engleski

Composition and structure of benthic macroinvertebrate communities in the Mediterranean karst river the Cetina and its tributary the Ruda, Croatia

Benthic invertebrate communities of the Cetina River and the upper reach of the Ruda River were sampled monthly at 11 sites from August 2004 to August 2005. The sampling sites were located along the longitudinal gradient of the Cetina and in the upper reach of the Cetina's largest tributary, the Ruda River. Throughout the study, a total of 310225 animals were collected in 366 samples. In the upper and middle reaches the most numerous taxa were Amphipoda and Gastropoda, while the most numerous taxon in the lower reaches was Gastropoda. The highest and the lowest population density of benthic invertebrates were recorded at the sites Preočki Most in June 2005 (22728 individuals/m2) and Radmanove Mlinice in November 2004 (90 individuals/m2), respecti vely. At sites Trilj I and Trilj II, the most numerous taxa were Oligochaeta and Chironomidae, indicators of watercourses with higher organic loads. The composition of benthic invertebrate communities at sites along the entire course of Cetina does not reflect the situation expected under natural conditions due to flow regulation and construction of hydroelectric power plants and reservoirs.

physico-chemical parameters; macroinvertebrate community structure; Mediterranean karst river; regulated river

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