Alvar
Encyclopedia
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
plain
Plain
In geography, a plain is land with relatively low relief, that is flat or gently rolling. Prairies and steppes are types of plains, and the archetype for a plain is often thought of as a grassland, but plains in their natural state may also be covered in shrublands, woodland and forest, or...
with thin or no soil and, as a result, sparse vegetation. It is also known as a pavement barren although this term is also used for similar landform
Landform
A landform or physical feature in the earth sciences and geology sub-fields, comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography...
s based on sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
the exposed landform is called a limestone pavement
Limestone pavement
A limestone pavement is a natural karst landform consisting of a flat, incised surface of exposed limestone that resembles an artificial pavement. The term is mainly used in the UK where many of these landforms have developed distinctive surface patterning resembling block of paving...
and thinly covered limestone is known as calcareous grassland
Calcareous grassland
Calcareous grassland is an ecosystem associated with thin basic soil, such as that on chalk and limestone downland. Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as clover...
. This challenging habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
supports a community of rare
Rare species
A rare species is a group of organisms that are very uncommon or scarce. This designation may be applied to either a plant or animal taxon, and may be distinct from the term "endangered" or "threatened species" but not "extinct"....
plants and animals, including species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
more commonly found on prairie
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...
grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s. Lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
and moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es are common species. Trees and bushes are absent or severely stunted. Alvars can be found in southern Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, northwest Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
and around the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
and Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
and Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. Alvars comprise a small percentage of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
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
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, alvars provide habitat for birds such as Bobolink
Bobolink
The Bobolink is a small New World blackbird and the only member of genus Dolichonyx.-Description:Adults are 16–18 cm long with short finch-like bills. They weigh about . Adult males are mostly black, although they do display creamy napes, and white scapulars, lower backs and rumps...
s, Eastern Meadowlark
Eastern Meadowlark
The Eastern Meadowlark, Sturnella magna, is a medium-sized icterid bird, very similar in appearance to the Western Meadowlark. It occurs from eastern North America to South America, where it is also most widespread in the east.-Description:...
s, Upland Sandpiper
Upland Sandpiper
The Upland Sandpiper is a large shorebird, closely related to the curlews . Older names are the Upland Plover and Bartram's Sandpiper. It is the only member of the genus Bartramia. The genus name and the old common name Bartram's Sandpiper commemorate the American naturalist William Bartram...
s, Eastern Towhee
Eastern Towhee
The Eastern Towhee, Pipilo erythrophthalmus, is a large New World sparrow. The taxonomy of the towhees has been under debate in recent decades, and formerly this bird and the Spotted Towhee were considered a single species, the Rufous-sided Towhee....
s, Brown Thrasher
Brown Thrasher
The Brown Thrasher , sometimes erroneously called the Brown Thrush, is a bird in the Mimidae family, a group that also includes the New World catbirds and mockingbirds.-Description:...
s and Loggerhead Shrike
Loggerhead Shrike
The Loggerhead Shrike is a passerine bird. It is the only member of the shrike family endemic to North America; the related Northern Shrike occurs north of its range but also in the Palearctic....
s whose habitat is declining elsewhere. Rare plants
Rare species
A rare species is a group of organisms that are very uncommon or scarce. This designation may be applied to either a plant or animal taxon, and may be distinct from the term "endangered" or "threatened species" but not "extinct"....
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
Cypripedium arietinum
The rare Ram's-Head Lady's-Slipper is an orchid that is native to the alvars around the Great Lakes in North America.The plant grows to 10-40 cm , and the flowers may reach 1-2 cm...
) and Dwarf Lake Iris
Dwarf Lake Iris
The Dwarf Lake Iris is a beardless rhizomatous iris native to the northern shores of Lake Michigan and Lake Huron....
(Iris lacustris
Dwarf Lake Iris
The Dwarf Lake Iris is a beardless rhizomatous iris native to the northern shores of Lake Michigan and Lake Huron....
