Jurassic Coast

  • Written by  Marc Grainger
  • Published in AONB
Durdle Door on the Jurassic Coast of Dorset Durdle Door on the Jurassic Coast of Dorset Shutterstock
Marc Grainger visits Dorset, where the wildlife-rich lowland heath is just a stone’s throw away from one of the world’s most geologically important coastlines

'That sounded like gunfire.’ I’m standing on the tranquil South Dorset Ridgeway looking south across the 29-kilometre-long gravel bank of Chesil Beach – part of the Jurassic Coast World Heritage area – and the English Channel on a sunny autumn day, chatting with two members of the Dorset Area of Outstanding Natural Beauty (AONB) team. We’ve just been rudely interrupted by the distant boom of artillery on an unseen naval vessel practicing out at sea.

There has long been a military presence in this part of the world. At Lulworth, there’s a Ministry of Defence base and firing range. Chesil Beach was used as practice for the Normandy landings during the Second World War. And just outside the AONB, the Isle of Portland was, until recently, the site of a Royal Navy base. Unsurprisingly, then, it isn’t the only time I hear shots during my visit.

Viewed on a map, Dorset AONB looks rather like a crocodile’s head: beginning at Lyme Regis in the west, the lower ‘jaw’ extends east along the coast to Poole Harbour, while the upper ‘jaw’ penetrates inland, stopping just short of Blandford Forum. It’s the UK’s fifth-largest AONB, covering 1,129 square kilometres (42 per cent of the county), with a population of about 70,000 in and around historical towns such as Bridport and Swanage, and many more on its outskirts in Dorchester, Weymouth and Poole. And unlike in some smaller AONBs, whose designation is based on a single distinctive feature, it’s difficult to pin down a defining characteristic of Dorset – the sheer variety of its landscape makes it special.

‘The larger area is chalk, which is characterised by high, round-topped hills with a steep escarpment side that is often high-quality chalk grassland habitat,’ says Tom Munro, the AONB manager. ‘The second-largest is heath, which has enormous biodiversity importance. Clay vales, river valleys and limestone areas make up the rest of it.’

 shutterstock 37387897 optA sika doe grooms her fawn in the RSPB reserve at Arne

Healthy heaths

The Isle of Purbeck – not actually an island but a peninsula in the east of the AONB – has extensive areas of lowland heath. Here, this internationally rare habitat – the UK has about a fifth of the world’s total – is home to rare birds such as the Dartford warbler and nightjar, as well as all six species of British reptile.

The climate here in the far south of Britain is a key factor in this diversity. ‘[The heaths] are mild and can get quite hot, and they’re wetter than the Thames Valley heaths, which is the other big area of lowland heath,’ says Munro. ‘This wetness is why you
get Dorset heath, which is a specific type of heather. Their expanse and intactness is why you get such a good variety of specialist butterflies and reptiles in the area.’

One such area is the 500-hectare Arne Royal Society for the Protection of Birds (RSPB) reserve, a small peninsula jutting out into Poole Harbour. As we walk through the reserve’s heathland, visitor manager Mark Singleton explains some of the unusual steps that conservationists are taking to encourage osprey to breed here. Not only have artificial nests been installed in the solitary trees that grow among the heather, but one nest has been populated with a pair of fake ospreys in order to give real ones the impression that others are already breeding there.

The RSPB hopes to have breeding ospreys here ‘within the next ten years; five if we’re really optimistic’, says Singleton. ‘If we can get one or two breeding pairs in the areas where we’ve put nests, then hopefully their range will expand out of that.’

Another patch of lowland heath is the Studland and Godlingston Heaths National Nature Reserve, near the sandy beach and dunes of Studland Bay. From a hide in the reserve, I can see across Poole Harbour towards Bournemouth and the moneyed suburbs of Sandbanks, as well as Brownsea Island, the birthplace of the Scouting movement and home to one of southern England’s few red squirrel colonies. In the foreground, little egrets frolic in the freshwater lagoon of Little Sea. The combination of wetland and heath provides a home for wading birds such as the avocet, godwit and spoonbill, as well as the rare Purbeck mason wasp and ladybird spider.

‘You can see the diversity: you have the wet woodland, the heath grading into the dunes, and then the wetland, so it’s a really nice mosaic of habitats,’ says Alison Turnock, the AONB’s biodiversity officer. ‘It’s one of the reasons this area is so important – it grades very quickly from one to another.’

