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• The degradation of hygrophilous plant associations of the Nyárjas Lake (E Hungary)

  63–77

  Mihály Vas

  Views:

  131

  The Nyárjas Lake (located near Kállósemjén, East Hungary) was one of the most typical bogs in the Nyírség until the early 1980’s. Most of its area was covered by the association of Carici-Menyanthetum. The number of species characteristic to the mentioned association was generally high. As the climate became drier, hotter and were characterised by higher magnitude of extremities, the water coverage became no longer as permanent. This resulted that the Menyanthes trifoliata and Listera ovata became extinct by 2000. Lemno-Potamea species were not found after 2010. Bidentetalia, Calystegietalia, Chenopodietea and Secalietea species became more prevalent, particularly in drier periods, and locations where Carici-Menyanthetum used to be characteristic. Cirsium arvense in the mid-1990’s and that of Urtica dioica in the mid-2010’s became dramatically abundant. Both the number and coverage of species indicating habitat degradation have increased. The composition of wet meadow plant associations shifted towards the drier Arrhenatheretea. A moderate revitalisation of wetland associations was, however, observed coinciding years with higher precipitation.

• Contributions to knowledge on the distribution of nine adventive or invasive algae species in Hungary

  11-21

  Enikő T-Krasznai

  Viktória B-Béres

  Zsuzsanna Kókai

  Krisztina Buczkó

  Csaba Balogh

  Péter Török

  Views:

  128

  Hungarian records of nine adventive or invasive algae [Didymosphenia geminata, Nitzschia closterium, Reimeria sinuata, Navicula schroeteri, Pleurosira laevis (Bacillariophyceae); Pediastrum simplex (Chlorophyceae), Cylindrospermopsis raciborskii, Cuspidothrix issatschenkoi, Sphaerospermopsis aphanizomenoides (Cyanobacteria)] are presented. Navicula schroeteri Meister is a new species for the Hungarian flora. Although the observed distribution patterns of these species were very different, the increasing frequency of their appearance indicates significant effect of climate change on abiotic environment of inland waters, such as the increase in water temperature, increase in salt concentration, and eutrophication. The significance of continuous biomonitoring is emphasized, which, through the recognition of natural and human-induced changes in species composition of algae, or the appearance and rapid expansion of non-indigenous species, can detect environmental changes of inland waters.