<abstract xmlns="http://www.w3.org/1999/xhtml">

Lake Modre is a lobelia lake. Numerous typical plant species occur here, including Lobelia dortmanna, Littorella uniflora, Isoetes lacustris, and Sphagnum denticulatum. They develop the following associations: Lobelietum dortmannae (Oswald 1923) Tx. ap. Dierss. 1972, Isoetetum lacustris Szańkowski et Kłosowski 1996 n.n., and a community with Sphagnum denticulatum Brid.
In 1991, the water of the lake was characterised by low concentrations of nutrients and calcium, acid reaction (pH&lt;5), and Secchi depth visibility of 12 m. Following fry stocking in the lake in 1993 fish farming took place until approximately 1996. During this period the water quality in the lake changed radically in physiochemical terms. Water transparency decreased. Thermal and oxygen stratification developed, with oxygen deficits in the near-bottom layer. Concentrations of nutrient elements increased.
Drastic long-term changes were observed in the spatial and quantitative features of the lake vegetation. These particularly related to the instability of Lobelia dortmanna, and the diminishment of the phytocoenosis of Lobelietum dortmannae. Consequently, the phytocoenosis occurred only in the shallowest part of the phytolittoral. L. uniflora expanded, increasing its occurrence annually. Significant fluctuations in quantities of S. denticulatum occurred, correlated with changes in physiochemical water parameters, but shifted in time.
</abstract>

Lake Modre is a lobelia lake. Numerous typical plant species occur here, including Lobelia dortmanna, Littorella uniflora, Isoetes lacustris, and Sphagnum denticulatum. They develop the following associations: Lobelietum dortmannae (Oswald 1923) Tx. ap. Dierss. 1972, Isoetetum lacustris Szańkowski et Kłosowski 1996 n.n., and a community with Sphagnum denticulatum Brid.
In 1991, the water of the lake was characterised by low concentrations of nutrients and calcium, acid reaction (pH<5), and Secchi depth visibility of 12 m. Following fry stocking in the lake in 1993 fish farming took place until approximately 1996. During this period the water quality in the lake changed radically in physiochemical terms. Water transparency decreased. Thermal and oxygen stratification developed, with oxygen deficits in the near-bottom layer. Concentrations of nutrient elements increased.
Drastic long-term changes were observed in the spatial and quantitative features of the lake vegetation. These particularly related to the instability of Lobelia dortmanna, and the diminishment of the phytocoenosis of Lobelietum dortmannae. Consequently, the phytocoenosis occurred only in the shallowest part of the phytolittoral. L. uniflora expanded, increasing its occurrence annually. Significant fluctuations in quantities of S. denticulatum occurred, correlated with changes in physiochemical water parameters, but shifted in time.

Anthropogenic changes in properties of the water and spatial structure of the vegetation of the lobelia lake Lake Modre in the Bytów Lakeland

Oceanological and Hydrobiological Studies

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Lake Modre is a lobelia lake. Numerous typical plant species occur here, including Lobelia dortmanna, Littorella uniflora, Isoetes lacustris, and Sphagnum...

Anthropogenic changes in properties of the water and spatial structure of the vegetation of the lobelia lake Lake Modre in the Bytów Lakeland

Published Online: Oct 03, 2013

Page range: 302 - 313

DOI: https://doi.org/10.2478/s13545-013-0087-6

Keywords
Lobelia lake, softwater acid lake, fish stocking, nitrogen and phosphorus enrichment, oxygen depletion, changes of vegetation

© 2013 Faculty of Oceanography and Geography, University of Gdańsk, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Anthropogenic changes in properties of the water and spatial structure of the vegetation of the lobelia lake Lake Modre in the Bytów Lakeland

Published Online: Oct 03, 2013

Page range: 302 - 313

DOI: https://doi.org/10.2478/s13545-013-0087-6

KeywordsLobelia lake, softwater acid lake, fish stocking, nitrogen and phosphorus enrichment, oxygen depletion, changes of vegetation

© 2013 Faculty of Oceanography and Geography, University of Gdańsk, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Lobelia lake, softwater acid lake, fish stocking, nitrogen and phosphorus enrichment, oxygen depletion, changes of vegetation