We investigated the dependence of macrophyte parameters (distribution depth, width of the reed belt, density and length of shoots) on a number of abiotic factors (wind patterns, nutrient loading, slope of the littoral, granulometric sediment composition) in a large, shallow, and eutrophic Lake Võrtsjärv (270 km2, average depth 2.8 m) in Estonia in 1997. The macrophytes colonized 18.8% of the lake area. The helophyte zone was the narrowest along the southern and eastern shores, and the widest but most variable along the northern shore of the lake. The most affected were the floating-leaved plants that colonized the smallest percentage (6%) of areas suitable for them with regard to depth. The factor analysis revealed a strong polarisation of the lake’s vegetation both in west-east and north-south direction caused by 1) dominating westerly and south-westerly winds, 2) the shape of the lake narrowing down from north to south, and 3) concentration of bigger inflows to the west and south shores of the lake. The eutrophication process caused the disappearance of several species, on one hand, and the extension of the distribution areas of some species, on the other hand. The Myriophyllum spicatum has become the dominating species among the submerged plants, replacing the earlier dominant, Potamogeton perfoliatus L. And also has become a nuisance in L. Võrtsjärv.

FELDMANN Tonu;  NOGES Peeter; 

2007-06-05

ELSEVIER SCIENCE BV

JRC34914

https://publications.jrc.ec.europa.eu/repository/handle/JRC34914,   

10.1016/j.aquabot.2007.01.004,