Macrophytes are a group of aquatic organisms affected by constant changes. One of the main factors influencing the rate and direction of these changes is the way of basin management. The aim of this study was to determine the effect of changes in the management of a lake catchment area in an agricultural landscape on the qualitative and quantitative structure of macrophytes and assessment of the ecological status of the lake in question. The study was conducted in the years 1996, 1999 and 2011 in Lake Głębokie Uścimowskie. This lake is small (20.8 ha surface) and shallow (about 6 m depth). In the 1990s in Lake Głębokie Uścimowskie from 14 to 15 plant communities occurred, which occupied 2.9 ha of the lake. This represented only 14.1% of the lake. In 2011 there was a slight growth in the number of phytocenoses (16), and significant increase in the area of phytolittoral - 5.98 ha. In the 1990s the range of ESMI index values, allowed the lake to be categorized as one with poor ecological status, but already in 2011 after a similar analysis, the lake was ranked in the upper limits of moderate ecological status of lakes. One of the main reasons for the rise in the ecological status of Lake Głębokie Uścimowskie, determined on the basis of the macrophyte index, as well as for the slight decline in trophy, was probably a sewerage system built in 2006 in Głębokie village.
Abstract. The aim of the study was to evaluate whether riparian trees limit growth of aquatic plants in lakes. In the studied lake, sections of the littoral zone were shaded to different degrees. The maximum extent of shading in the studied lake did not exceed 15 m. Regardless of the amount of light reaching the lake three groups of macrophytes developed. The data suggest that shading by riparian vegetation was not limiting to growth of all aquatic plants in the studied lake but did significantly limit development of macrophyte communities. The extent of shading was correlated with both the structure of macrophyte communities in addition to their range. In shady areas density, colonization depth, biomass and diversity index of emergent macrophytes were significantly lower. Submerged macrophytes in the lake were generally outside the scope of shadow impact. Only macrophytes occurring between 0.5 and 1 m depth were influenced by shade. Generally, submerged macrophyes were outside of the influence of shade. However, along the northern shore, lush growth of adjacent rushes may have effected submerged macrophytes and in these areas their measured values (biomass, density, abundance) were lower. In the southern part of the lake, rushes achieve lower density and extent of occurrence, but submerged macrophytes grew better, and both biomass and species richness were higher than along northern shores.
In view of the sensitivity of Liparis loeselii to changes in habitat conditions, we carried out a study with the aim to monitor population numbers, identify the individual features of the Liparis loeselii population, analyse habitat conditions, identify threats and propose conservation measures to preserve the species. The investigations were conducted in seven unmanaged objects located in three Natura 2000 areas in eastern Poland. The results of this study provide a new insight into Liparis loeselii ecology. The analysed populations inhabited some habitat types: extremely poor fen, transitional mire, rich fen, calcareous fen, spring-fed fen. The content of nutrients was similar in all the habitats. A CCA analysis revealed that the total carbon content, pH, and redox potential of the substrate determine differences between the habitats analysed. Juvenile individuals represented a maximum of 12% of the analysed populations and were the least abundant group of these plants. The flowering was primarily influenced by hydrological conditions. Based on the long-term observations reported in this article, it can be assumed that the species stands a chance of surviving at the localities analysed, provided that the habitat conditions do not change dramatically.
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