The aquatic vegetation present in lakes in the delta of the River Danube wa
s studied using field survey data and satellite image. Based on the spectra
l information from satellite images, three categories of lakes were disting
uished: clear / macrophyte-dominated, intermediate and turbid / poorly vege
tated. The satellite-based classification was consistent with vegetation co
ver and water transparency measured in the field. Cluster analysis of veget
ation data from 235 releves made in 22 lakes (1996-1998, each year in June)
identified ten submerged vegetation types. The lakes were characterised by
the frequency of occurrence of each vegetation type and ordinated, using P
rincipal Components Analysis (PCA). A strong relationship appeared between
the composition and density of aquatic vegetation and water transparency. I
solated lakes within the extensive beds of floating reed (plaur lakes) form
ed a separate group. Based on the ordination analysis, connectivity of lake
s in the Danube Delta was concluded to be a major factor for the developmen
t of dense macrophyte vegetation.