Downland
Encyclopedia
A downland is an area of open chalk
Chalk
Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

 hill
Hill
A hill is a landform that extends above the surrounding terrain. Hills often have a distinct summit, although in areas with scarp/dip topography a hill may refer to a particular section of flat terrain without a massive summit A hill is a landform that extends above the surrounding terrain. Hills...

s. This term is especially used to describe the chalk
Chalk
Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

 countryside in southern England. Areas of downland are often referred to as Downs.

The word 'down' derives from a medieval Germanic
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 or Norse word — "dun", a hill.

Formation of downland

Downland is formed when chalk formation
Chalk Formation
The Chalk Group is a lithostratigraphic unit in the northwestern part of Europe. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment during the Upper Cretaceous period.Chalk is a limestone that consists of coccolith biomicrite...

s are raised above the surrounding rocks. The chalk slowly erodes
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 to form characteristic rolling hills and valleys. As the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 chalk layer in southern England is typically tilted, chalk downland formations often have a marked scarp
Escarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...

 slope on one side, which is very steep, and a dip
Escarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...

 slope on the other, which is much shallower. Where the downs meet the sea, characteristic white chalk cliff
Cliff
In geography and geology, a cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually...

s form, such as the White Cliffs of Dover
White cliffs of Dover
The White Cliffs of Dover are cliffs which form part of the British coastline facing the Strait of Dover and France. The cliffs are part of the North Downs formation. The cliff face, which reaches up to , owes its striking façade to its composition of chalk accentuated by streaks of black flint...

 and Beachy Head
Beachy Head
Beachy Head is a chalk headland on the south coast of England, close to the town of Eastbourne in the county of East Sussex, immediately east of the Seven Sisters. The cliff there is the highest chalk sea cliff in Britain, rising to 162 m above sea level. The peak allows views of the south...

.

Hydrology

Chalk deposits are very porous, so the height of the water table
Water table
The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...

 in chalk hills rises in winter and falls in summer. This leads to characteristic chalk downland features such as dry valleys or coombe
Coombe
-Places in England:* Coombe, Buckinghamshire* Coombe, Bude, Cornwall* Coombe, Camborne, Cornwall* Coombe, Liskeard, Cornwall* Coombe, Redruth, Cornwall* Coombe, St...

s, and seasonally-flowing streams or winterbournes
Winterbourne (stream)
A winterbourne is a stream or river that is dry through the summer months. A winterbourne is sometimes simply called a bourne, from the Anglo-Saxon for a stream flowing from a spring, although this term can also be used for all-year water courses....

. The modern practice of extracting water from this 'reservoir', in order to satisfy demand for water, may be putting some of these streams under extreme stress.

In the valleys below the downs there is typically a clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 soil, and at the interface between the two a springline can occur where water emerges from the porous chalk. Along this line, settlements and farms were often built, as on the higher land no water was available. This is demonstrated very clearly beneath the scarp
Escarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...

 of the White Horse Hills, above the Vale of White Horse
Vale of White Horse
The Vale of White Horse is a local government district of Oxfordshire in England. The main town is Abingdon, other places include Faringdon and Wantage. There are 68 parishes within the district...

. In many chalk downland areas there is no surface water at all other than artificially created dewponds.

Downland soil

The soil profile of chalk downland in England is a thin soil overlaying the parent
Parent material
In soil science, parent material is the underlying geological material in which soil horizons form...

 chalk
Chalk
Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

. Weathering of the chalk has created a characteristic soil known as rendzina
Rendzina
Rendzina is a dark, grayish-brown, humus-rich, intrazonal soil. It is one of the soils most closely associated with the bedrock type and an example of initial stages of soil development...

. Unlike many soils in which there are easily distinguished layers or soil horizon
Soil horizon
A soil horizon is a specific layer in the land area that is parallel to the soil surface and possesses physical characteristics which differ from the layers above and beneath. Horizon formation is a function of a range of geological, chemical, and biological processes and occurs over long time...

s, a chalk rendzina soil consists of only a shallow dark humus rich surface layer which grades through a lighter brown hillwash containing small pellets of chalk, to the white of the chalk itself. This is largely because of the purity of the chalk which is here about 98% calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 and the consequent absence of soil-building clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 minerals which are abundant, for example, in valley floors.

Steep slopes on chalk downland develop a ribbed pattern of grass covered horizontal steps a foot or two high. Although subsequently emphasised by cattle and sheep walking along them, these terracettes (commonly known as sheep tracks) were formed by the movement of soil downhill, a process known as soil creep.

