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Chalkland biodiversity
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The landscapes of the East of England include a distinctive range of
habitats and a rich biodiversity which owe their existence to the underlying Chalk and its water-holding ability.
Chalk grassland is perhaps the most famous, with its downland turf and busy insect life; chalk heath is an East
Anglian variant influenced by 'drift' deposits. The Chalk also contributes springs, rivers and wetlands which have a
distinctive wildlife, including several invertebrate rarities. The slopes and plateaux areas of the Chilterns are
famous for their lofty beech woods. |
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Select an area of
interest below
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Chalk grassland
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Chalk rivers
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Chalk heath
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Springs and wetlands
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Beech woodland
• Chalk reefs |
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Chalk grassland on the Sundon Hills, Bedfordshire |
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Chalk grassland |
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Chalk grassland is one of the special features of the East of England
landscape. It is part of a belt of chalk downland which stretches from Wessex to Norfolk. Much of it originated in
prehistoric times, when Neolithic and Bronze Age farmers first cleared the land, while centuries of cultivation and
grazing have maintained its character. Unfortunately much has become degraded and fragmented by agricultural
changes over the last one hundred years. The stretches that remain are a precious resource for a distinctive wildlife.
Continued grazing by sheep and rabbits helps to prevent it from becoming scrubbed over. |
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Species-rich chalk grassland at Totternhoe Quarry SSSI, Beds. Pink sainfoin can be seen in the foreground, with field scabious and hawkweed. |
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Summer at Tring Park SSSI, Herts. The grassland is maintained by the Woodland Trust by grazing with cattle. Harebell is carpeting the foreground. |
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Mating chalkhill blue butterflies at Totternhoe Quarry SSSI, Beds. This species is restricted to calcareous grassland sites in southern England. |
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Chalk grassland on the Devil's Dyke SSSI, near Newmarket, Suffolk. The site is a refuge for chalkland plants once living on Newmarket Heath and nearby fields
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The pasque flower is a springtime feature of Therfield Heath SSSI, Herts. This is the best place in Britain to see this plant. |
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Aldbury Nowers SSSI, near Berkhamsted, Herts. The site is being managed for wildlife by the Herts & Middlesex Wildlife Trust by scrub clearance and removal of topsoil down to the chalk. |
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For more information about chalk grassland see the
Resources page. |
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Chalk rivers |
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Chalk rivers and streams are a feature of the East of England,
and total over 1000 km (621 miles) in length. A chalk river is one which flows over chalk bedrock or
takes most of its water from chalk springs. Some of the region's chalk rivers
are intermittent, particularly in the headwaters, where they are
called 'bournes', and stretches of them only flow after periods of rainfall.
The River Ver, for example, is intermittent upstream of Redbourn, Herts. |
Chalk rivers are an important resource in the region for wildlife. They are home to threatened species such as the water
vole and white-clawed crayfish. The invasion of non-native species such as mink, Japanese knotweed and signal crayfish
is prompting eradication programmes.
The region's chalk rivers are a vital resource for people as well as wildlife.
They supply water for drinking, industry and farming; many of them support angling for trout, salmon and coarse fish;
watercress beds directly rely on them. Many of them are significantly threatened by over-abstraction of water, flood
defence and land drainage work, and pollution, including sewerage discharges; river restoration programmes are
underway in several catchments. |
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A crystal-clear chalk brook at Fowlmere SSSI, Cambs, with watercress and submerged leaves of lesser water-parsnip.
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The River Kennett at Moulton, Suffolk. Evidently water flows were higher in the 15th century when this pack-horse bridge was built.
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The River Bulbourne near Berkhamsted, Herts. It often dries out in summer due to over-abstraction of water. There is a plan to reintroduce brown trout which once bred in it. |
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The River Nar at Castle Acre, Norfolk. This is a pristine example of a spring-fed chalk river |
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For more information about the region's chalk rivers see the
Resources page. |
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Chalk heath |
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Chalk heath is a speciality of the East of England region,
particularly in the Breckland of Norfolk and Suffolk. It occurs where chalky subsoil is combined with sandy
superficial deposits. Periglacial disturbance during the Ice Age has produced blends and also mosaics of different
soils, often within a few metres of each other.
