About the project

The Biodiversity in Urban Gardens 2 project was carried out over three years (2004-2007) to develop a better understanding of the role that domestic gardens play in providing green space across urban areas, and how the resource they provide interacts with current, and potential future, urban forms.

The work was carried out in five cities: Leicester, Oxford, Cardiff and Belfast and Edinburgh. This provided a diverse range of urban areas, in terms of urban form and history, and climate. The project had three components.

First the extent and nature of the domestic garden resource was characterised. Whilst the potential value of domestic gardens has been much discussed, data on the structure of the existing garden resource are very scarce. In each city aerial photography and GIS were used to assess the size distributions of gardens, and patterns of spatial variation in size, shape and connectivity, and the relationship of these to housing type.

Second, the features of domestic gardens were characterised. There are many features that occur in domestic gardens that are known to be of importance in the maintenance of biodiversity, provision of ecosystem services, and human well-being. These include trees and mature shrubs, lawn areas, ponds, compost heaps, nest-boxes, and food plants for other organisms. However, the frequency with which these resources occur in gardens, their extent, and their permanence (in the face of changing occupancy and ownership of dwellings) remain poorly understood. For the study cities these are being assessed by ground survey and questionnaire techniques.

Third, the floristic diversity of domestic gardens was determined. Domestic gardens provide resources and habitat for a wide range of species, some of which are of conservation concern (detailed surveys of gardens in Sheffield have recorded species of national, regional and local significance). The composition of garden floras, which provide the basis for much of this diversity, was determined for a sample of gardens that captured the breadth of variation in degree of urbanisation, area, house type and age etc. Particular attention was paid to documenting the occurrence of native species (which constituted approximately a third of plant species in gardens in a similar survey in Sheffield), and to the occurrence of plants that are encouraged for wildlife gardening.

The results of the project provide the first systematic appraisal of gardens as a habitat and wildlife resource across different kinds of urban area in the UK, and will feed into Biodiversity Action Plans for urban areas, research on urban ecology, and debates about sustainable urban development.