COAST - PURBECK: STUDLAND HEATH

The dune system at Studland is one of the most extensive in lowland England, and while the first ridge contains all the pioneer plants that help bind the habitat together and allow its development, notably Marram Grass (Ammophila arenaria) and Sea Bindweed (Calystegia soldanella), the second is full of true heathland species led by heather.

Sea Bindweed is from the same family as the often-unpopular takeover merchant Field Bindweed (Convolvulus arvensis), and combined with grasses can cover fair-sized chunks of a dune system. Common Centaury (Centaurium erythraea) is not a pioneer but is often found in bare patches of sand, flowering from June to October.

Fire has always been a valuable management tool for heathland but nowadays carelessness or vandalism, plus a decline in rainfall and the difficulties the habitat presents to fire fighters, make it less controllable. This means it is much more dangerous to an environment that is a fraction of the size it was in the days when Thomas Hardy was writing so feelingly about Egdon Heath.

To give a few sad examples, Canford Heath near Poole was seriously affected by an act of arson in the first part of 2006, and heather-based areas of Studland suffered this way in the mid-'90s and in May 2008, when 2.6 hectares (6 acres) were destroyed. The latter was assumed to have been caused by a stupidly discarded cigarette.

Some distance away, Thursley National Nature Reserve in Surrey suffered a massive burn, believed to have been started deliberately, in July 2006. However, good came out of bad there owing to a couple of pretty wet summers, since the Heather regenerated faster than anticipated and flowers, principally Ragwort and Creeping Thistle, grew in abundance. This opening up of the habitat allowed rapid recolonisation and even new colonists by the end of 2008 including nine species of bee and wasp not seen at Thursley before.

In normal climatic conditions, though, regrowth is indeed pretty slow, indicating the impoverished nature of the habitat in terms of nutrients. Despite this, or in some instances because of this, gorse and heather provide a home for a large array of invertebrates, and hence for various bird species.

Dartford Warblers, which are covered in depth in the Heathland pages here, are among the main beneficiaries together with Stonechats (Saxicola torquata, wingspan 12cm). The latter, which are at Studland year-round, can have two or three broods each season but the species has declined over the last 30 years. This is almost certainly a result of human impact rather than hard winters, which can affect the Stonechat as well as the Dartford Warbler quite badly.

Stonechats nest on or close to the ground and are great perchers for the purpose of singing or looking out, using posts, gorse bushes or anything else convenient.

Invertebrates found almost exclusively on the coast include the so-called Silvery Leaf-cutter Bee (Megachile leachella, 12mm), which builds cells within the nest from plant matter and can form large colonies in stable sand.

One of the most striking groups of bees are the six from the Colletes genus, who have short tongues, carry a lot of hair and mostly nest in sandy locations, with dunes one of the preferred habitats. They can be quite gregarious. Each female burrows up to 25cm to make her nest, which contains a number of cells each of which holds an egg and a mixture of honey and pollen. Colletes fodiens (11mm) is found inland but is most numerous along the south coast.

If there are hard-working bees collecting pollen for their progeny to feed on, there are always cuckoo bees to take advantage. The striking Epeolus variegatus (7mm), with brown eyes, is one of them, cleptoparasitising bees from the Colletes group including Colletes fodiens.

Various solitary wasps are very much at home on coastal dunes. One Purbeck speciality is the sizeable Podalonia hirsuta (15mm), which resembles the Ammophila species shown in the Heathland pages on this website until one gets close and sees the masses of fairly long dark hairs on the head and thorax.

They are also found in Norfolk, Cornwall and the Welsh coast but nowhere inland for many years. Females, which overwinter, are in flight from March to September and prey consists mostly of the caterpillars of 'cutworm' Noctuid moths which have to be dug out of the ground before being reinterred.

The male of the Coastal Silver-stiletto Fly (Acrosathe annulata, 10mm) could not be mistaken for any other species with his wraith-like covering of white hairs. The female, requiring better camouflage for breeding - the larvae live in the sand and can be fierce predators - is altogether duller. This is one of the favourite prey species of the common digger wasp Crabro peltarius.

With the substantial freshwater Little Sea nearby, and wet areas within parts of the dunes, amphibians do well at Studland. One of these is the Palmate Newt (Triturus helveticus, 6cm), which is the smallest of our native newts and commoner in Dorset than many areas because it is suited by acidic water. Their diet includes invertebrates and frog tadpoles.

In such a hostile environment the chances of a newt or any other amphibian living a long time are slim, but nothing goes to waste.

While some books describe Woodlice as eating solely decaying vegetation and algae, these scavenging crustaceans, which cope pretty well with heathland because the ground beneath heather is relatively cool, can and do take advantage of carcasses. The accompanying picture of them feeding en masse on a dead Common Toad (Bufo bufo) confirms as much.

This may not look pretty, but in nature prettiness, where it occurs, tends to be an index of efficiency in propagation. What we take to be ugliness is often also an index of efficiency, in recycling waste among other things.

Images © Jeremy Early. All rights reserved.

In 2013 I published My Side of the Fence - the Natural History of a Surrey Garden. Details may be found, and orders placed, via this hyperlink My Side of the Fence. In November 2015 Surrey Wildlife Trust published the atlas Soldierflies, their allies and Conopidae of Surrey, jointly written by David Baldock and me. Details are on this web page: Atlas.