Determining optimal sampling strategies for monitoring threatened endemic macro-invertebrates in Australia's artesian springs

Conservation concern for imperilled invertebrates grows but action is stalled by data deficiency. Great Artesian Basin springs present a textbook case; they are hotspots for endemic invertebrate diversity, but a persistent struggle to conserve them remains because of a lack of data. Spring research outside Australia suggests that biases created by sampling regimes make compiling and comparing disparate data sources problematic. We compared existing methods and their efficacy for sampling diversity and abundance of spring macro-invertebrates (>1 mm) associated with sediment and vegetation within limnocrenic wetlands characteristic of Australian arid-zone artesian springs, with the aim of presenting an optimum sampling strategy. The three methods tested gave similar estimates of richness, but measures of abundance for each taxon were sensitive to method choice. Both richness and abundance were significantly different among springs and areas within each spring. Direct method comparisons such as this ensure consistency and comparability between past and future studies and provide a framework for future monitoring. Species richness can be assessed rapidly and disparate data sources can be combined. However, assessments requiring abundance will need to be sensitive to the biases created by species identity, method and area.