Downland habitat

In temperate regions chalk downland is typically 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...

, a 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...

 formed by grazing from both livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...

 and wild animals. Chalk downland is often unsuitable for intensive agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

, horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

 or development, because of the nutrient-poor, shallow soil and difficult slopes. For this reason downland often survived uncultivated when other, more easily worked land was ploughed or reseeded. However, equally this shallow soil structure makes downland ecosystems extremely fragile and easy to destroy. With modern machinery and fertilizing techniques it has become possible to use some previously uncultivated downland for arable farming, and the decline of extensive grazing has meant that many areas of downland, whilst not cultivated, when ungrazed revert to scrub or other less rare habitat, essentially destroying the delicate calcareous grassland. The UK cover of lowland 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...

 has suffered a sharp decline in extent since the middle of the 20th century. There are no comprehensive figures, but a sample of chalk sites in England surveyed in 1966 and 1980 showed a 20% loss in that period and an assessment of chalk grassland in Dorset
Dorset
Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...

 found that over 50% had been lost between the mid-1950s and the early 1990s. Much remaining chalk downland has been protected against future development, due to its unique biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

.

The Southern England Chalk Formation

  • Berkshire Downs
    Berkshire Downs
    The Berkshire Downs are a range of chalk downland hills in southern England, part of the North Wessex Downs Area of Outstanding Natural Beauty...

     and White Horse Hills
    Uffington White Horse
    The Uffington White Horse is a highly stylised prehistoric hill figure, 110 m long , formed from deep trenches filled with crushed white chalk...

  • Chiltern Hills
    Chiltern Hills
    The Chiltern Hills form a chalk escarpment in South East England. They are known locally as "the Chilterns". A large portion of the hills was designated officially as an Area of Outstanding Natural Beauty in 1965.-Location:...

     (Dunstable Downs
    Dunstable Downs
    Dunstable Downs are part of the Chiltern Hills, in southern Bedfordshire in England. They are a chalk escarpment forming the north-eastern reaches of the Chilterns...

    )
  • Cranborne Chase
    Cranborne Chase
    Cranborne Chase is a Chalk plateau in central southern England, straddling the counties Dorset, Hampshire and Wiltshire. The plateau is part of the English Chalk Formation and is adjacent to Salisbury Plain and the West Wiltshire Downs in the north, the Dorset Downs to the south west and the...

  • Dorset Downs
    Dorset Downs
    The Dorset Downs are an area of Chalk downland in the centre of the county Dorset in south west England. The downs are the most western part of a larger Chalk Formation which also includes Cranborne Chase, Salisbury Plain, Hampshire Downs, Chiltern Hills, North Downs and South Downs.The Dorset...

     (Hambledon Hill
    Hambledon Hill
    Hambledon Hill is a prehistoric hill fort in Dorset, England, situated in the Blackmore Vale five miles north of Blandford Forum. The hill is a Chalk outcrop, on the south western corner of Cranborne Chase, separated from the Dorset Downs by the River Stour....

    , Hodd Hill, Maiden Castle
    Maiden Castle, Dorset
    Maiden Castle is an Iron Age hill fort south west of Dorchester, in the English county of Dorset. Hill forts were fortified hill-top settlements constructed across Britain during the Iron Age...

    , Cerne Abbas Giant
    Cerne Abbas giant
    The Cerne Abbas Giant, also referred to as the Rude Man or the Rude Giant, is a hill figure of a giant naked man on a hillside near the village of Cerne Abbas, to the north of Dorchester, in Dorset, England. The high, wide figure is carved into the side of a steep hill, and is best viewed from...

    )
  • Isle of Wight
    Isle of Wight
    The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...

     (The Needles
    The Needles
    The Needles is a row of three distinctive stacks of chalk that rise out of the sea off the western extremity of the Isle of Wight, England, close to Alum Bay. The Needles lighthouse stands at the end of the formation...

    , Tennyson Down
    Tennyson Down
    Tennyson Down is a hill at the west end of the Isle of Wight just south of Totland. Tennyson Down is a grassy, whale-backed ridge of chalk which rises to 482 ft/147m above sea level. Tennyson Down is named after the poet Lord Tennyson who lived at nearby Farringdon House for nearly 40 years...

