Evaluating the Effectiveness of Five Mineral Artificial Substrates for the Sampling of Benthic Macroinvertebrates

Abstract

ABSTRACT We evaluated the effectiveness of five artificial substrates to recreate the natural benthic macroinvertebrate community in an upper reach of the Henares river (Guadalajara, Spain). Five different substrates were built with natural mineral materials from the same reach. These included small, medium and large stones, with mean maximum diameters of 1.9, 4.9 and 9.0 cm, respectively, plus a mixture of three stone sizes and a treatment without stones (slab). Four replicates of each substrate were left in the stream for 30 days, and then they were removed for community analysis. The natural community was sampled with a Hess sampler near the experimental substrates. No significant differences were found between treatments for several community metrics (taxa richness, EPT richness, EPT density, diversity and dominance indices, and two biotic indices). However, densities of particular taxa were affected by treatments; Coleoptera and Diptera densities were the highest in the natural community and in the small stone treatment, respectively. Some families showed differences between treatments. The highest Elmidae and Scirtidae densities were found in the natural community. Medium stone treatment had the highest density of Simuliidae, while that of Chironomidae was the highest in the small stone treatment. The smallest density of Glossosomatidae was found in slab treatment. The macroinvertebrate communities colonizing the artificial substrates were similar to the natural one, although the densities of some groups varied.