hrvatski

Aquatic vegetation of Lake Visovac

Lake Visovac is situated in Krka National Park and it represents the largest extension of Krka River. In summer 2018 the line transect sampling method was applied for vegetation mapping. In total 21 transcts perpendicular to the shore up to the depth at which the macrophytes cease to appear were made, generating as much as 293 species/location records. In total, 26 species of aquatic plants was found, including one yellow-green algae, eight charophytes, two mosses and 15 vascular plants. The most common species in the flora of Lake Visovac are Myriophyllum verticillatum, Najas marina, Phragmites australis and Potamogeton perfoliatus. Discovery of a rare aquatic moss Fissidens fontanus is of great importance, being the second in Croatia. There are four main vegetation belts in the aquatic vegetation of Lake Visovac: helophytic (dominantly reed) vegetation, submerged vegetation with or without floating leaves (belonging to NATURA 2000 habitat type 3150 Natural eutrophic lakes with Magnopotamion or Hydrocharition) and charophyte vegetation (NATURA 2000 habitat type 3140 Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.). Lake Visovac is dominated by plants of light, warm habitats which survive unfavorable living conditions with their buds in water and which prefer supstrata rich in nutrients and water with neutral pH and low salinity. The increased inlet of nutrient rich water and the anchoring represent the main threats to the preservation of Lake Visovac vegetation.

Visovac, Krka, vodeno bilje

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