Plecoptera taxocenoses and degradation of watercourses in the Czech Republic: changes after 50 years
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| Year of publication | 2012 |
| Type | Conference abstract |
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| Description | The existence of a unique historical dataset on Plecoptera collected between 1946 and 1960 at 170 sites representatively distributed throughout the Czech Republic enables to compare present and historical species presence/absence data and to evaluate sites changes. The following principle changes of sampling sites affecting stonefly taxocenoses were determined: (i) Construction of large dams, (ii) Construction of other impoundments to regulate discharge regime, (iii) Channelization connected with water quality changes, (iv) Strong pollution or acidification without apparent morphological changes of streams. Seventy sites showed considerable decrease of the number of species; stoneflies completely disappeared from 18 sites. Eighty-one sites showed nearly the same taxocenoses at present (including 13 sites with species-poor taxocenoses already in the past). Total number of species decreased from 77 to 72 (82 species recorded altogether), however the majority of them decreased their frequency. A strong decrease by 50% of earlier occurrences was recorded in 16 sensitive species (e.g., Amphinemura borealis, Perla abdominalis, Protonemura hrabei, and Siphonoperla taurica); eight widespread species showed less considerable decrease. Only 5 species increased their frequency (especially Brachyptera risi and Leuctra geniculata). Nine species have not been found at present (e.g., Amphinemura borealis, Leuctra major, and Marthamea vitripennis) |
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