L. Hably szerk.: Studia Botanica Hungarica 23. 1992 (Budapest, 1992)

Papp, Beáta: Phytocoenological survey along the Koloska stream (Balaton-felvidék region, Hungary)

weeds may be due to the pollution of the stream. It is the first macrophytic community along the stream after a small artificial lake, which was formed by the spring and is frequently visited by tourists. In the lower part of the valley another variant of the Glycerio-Sparganietum can be found: the var. sparganietosum. This community and the Glycerio-Sparganietum var. typicum share many species which occur with similar abundance e.g. Mentha longifolia, Scrophularia umbrosa, Eupatorium cannabinum. Yet the high cover values of Carex acutiformis, Carex riparia, Equisetum palustre, Equisetum fluviatile and the occurrence of Mentha aquatica, Phragmites communis, Typha latifolia indicate considerable differences between the two variants. Several individuals of Sparganium erectum (the other characteristic species) can be observed in the slowly running freshwater. Further differences can be noted in the species composition of the stand of Glycerio-Sparganietum var. sparganietosum (H) which is situated near the Koloska restaurant. Angelica silvestris, Cirsium canum, Catystegia septum appear with increasing abundance. Diversity increases, mainly due to colonization by several weed species. In the W value diagram of Glycerio-Sparganietum var. sparganietosum (F), a large number of W=8,

9 and 10 value species can be observed (Fig. 4). This reflects the better water supply of the area as compared to the Glycerio-Sparganietum var. typicum (A). In the species composition of the stand of Glycerio-Sparganietum var. sparganietosum situated near the Koloska restaurant (H), many W=3, 5, 6 value species can be found beside the high proportion of W=8, 9 value species (Fig. 5). So this is a drier area than the upper part of the Glycerio-Sparganietum var. sparganietosum. Fig. 4. W- and NC value scatter diagrams of Glycerio-Sparganietum var. sparganietosum (F) The high proportion of native components (E+K) characterizes the GlycerioSparganietum var. sparganietosum on the basis of the NC value diagrams (Fig. 4). However in the stand situated near the Koloska restaurant (H), increasing quantity of disturbance tolérants (TZ) and weeds (GY) can be seen (Fig. 5). The nearby Koloska restaurant and the tourist path are disturbance factors for the plant community of this area.