Fragments, functions and flows - the scaling of biodiversity and ecosystem services in urban ecosystems

Urban areas cover just 2.8% of the Earth's land area, but over 50% of the human population lives in them, and these proportions are growing rapidly. Such heavy concentration of people has a wide variety of important consequences. Those for their relations with the environment have attracted much recent attention from the media, pressure groups, policy makers, researchers, and local and national government. Of particular concern have been how improvements can most effectively be made to the environmental conditions experienced in urban areas, to the levels of interaction between urban dwellers and the natural environment, and to the contribution of urban areas to the broader scale provision of ecosystem services. This raises the key issue of the form of relationships between biodiversity and ecosystem services in urban areas, how the structure of urban areas (the spatial structure of the different kinds and extents of impermeable and permeable surfaces; urban form) influences these relationships, and thus how the existing structure can best be managed and how future structure can be planned to best effect.

Although understanding of the levels and distributions both of biodiversity and of ecosystem services in urban areas has improved dramatically in recent years the relationships between biodiversity and ecosystem services have been extremely poorly studied in urban areas (and are largely absent from major collations of empirical studies). Indeed, these environments pose significant and unusual challenges:

- the urban landscape is highly fragmented, with large portions sealed by buildings and paving;
- greenspaces are embedded in a complex mosaic of buildings and roads that imposes major constraints and directionality on the flows of biodiversity and ecosystem service delivery across the urban landscape;
- the intensity of human management of these environments can give rise to spatial patterns and scales of flows of energy, materials and biodiversity on which ecosystem services depend that would not naturally occur; and,
- the very aggregations of people that give rise to urban areas typically necessitate less conventional approaches to conducting ecological research therein, involving greater engagement with the general public, and less dependence on the use of large pieces of equipment, which is "out of bounds" to the general population.

In order to determine these biodiversity-ecosystem service relationships, develop deeper understanding and to test this understanding our overall approach to this project involves five main steps. We shall:

- characterise the spatial ecological structure of urban areas;
- determine biodiversity-ecosystem service relationships and the influence of connectivity on them;
- determine the flows of biodiversity, and service delivery in selected cases;
- experimentally perturb those flows to determine the impact on ecosystem service delivery; and
- integrate these findings in the form of spatially explicit models which will form the basis of an "ecosystem service" layer for GIS models.

This will enable us to deepen understanding, and to provide illustrations for stakeholders (such as planners, local people and NGOs) as to how "scenarios" of different development proposals might be tested, to provide support for decisions based on sound science and stakeholder engagement.

Academic Impact
The data, techniques and results from this project will be of value to academic researchers in areas such as urban ecology, ecosystem services, human-nature interactions, and remote sensing. In addition, they will provide valuable insights into solving the challenges of bringing together different approaches to the assessment of ecosystem services, and will develop new approaches and techniques in this difficult interdisciplinary area of science. The study will generate valuable research experience in the management and use of hyperspectral imaging and full waveform LiDAR data, network modelling of urban systems, automated collection of bird movement data, and large scale deployment of ecosystem service assays across a range of services. These benefits will accrue to the research community through the publication of academic papers detailing the work, and also through the training and experience of the post-doctoral researchers employed on the project. This latter benefit will be particularly strong as a result of the management of the researchers as an integrated team, using the same field sites, with interacting and overlapping responsibilities for different project elements. Each researcher will both develop a range of skills and experience in their own area, but also benefit from the exchange of skills and experience resulting from working collaboratively with others with different skill sets on the same system. Generic skills such as team working, interaction with partners and the public, and communication of results to non-specialist audiences are also important elements of experience that the researchers will acquire.

Economic and Societal Impact
The insights from this project are directly aimed at providing the underpinning knowledge for making policy and management decisions that enhance quality of life, health and well-being in urban areas. The results will contribute directly to evidence-based policy making, for example addressing questions about the ecosystem service consequences of changes in urban density and form - a key current debate at local, national, and international levels. The project will address issues of both spatial structure, and management of urban greenspace. Results from the latter in particular will be of benefit for the many organizations and individuals involved in such management (including, of course, key project partners, as well as garden owners, local authorities and nature conservation groups), providing evidence both about the biodiversity and ecosystem service value of different greenspace types, and also about the consequences of different management regimes for these relationships. Our experimental manipulations - grassland maintenance, bird feeding, and urban meadow planting - have been chosen closely to match the types of management questions that are currently of interest to those managing urban land, or biodiversity within it, ensuring the relevance of the results to actual practice.

By taking into account multiple ecosystem services in our assessment of the role of greenspaces, and the effects of management, the results will allow a more holistic appraisal of the roles of different sorts of urban greenspace, and the relationship of those to biodiversity, than is usually the case. This will provide a more complete assessment of the contribution of urban greenspace to the environmental sustainability of urban systems. The outcomes of the project, in addition to providing evidence to underpin policy will, equally importantly, provide the data and understanding from which tools for spatial planning and management of urban greenspace can be developed.