Analysis of the connections between hydromorphological conditions and biocenotic diversity on the example of the Zwolenka River

摘要

Analysis of the connections between hydromorphological conditions and biocenotic diversity on the example of the Zwolenka River. The paper presents the evaluation of ecological status of two hydromorphologically diverse stream reaches of the ZwolenkaRiver. The studied sections of 500 m length are localized in a natural river-bed (Siekierka) and river-bed transformed due to a regulation (Zwoleh). The hydromorphological assessment of the stream has been performed by means of River Habitat Survey method (RHS). Level of habitat transformation has been determined with a help of numerical indices of the method: HMS and HQ A; their naturalness has been also evaluated. Biotic conditions have been evaluated on a base of macrophyte river assessment and benthos macroinvertebrates. Macro-invertebrates have been determined to the level of family and following water quality indices have been also calculated: BMWP-P1, ASPT, and EPT%. Value of BMWP-P1 has revealed that waters within the natural section of the stream could be qualified to the II grade of quality, while those in transformed section - to III grade. Moreover, it has been found that EPT% indicator has been much higher in non-transformed section. Evaluation of examined stream sections on a basis of Macrophyte Index for Rivers (MIR) has revealed that the numerical value of the indicator has been almost unaffected by the river-bed transformation degree. In both cases, examined fragments of the stream have been qualified as the II grade. In addition, physicochemical determinations of water have been carried out. However, no substantial differences of water quality, that could influenceon biocenotic diversity of those habitats, between analyzed stream sections, have been recorded. Content of organic particles in sediments as well as granulation characteristics have been determined as well.Therefore, the present research has allowed to learn some relationships between abiotic and biotic elements of a small lowland river, which can be an initial point for further studies.