The utility of site‐based datasets and regional ecosystem mapping for biodiversity conservation in the Southeast Queensland Bioregion: Past, present, future

Abstract

The utility of site-based datasets and regional ecosystem mapping for biodiversity conservation in the Southeast Queensland Bioregion: Past, present, future. Ben E. Lawson. School of Natural and Rural Systems Management (NRSM) & School of Geography, Planning and Architecture (GPA), The University of Queensland, Brisbane 4072, Australia. Email: b.lawson@uq.edu.au. Key words: conservation, ecosystem mapping, regional ecosystems, site-based data. Ecosystem mapping and site-based datasets are core components of conservation planning and management schemes. In Queensland, regional ecosystem mapping is used for landscape-level planning, underpinned by site-based data. This doctoral research assesses their utility as surrogates for biodiversity patterns with a view to future needs. The research is supervised by Dr Grant Wardell-Johnson, Associate Professor Bob Beeton (NRSM) and Dr David Pullar (GPA) from the University of Queensland. The ecologically diverse Southeast Queensland (SEQ) Bioregion is the focus of this research. Issues and limitations in the two datasets, which underpin this research, were the first component examined. Regional ecosystem mapping showed a decrease in the number of heterogeneous polygons (i.e. a polygon with multiple ecosystems assigned) across successive versions. Polygon heterogeneity levels were positively correlated with endangered ecosystems and lower polygon accuracy, and strongly related to particular regional ecosystem and geomorphology types (see Lawson 2006). Retrospective analysis of the Queensland Herbarium's site-based floristic dataset, ‘CORVEG’, showed improved data quality and completeness in the past decade as a consequence of more explicit sampling protocols, although missing information continues to limit data utility (see Lawson in press). Case studies were used to explore the application of regional ecosystem mapping in varied circumstances. The first case study examined SEQ sand islands where high levels of map unit homogeneity relative to adjacent mainland areas were observed. Analysis showed that mapping effectively portrayed ecological patterns and that homogeneity existed across various map scales and map authors across the islands, suggesting that high polygon homogeneity were ecological, not cartographic, phenomena (see Lawson & Wardell-Johnson in press). The second case study came from Toohey Forest in southern SEQ, an area mapped as a single regional ecosystem type at 1:100 000 scale despite its recognized biotic and abiotic diversity. Fine-scale mapping approaches were explored to assess the representation of floristic patterns, indicating that ongoing reduction in regional ecosystem mapping scale and incorporation of fine-scale geomorphic mapping were vital to improve the representation of floristic diversity. Core components of the research which are yet to be completed will elucidate species richness and dissimilarity patterns within and between map units and reveal the ecosystem types that are (and aren't) well portrayed by the mapped patterns, the reasons for this, and measures to improve representation. Queensland's regional ecosystem mapping program shows continued improvement in the representation of biodiversity patterns, with some areas more effectively portrayed than others. The use of heterogeneous polygons to identify ecosystems otherwise unrecognizable at particular map scales is simultaneously a major advantage and disadvantage to representing biodiversity patterns. Opportunities are available to focus limited resources on particular geomorphological and regional ecosystem types, and for alternate methods of representing geographically restricted ecosystems. Greater consideration of current and future uses of site-based floristic data is necessary. For example, hierarchical datasets serving multiple biodiversity objectives should be considered. These issues are directly relevant to the mapping of biodiversity condition.