Landscape Planning and Heritage

Heathland Biodiversity

Heathlands are landscapes with a wide range of natural components. Each of these components have specialist wildlife associated with them and together form the heathland landscape.  Most heathlands have open, treeless areas, dominated by heather, a scrub or wooded component, areas of bare ground and wet areas where the ground is boggy or there is open water.

A number of factors make heathlands very special places for wildlife:

  • They are areas of open land with few trees. This allows the sun to heat the soil, encouraging wildlife which would not normally be able to survive so far north.

  • Heathlands are found on nutrient-poor, often sandy, acid soils. Many animals rely on these soils to hunt on or burrow into.

  • The unique vegetation structure of low growing shrubs like heather and gorse provide homes to a wide variety of animals.

These factors enable a special range of wildlife to inhabit heathlands.  It is the complex interaction between the plants, animals and the conditions in which they live that make heathlands so special and important.

Some of the plants and animals found on heathlands are listed below.  All of them rely on the important management work that initiatives such as the Hampshire Heathland Project undertake.


       Types of heathland

       Heathers

       Other plants

       Heathland birds

       Invertebrates

       Reptiles and amphibians



Types of heathland

Heathlands can be classified by the amount of water in the soil. Different amounts of water lead to different qualities in the soil which in turn support different plants.

Dry heaths tend to be dominated by ling and bell heather. Nutrients from decomposed leaf litter are quickly washed through the sandy soils making the land inhospitable to many other plants. Dry, sandy areas are home to sand wasps and sand lizards.

Wet heaths have waterlogged soils for much of the year. Dead vegetation is not able to rot because of a lack of oxygen. This leads to a build up of peat and very low available nutrients, especially nitrogen compounds which are very water soluble. Plants such as cross-leaved heath and insectivorous plants are able to cope with these difficult conditions. The bog bush cricket and raft spider live in these wet areas.

Heathers

Three species of heather are found on most of Hampshire’s heathlands. Although widespread, they grow in specific conditions and can be easily differentiated. These plants are able to flourish on the nutrient-poor, acidic heathland soils where grasses are less able to cope. Many invertebrates feed on the heathers and rely on the structure that they provide.

Ling is the commonest of the heathers. It produces a lilac carpet of flowers in late August and September. The leaves are small and scale-like while the tiny flowers have separate petals.

Bell heather, as the name suggests, produces purple, bell shaped flowers in mid summer. This heather is widespread, but is only found on drier areas of the heath. The leaves are dark green and needle shaped.

Crossed-leaved heath is a close relation of bell heather but is only found in the wetter areas of a heath. The light pink, bell shaped flowers are present in early summer. The hairy, needle shaped leaves form a cross shape around the stem.

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Other plants

Heathlands are relatively poor in diversity of plant species, but they do support a number of plants which are not found elsewhere.  Many of these plants rely on the nutrient-poor, acidic soils to reduce competition from other, more common plant species.

Two species of gorse are common on Hampshire’s heaths. Their spiky foliage and yellow, coconut scented flowers make them unmistakable. Dwarf gorse grows amongst the heathers and is of a similar size.  It flowers in mid summer. Common gorse is larger and forms dense bushes which mostly flower in the spring. Both species support large numbers of animals, including many species of spider and nesting Dartford warblers.

Grasses are an important component of heathland vegetation. Most species find it difficult to grow on heathland soils, but those that are able to survive provide food and shelter for a rich variety of insects.

Insectivorous plants are able to gain nutrients from catching and feeding on insects. They grow on waterlogged soils where nitrogen availability from the soil is low. Sundews have sticky secretions on their leaves which trap insects, and slowly curl over before digesting them. Butterwort and bladderwort are other insectivorous plants which live in wet areas of heathland.

A variety of herbaceous plants are found in the wetter areas of a heathland. These are important nectar sources at different times of the year and are often food supplies for specific insects. Common herbaceous plants found on a heath include tormentil, a small yellow four-petalled flower and the tiny milkwort, with two blue petals either side of a white trumpet.

Mosses and lichens are an important component of a heathland. Different species thrive in different conditions. In wet areas ‘bog mosses’ can create a thick mat on which other plants grow, and In drier areas pale green ‘cup lichens’ grow in patches between heather plants.

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Heathland birds

Many birds feed on the large number of insects found on heathlands. Several nest on the ground or in low growing vegetation, and are very susceptible to disturbance from activity on the heath. A number of heathland areas in Hampshire are designated as ‘Special Protection Areas’ under the European ‘Birds Directive’ because of populations of rare birds that breed on them.  The following birds are examples of species which rely on heathlands:

Nightjars produce an eerie ‘churring’ song at dusk. They are nocturnal birds which hunt moths and beetles. During the day they stay on the ground where they are very well camouflaged. Nightjars are summer visitors between May and October.

Woodlarks also nest on the ground and rely on areas free of vegetation to hunt for insects. They have a very melodic song in spring and join other birds in flocks to feed on fields during the winter.

Dartford warblers are small, active birds which nest in dense gorse bushes. They hunt insects on the gorse and heather and can be recognised by their characteristic ‘cocked tail’ pose and scratchy call.

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Invertebrates

The most common animals on a heathland are invertebrates. This group includes insects and spiders. They rely on the structure provided by the soil and vegetation to nest and feed. Many also require the warmth that is made available by sunlight reaching the ground. Invertebrates have very particular requirements and are therefore sensitive to changes in their habitat. A few of the invertebrates found on heathland are described below:

Silver-studded blue butterflies are on the wing in July and August where they flit around heathy rides and other areas of short heather. Their green caterpillars have a very close relationship with certain species of ant which provide protection in exchange for sugary secretions.

The emperor moth is one of the largest moths found in the UK. They, and many other species, feed on heather plants as caterpillars.

Potter wasps build tiny pots from mud and sand on heather stems in which to lay eggs. The wasp collects food from the heath and places it in the pot for the larvae to feed on.

Sand wasps burrow into the hard sand at the edge of paths. They are solitary wasps, so they do not create hives and nests

Many spiders rely on plants like gorse and heather to build their webs. Their webs are best seen in the morning when covered in dew. The raft spider is the UK’s largest spider and hunts prey in bogs by resting its front legs on the water and feeling for the presence of underwater insects and even small fish.

Bog bush crickets are grasshopper-like insects which eat purple moor grass in wet areas of heath. They are recognised by their long antennae and U-shaped light mark at the side of their head.

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Reptiles and amphibians

Heathlands are the most important areas in the UK for reptiles. The heaths provide warm, open areas for basking and egg laying and are a great source of invertebrate food. Amphibians make their home in damper areas and need open water to lay their eggs in. Woolmer Forest, a heathland in east Hampshire, is home to native populations of all twelve species of reptile and amphibian – the only site in the country. A number of these species found at Woolmer and elsewhere are listed here:

Smooth snakes kill their prey of lizards or small mammals by constricting them in coils of its body. They live among mature heather plants and bask in the sun entwined in the stems. Smooth snakes are the UK’s rarest reptile and are mainly found on heathlands in Hampshire and Dorset.

Natterjack toads are smaller than common toads with shorter legs, and have a distinctive yellow stripe along their back.  They require warm, shallow pools in which to lay their strings of eggs and sandy banks in which to burrow over winter.  They hunt prey on short turf or bare ground.

Sand lizards are so-called because they rely upon the sandy conditions found on heathlands or sand dunes. They lay their eggs in patches of bare sand where they are able to develop in the warmth. During the breeding season, April and May, the males have bright green flanks to attract a mate.



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