M. SAVCHOVSKA1, A. TOSHEVA1 and I. TRAYKOV2
1 University St.”Kl.Ohridski”, Dep. of Botany, Faculty of Biology, BG – 1164 Sofia, Bulgaria
2 University St.”Kl.Ohridski”, Dep. of Ecology and EP, Faculty of Biology, BG – 1164 Sofia, Bulgaria
Savchovska, M., A. Tosheva and I. Traykov, 2013. Macrophytes mapping and spatial heterogeneity of some physicochemical parameters in Ognyanovo reservoir. Bulg. J. Agric. Sci., Supplement 2, 19: 267–270
Longitudinal differences in physical and chemical parameters lead to a trophic gradient in the reservoirs. Marked differences in abiotic parameters and trophic response were observed between the riverine and the lacustrine part of Ognyanovo reservoir in relation to nutrients loading. Abundance and species composition of aquatic macrophytes were studied between 2009 and 2012. The observations at each sampling station are based on transect monitoring data. Strong influence of water level fluctuations and seasonal dynamics were observed, which emphasizes the problem of what the proper time is for macrophytes sampling in reservoirs to provide an adequate definition of the ecological state in the future. The gathered data are used to produce a map of the macrophytes distribution in the reservoir. Rapid spread of the invasive species Elodea nuttallii is described after it appeared in the reservoir. A multiple point of spreading of E. nuttallii is observed in relation to fishermen and recreational activities. The E. nuttallii range expansion is assessed by its maximum linear rate of spread.