Chalk heath is a rare habitat, in the

temperate grasslands, savannas, and shrublands Temperate grasslands, savannas, and shrublands is a terrestrial biome defined by the World Wide Fund for Nature. The predominant vegetation in this biome consists of grass and/or shrubs. The climate is temperate and ranges from Semi-arid climate ...

biome A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...

, formed of a paradoxical mixture of shallow-rooted

calcifuge A calcifuge is a plant that does not tolerate alkaline (basic) soil. The word is derived from the Latin 'to flee from chalk'. These plants are also described as ericaceous, as the prototypical calcifuge is the genus ''Erica'' (heaths). It is not ...

("calcium-hating") and deeper-rooted

calcicole A calcicole, calciphyte or calciphile is a plant that thrives in lime rich soil. The word is derived from the Latin 'to dwell on chalk'. Under acidic conditions, aluminium becomes more soluble and phosphate less. As a consequence, calcicoles grown ...

("calcium-loving") plants, growing on a thin layer of

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

ic soil over an

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

ne substrate. Chalk heath is intermediate between two much more widespread habitats,

chalk grassland Calcareous grassland (or alkaline 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 clove ...

and

heathland A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler ...

Ecology

Chalk heath occurs where a thin layer of acidic soil (often

loess Loess (, ; from german: Löss ) is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loess or similar deposits. Loess is a periglacial or aeolian ...

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

) overlies a

basic BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

(alkaline) one, such as

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk ...

. Shallow-

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

ed plants grow only in the acidic soil (typically a few centimetres thick), and so these are species characteristic of acidic habitats. Deeper-rooted plants can reach the underlying alkaline substrate, and so these include species characteristic of alkaline habitats. Plants also occur which are able to tolerate both acidic and basic conditions. There are no plants restricted entirely to chalk heath, and the animals are also those characteristic of chalk grassland and heathland. The vegetation structure of chalk heath resembles grass heath, being short grassy vegetation with heather growing up through it, with some scattered heather bushes. Chalk heath often occurs at the tops of slopes, at the thin margins of acidic deposits which often cap the flatter tops of chalk hills. It usually gives way to chalk grassland on lower slopes where these deposits have been eroded away, and often to heathland on the hilltops where the acidic deposits are thicker. Chalk heath tends to occur as narrow strips and scattered fragments, being limited to places where the conditions are exactly right for its development and survival. Chalk heath is a

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

habitat, created and maintained by

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...

(usually

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...

and

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

) and

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...

Vegetation

Chalk heath in southern

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

includes calcicoles such as

salad burnet ''Sanguisorba minor'', the salad burnet, garden burnet, small burnet, burnet (also used for ''Sanguisorba'' generally), pimpernelle, Toper's plant, and burnet-bloodwort, is an edible perennial herbaceous plant in the family Rosaceae. It has fe ...

(''Sanguisorba minor''), dropwort (''

Filipendula vulgaris ''Filipendula vulgaris'', commonly known as dropwort or fern-leaf dropwort, is a perennial herbaceous plant in the family Rosaceae, closely related to meadowsweet (''Filipendula ulmaria''). It is found in dry pastures across much of Europe an ...

'') and common milkwort (''

Polygala vulgaris ''Polygala vulgaris'', known as the common milkwort, is a herbaceous perennial plant of the genus '' Polygala'' in the family Polygalaceae. Description The biological form of ''Polygala vulgaris'' is '' hemicryptophyte'' ''scapose'',Pignatti S. ...

''), and calcifuges such as bell heather (''

Erica cinerea ''Erica cinerea'', the bell heather, is a species of flowering plant in the heath family Ericaceae, native to western and central Europe. The plant provides a great deal of nectar for pollinators. It was rated in the top 5 for most nectar produ ...

''), ling heather (''

Calluna ''Calluna vulgaris'', common heather, ling, or simply heather, is the sole species in the genus ''Calluna'' in the flowering plant family Ericaceae. It is a low-growing evergreen shrub growing to tall, or rarely to and taller, and is found wide ...

vulgaris''), heath grass (''

Danthonia decumbens ''Danthonia decumbens'' (formerly ''Sieglingia decumbens'') is a species of grass commonly known as the heath grass, heath-grass, or staggers grass It is a tussock grass native to Europe and adjacent parts of Asia and North Africa. It may also be ...

