Spatial assessment and mapping of biodiversity and conservation priorities in a heavily modified and fragmented production landscape in north-central Victoria, Australia
Introduction
In recent years, the importance of biodiversity to global economies, human welfare and survival has been well documented and widely recognised (Butchart et al., 2010, Duffy, 2009, Rands et al., 2010, Steffen et al., 2009, TEEB, 2009). In Australia, biodiversity continues to decline in spite of Federal and state government efforts to manage threats (Bennett, 2003, DSE, 2010, NRMC, 2010, OECD, 2008, SoE, 2011, Steffen et al., 2009) with similar trends globally (Butchart et al., 2010, CBD, 2010, MEA, 2005, Steffen et al., 2009). Moreover, Australia has suffered the largest documented extinction of species of any continent over the last 200 years (DSEWPC, 2011). The main identified threats to biodiversity in Australia include loss, fragmentation and degradation of habitat or natural ecosystems, spread of invasive species, unsustainable use of natural resources, inappropriate fire regimes, and climate change (Bennett, 2003, NRMC, 2010, Steffen et al., 2009).
With significant expansion in production landscapes for agricultural activity around the world and a resultant ongoing decline of natural systems (FAO, 2005, World Bank, 2010), there is an increasing focus on the role of production landscapes in conserving biodiversity and providing a variety of ecosystem services (Bélair et al., 2010, Kandziora et al., 2013, Wilson et al., 2010). Securing biodiversity in the production landscape can enhance agricultural productivity through pollination and pest regulation, water quality and nutrient regulation, soil stabilisation, and carbon sequestration (Hooper et al., 2005, Kasel et al., 2011, Scherr and McNeely, 2008, Tscharntke et al., 2005). While there is ongoing debate about the relative merits of integrated versus partitioned conservation activity (Phalan et al., 2011, Tscharntke et al., 2012), conservation policy makers and land managers are giving strong support to conserving biodiversity in highly modified production landscapes (Wilson et al., 2010). Spatial assessment and mapping of conditions suitable for biodiversity conservation or restoration are also essential for the establishment of baseline biological data that will aid successful conservation planning and management in highly modified landscapes (Eigenbrod et al., 2009, Jones-Walters, 2008) and help identify priority sites for allocating limited resources (Brooks et al., 2006, Higgins, 2006).
Extent and quality of habitat conditions are often used as proxies of biodiversity (Nelson et al., 2011, Tallis et al., 2010) and remote sensing based techniques are being increasingly employed to generate biodiversity and ecosystem services indicators (García-Gómez and Maestre, 2011, Lück-Vogel et al., 2013, Nagendra et al., 2013, Spanhove et al., 2012). Recent research has focused on linking current land use and vegetation types to biodiversity and associated ecosystem services (Burkhard et al., 2012, Falcucci et al., 2007, Foley et al., 2005, Hector and Bachi, 2007, Kandziora et al., 2013, Yapp et al., 2010). A variety of approaches have been used to identify conservation priority sites within production landscapes, each focused on a different aspect of biodiversity (e.g., Kandziora et al., 2013, Schneiders et al., 2012, Tallis et al., 2010) from global (Brooks et al., 2006, Jongman, 2013) to local scale (Higgins, 2006, Jongman, 2013). Given the imperative for expeditious implementation of conservation solutions (Watts and Handley, 2010), rapid assessment approaches that use readily available data and tools are highly desirable (Baral et al., 2013, Burkhard et al., 2012, Grantham et al., 2008, Grantham et al., 2009).
The aim of this study is to spatially characterise a heavily modified and fragmented production landscape and assess biodiversity value using readily available data and tools in order to identify conservation priority sites. An additional aim is to assess the effect of land-use change on the provision of biodiversity and associated ecosystem services. To achieve these objectives we used spatial approaches and tools for biodiversity assessment and mapping such as Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) biodiversity models (Tallis et al., 2010) and patch analyst tool (Rempel et al., 1999, Rempel et al., 2012). The resulting data and maps and subsequent analyses are used to consider the opportunities for re-configuring natural vegetation in cleared, modified and degraded landscapes to meet new sustainable landscape management objectives. Furthermore, we comment on the suitability of InVEST tools for habitat quality assessment and conservation planning.
Section snippets
Study site
The study site is located in north-central Victoria, Australia between Kerang and Lake Boga, approximately 320 km north-west of Melbourne (35.972° S, 143.228° E, Fig. 1). The total area spans about 30,000 ha, essentially defined by the boundaries of the Little Murray and Lower Loddon Rivers in the North, West and South and the Murray Valley Highway in the West. Within the study area lies the Winlaton and Reedy Lakes Future Farming Landscapes (FFL) projects managed by Kilter Pty Ltd. The terrain
Spatial characterisation of the landscape – Patch Analyst tool
Twenty two percent of the study area (6800 ha) supported native vegetation. This vegetation was highly fragmented, in more than 4000 irregularly shaped patches. Of these patches 98.5% were small sized patches (<10 ha), 1.2% were medium sized (10–50 ha) and only 0.3% were large sized (>50 ha). Although there was one large block of approximately 1800 ha intact native vegetation (Fig. 2), the small sized patches of native vegetation dominated the landscape with mean patch size of 1.8 ha and median patch
Discussion
This study demonstrates that readily available spatial datasets and tools can be used to assess habitat quality and biodiversity values in human-dominated landscapes and can be useful for initial assessment and conservation planning. Our analysis also indicates that there is a high potential for protecting and enlarging small remnant patches for reducing fragmentation and increasing connectivity and associated biodiversity at the landscape scale.
Conclusions
Conservation of biodiversity and associated ecosystem services in highly modified and fragmented production landscapes is a crucial natural resource management issue in Australia and elsewhere. Availability of data and appropriate tools are often identified as issues in assessment of biodiversity and ecosystem services. Here we successfully demonstrate spatial approaches to classifying the landscape for habitat quality, based on the size, density, distribution and condition of native remnant
Acknowledgements
Himlal Baral was supported by a University of Melbourne Research Scholarship and top-up scholarship from the Cooperative Research Centre for Forestry. Spatial data were provided by the Victorian Department of Sustainability and Environment (DSE) through the University of Melbourne and the North Central Catchment Management Authority. We thank Graeme Newell from the Arthur Rylah Institute of Environmental Research, DSE and Kilter Pty Ltd for supplementary data and ongoing support. We thank two
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