). Also associated with alvars are rare butterflies
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
and snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s.
The use of the word "alvar" to refer to this type of environment originated in Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
. The largest alvar in Europe is located on the Swedish island of Öland
Öland
' is the second largest Swedish island and the smallest of the traditional provinces of Sweden. Öland has an area of 1,342 km² and is located in the Baltic Sea just off the coast of Småland. The island has 25,000 inhabitants, but during Swedish Midsummer it is visited by up to 500,000 people...
. 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. The landscape there has been designated a UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
World heritage site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
.
European alvar locations
- SwedenSwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
- ÖlandÖland' is the second largest Swedish island and the smallest of the traditional provinces of Sweden. Öland has an area of 1,342 km² and is located in the Baltic Sea just off the coast of Småland. The island has 25,000 inhabitants, but during Swedish Midsummer it is visited by up to 500,000 people...
– Stora AlvaretStora AlvaretThe Stora Alvaret is a limestone barren plain on the island of Öland, Sweden. Because of the thin soil mantle and high pH levels, a great assortment of vegetation is found including numerous rare species. Stora Alvaret has been designated as a World Heritage Site by UNESCO due to its...
– largest alvar extent in Europe - GotlandGotlandGotland is a county, province, municipality and diocese of Sweden; it is Sweden's largest island and the largest island in the Baltic Sea. At 3,140 square kilometers in area, the region makes up less than one percent of Sweden's total land area...
- VästergötlandVästergötland', English exonym: West Gothland, is one of the 25 traditional non-administrative provinces of Sweden , situated in the southwest of Sweden. In older English literature one may also encounter the Latinized version Westrogothia....
– several locations on limestone mountain KinnekulleKinnekulle- External links :* *...
, smaller fragments on FalbygdenFalbygdenFalbygden is a geographical area, centered at the town of Falköping,in southern Sweden, and covered mostly by farmland. It is known for its geology, flora and megalithic culture....
, e.g. in Dala and Högstena parishes.
- Öland
- EstoniaEstoniaEstonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
- Alvars are distributed along the whole northern cost of Estonia from approx. the town of PaldiskiPaldiskiPaldiski is a town and Baltic Sea port situated on the Pakri peninsula of north-western Estonia. Originally a Swedish settlement known as Rågervik, it became a Russian naval base in the 18th century. The Russians renamed it Балтийский Порт Paldiski is a town and Baltic Sea port situated on the...
to SillamäeSillamäeSillamäe is a town in Ida-Viru County in the northern part of Estonia, on the southern coast of the Gulf of Finland. It has a population of 16,183 and covers an area of 10.54 km²...
, wherever limestone comes to the surface near the seashore (see Baltic KlintBaltic KlintThe Baltic Klint is an erosional limestone escarpment on several islands of the Baltic Sea, in Estonia and in Leningrad Oblast of Russia...
), 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 hectars in the 1930s to 12,000 hectars in 2000, and approximately 9,000 hectars in 2010. Estonian alvars are home to 267 speciesSpeciesIn biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of vascular plantVascular plantVascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...
s, approximately one fifth of which are protected. There are also 142 species of bryophyteBryophyteBryophyte is a traditional name used to refer to all embryophytes that do not have true vascular tissue and are therefore called 'non-vascular plants'. Some bryophytes do have specialized tissues for the transport of water; however since these do not contain lignin, they are not considered to be...
s and 263 species of lichenLichenLichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s. The Estonian governmentGovernment of the Republic of EstoniaThe Government of the Republic of Estonia exercises executive power pursuant to the Constitution and the laws of the Republic of Estonia...
has committed itself to protect at least 9,800 hectars of the country's alvars as part of the Natura 2000Natura 2000Natura 2000 is an ecological network of protected areas in the territory of the European Union.-Origins:In May 1992, the governments of the European Communities adopted legislation designed to protect the most seriously threatened habitats and species across Europe. This legislation is called the...
network.