''),

sheep's sorrel ''Rumex acetosella'', commonly known as red sorrel, sheep's sorrel, field sorrel and sour weed, is a species of flowering plant in the buckwheat family Polygonaceae. Native to Eurasia and the British Isles, the plant and its subspecies are commo ...

(''Rumex acetosella'') and betony (''

Stachys officinalis ''Betonica officinalis'' ( syn. ''Stachys officinalis''), commonly known as common hedgenettle, betony, purple betony, wood betony, bishopwort, or bishop's wort, is a species of flowering plant in the mint family Lamiaceae, native to Europe, wes ...

''). It also includes plants which can tolerate both acidic and basic conditions, such as common bent (''

Agrostis capillaris ''Agrostis capillaris'', the common bent, colonial bent, or browntop, is a rhizomatous and stoloniferous perennial in the grass family (Poaceae). It is native to Eurasia and has been widely introduced in many parts of the world. Colonial ben ...

''), wood sage (''

Teucrium scorodonia ''Teucrium scorodonia'', common name the woodland germander or wood sage, is a species of flowering plant in the genus ''Teucrium'' of the family Lamiaceae. It is native to Western Europe and Tunisia, but cultivated in many places as an ornament ...

'') and sometimes juniper (''

Juniperus communis ''Juniperus communis'', the common juniper, is a species of small tree or shrub in the cypress family Cupressaceae. An evergreen conifer, it has the largest geographical range of any woody plant, with a circumpolar distribution throughout the coo ...

'').

Conservation

Chalk heath has suffered a parallel decline to those of heathland and chalk grassland, but because of the scattered and fragmented distribution of suitable soil conditions it has declined even more than those habitats. Many examples have disappeared due to agricultural improvement, or to a lack of grazing management, which leads to replacement by species-poor scrub and woodland. Chalk heath is especially sensitive to soil disturbance such as

plough A plough or plow ( US; both ) is a farm tool for loosening or turning the soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses, but in modern farms are drawn by tractors. A plough may have a wooden, iron or ...

ing, which mixes the thin layer of acidic soil with the chalk beneath.

Example locations

* Headley Heath in

Surrey Surrey () is a ceremonial and non-metropolitan county in South East England, bordering Greater London to the south west. Surrey has a large rural area, and several significant urban areas which form part of the Greater London Built-up Area. ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. Small areas of chalk heath surrounding a larger plateau of heathland. * Lullington Heath in

East Sussex East Sussex is a ceremonial and non-metropolitan county in South East England on the English Channel coast. It is bordered by Kent to the north and east, West Sussex to the west, and Surrey to the north-west. The largest settlement in East Su ...

, England. Relatively large areas of chalk heath with some chalk grassland. *

Kingley Vale National Nature Reserve Kingley Vale is a biological Site of Special Scientific Interest north of Chichester in West Sussex. It is also a Special Area of Conservation and a Nature Conservation Review site, Grade I. An area of is a national nature reserve. The site ...

, in

West Sussex West Sussex is a county in South East England on the English Channel coast. The ceremonial county comprises the shire districts of Adur, Arun, Chichester, Horsham, and Mid Sussex, and the boroughs of Crawley and Worthing. Covering an ar ...

, England. Small areas of chalk heath at the top of a steep chalk

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escar ...

. *

Porton Porton is a village in the Bourne valley, Wiltshire, England, about northeast of Salisbury. It is the largest settlement in Idmiston civil parish. The village gives its name to the nearby Porton Down military science park, which is home to th ...

Down, in

Wiltshire Wiltshire (; abbreviated Wilts) is a historic and ceremonial county in South West England with an area of . It is landlocked and borders the counties of Dorset to the southwest, Somerset to the west, Hampshire to the southeast, Gloucestershire ...

, England.Natural England citation for Porton Down SSSI.
Chalk heath surrounded by extensive chalk grassland.

References

{{DEFAULTSORT:Chalk Heath Temperate grasslands, savannas, and shrublands Habitats Heaths Land management Cultural landscapes

Ecology

Vegetation

Conservation

Example locations

See also

References