ASSESSMENT OF THE ENVIRONMENTAL STATUS OF THE SURFACE WATERS OF THE STYR RIVER BY THE MACROPHYTE INDEX MIR

Abstract

The water management complex of the southern part of the Volyn region and of the western part of the Rivne region belongs to the Styr river basin, which has a significant degree of development. Thus it is necessary to observe the strategic principles of rational nature management to restore and preserve the optimal ecological state of the river basin. Here, an ecological assessment of water quality by the state of macrophytes is presented. Four test sites of at least 100 m length each were laid to perform research and to determine the ecological state of the rivers of the Styr basin. In the research, 48 species of higher aquatic and coastal aquatic plants were found in the test areas of the Styr River, all species belonging to the Magnoliophyta division. 35 macrophyte indicator species were selected in the test sections of the channel to determine the Macrophyte Index for Rivers (MIR). Macrophyte species which are characterized by almost the same percentage of projective coverage were found in all test sections of the Styr River bed: Glyceria maxima (Hartm.) Holmb., Nuphar lutea (L.) Smith., Myosotis scorpiodes L., Acorus calamus L. In addition, macrophyte species were recorded as occurring only on one of the test plots. For instance, on the test plot No. 3 (Mayunychi village) macrophytes species Lysimachia nummularia L., Myriophyllum verticillatum L., Potamogeton pe rfoliatus L., Scirpus sylvaticus L. were found; the species Carex acutiformis Ehrh. was found on the test site No 4 (Zarichne village).  According to the classification, the Styr River belongs to lowland watercourses, with the macrophyte type M-VIII (organic rivers). As a result of the calculated Macrophyte Index for Rivers, it was determined that the water quality in the Styr River at test sites No. 1 (Shchurovychi village) and No. 3. (Mayunychi village) has good ecological condition, MIR is 36.1 and 40.6, respectively; at test sites No. 2 (Lutsk) and No. 4 (Zarichne village), the quality of surface water is satisfactory or moderate, and the ecological status by MIR is 36.1 and 33.57, respectively.