Chalk heath is a rare habitat, in the

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

biome A biome () is a distinct geographical region with specific climate, vegetation, and animal life. It consists of a biological community that has formed in response to its physical environment and regional climate. In 1935, Tansley added the ...

, 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 An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

ic soil over an

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic 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 soluble base has a pH greater than 7.0. The a ...

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

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

Ecology

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

loess A loess (, ; from ) is a clastic rock, 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 loesses or similar deposition (geology), deposits. A loess ...

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

) overlies a

basic Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...

(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. Ch ...

. Shallow-

root In vascular plants, the roots are the plant organ, 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 bel ...

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 free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

habitat, created and maintained by

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

(usually

sheep Sheep (: sheep) or domestic sheep (''Ovis aries'') are a domesticated, ruminant mammal 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 d ...

and

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

) and

rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...

Vegetation

Chalk heath in southern

Britain Britain most often refers to: * Great Britain, a large island comprising the countries of England, Scotland and Wales * The United Kingdom of Great Britain and Northern Ireland, a sovereign state in Europe comprising Great Britain and the north-eas ...

includes calcicoles such as salad burnet (''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 Europe, western Siberia, Asia Minor, the ...

'') and common milkwort ('' Polygala vulgaris''), 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. Description It is a low, spreading shrub growing to tall, with fine needle-like leaves long arranged in ...

''), 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 b ...

''), sheep's sorrel (''Rumex acetosella'') and betony ('' Stachys officinalis''). 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 be ...

''), wood sage ('' Teucrium scorodonia'') 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 ( US) plow (both pronounced ) is a farm tool for loosening or turning the soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses but modern ploughs are drawn by tractors. A plough may have a wooden ...

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

Example locations

* Headley Heath in

Surrey Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

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

East Sussex East Sussex is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Kent to the north-east, West Sussex to the west, Surrey to the north-west, and the English Channel to the south. The largest settlement ...

, 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 (United Kingd ...

, in

West Sussex West Sussex is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Surrey to the north, East Sussex to the east, the English Channel to the south, and Hampshire to the west. The largest settlement is Cr ...

, 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. Due to the similarity, the term '' scarp'' may mistakenly be incorrectly used inte ...

. * Porton Down, in

Wiltshire Wiltshire (; abbreviated to Wilts) is a ceremonial county in South West England. It borders Gloucestershire to the north, Oxfordshire to the north-east, Berkshire to the east, Hampshire to the south-east, Dorset to the south, and Somerset to ...

, 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