Alvar
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:''This article is about the landform. For the Tamil saints, see [[Alvars]]; for the village in Armenia, see [[Alvar, Armenia]].''
[[Image:Österplana hed.jpg|thumb|right|250px|Alvar at [[Kinnekulle]], [[Sweden]]. Most plants are confined to the numerous cracks in the limestone.]]
[[Image:Österplana hed vegetation.jpg|thumb|right|250px|Sparse vegetation. [[Kinnekulle]], [[Sweden]].]]
[[Image:Alvar2.jpg|thumb|right|250px|[[Lichen]], [[moss]] and grasses on [[limestone]] surface. [[Kelley's Island]], [[Ohio]] in [[Lake Erie]].]]
An '''alvar''' or '''pavement barren''' is a biological environment based on a [[limestone]] [[plain]] with thin or no soil and, as a result, sparse vegetation. In the [[United Kingdom]] this [[landform]] is called a '''limestone pavement'''. This challenging [[Habitat (ecology)|habitat]] supports a community of [[rare species|rare]] plants and animals, including [[species]] more commonly found on [[prairie]] [[grassland]]s. [[Lichen]] and [[moss]]es are common species. Trees and bushes are absent or severely stunted. Alvars can be found in southern [[Sweden]], northwest [[Estonia]] and around the [[Great Lakes]] in [[Michigan]], [[New York]] and [[Ohio]] in the [[United States]] and in [[Ontario]] and [[Quebec]] in [[Canada]]. Alvars comprise a small percentage of the [[Earth]]'s [[ecosystem]]s by land extent; although, some 120 exist in the Great Lakes region, they comprise only 0.2% of the land area there.
In [[North America]], alvars provide habitat for birds such as [[Bobolink]]s, [[Eastern Meadowlark]]s, [[Upland Sandpiper]]s, [[Eastern Towhee]]s, [[Brown Thrasher]]s and [[Loggerhead Shrike]]s whose habitat is declining elsewhere. [[Rare species|Rare plants]] include [[northern bog violet]], [[balsam squaw-weed]], [[Kalm's lobelia]], [[Pringle's aster]], [[Juniper sedge]] (''[[Carex juniperorum]]''), [[Lakeside daisy]] (''[[Hymenoxys acaulis]]''), [[Ram's-head Lady's-slipper]] (''[[Cypripedium arietinum]]'') and [[Dwarf Lake Iris]] (''[[Dwarf Lake Iris|Iris lacustris]]''). Also associated with alvars are rare [[butterfly|butterflies]] and [[snail]]s.
The use of the word "alvar" to refer to this type of environment originated in [[Scandinavia]]. The largest alvar in Europe is located on the Swedish island of [[Öland]]. Here the thin soil mantle is only .5 to 2.0 centimeters thick in most places and in many extents consists of exposed limestone slabs<ref>C.M. Hogan, ''The Stora Alvaret on Öland'', Lumina Technologies, Santa Rosa, Ca. July 21, 2006</ref><ref>''The countryside of eastern Smaland'', ed. by Markus Forslund, Kalmarsund, Tryck (1999) ISBN 91-630-7610-1</ref>. The landscape there has been designated a [[UNESCO]] [[World heritage site]].
==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 cost 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 [[Moonsund archipelago|West Estonian Archipelago]].
*[[England]]
**[[Cumbria]] and North [[Yorkshire]] - under protection in the UK [[Biodiversity Action Plan]]
==North American alvar locations==
*[[Lake Erie]]
**[[Kelley's Island]], [[Ohio]] - North Shore Alvar State Nature Preserve[http://www.ohiodnr.com/dnap/location/alvar.htm]
**[[Marblehead, Ohio]] - mostly destroyed by limestone quarrying
**[[Pelee Island]], [[Ontario]] - Stone Road Alvar Nature Reserve[http://www.ontarionature.org/enviroandcons/reserves/res_stone_road_alvar.html]
*[[Lake Huron]]
**Maxton Plains Proposed Natural Area, [[Drummond Island]], [[Michigan]][http://www.michigan.gov/dnr/0,1607,7-153-10367_11854-54020--,00.html]
**Belanger Bay Alvar, [[Manitoulin Island]], Ontario[http://www.mnr.gov.on.ca/MNR/csb/news/oct19nr99.html]
**Quarry Bay Nature Reserve, Manitoulin Island, Ontario[http://www.ontarionature.org/enviroandcons/reserves/res_quarry.html]
**Bruce Alvar Nature Reserve, [[Bruce Peninsula]], Ontario [http://www.ontarionature.org/enviroandcons/reserves/res_bruce_alvar.html]
**Baptise Harbour Nature Reserve, Bruce Peninsula, Ontario[http://www.ontarionature.org/enviroandcons/reserves/res_baptist.html]
*[[Lake Ontario]]
**Carden Plain Alvar, City of Kawartha Lakes, Ontario [http://www.couchconservancy.ca/cameronranch.htm]
**Chaumont Barrens Preserve, New York[http://www.nature.org/wherewework/northamerica/states/newyork/preserves/art11823.html]
**Three Mile Creek Barrens, New York
**Near Almonte Ontario, particularly extensive and diverse according to Nature Conservancy of Canada
**[[Balsam Lake]] Indian Point Provincial Park, Ontario[http://www.ontarioparks.com/english/indi.html]
*[[Quebec]]
**[[Aylmer]] [http://www.canada.com/ottawacitizen/news/city/story.html?id=fa6a428a-57da-45bd-8294-1fffa571f628]
==See also==
* [[Limestone pavement]]
==References==
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[[Category:Landforms]]
[[Category:Gotland]]
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