Development of a Methodology for
Predicting the Impact of Demographic Change and Urban Development on
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
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.
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.
- Although use of “What if?”, a GIS based
geographical modelling tool, appeared initially to be the best approach
for carrying out the modelling for Stage 1, it was only apparent after
the modelling had been completed that alternate approaches would have
been simpler and potentially quicker to use. For example GIS could have
been used to select land parcels manually within the planned
development areas based on land use and consultation with local
- Current habitat assessment data of greenspaces needs to be
collated into a format more compatible with OS MasterMap® which
can incorporate the diversity of types, and qualities, of landcover
within each site.
- The performance of the models for birds, in particular,
could have been improved by using a larger case study area. Increasing
the study area would have involved the use of different landcover data
sets, such as LCM2000 (Landcover Map 2000) which cover the whole of the
UK. This would have had the disadvantage of being out of date relative
to the more contemporary Greenspace databases and also the data is
provided at a lower resolution.
- Data from other taxonomic groups may have performed better
at the scale chosen for this project. Birds are species with high
dispersal rates and are less sensitive to habitat fragmentation
effects. If this methodology were to be further developed then
appropriate budgeting for the acquisition of the datasets or involving
potential data providers, for other species, in a more collaborative
approach would be necessary.
- In general, there is very little information collected on
urban biodiversity. Collation of long term datasets of urban species at
the right scale and level of coverage would be invaluable in the
modelling approaches presented here.
- It is important to test the methodology within areas with
strategic plans for greenspace development and to also compare between
different local authority areas. This would enable the methodology to
be explored in places which have more land and resources available to
increase the extent of multifunctional greenspace networks and to
enable greenspace planning to extend across local and regional
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