Broad-scale assessment of aquatic ecosystem condition is widely known as a principal component in land and water resource management. Natural variability can influence and complicate assessments. To account for some of this natural variability sampling can be stratified using a bioregionalisation approach. Bioregionalisation provides a useful tool for outlining complex patterns of biodiversity and identify broad-scale areas of greater similarity as bioregions or provinces. Our objective was to undertake a bioregionalisation of Queensland river basins using long-term aquatic macroinvertebrate community data.
Queensland has had an active biological assessment program to monitor the ecological condition of state-wide riverine ecosystems since 2004 and continues today. This robust data includes aquatic macroinvertebrate samples that were collected from specific habitat types including edges along wetted sections of riverine sites throughout Queensland. We used a multivariate comparative analysis conducted at a whole-basin scale to develop a bioregionalisation. The comparative analyses (ANOSIM) were used to identify basins that were significantly different from others.
The strength of regional patterns and their relevance to freshwater fish were also analysed, with convergence of patterns across faunal elements. This suggests broad ecological relevance and follows the theory that landscape drivers provide the template for aquatic communities and ecosystem function. Assessment and reporting of aquatic ecosystem condition in Queensland has been based on basin, government, or jurisdictional boundaries rather than ecological understanding. Adoption of our bioregionalisation of riverine ecosystems can increase the strength of sampling design and improve accounting for large-scale variability.