Zs. K. Komáromy szerk.: Studia Botanica Hungarica 17. 1984 (Budapest, 1984)
Siklósi, Engelbert: The flora of the pits in the Nature Preservation Area of Ócsa
MATERIAL AND METHOD The objective of the study originated after a pilot survey of the area in 1980. The actual cenological investigations we made from March 1981 to August 1982. We have taken 140 samples from 5 mine lakes and a canal in the "Öregturján" (this is part of the protected area [Map]). These are: Canal 40 samples, lake 1. 20 samples, lake 2. 50 samples, lake 3. 5 samples, lake 4. 5 samples, lake 5. 20 samples. We took samples throughout the vegetation period. The sample plot first selected were revisited every month and the new species were recorded. We used 3 x 3 m sample plots suitable for the requirements. In the case of the canal the plot included the 1-1.5 m zone of the coast and the drift. In the case of the lakes the 1-1.5 m zone of coast and the water surface situated next to the sample plot were induded. We assigned the A-D (abundance, dominance) values with scores of + to 5 according to the scale of BRAUN-BLANQUET (1951). After having tabulated the data, we counted the F (fidelity) values of the species (se Tables 1 to 5). Then we placed the distribution of the A-D values as a function of the number of sample plots. On the basis of the counted values we entered the several plant associations according to SOO s system (1964-1973) into the appropriate cenological category. The turf-pit has been carried out in the area since the beginning of this century. This was not notable up to the fifties because it was seasonable and carried out by hand. In the fifties began the large-scale production. These lakes originated as a result of the above-metioned activity. The oldest mine lakes are indicated in the map by numbers 1.2 and 3 (Map) and their ages vary between 25 and 30 years. The turf-pit was finished at the beginning of the seventies in case of lakes 3, 4 and 5, so they are about 7-10 years old. The differences in age are observable in the external appearance of the lakes (high, steep collapsed shore) and in the physiognomy of the vegetation. We give these differences at the detailed description of the lakes. We could examine only the qualitative characters of the water because of lack of facilities. Alkali ions were found in large quantities (Na + , K + ) and considerable was the concentration of Ca 2+ , Mg2+ and Al 3+ ions. The next most concentrated anions in the water were PO^ 3 , CO3 2 , HC0 3 ~, SO4 2 " and CI". The NO3" anion, not mentioned above, appeared in large quantities. This high nitrate level is characteristic for all the surroundings (at times it appears in sunken wells in the village Ocsa), probably the result of extensive fertilizing of cultivated land. DESCRIPTION AND CENOLOGICAL CHARACTERIZATION OF THE AREAS Canal At the edge of the studied area streches the one and only canal containing water even now. The other canals and drainage ditches have become filled up in the course of time. This canal will slowly come to this condition as well. The far end of the canal at the village almost completely dried up in the summer between lakes 2 and 3. The breadth of the canal varies between 1 and 1.5 m and its depth is on the average 15-20 cm. The greatest depth is about 40-45 cm but such places are at the end of the village Ocsa near a bridge. The water current is negligible, it should be more property called ditch water. Its chemical reaction is neutral or possibly slightly alkaline (7-7.8 pH). The bank increases steeply and above it on both banks there is a road on the dam we could find patches of weed association. Some characteristic species of the dam and the near by arable land could be found on the bank (Potentilla anserina, Lolium perenne, Melilotus albus, Tussilago farfara). Thick inpenetrable reeds border almost the entire length of the canal, which are mixed with Callistegia sepium. Typha latifolia mingles with the reeds especially in places where the stand of Phragmites communis becomes thin. The reeds disappear here and there, so in those places A- lisma plantago-aquatica forms little stands at the edge of the water surface, or in the water. These spots are variegated by single specimens of wonderful Butomus umbellatus . Sium erectum , Sium latifolium , Myosotis palustris and Polygonum lapathifolium comprise the low grass layer in the reeds. Beside the reeds, on the higher ground dominate Carex elata, Eupatorium cannabinum , Cyperus fuscus , Juncus bufonius and Juncus inflexus . The plant associations could be allocated to the following cenological units of the literature
