Dynamics of emergent macrophytes for 50 years in the coastal Lake Engure, Latvia
Coastal Lake Engure is a Ramsar site — a wetland of great importance due to its biological diversity and unique properties, especially its coverage of macrophytes, shallowness and size. This study assesses the dynamics of emergent macrophytes in the lake based on analysis of historical aerial photographs and digital orthophoto maps. The area of emergent macrophytes was shown to have increased by 781 ha (15 ha/year) in the period 1956 to 2007. The expansion rate differed during this period. Expansion was much faster (31 ha/year) from 1956 to 1972, but declined to 6 ha/year from 1972 to 1994 and increased again to 11 ha/year from 1994 to 2007. The greatest rates of expansion of emergent macrophytes from 1956 to 1972 can be partly explained by ceased grazing and hay harvesting activities. As the area covered by emergent macrophytes changes seasonally, only remote sensing materials acquired during the same season should be compared. The open water territory in 2007 was only 22.9 km2, compared to 30.7 km2 in 1956. Emergent vegetation has been mostly limited to areas where the depth does not exceed 0.5 m. Expansion of emergent vegetation was found to differ in various parts of the lake. The main factors affecting the rates of its development were wave disturbances, hydrological regime and ceased agricultural activities in the lake.
Anderson, B. (2001). Macrophyte development and habitat characteristics in Sweden's large lakes. Ambio, 20(8), 503-515.
Auniņš, A., Zviedre, E., Brūmelis, G. (2000). Preliminary results of remote sensing based vegetation mapping of lake Engures (Engure), Latvia. Proc. Latvian Acad. Sci., Sect. B, 54(5), 170-176.
Briede, A., Kļaviņš, M., Rodinovs, V. (2000). Chemical compositions of Lake Engures (Engure), Latvia. Proc. Latvian Acad. Sci., Sect. B, 54(5), 160-163.
Dahdouh-Guebas, F., Koedam, N. (2008). Long-term retrospection on man-grove development using transdisciplinary approaches: A review. Aquat. Bot., 89(2), 80-92.
Dekker, A. G., Brando, V. E., Anstee, J. M. (2005). Retrospective seagrass change detection in a shallow coastal tidal Australian lake. Rem. Sensing Environ., 97(4), 415-433.
Eberhards, G., Saltupe, B. (2000). Geological history, relief, and deposits of Lake Engure area along the Baltic Sea. Proc. Latvian Acad. Sci., Sect. B, 54(5), 141-147.
Engloner, A. I. (2009). Structure, growth dynamics and biomass of reed (Phragmites australis): A review. Flora, 204(5), 331-346.
Feldman, T. Nõges, P. (2007). Factors controling macrophyte distribution in large shallow Lake Võrtsjärv. Aquat. Bot., 87(1), 15-21.
Fredriksen, M., Krause-Jensen, D., Holmer, M., Sund Laursen, J. (2004). Long-term changes in area distribution of eelgrass (Zostera marina) in Danish coastal waters. Aquat. Bot., 78(2), 167-181.
Gavrilova, G., Baroniņa, V. (2000). Vascular plant flora of the lake Engures (Engure) drainage basin, Latvia, and the coastal zone of the Gulf of Riga. Proc. Latvian Acad. Sci., Sect. B, 54(5), 177-189.
Jenesn, J. R. (2005) Introductory Digital Image Processing: A Remote Sensing Perspective, 3rd edn. Upper Saddle River: Pearson Prentice Hall. 536 pp.
Lampert, W., Sommer, U. (2007). Limnoecology, 2nd edn. Oxford: Oxford University Press. 235 pp.
Lehmann, A., Lachavanne, J. B. (1997). Geographical information systems and remote sensing in aquatic botany. Aquat. Bot., 58(3-4), 195-207.
Liira. J., Feldman, T., Mäemets, H., Peterson, U. (2010). Two decades of macrophyte expansion on the shores of a large shallow northern temperate lake: Aretrospective series of satelite images. Aquat. Bot., 93(4), 207-215.
Nõges, P., Kangur, K., Nõges, T., Reinart., A. Simola, H., Viljanen, M. (2008). Highlights of large lake research and management in Europe. Hydrobiologia, 599(1), 259-276.
Partanen, S., Hellstenm S. (2005). Changes of emergent aquatic macrophyte cover in seven large boreal lakes in Finand with special reference to water level regulation. Fennia, 183(1), 57-79.
Partanen, S., Luoto, M. (2006). Environmental determinants of littoral paludification in boreal lakes. Limnologica, 36(2), 98-109.
Schmieder, K., Dienst, M., Ostendorp, W., Jöhnk, K. (2004). Effects of water level variations on the dynamics of the reed belts of Lake Constance. Ecohydrol. Hydrobiol., 4(4), 229-240.
Schmitz, D., Blank, M., Ammondt, S., Patten, D. T. (2009). Using historic aerial photography and paleohydrologic techniques to assess long-term ecological response to two Montana dam removals. J. Environ. Manag.90(3), S237-S248.
Spriņge, G., Druvietis, I., Parele, E. (2000). The plankton and benthos communities of the lagoon lake Engures (Engure), Latvia. Proc. Latvian Acad. Sci., Sect. B, 54(5), 164-169.
Valta-Hulkkonen, K., Kanninen, A., Pellikka, P. (2004). Remote sensing and GIS for detecting changes in the aquatic vegetation of rehabilitated lake. Int. J. Rem. Sensing, 25(24), 5745-5758.
Vīksne, J (2000). Changes of nesting bird fauna at the Engure Ramsar site Latvia, during the last 50 years. Proc. Latvian Acad. Sci., Sect. B, 54(5), 213-220.
Viksne, J. (1997). The Bird Lake Engure. Rīga: Jāņa sēta, 111 pp.
Wetzel, R. G. (2001). Limnology: Lake and River Ecosystems, 3rd edn. San Diego: Academic Press. 1006 pp.
Zelcs, V., Markots, A. (2004). Deglaciation history of Latvia. In: Developments in Quaternary Science. Quaternary Glaciations Extent and Chronology. Part I: Europe. (pp. 225-243). Ehlers, E., Gibbard, P. L. (eds.). Amstedam: Elsevier.