Development of floating-leaved vegetation in three lakes of varied trophy (Leczna-Wlodawa Lakeland)
Nymphaeids are a typical component of littoral vegetation in European lakes. In different types of water bodies they create large stands. This group of macrophyte species grows not deeper than 3 metres, but depending on clarity and depth. The aim of this study was to determine the percentage share and biomass of nymphaeids in investigated lakes with varying trophy and way of use. Furthermore, another aim of the study was a comparative analysis of morphometric features among dominant species of nymphaeids. The studied lakes are a group of eutrophic lakes, in various stages of its advancement from the low eutrophic Lake Płotycze Sobiborskie, through the eutrophic Lake Płotycze Urszulińskie to the highly eutrophic Lake Zienkowskie. In the studied lakes, nymphaeids formed a large part of the phytolittoral as well as macrophyte biomass, the smallest in the strongly eutrophic lake, the largest in the eutrophic lake. In the studied lakes appeared both Nymphaea candida species as well as intermediate forms. Neither the use of the lake nor habitat conditions affected the differentiation of the analysed characteristics of Nuphar lutea, while the most sensitive species was Nymphaea candida.
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.
The aim of this study was to determine the relationship between the development of rush zones in small lakes and the utilization and condition of surrounding lands. Generally, the width of the helophyte zone increased along shores with gentle slopes (>5˚) that were covered with vegetation. The most favourable conditions for rush development and spread were along sloped areas bordered by farmlands and rural developments. In addition, pasturelands that developed on top of peat accumulation adjacent to lakes were found to facilitate the development of rushes. We observed a positive effect of anthropogenic development, especially agriculture and infrastructure, on stem density and total biomass of Phragmites austalis populations in the lakes studied. However, individual stem biomass of plants was lower. In different parts of the studied lakes, macrophyte distribution patterns were influenced by environmental conditions including nutrient availability, wind exposure, and bottom slope. The poorest macrophyte communities were found in areas within the lakes that were shaded by trees growing on neighboring banks and where slopes were forested rush zones were absent altogether.
Aquatic vegetation greatly impacts lake functions. Forest ecosystems surrounding lakes are effective protection zone of lakes and their associated flora and fauna. The presence of aquatic plants depends on many factors, including the chemical composition and acidity of water, the shape of the lake catchment, the angle of slope along shorelines and the management of surrounding lands. Natural ecosystems throughout Eastern Europe are threatened by anthropogenic activities. Aquatic systems and bogs are particularly sensitive to disturbances. The aim of the study was to determine the influence of land management, forest type and stand age on aquatic plant colonisation within lakes as well as to quantify and qualify the structure of macrophyte communities within two lakes, Płotycze Sobiborskie and Orchowe, located in the Sobibór Landscape Park in western Poland. Even though there were few bogs within the catchment areas and lake buffer zones, where they did occur they had the greatest effect on macrophyte presence. The results of this research indicate that in the absence of anthropogenic disturbances midforest water-bog complexes are relatively stable systems and preserve their natural character. The applied multi-criteria evaluation of macrophytes in the studied lakes and their surrounding buffer zones and catchment areas allowed the lakes to be characterised as lakes with a good ecological status.