Patterned ground is a feature of Breckland, formed when seasonal melting and thawing of
permafrost caused soil to become sorted into contrasting bands of sandy and chalky material.
This has given rise to an interesting mosaic of plant communities, with chalk grassland and acid
heathland species occurring side by side, sometimes in a pattern of stripes and polygons. Heather
and sheep's sorrel, for example, grow on acid soil, while stemless thistle and quaking grass grow on
lime-rich soil.
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Spanish catchfly is a rare plant of the Breckland heaths; it favours disturbed,
chalk-rich, sandy soils. The blue flowers are Viper's Bugloss, a common plant of
dry, sandy habitat.
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Chalk heathland at Grimes Graves SSSI, near Weeting, Norfolk, on mounds of chalk spoil thrown up by prehistoric flint mining.
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Vegetation stripes at Knettishall Heath SSSI, Suffolk. The dark patches are sheep's sorrel growing over bands of sandy soil. |
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For more information about the region's chalk heathland see the
Resources page. |
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| Springs and wetlands |
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The Chalk is the
most important aquifer in the region, which is one of the driest in the
UK. It supplies springs and associated wetlands, which occur at
spring-lines along the Chalk escarpment, and where river valleys have
cut down through overlying deposits to intercept the aquifer. |
Chalk springs are an important resource for wildlife.
They produce clear, pure, oxygenated water and tend to keep an even temperature throughout the year.
Many uncommon invertebrate species are found in them, and some are even thought to be survivals from the Ice Age.
Their lime-rich waters feed the headwaters of chalk streams, and give rise to local fens and marshy grasslands which
harbour a rich biodiversity; examples include Redgrave Fen (Suffolk), Chippenham Fen (Cambs) and Oughtonhead Common,
Hitchin (Herts). |
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Ashwell Springs, Herts, emerge at the Melbourn Rock horizon of the Middle Chalk. Rare flatworms are believed to have been present here since the Ice Age.
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One of the chalk springs at Fowlmere, Cambs. They supply Fowlmere Fen and its old watercress beds, and are home to a rare fairy shrimp species.
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A marl lake at Houghton Regis, Beds, in a disused Lower Chalk quarry. The site is designated a SSSI for its charophyte flora and rare molluscan fauna. |
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Reed-beds at Fowlmere Fen SSSI, Cambs, a former lake situated at the Melbourn Rock horizon of the Middle Chalk. Reed warblers and water rails breed here. |
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Find out more about the region's chalk springs and wetlands see the
Resources page. |
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| Beech woodlands |
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The Chalk of the northern Chilterns supports many beech woods,
famous for their lofty beauty. Originally a minor component of the woodland, beech became important as demand
for its wood grew for furniture making in the 19th century. As a result old coppiced woodland gave way to stands
of mixed beech forest we see today, especially on the plateaux and valley sides. Rare wildlife includes the dormouse
and violet helleborine orchid.
Beech woods are also found in the open landscape of the East Anglian chalklands,
as hill-top clumps and shelter-belts along roads and other boundaries.
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Beech forest on chalky soil on the Ashridge Estate, near Berkhamsted, Herts.
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A mixed beech plantation on clay-with-flints soil at Nettleden, Herts. Bluebell adds local character in spring. |
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A beech belt planted on chalk downland at Therfield Heath, Herts.
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For more information about the region's beech woods see the
Resources page |
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| Chalk reefs |
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The shores of the East of England region are typically made of sand, silt, gravel or mud.
However the wave-cut platforms on Sheringham and West Runton beaches, Norfolk, are the only well-developed chalk reef found between
North Yorkshire and Kent, and are a unique regional resource for wildlife. |
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A wave-cut platform in Chalk bedrock at Sidestrand beach, Norfolk. |
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For more information about chalk reefs see the
Resources page |
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