Impact of human activities on stonefly (Insecta, Plecoptera) ecological metrics in the Hron River (Slovakia)
2007
Krno, Il’ja
A total of 57 stonefly species have been recorded in the Hron River. The natural gradient (slope and stream width) and pollution gradient of the river were defined using CCA based on physical, chemical and stonefly data. Stonefly metrics (abundance, richness/diversity, sensitivy/tolerance and functional metrics) were used to estimate the quality of the Hron River and the degree of proximity to its natural state. Similar results were obtained using two different methods. The first method was based on the homogeneity of variance and the interquartile range of different groups of stretches of the Hron River and the second was based on deviations from the expected values of biological metrics in a given stretch of the river. These values continuously decreased with increasing distance from the spring area, with the exception of the saprobic index, which increased in a downstream direction, and the stonefly average score, which did not change significantly along the whole river flow. The Stonefly Average Score (SAS) metric is universal for a variety of habitats such as the Hron River upstream and downstream, and is a reliable indicator of water quality and the natural course of a stream.
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