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• Biomassza-fajgazdagság kapcsolatok vizsgálata szikes gyepekben és vizes élőhelyeken

  57-61

  Katalin Tóth

  Views:

  50

  For an effective conservation and management in grasslands and wetlands it is essential to understand mechanisms sustaining biodiversity. Understanding biomass-species richness relationships is in the focus of recent scientific interest both from the agricultural and nature conservation point of view. We provided a detailed analysis of the relationship between major biomass components (total aboveground biomass and litter), and species richness along a long productivity gradient in grasslands and wetlands. We studied eight types of alkali and loess grasslands and five types of alkali wetlands in Hortobágy National Park, East-Hungary. We found that the relationship between total biomass and species richness can be described by humped-back curves both in grasslands and wetlands. was valid for the relation of total biomass and species richness. We detected the maximum of species richness at total biomass scores of 750 g/m2 in grasslands and at 2000 g/m2 in wetlands. Our results suggest that litter is one of the major factors controlling species richness in highly productive grasslands and wetlands. 

• Felhagyott jószágállások növényzetének vizsgálata a Hortobágyi Nemzeti Parkban

  21-27

  István Hődör

  Views:

  62

  Extensive grazing, especially sheep grazing is the most important land use type in alkali grasslands of the Hortobágy National Park. Extensive grazing systems rely on some basic infrastructure, such as sheep corrals, wells and stables. Sheep corrals are characterised by intensive land use: grazing, trampling and manuring is concentrated in these places, thus the vegetation of actively used corrals is markedly different from the vegetation of extensively grazed grasslands. I studied the vegetation composition of eight-year-old and sixty-year-old abandoned sheep corrals and extensively grazed pastures in Hortobágy National Park. I recorded the percentage cover of vascular plants in twenty 2×2-m plots. The cluster analysis showed that the vegetation of abandoned sheep corrals was different from pastures. I found that the cover of annual and biennial species was higher, while the cover of perennials was lower in abandoned sheep corrals compared to the pastures. Due to the intensive land use in the past, the proportion of nitrophilous species was higher in sheep corrals, than in the pastures. The cover of competitors was lower, while the cover of disturbance tolerants, weeds and ruderal competitors was higher in sheep corrals than in the pastures. The results suggest that even grassland regeneration started in the sheep corrals and several target species established in the vegetation, the recovery of grasslands similar to extensively grazed pastures takes longer time.