    , St Boniface Down
    St Boniface Down
    St Boniface Down is a chalk down on the Isle of Wight, England. It is located close to the town of Ventnor, in the southeast of the Island, and rises to , the Island's highest point, north of the town...

    , Culver Down
    Culver Down
    Culver Down is a chalk down to the north of Sandown, Isle of Wight.It is believed that its name derives from "Culfre" - old English for "dove"....

    )
  • North Downs
    North Downs
    The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. The North Downs lie within two Areas of Outstanding Natural Beauty , the Surrey Hills and the Kent Downs...

     (White Cliffs of Dover
    White cliffs of Dover
    The White Cliffs of Dover are cliffs which form part of the British coastline facing the Strait of Dover and France. The cliffs are part of the North Downs formation. The cliff face, which reaches up to , owes its striking façade to its composition of chalk accentuated by streaks of black flint...

    , Langdon Bay
    Langdon Bay, Kent
    Langdon Bay is a bay in east Kent, England. It is two miles east of the town of Dover, and is named after the nearby villages of Langdon, East Langdon and West Langdon...

    , Box Hill, Hog's Back
    Hog's Back
    The Hog's Back is a part of the North Downs in Surrey, England, that lies between Farnham, Surrey in the west and Guildford in the east.-Name:Compared with the main part of the Downs to the east of it, it is a narrow elongated ridge, hence its name....

    )
  • Purbeck Hills
    Purbeck Hills
    The Purbeck Hills and South Dorset Downs are a ridge of chalk downs in Dorset, England. The hills extend from the Dorset Downs west of Dorchester, where the River Frome begins to form a valley dividing them from the larger area of downland to the north. The ridge then runs east through the Isle...

     (Ballard Down
    Ballard Down
    Ballard Down is an area of chalk downland in Dorset, southern England.The down forms a headland, Ballard Point, between Studland and Swanage bays in the English Channel, and once formed part of a continuous chalk ridge between what are now west Dorset and the Isle of Wight, part of the Southern...

    , Lulworth Cove
    Lulworth Cove
    Lulworth Cove is a cove near the village of West Lulworth, on the Jurassic Coast World Heritage Site in Dorset, southern England. The cove is one of the world's finest examples of such a landform, and is a tourist location with over 1 million visitors a year...

    , Old Harry Rocks
    Old Harry Rocks
    The Old Harry Rocks are two chalk sea stacks located at Handfast Point, on the Isle of Purbeck in Dorset, southern England.- Location :Old Harry Rocks lie directly east of Studland, about 4 kilometres northeast of Swanage, and about 10 kilometres south of the large towns of Poole and...

    , White Nothe
    White Nothe
    White Nothe is a chalk headland on the English Channel coast at the eastern end of Ringstead Bay, east of Weymouth in Dorset, England. The area is well-known for its geology and fossils...

    )
  • Salisbury Plain
    Salisbury Plain
    Salisbury Plain is a chalk plateau in central southern England covering . It is part of the Southern England Chalk Formation and largely lies within the county of Wiltshire, with a little in Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known...

  • South Downs
    South Downs
    The South Downs is a range of chalk hills that extends for about across the south-eastern coastal counties of England from the Itchen Valley of Hampshire in the west to Beachy Head, near Eastbourne, East Sussex, in the east. It is bounded on its northern side by a steep escarpment, from whose...

     (Beachy Head
    Beachy Head
    Beachy Head is a chalk headland on the south coast of England, close to the town of Eastbourne in the county of East Sussex, immediately east of the Seven Sisters. The cliff there is the highest chalk sea cliff in Britain, rising to 162 m above sea level. The peak allows views of the south...

    , Seven Sisters
    Seven Sisters, Sussex
    The Seven Sisters are a series of chalk cliffs by the English Channel. They form part of the South Downs in East Sussex, between the towns of Seaford and Eastbourne in southern England. They are within the Seven Sisters Country Park...

    , Ditchling Beacon
    Ditchling Beacon
    Ditchling Beacon is the third-highest point on the South Downs in south-east England, behind Butser Hill and Crown Tegleaze . It consists of a large chalk hill with a particularly steep northern face, covered with open grassland and sheep-grazing areas...

    , Butser Hill
    Butser Hill
    Butser Hill is a chalk hill and one of the highest points in Hampshire. It is also the highest point on the chalk ridge of the South Downs and the second highest point in the South Downs National Park after Blackdown in the Western Weald. Although only high, it qualifies as one of England's...

    )

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