Overgrowing of two polymictic lakes in Central-Western Poland

Abstract

Overgrowing of two polymictic lakes in Central-Western PolandThis study examined the overgrowth in two eutrophic lakes during the period 1961-2008. In addition, for comparative studies, analyses of plant community structures in these lakes were performed to assess the effects of human pressure, such as water level reduction and increase of nutrient availability on changes in the range of the littoral zone surface. To achieve these aims aerial photos, ortophotmaps, GPS measurements were used to evaluate changes in plant cover in two lakes: Niepruszewskie and Tomickie. Considerable differences between the studied lakes located in an agricultural catchment were observed. Lake Niepruszewskie was characterised by a threefold higher rate of overgrowing, measured per hectare, in comparison with Lake Tomickie. Moreover, in comparison with lake areas, rates of overgrowing were substantialy higher in Lake Tomickie than Lake Niepruszewskie, which is almost seven times bigger. The littoral zones of both lakes are dominated by emergent vegetation. Compared to the data from 1961, the zone of Lake Niepruszewskie increased almost threefold. The biggest changes in overgrowing were observed after reduction of water level (>2002) which was 1.30 ha yr-1. During almost 50 years, emergent vegetation in Lake Tomickie increased more than fivefold. The most intensive growth was observed in years from 1961 to 1986, which amounted to 0.73 ha yr-1. Probably, water level reductions in Lake Niepruszewskie and high eutrophication in Lake Tomickie were recognised as major factors causing intensive overgrowing in the studied lakes.

Changes in Water Resources of Polish Lakes as Influenced by Natural and Anthropogenic Factors

“…8. The scale and rate of lake overgrowth, next to direct human interference, is connected with the lowering of water levels in lakes (i.e., when water damming on a larger scale is rather exceptional), and thus the exposure of the shallower sections of the littoral zone has been considerably accelerated by the inflow of biogens from agricultural sources [47]. This manifestation of the human impact on lake ecosystems was limited, e.g., at Poland's accession to the European Union.…”

Evaluation of the potential for the use of lakes in restoring water resources and flood protection, with the example of the Noteć Zachodnia River catchment (Gniezno Lakeland, Poland)

“…This is an effect of unfavourable climate changes (Kędziora 2008(Kędziora , 2011, deforestation, incorrect meliorations (Choiński, Ptak 2008;Kaniecki 2011;Marszelewski et al 2011;Przybyłek, Nowak 2011a;Choiński et al 2012;Nowak, Gezella-Nowak 2012;Ptak et al 2013;Choiński et al 2016;Nowak 2018a), excessive uptake of water for municipal and economic purposes, and mining drainage (Ilnicki 1996;Ilnicki, Orłowski 2006a, b;Orłowski, Ilnicki 2007;Przybyłek, Nowak 2011a, b). Some of the most visible effects of those transformations is the disappearance of wetlands and small water bodies (Choiński, Ptak 2008;Ilnicki et al 2012aIlnicki et al , b, 2017Nowak 2018a), recession of the shoreline of lakes (Choiński, Ptak 2008;Marszelewski, Radomski 2008;Kunz et al 2010;Ławniczak et al 2011;Marszelewski et al 2011;Ptak, Ławniczak 2011;Ilnicki et al 2012a, b;Nowak, GezellaNowak 2012;Piasecki, Marszelewski 2013;Ptak 2013;Piasecki, Skowron 2014;Ławniczak, Kutyła 2015;Stachowski et al 2016;Nowak 2018a), seasonal drying-up of smaller water courses (Przybyłek, Nowak 2011a;Nowak 2018a), and overgrowing of water reservoirs (Ławniczak 2010;Nowak et al 2011a;…”

Indicator Values of Emergent Vegetation in Overgrowing Lakes in Relation to Water and Sediment Chemistry

“…Excessive human pressure intensifying the process of eutrophication of waters is the main factor affecting overgrowing of lakes [9][10][11]. This results in a high availability of nutrients in the lake.…”

“…Field tests of this type are conducted mostly in relation to selected water bodies [10,20]. Therefore, it is reasonable to use available archival cartographic materials to assess the scale of this phenomenon.…”

“…The rate of overgrowth of lakes varies depending on morphometric parameters of the lakes, size and depth primarily, and the availability of nutrients [9][10][11]. In shallow lakes, succession of macrophytes occurs faster, which is influenced by greater availability of areas of low depth, which is not a barrier to the succession of vegetation towards water depth.…”