Development of a Methodology for Predicting the Impact of Demographic Change and Urban Development on Biodiversity
September 2008


Background to research

Despite an overall decline in Scotland’s population over the last ten years, there have been marked differences in population changes for local authorities. In regions where the population is increasing, this will be reflected in higher demand for housing developments. Even in areas of population decline, the numbers of new houses needed could still potentially continue to grow due to ever increasing demand for single occupancy households.
As result of the increased requirements for housing, the Scottish Government in the Scottish Planning Policy 3, has proposed a target number of an extra 10,000 homes to be built in Scotland each year. Councils will be encouraged to release more land for housing and to make more use of Brownfield land relative to Greenfield land for the purpose of development.
The Scottish Government has also highlighted the importance of urban biodiversity in its strategy for the conservation and enhancement of biodiversity in Scotland and is one of the key topics in the strategy implementation plans. Moreover they have stressed the need for the integration of biodiversity into urban regeneration, development and planning systems.

Objectives of research

The overall aim of this project was to develop a methodology which predicts the impact of demographic change and urban development on biodiversity, which was achieved by addressing the following objectives: to quantify current and future land use in an urbanised region of Scotland; to quantify the biodiversity value of key habitats and habitat networks within the study region; and, to link land use and biodiversity data sets and develop analytical techniques that could assess the potential impacts of urban development on biodiversity.
We chose to use the case study of City of Edinburgh Council, an area which has been identified as an area of high demand for housing development. Birds were the obvious choice to be used for the biodiversity component of the methodology, due to the availability of data from long-term large-scale monitoring programmes. They are known to reflect the state of other taxa in the ecosystem and therefore, are representative of generic urban biodiversity. The methodology presented here is only meant to provide a demonstration of how this approach can be used and adapted for use in other regions and other taxonomic groups. It does not set out to provide recommendations on how Edinburgh could be developed per se.

Key findings

A three stage process was adopted: Stage 1: quantification of urban development in the study area, and projection of future residential and commercial land use areas under different development scenarios; Stage 2: quantification of the biodiversity value of greenspace habitat networks, based on data and scenarios from Stage 1; Stage 3: assessment of the relationships between garden bird occurrence and the biodiversity value of habitat networks, and predictions of the impacts of different development scenarios on birds. We were successful in that we were able to develop an original, innovative methodology that linked land cover, habitat quality and biodiversity data sets and that was able to predict impacts of future urbanisation on bird occurrence using different scenarios of development. The methodology requires a high level of expertise in use of GIS, spatial modelling software and generalised linear modelling. Nevertheless, the approach adopts a clear logical framework which is applicable to any other urban area and any other taxa with appropriate data.

The developed methodology satisfied the objectives of the project. There are, however, modifications which would largely help refine the approach which are discussed below. The outputs generated by the methodology suggested that, in general, responsible developments are much preferable to insensitive developments, which result in a loss in the area and connectivity of greenspaces. The sensitivity of a development is critical, as it can make the difference between an increase and a decline across all of the garden bird species examined in this study. Therefore the environmental cost of a development should be quantified before it is allowed to proceed.


Various issues encountered in the development of this methodology have led to a number of recommendations to refine the process in the future:
Keywords: birds, connectivity, development scenarios, Edinburgh, GIS, greenspace, habitat networks, urbanisation.

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N.B. The report is available for download from the SNIFFER Website