"alvar" to refer to this type of environment originated in Sweden. The largest alvar in Europe is located on the Swedish island of Öland. Here the thin soil mantle is only 0.5 to 2.0 centimeters thick in most places and in many extents consists of exposed limestone slabs. The landscape there has been designated a UNESCO World Heritage Site. There are other more local names for similar landforms, such as a pavement barren, although this term is also used for similar landforms based on sandstone. In the United Kingdom the exposed landform is called a limestone pavement and thinly covered limestone is known as calcareous grassland. European alvar locations Sweden Öland – Stora Alvaret – largest alvar extent in Europe Gotland Västergötland – several locations on limestone mountain Kinnekulle, smaller fragments on Falbygden, e.g. in Dala and Högstena parishes Estonia Alvars are distributed along the whole northern coast of Estonia from approx. the town of Paldiski to Sillamäe, wherever limestone comes to the surface near the seashore (see Baltic Klint), as well as on the islands of the West Estonian archipelago. Estonia used to be home to approximately one third of the world's alvars; however, the total area of alvars has decreased from 43,000 hectares in the 1930s to 12,000 hectares in 2000, and approximately 9,000 hectares in 2010. Estonian alvars are home to 267 species of vascular plants, approximately one fifth of which are protected. There are also 142 species of bryophytes and 263 species of lichens. The Estonian government has committed itself to protect at least 9,800 hectares of the country's alvars as part of the Natura 2000 network. The Loopealse subdistrict of Tallinn is named after alvar. Vardi Nature Reserve in Rapla County is an Estonian nature reserve especially designated to protect one of the more representative alvar areas of Estonia. England Cumbria and North Yorkshire – under protection in the UK Biodiversity Action Plan Ireland The Burren, a large alvar in northwest County Clare Some North American alvar locations The rare Charitable Research Reserve – Cambridge, Ontario Lake Erie Kelley's Island, Ohio – North Shore Alvar State Nature Preserve Marblehead, Ohio – mostly destroyed by limestone quarrying Pelee Island, Ontario – Stone Road Alvar Nature Reserve Lake Huron Maxton Plains Proposed Natural Area, Drummond Island, Michigan Belanger Bay Alvar, Manitoulin Island, Ontario Quarry Bay Nature Reserve, Manitoulin Island, Ontario Bruce Alvar Nature Reserve, Bruce Peninsula, Ontario