Conservation problems in the Neusiedler See–Seewinkel National Park, Austria: an arachnological perspective

The plain east of the Neusiedler See, the “Seewinkel” (Fig. 1), is one of the most important biodiversity hot-spot regions in Austria. A number of factors contribute to its richness: (1) The area is situated geographically within the Hungarian plain, i.e. open towards the east but isolated from the west by several mountain ridges. Thus, many organisms with a Central Asian or ancient Mediterranean distribution reach their western limit in eastern Austria (Mazek-Fialla, 1936). (2) Climatically, the region is characterized by high summer temperatures, high radiation values, high wind velocities, and occasional semi-arid conditions during summer. This permits the existence of many xero-thermophilic Mediterranean species. (3) Geological (a salty soil horizon), climatic (see above) and geomorphological (a plain with internal drainage) conditions have led to soda accumulation in the soil and to the existence of salt pans (large, shallow, often ephemeral, alkaline waters). The Seewinkel is the largest inland salt region in Austria, one of the most important in Europe, and the westernmost soda salt pan region in Eurasia (Löffler, 1982). (4) Land use formerly dominated by extensive cattle grazing led to an open mosaic of dry grassland, semiterrestrial swampland and salt marshes of high attractiveness for many organisms, notably breeding birds (Kohler et al., 1994). These four components together permit the coexistence of ecologically specialized forms alongside the ubiquitous Central European species on a small scale. However, within the past 150 years, habitat loss and habitat devaluation has proceeded at an accelerating pace. The number of salt pans has decreased from 139, covering an area of 3615 ha in 1850, to 79 (1360 ha) in 1957, and to 63 (805 ha) in 1986 (Kohler et al., 1994). Today, about 40 salt pans are left, but typical conditions (vegetation zonation, salt content, hydrology) prevail in fewer than 20 of these (Milasowszky Conservation problems in the Neusiedler See–Seewinkel National Park, Austria: an arachnological perspective