Integrating conservation planning and landuse planning in urban landscapes

Abstract

The rapid growth of cities around the world is now seen as a major contributor to global biodiversity loss and many governments include biodiversity conservation as an explicit policy goal. To help prevent further loss of biodiversity, there is an urgent need for more strategic approaches to conservation planning in urban environments based on a scientific understanding of landscape patterns, species requirements and development pressures. In this study, we demonstrate the use of new conservation planning tools to better integrate information on threatened species into landuse planning. We present a case study in the Greater Melbourne area that utilises the Zonation conservation planning tool with data for 30 threatened fauna species. We perform a multi-species spatial prioritisation that incorporates species-specific connectivity requirements and demonstrate the use of this information in a number of landuse planning contexts. First, we quantitatively assess the differences between Melbourne's current conservation areas with the locations prioritised by Zonation and determine priority areas for their extension. We then show how the prioritisation can be used in decisions regarding Melbourne's Urban Growth Boundary and in rezoning land for development. Finally, we demonstrate how the prioritisation can be used to identify areas of conservation significance within individual developments that account for the wider landscape context. These results demonstrate how conservation planning tools can be better integrated into the different stages of landuse planning for future urban growth.

Introduction

The global biodiversity crisis (Western, 1992) has come about due to major landuse changes resulting from human activities (Hilty et al., 2006). This is particularly prevalent in urban areas where high levels of fragmentation are common and the greater intensity of land modification in the matrix surrounding remaining habitat is generally unsuitable for many species. The expansion of urban areas is a major threat to the biodiversity values of peri-urban areas (Williams et al., 2001), and can lead to a simplification of indigenous biodiversity (Knight, 1999). Important values are at stake; for example, in Australia, it is estimated that more than 50% of threatened species have habitat in and around major cities or in population growth areas (Yencken and Wilkinson, 2000). Mitigating the impacts of the growth of cities on natural systems and processes is complicated by high land values, a diversity of stakeholders and land tenures (Bekessy and Gordon, 2007), and is hampered by a lack of practical research concerning the threat of urbanisation to biodiversity (Miller and Hobbs, 2002).

In addition to ecological imperatives, retaining biodiversity in urban and peri-urban areas provides a number of important ecosystem services (Binning et al., 2001) and benefits for human well-being (Tzoulas et al., 2007). Furthermore, the conservation of native ecological communities close to where people live and work provides opportunities for formal education and enhances community awareness of environmental issues (Miller and Hobbs, 2002).

In Australia, the responsibility for protecting biodiversity rests with all levels of government. The Federal Government and all Australian State and Territory Governments are signatories to the National Strategy for the Conservation of Australia's Biological Diversity (Department of Environment, Sport and Territories, 1996). The Federal Government also has the power to restrict activities (including urban development) that may have a significant impact on threatened species and communities though the Environment Protection and Biodiversity Conservation (EPBC) Act 1999. Despite these commitments, conflicts between biodiversity conservation and the development of land for population and economic growth are acute (Bekessy and Gordon, 2007).

The causal chain of events that leads to development activities around cities can be grouped into three general stages, namely strategic, rezoning, and development stages. The strategic stage involves long-term strategic planning to determine where landuse change should be occurring at a regional level. An Australian example is the planning document Melbourne 2030, which was development by the Victorian State Government to address long-term planning across the greater Melbourne region (Department of Sustainability and Environment, 2002). The second category of activities comprises the rezoning of specific tracts of land. The zoning of land designates permitted and prohibited uses, and the uses for which additional formal authorisation is required. In a peri-urban setting, this would typically result in areas with rural (farming) zonings being changed to allow residential development. The development stage involves fine scale activities, such as the subdivision of land for urban development. For effective biodiversity conservation, input is required at all three stages of the development process.

Systematic conservation planning (Margules and Pressey, 2000) is a suite of methods used to determine, implement and manage a set of areas containing desired conservation targets with the minimum expenditure of resources. A range of quantitative tools have been used to address the problem of prioritising areas for protection and these tools have potential to improve the way biodiversity is incorporated into urban planning. Methods used to address this problem include simple procedures such as ranking sites by a set of criteria such as species richness and presence of threatened species (Margules et al., 1991), to more sophisticated measures such as irreplaceability (Ferrier et al., 2000). Integer programming techniques have been applied to provide exact solutions to a range of coverage problems related to area prioritisation, where the aim is to determine the smallest set of locations needed to represent all species, or to maximise the number of species represented for a given budget (ReVelle et al., 2002, Williams et al., 2004). Spatial attributes have also been incorporated into this type of approach (J.C. Williams et al., 2005). Freely available software such as MARXAN (Ball and Possingham, 2000), C-Plan (NSW NPWS, 1999) and SITES (Andelman et al., 1999) can be used to determine networks of conservation reserves that meet specified targets for reservation (e.g. 30% of the habitat for all species) while minimising other constraints such as economic cost and the reserve boundary length.

Systematic conservation planning techniques have been applied in many areas around the world (Cabeza and Moilanen, 2001, Cowling and Pressey, 2003, Lombard et al., 2003, Margules and Pressey, 2000, Pressey et al., 1993), however they have generally been conducted in non-urban regions due to the preference of scientists to study more pristine landscapes and the difficulties of undertaking conservation activities in urban areas (Miller and Hobbs, 2002, Marzluff, 2002, Crossman et al., 2007, Bekessy and Gordon, 2007). Applying systematic conservation planning in human dominated landscapes poses significant challenges, including the need to address multiple objectives, the likelihood that many priority areas will not be available for conservation and may degrade and alter in their availability over time (Haight et al., 2005, van Langevelde et al., 2002, Weber et al., 2006). Other obstacles include political pressures for development, high land prices and small land parcels (Bekessy and Gordon, 2007). Furthermore, conservation planning in urban areas is often ancillary to planning for the provision of recreation and landscape amenity and has focussed on creating open space (Ahern, 2004, Ruliffson et al., 2003).

This paper focuses on the area prioritisation aspect of systematic conservation planning, and how it can be used to integrate information on threatened species into landuse planning at multiple scales. We present the results of a case study in the Greater Melbourne area which uses the Zonation conservation planning tool (Moilanen and Kujala, 2006) to identify conservation priorities for thirty threatened fauna species. We demonstrate how the tool can be used to quantitatively compare the current arrangement of conservation areas to the areas prioritised by Zonation, and to identify areas for their extension. We also demonstrate how the tool can be used to prioritise areas to extend Melbourne's Urban Growth Boundary (UGB) and to prioritise land not yet zoned for development, but under high (or certain) risk of being developed.