site to ensure high standards are maintained.
Edinburgh Park, Edinburgh
The Edinburgh Park Master Plan aimed to carry out landscaping improvements to the business park. A number of water features were constructed, alongside the normal infrastructure. Since then, a rich series of natural and social environments have been developed for meeting and socialising. Today Edinburgh Park is one of the most renowned business parks in the UK. Edinburgh Park’s commitment to quality of lifestyle continues in the development of the new phases of the Park. Developments include the new civic square to the Park which provides further seating, petanque pistes, paths and water features.
CABE Space (2004). Green space strategies: a good practice guide. CABE Space, London.
Gill, S., Handley, J., Ennos, R. and Pauliet, S. (2006). Adapting cities for climate change: the role of the green infrastructure. University of Manchester.
Gledhill, D.G., James, P. and Davies, D.H. (2008). Pond density as a determinant of aquatic species richness in an urban landscape(PDF-221K). Landscape Ecology.