The Heathland Experience - Wet & Dry Heathland

Lowland Heathland for Wildlife - Description

England's most extensive lowland heathlands below 300m in height, are concentrated mainly in the counties of Surrey, Sussex, Berkshire, Hampshire, Dorset, Norfolk, Suffolk and Devon. This website is mainly concerned with the first five counties. Other lowland heathland's on higher ground occur in Yorkshire, Lincolnshire, Nottinghamshire, Somerset and Cornwall. These latter sites are often colder, have a higher rainfall or are based on soils formed from rock strata, e.g. granite as in Cornwall and often have a smaller native fauna.

The dwarf shrub habitat on the central southern heathlands, consists of Ling (Calluna vulgaris) and Bell Heather (Erica cinerea) mainly in the drier parts, with Cross-leaved Heath (Erica tetralix) occurring more frequently in the wetter areas. Other important flowering plants that often occur at the heathland edge are; Buttercup species (Ranunculus), Tormentil (Potentilla erecta), Blackberry species (Rubus), Bilberry (Vaccinium myrtillus), Wood Sage (Teucrium scorodonia), yellow composites (Taraxacum, Hypochoeris, Leontodon, Crepis, Hieracium, Pilosella and Sonchus), Common Ragwort (Senecio jacobaea), Thistles (Cirsium). These are particularly valuable for invertebrates, including some fly species, butterflies and moths and the solitary bees and wasps, for the nectar and pollen food supplies that they provide.

A number of specialist heathland species are dependent on aspects of its' structure, microclimate and dwarf shrub vegetation or combinations of these. These are particularly small numbers of birds, extensive species of insects, invertebrates and flowering and non-flowering plants.

Bird species also compose an important component of the heathland fauna ranging from the Hobby (Falco subbuteo), Woodcock (Scolopax rusticola), Nightjar (Caprimulgus europaeus), Green Woodpecker (Picus viridis), Turtle Dove (Streptopelia turtur), Yellowhammer (Emberiza citrinella), Woodlark (Lululla arborea) and the real specialist, the Dartford Warbler (Sylvia undata) to name but a few. Some of these birds have been important in gaining some protection for our heaths because of the presence of some of these species on them following the issue of Annex 1 of the European Bird's Directive.

Dry Heathland

ABOVE: A dry heathland gully illustrating the mosaic of different micro-habitats that suit a variety of insect species both for nesting in the bare ground and for collecting nectar and pollen from the flowers. © Copyright SMiles.

The dry, open heathland habitat on sandy soils holds a rich invertebrate fauna and the herpetological fauna is also significant. The structure of the southern heathland's which have many old sandy paths and tracks going across them or other areas of bare ground intermixed with disturbed ground are most important. Such disturbance is often the result of military training which has been a popular use of many of our major heathland's since the 19th century. Many of the paths and tracks composed of the bare, natural soil have been used for hundreds of years in this condition, until recently. Other crucial features for biodiversity are banks and ditches, sand-pits, areas exhibiting erosion and ruderal areas at the edge of heathland. Solitary bees and wasps and their parasites plus some beetles such as some tiger beetles exploit this habitat as it is easily excavated. They use both the flat surfaces of sandy footpaths, tracks and bridleways as well as the vertical sand cliffs and banks. These areas heat up quickly and also the cliffs and banks often stay relatively dry even when it is raining and wet, both important features for insects.

Wet Heathland

Wet heathland containing mires, seepages and small streams, ditches, ponds, lakes, seasonal ponds and also permanent waters with floating vegetation are equally important in contributing to the total species' richness of lowland heathland and associated habitats. The ponds that are particularly important for amphibians like frogs and toads are the ones like Forey's Pond, in Hogmoor Inclosure in Bordon, pictured below, that contain no predators, such as birds or fish, which would take their tadpoles for food and which are generally difficult for the public to access with their destructive loose dogs. The absence of predators is because this seasonal pond is very shallow and thus it dries out readily in drought years.

ABOVE: Forey's Pond, Hogmoor Inclosure, Bordon in early spring 2014 after a wet winter. © Copyright SMiles.

