Delving into the Datasets I: Trends in Regional Ecosystem Mapping in Queensland

Abstract

Vegetation mapping is used in many parts of Australia and worldwide for conservation planning and other purposes. In Queensland, mapping of ‘regional ecosystems’ serves as a general measure of biodiversity for landscape-level planning. This study assesses regional ecosystem mapping trends with the aim of better understanding the mapping process and the representation of biodiversity patterns, using the northern half of the South-east Queensland Bioregion as a case study. Three successive regional ecosystem map versions were examined, and showed a decrease with time in the number of heterogeneous polygons (i.e. a polygon enclosing multiple ecosystems). Spatial analysis revealed that polygon heterogeneity levels were consistently positively correlated with polygon area, perimeter, and area/perimeter ratio. High percentages of endangered ecosystems, and lower accuracy of polygon line-work and attribution, were also associated with heterogeneous polygons. Regional ecosystem type and geomorphology exhibited strong relationships to polygon heterogeneity levels. It is concluded that Queensland's regional ecosystem mapping program shows ongoing refinement in the representation of ecosystem types, with further opportunities to focus limited mapping resources on particular geomorphological and regional ecosystem types. Additionally, the wider adoption of alternate methods of representing small ecosystems within current cartographic limits may improve the identification, conservation and management of ecologically important areas.