Hungarian alkali vegetation: Origins, landscape history, syntaxonomy, conservation
Molná r, Zsolt; Borhidi, Atilla
Alkali vegetation has been a recurrent research object of Hungarian botany. Studies on landscape history and vegetation dynamics beginning in the 1990s amplified considerably our knowledge of alkali vegetation. The present paper features some thoughts about the origins of the alkali vegetation, summarises its principal characteristics, and presents some new views on the primary versus secondary status of this vegetation type in Hungary. The origins of alkali vegetation linked to pastures, low sensitivity to disturbance, and quick regeneration potential of alkali vegetation are emphasised in relation to nature conservation. Semi-natural alkali vegetation covers approx. 150,000 ha in Hungary, and includes steppes, steppic pastures, meadows, marshes, lakes, and woodlands characterised by endemic, Pontic, and Southern-Eurasian species. Altogether 53 plant communities belong chiefly to the three major vegetation classes, such as the Thero-Suaedetea, the Crypsidetea aculeatae, and the Festuco-Puccinellietea. Alkali steppes were initially supporting native ungulates, then nomadic herds, and finally served for extensive grazing later in history. In the past 150 years, ploughing, amelioration of grasslands, and drainage led to demisse or degradation of many alkali habitats. Through an "experiment by chance" we document that floodplain meadows were transformed to short-grass secondary alkali steppes and loess steppes, while marshes were transformed into alkali meadows. By comparing the species composition, vegetation mosaic patterns, soil types, and entire landscape context of 19 alkali oak woodlands, we demonstrate that although these woodlands are partly primary, a greater part can be derived from oak-elm-ash woodlands due to desiccation and alkalisation processes. We provide new support for the old, and generally disregarded, hypothesis claiming that solonetz vegetation has two sources of origin: before and after river regulations. Primary vegetation is characterised by contrasted vegetation mosaics, species richness, well-developed alkali geomorphology, and the lack or subordination of floodplain species. Primary alkali steppes, several thousand years old, occur as patches as large as 100 - 1000 ha in the Tiszántúl region.