Other wet spots such as the valley mires as in this location (below) in Bordon, Hampshire, are the home of many specialist invertebrate species such as the large raft or swamp spider, Dolomedes fimbriatus, which habitually sits on the water surface waiting for the vibrations caused by distressed insects about to drown through the water's surface film. Another species that occurs here is Roesel's Bush Cricket, (Metrioptera roeselii), others are the hoverflies, Sericomyia borealis and S. lappona which are large species with separated yellow or cream stripes respectively on their abdomens. Plants such as the familiar dwarf shrub, Cross-leaved Heath, (Erica tetralix) occur in the wetter areas of heathland as well as many scarce plants such as Cranberry (Vaccinium oxycoccus) and Bog Asphodel (Narthecium ossifragum), a member of the lily family and a whole variety of specialist sedges, sphagnum mosses, rushes and cotton-grasses. It is significant that Gilbert White recorded the first instance of Cranberry in North Hampshire since Selborne is only three miles away from Woolmer Forest, which as a district covered a much larger area than it does today.

The underlying geology and soils also influence what plants grow, for instance Bordon and Woolmer Forest and the Wealden heathlands at Frensham, Thursley and those near Midhurst and Petersfield are on the Greensands and related deposits of the Folkestone Beds. Bog Myrtle, the small shrub is not at all found on these Wealden sites but can be readily found on the Tertiary sands related to the Bagshot Beds in Dorset, the New Forest, north Hampshire around Aldershot and Surrey, north of the Hog's Back continuous hill feature situated between Farnham and Guildford.

ABOVE: A heathland mire near Bordon, Hampshire. © Copyright SMiles.

ABOVE: The photograph shows Oblong-leaved Sundew growing on a bare patch of damp soil adjacent to a heathland mire in Bordon, Hampshire in 2012. © Copyright SMiles.

Heathland Edge

Shrubs of the heathland edge are also very important for insects and other invertebrates, ranging from Alder Buckthorn (Frangula alnus) and Purging Buckthorn (Rhamnus catharticus) as foodplants for the Brimstone butterfly caterpillar to the weevil larvae that need the seed pods of Broom (Sarothamnus scoparius) and Gorse (Ulex) for their larval development. Many shrubs and small trees growing on heathland and at the heathland edge such as Cherry (Prunus sp.), Willows (Salix sp.) particularly Sallow (Salix caprea), Broom (Sarothamnus scoparius) and Gorse (Ulex) species are also important to many insects for the nectar and pollen sources they supply early in the year. These food sources are used by both the adults and their progeny.

Many of these trees and shrubs, as well as the heathers and many grass species' provide food for the caterpillars of the large numbers of butterfly and moth species, such as the Grayling butterfly and the Fox moth that occur on lowland heathland.

Where mature trees occur as most frequently at the heathland edge, these often add additional habitat opportunities for invertebrates in terms of their use of the wood and fungal elements as food sources as well as the use of these tree and leaf structures for oviposition and nesting sites.

Those plants that grow on the heathland edge having stems that are hollow e.g. Elder, (Sambucus nigra) or, those that can have the pith hollowed out from their stems such as Blackberry, (Rubus sp.) are important for the the cavity dwelling insects such as nesting solitary bees and wasps.

Thus lowland heathland and its' heathland edge is a rich but sensitive habitat, too many people roaming over it or cycling over the bare ground of its' footpaths and tracks will both destroy and disturb its' wildlife, as is currently occurring in southern England and probably the rest of the country too. New housing, roads and drainage also needs to be kept away from such heathland sites or we will lose their biodiversity.

Further reading and references, some of which are referred to in the text above.

1 - DIRECTIVE 2009/147/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL; of 30 November 2009; On the Conservation of Wild Birds

2 - Heathlands - A Natural History of Britain's Lowland Heaths by N Webb, The New Naturalist series published by William Collins Sons and Co. Ltd in 1986

3 - Natural History and Antiquities of Selborne by G White, Macmillan and Company Edition published in 1891

4 - The Flora of Hampshire by A Brewis et al, published by Harley Books in 1996

Heathland Management For Insects →