B. Papp szerk.: Studia Botanica Hungarica 38. 2007 (Budapest, 2007)
Szollát, György, Seregélyes, Tibor, S. Csomós, Ágnes; Standovár, Tibor: The flora and vegetation of Gödi Láprét near Göd, Pest county, Hungary
Present state and recent changes in the flora and vegetation of the Gödi Láprét A wide range of degrading effects have been observed in the surveyed area, which further contribute to the serious alteration of the (semi-)natural vegetation. On the calciphilous sand steppes the effect of former grazing is obvious, but the most severe problem was the plantation of black pine (Pinus nigra) decades ago on several places in the area. Introduction of alien species in more or less natural vegetation often means the establishment of invasive species; here, the regenerating pine offspring occupies valuable space from less competitive native (including protected) species. Digging drainage ditches also had an unfavourable effect on the wet sites: this, and the discontinued scything earlier practiced by the local population, allowed the expansion of reed. As an effect of the drainage, the rich fens were taken over by purple moorgrass meadows. In some sites on the other hand, a positive effect of constant water supply can also be observed in the area. The purple moorgrass meadows were partly ploughed between 1987 and 1991, but then abandoned (some parts were even subsequently cultivated). Regeneration was rather fast; the effects of the disturbance on the first ploughed sites could only hardly be registered in 1992: on these slightly degraded patches Ononis spinosa, Pulicaria dysenterica, in some sites Colchicum autumnale and Potentilla anserina were rather abundant indicating the former disturbance. Elsewhere, the uneven soil surface and the expansion of Phragmites australis and Solidago canadensis showed the signs of ploughing. (These regenerating purple moorgrass meadows were utterly destroyed during the construction of the golf course). During the 14 years of the survey period we have not noticed a significant dramatic change in the vegetation of the Gödi Láprét - the general state of the sandy grasslands, the rich fens and the purple moorgrass meadows has not changed essentially. Merely the sand meadow-steppe became slightly more mesophilous, so the width of the surrounding zone of the vegetation considered as transition between the meadow-steppe and purple moorgrass meadow associations, has visibly increased. In the stands of the aggressively spreading plants and in the population sizes of some protected species though, we have registered considerable changes between 1992 and 2005. The population of Epipactis palustris decreased from several thousands to about one thousand and then to a few hundred individuals, partly because of the expansion of reed. Several thousand plants of Eriophorum angustifolium disappeared from a certain site (which does not exist any more) by the year 1998, presumably because of burning in that area in the previous year, while in some other sites its existing populations became stronger, or new populations containing hundreds of individuals have subsequently appeared. In 1992 there were altogether about 100 specimens of Orchis coriophora at some sites, while in 1998 we estimated its population around 4,000. A possible reason for this is the discontinued disturbance, since grazing was stopped from the middle of the nineties. In 1992 many thousand individuals of Parnassia palustris were detected (which might have been the biggest known population in Hungary at the time). In 1997 though, we registered (by estimation) only a hundred flowering specimens, and even less in 2005. This clearly exceeds the degree of "natural" fluctuation:
