A
heath or
heathland is a
dwarf-shrub habitat found on mainly infertile
acidic soils, characterised by open, low growing woody
vegetation, often
dominated by plants of the
Ericaceae. There is no clear difference between
heath and
moorland but
moorland is generally related to high-ground heaths with — especially in Great Britain — a cooler and damper climate.
Heaths are widespread worldwide. They form extensive and highly diverse communities across
Australia in humid and sub-humid areas. Fire regimes with recurring burning are required for the maintenance of the heathlands. Even more diverse though less widespread heath communities occur in Southern Africa. Extensive heath communities can also be found in
California,
New Caledonia, central
Chile and along the shores of the
Mediterranean Sea. In addition to these extensive heath areas, the vegetation type is also found in scattered locations across all continents, except Antarctica.
Characteristics
Heathland is favoured where climatic conditions are typically warm and dry, particularly in summer, and soils acidic, of low fertility, and often
sandy and very free-draining;
bogs do occur where drainage is poor, but are usually only small in extent. Heaths are dominated by low
shrubs, 0.2–2 m tall.
Heath vegetation is extremely plant-species rich, and heathlands of Australia are home to some 3,700 endemic or typical species in addition to numerous less restricted species. The
fynbos heathlands of South Africa are second only to tropical rainforests in plant biodiversity with over 7,000 species. In marked contrast the tiny pockets of heathland in Europe are extremely depauperate with a flora comprised primarily of
heather (
Calluna vulgaris),
heath (
Erica species) and
gorse (
Ulex species).
The bird
fauna of heathlands are usually cosmopolitan species of the region. In the depauperate heathlands of Europe bird species tend to be more characteristic of the community and include
Montagu's Harrier, and the
Tree Pipit. In Australia the heathland avian fauna is dominated by nectar feeding birds such as
Honey-eaters and
lorikeets although numerous other birds from
emus to
eagles are also common Australian heathlands. Australian heathlands are also home to the world's only nectar feeding terrestrial mammal: the
Honey Possum. The bird fauna of the South African fynbos includes
sunbirds warblers and siskins. Heathlands are also an excellent habitat for insects including
ants, moths, butterflies and wasps with many species being restricted entirely to it.
Anthropogenic heaths
Anthropogenic heaths habitats are a
cultural landscape that can be found worldwide in locations as diverse as northern and western Europe, the
Americas, Australia,
New Zealand,
Madagascar and
New Guinea.
These heaths were originally created or expanded by centuries of human clearance of the natural
forest and
woodland vegetation, by grazing and
burning. In some cases this clearance went so far that parts of the heathland have given way to open spots of pure sand and
sand dunes, with a very local desert climate that, even in Europe can create local temperatures of 50 degrees Celsius in summer, drying the sand spot bordering the heathland and further raising its vulnerability for wildfires.
In recent years the conservation value of even these man-made heaths has become much more appreciated, and consequently most heathlands are protected. However they are also threatened by tree incursion because of the discontinuation of traditional management techniques such as grazing and burning that mediated the landscapes. Some are also threatened by
urban sprawl. Anthropogenic heathlands are maintained artificially by a combination of grazing and periodic burning (known as Swailing), or (rarely) mowing; if not so maintained, they are rapidly re-colonised by forest or woodland. The re-colonising tree species will depend on what is available as the local seed source, and thus it may not reflect the natural vegetation before the heathland became established.
See also
Specific references
