Alvar Vegetation of Öland—Changes, Monitoring and Restoration
2006
Rosén, Ejvind
<p>Alvars are habitats characterised by thin soils on limestone bedrock. The largest alvar area in the world is the Stora Alvaret, Öland (25,500 hectares), which is characterised by the presence of several plant communities of high conservation value. Emigration at the end of the nineteenth century reduced land-use intensity resulting in scrub encroachment, mainly by <i>Juniperus communis</i> L. This later accelerated, leading to abandonment because grazing in the low-productivity pastures was uneconomic.</p><p>Monitoring in permanent plots over a twenty-year period (1971–91) showed an increase in juniper cover over time and a clear correlation with a decline of other vascular plant species. This resulted in a gradual loss of both a valuable mosaic structure and a high level of bio-diversity in the landscape</p><p>An EU funded LIFE project (1996–99), which examined the effects of grazing and scrub clearance, is outlined. Various management techniques were tested and evaluated, providing valuable information for the present large-scale restoration and management programme supported by the European Union agri-environment schemes. In 1994 less than 60% of the Stora Alvaret was grazed. By 2005 this had increased to 98%.</p><p>The reintroduction of grazing has resulted in a significant increase in the abundance of twelve out of 72 vascular species in permanent plots (1997–2001). Sheep and cattle numbers increased in Öland during the last decade, whereas they decreased in Sweden as a whole over the same period. Sixteen nature reserves have been established in Stora Alvaret, and a functioning alvar pasture landscape has been re-established. Almost all alvars in Öland have been designated as Natura 2000 areas.</p>
显示更多 [+] 显示较少 [-]