 Burton Bradstock Cliff optThe sandstone cliffs at Burton Bradstock are prone to landslips, making them a rich source of ammonite fossils

Coast with the most

Dorset’s undeveloped coastline forms the bulk of the Jurassic Coast. Heading westwards from the hard limestone cliffs of Purbeck, the rock gets progressively softer – the sandstone, shale and mud coast between Bridport and Lyme Regis suffers frequent landslips that have yielded famous fossil discoveries, lending the coast its Jurassic moniker.

Chesil Beach is a significant part of this region. Stretching from Portland to West Bay near Bridport, it was formed at the end of the last ice age when rising sea levels dumped ashore gravel deposits that had originated in Devon and accumulated offshore over millions of years. Between it and the mainland is the Fleet – at 13 kilometres long, the largest tidal lagoon in Britain and home to the only managed colony of mute swans in the world.

‘That gravel source is used up; that process of sediment moving has stopped – so we’re in an enclosed system here,’ says Ian Rees, countryside officer at the AONB. ‘So what gravel we’ve got is what we’ve got, and if it’s taken away or eroded, it’s gone.’ The varying size of the stones is helpful if you want to gauge how far along the coast you are, he says: ‘They’re potato-sized up there [to the east] and pea-sized down there [to the west]. Smugglers used to come ashore and just [feel the shingle] – “Aha, I’m in Abbotsbury”.’

To the east of Portland, the processes of coastal erosion have created two of the AONB’s most photogenic and geologically significant locations: Lulworth Cove – a perfect horseshoe-shaped example of such a landform – and Durdle Door, an impressive natural arch. Groups of geography students mill around both locales, taking notes; at Durdle Door, newlyweds have their photographs taken on the beach with the arch as a backdrop.

 shutterstock 56997169 optThe 11th-century ruins of Corfe Castle in the Purbeck Hills. During the Civil War, it was besieged by the Roundheads several times and finally destroyed in 1646

Prehistoric path

A walk along the South Dorset Ridgeway, part of the South West Coast Path, reveals the AONB’s long human history. Successive prehistoric peoples have left their mark on the inland chalk hills with Neolithic long barrows, Bronze Age round barrows and stone circles, and Iron Age hillforts such as Maiden Castle, the largest in Britain. With at least 500 scheduled monuments within its 36 square kilometres, the Ridgeway rivals Stonehenge and Avebury in archaeological importance.

‘They were built to be visible,’ says Munro. ‘They’re on the hilltops where the villagers can see them. There’s good archaeological evidence to show that they had been weeded or re-covered with chalk to keep them gleaming white.’

Elsewhere in the AONB, historical farming practices are also apparent. Strip lynchets, step-like soil formations that date back to Saxon times, adorn the sides of hills, much like the rice terraces of Asia.

The coast path cuts though the military range at Lulworth, which means that it’s closed to the public during firing – a situation that has certain benefits. ‘There’s a long history of military practice between there [Lulworth] and Bovington Heath,’ says Munro. ‘It does put pressure on tourism, because people can’t use that bit of coast – but then again, it keeps people out, and the biodiversity of the area is fantastic and very well managed.’

Durdle Door by Tony Gi optThe natural arch of Durdle Door was formed when the sea eroded and breached weaker rock behind the more resistant oolitic limestone



Snorkel beneath Scratchy Bottom
‘On a summer’s day, the downland of Scratchy Bottom leading to the beach west of Durdle Door is alive with grasshoppers and butterflies. The beach is always inviting; the sea’s often crystal clear and it’s a favourite snorkelling spot, with mullet, bass and spider crabs loitering around the rocks.’
Tom Munro, AONB manager

Hillfort views

‘Cycle up Spyway Hill and you’ll be rewarded with stunning views from the Iron Age hillfort of Eggardon over the Marshwood Vale. Pilsdon Pen and Lewesden Hill mark the horizon and the network of ancient fields spread out below you to the sea. It’s well worth the slog.’

Ian Rees, AONB countryside officer

Riding on the moor

‘I often cycle on Hartland Moor – the ride over the River Frome and then around the heath looks different throughout the year, but is always stunning. It’s a place for an abundance of wildlife – on late evenings in the summer, it’s particularly evocative for the eerie churr of the visiting nightjar.’

Alison Turnock, AONB biodiversity officer

South Dorset sensations
‘Walking the South Dorset Ridgeway excites all of the senses. It’s a visual feast, with 360° views over Lyme and Weymouth bays, Chesil Beach, Purbeck cliffs, chalk downland and hillforts. There’s the sound of buzzards and sheep, the taste of the sea, and the sweet smell of gorse on the wind.’

Sue Mitchell, AONB transport, access and recreation officer

Marc Grainger stayed at Highway Farm, Bridport (www.highwayfarm.co.uk). For more information about Dorset AONB, visit www.dorsetaonb.org.uk

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