- Alvars are distributed along the whole northern cost of Estonia from approx. the town of Paldiski
- EnglandEnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
- CumbriaCumbriaCumbria , is a non-metropolitan county in North West England. The county and Cumbria County Council, its local authority, came into existence in 1974 after the passage of the Local Government Act 1972. Cumbria's largest settlement and county town is Carlisle. It consists of six districts, and in...
and North YorkshireYorkshireYorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
- under protection in the UK Biodiversity Action PlanBiodiversity Action PlanA Biodiversity Action Plan is an internationally recognized program addressing threatened species and habitats and is designed to protect and restore biological systems. The original impetus for these plans derives from the 1992 Convention on Biological Diversity...
- Cumbria
- IrelandIrelandIreland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
- The BurrenThe BurrenThe Burren is a karst-landscape region or alvar in northwest County Clare, in Ireland. It is one of the largest karst landscapes in Europe. The region measures approximately 250 square kilometres and is enclosed roughly within the circle made by the villages Ballyvaughan, Kinvara, Tubber, Corofin,...
, a large alvar in northwest County ClareCounty Clare-History:There was a Neolithic civilisation in the Clare area — the name of the peoples is unknown, but the Prehistoric peoples left evidence behind in the form of ancient dolmen; single-chamber megalithic tombs, usually consisting of three or more upright stones...
- The Burren
North American alvar locations
- Lake ErieLake ErieLake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...
- Kelley's Island, OhioOhioOhio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
- North Shore Alvar State Nature Preserve http://www.ohiodnr.com/dnap/location/alvar.htm - Marblehead, OhioMarblehead, OhioMarblehead is a village in Ottawa County, Ohio, United States. The population was 762 at the 2000 census.It sits at the tip of the Marblehead Peninsula, which divides Lake Erie proper from Sandusky Bay...
- mostly destroyed by limestone quarrying - Pelee Island, OntarioOntarioOntario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
- Stone Road Alvar Nature Reserve http://www.ontarionature.org/enviroandcons/reserves/res_stone_road_alvar.html
- Kelley's Island, Ohio
- Lake HuronLake HuronLake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
- Maxton Plains Proposed Natural Area, Drummond Island, MichiganMichiganMichigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
http://www.michigan.gov/dnr/0,1607,7-153-10367_11854-54020--,00.html - Belanger Bay Alvar, Manitoulin IslandManitoulin IslandManitoulin Island is a Canadian island in Lake Huron, in the province of Ontario. It is the largest island in a freshwater lake in the world. In addition to the historic Anishinaabe and European settlement of the island, archeological discoveries at Sheguiandah have demonstrated Paleo-Indian and...
, 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 PeninsulaBruce PeninsulaThe Bruce Peninsula is a peninsula in Ontario, Canada that lies between Georgian Bay and the main basin of Lake Huron. The peninsula extends roughly northwestwards from the rest of Southern Ontario, pointing towards Manitoulin Island, with which it forms the widest strait joining Georgian Bay to...
, 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
- Maxton Plains Proposed Natural Area, Drummond Island, Michigan
- Lake OntarioLake OntarioLake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...
- 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 LakeBalsam LakeBalsam Lake may refer to:*in the United States,**Wisconsin***Balsam Lake , the lake***Balsam Lake, Wisconsin, a village***Balsam Lake , Wisconsin...
Indian Point Provincial Park, Ontario http://www.ontarioparks.com/english/indi.html
- QuebecQuebecQuebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
- AylmerAylmerAylmer is a surname, and may refer to:* Felix Aylmer, English stage actor* Sir Fenton Aylmer, 13th Baronet, British Army general and Victoria Cross recipient* Jennifer Aylmer, American operatic soprano* John Aylmer...
http://www.canada.com/ottawacitizen/news/city/story.html?id=fa6a428a-57da-45bd-8294-1fffa571f628
- Aylmer