Environment Report for the Wild Purbeck Nature Improvement Area

Prepared for Wildlife Trust & Dorset AONB By Dorset Environmental Records Centre

March 2013

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Cover photograph © Bryan Edwards

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This report is a collation of biological information about the Wild Purbeck area. The majority of the information has come from reports, species and habitat records held at Dorset Environmental Records Centre. DERC has been established for over 30 years and during this time data has been collected and collated from a huge number of organisations and individuals. Species data, in particular, has come from many enthusiastic local naturalists. The majority of the habitat data has come from surveys for landowners (eg at ) and surveys of local sites (notably through the SNCI Project).

Site boundaries for local sites are maintained by DERC. These are complimented by boundaries for national and international sites downloaded from the appropriate websites.

This report is divided into sections as follows:

Sites and designations looks at the areas currently recognised for their conservation value. The Wild Purbeck area has a huge number of designations and the text gives an overview of these.

Habitat maps show the current resource within the Wild Purbeck area. This is followed by two maps; one showing sites recorded during the 1930s (the Good Archive) and the other a follow-on survey which looked at changes in habitat. A list of micro-habitats focuses on some habitats in more detail and highlights possible areas for future work.

Species data currently concentrates on threatened plants and reviews changes and losses within the main habitats.

This is an initial report based on data available at the start of the NIA process. The final report will include updates to the information and case studies based on work completed within the Wild Purbeck area.

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Page Sites and designations Site designations 5 Special Areas of Conservation 6 Special Protection Areas 7 Ramsar Sites 8 AONB, NNR and World Heritage Site 9 Sites of Special Scientific Interest 10 Sites of Nature Conservation Interest 11 Local sites 12 Ancient Woodland and Veteran Trees 13 Regionally Important Geological Sites 14

Habitats Lowland heathland, Mire, Fen and Acid grassland 16 Lowland calcareous grassland, Lowland meadows and 17 Purple moor-grass and rush pasture Coastal habitats and Floodplain grazing marsh 18 Lowland mixed deciduous woodland, Wet woodland and 19 Wood pasture & parkland Professor Good Archive 20 Professor Good stands re-visited by Anne Horsfall 21

Species data Changes in declining and threatened plants 22

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Wild Purbeck SITE DESIGNATIONS

Wild Purbeck is a fantastic area for wildlife. It covers a huge array of habitats through rocky shores, limestone grassland, heathland and a natural harbour. This wonderful diversity is reflected in the number of sites and designations crammed into an area which covers only 17% of Dorset.

A popular tourist destination and sitting adjacent to the conurbation, there are many pressures on this small area. The protection given through European designations and statutory sites is vital. Local sites show that even outside these “top” areas there are still many places which should be valued and conserved.

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Wild Purbeck Special Areas of Conservation

There are four SACs within the Wild Purbeck area. These Special Areas of Conservation have been designated as some of the most important sites for wildlife in Europe. They form part of a network of protected wildlife areas that includes SACs and SPAs.

Two of the SACs, SAC and Dorset Heaths (Purbeck & Wareham) & Studland SAC are designated for habitat and species interests. This includes wet and dry heath, peat vegetation, dunes and other associated habitats. Southern Damselfly (Coenagrion mercuriale) and Great Crested Newt (Triturus cristatus) are also included.

The to Studland Cliffs SAC is important for Early Gentian (Gentianella anglica) and several important habitats including drift line vegetation and vegetated sea cliffs.

St Albans Head to Durlston Head SAC is the smallest SAC within the Wild Purbeck boundary. It has been designated for Greater Horseshoe Bat (Rhinolophus ferrumequinum), Early Gentian, vegetated sea cliffs and calcareous grassland with important orchid populations, especially Early Spider Orchid.

Together the four SACs cover 6,790 ha, nearly 15% of the Wild Purbeck area.

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Wild Purbeck Special Protection Areas

Dorset has three SPAs, Special Protection Areas, and two of these are within the Wild Purbeck area. They have been designated under the European Birds Directive.

Dorset Heathlands SPA supports nationally important breeding populations for Nightjar (Caprimulgus European), Woodlark (Lulla arborea) and Dartford Warbler (Sylvia undata) and wintering populations of Hen Harrier (Circus cyaneus) and Merlin (Falco columbaris).

Poole Harbour SPA supports nationally important populations of Avocet (Recurvirostra avosetta), Mediterranean Gull (Larus melanocephalus) and Common Tern (Sterna hirunda). It is also an important migratory site for Black-tailed Godwit (Limosa limosa) and Shelduck (Tadorna tadorna) and is regularly used by over 20,000 waterfowl and seabirds throughout the year.

These two SPAs cover 7,915 ha within Purbeck, nearly 17% of the Wild Purbeck area.

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Wild Purbeck Ramsar Sites

The Ramsar designation relates to wetlands of international importance and was adopted in recognition of the progressive encroachment on, and loss of, wetlands.

Poole Harbour Ramsar, in addition to the birds already mentioned under the SPA, supports the only known British population of Vipers Grass (Scozonera humilis) plus several other British Red Data Book species. Poole Harbour Ramsar is also one of the best and largest examples of a “natural harbour” type estuary in Great Britain and it has special value for its ecological diversity.

Dorset Heathlands Ramsar supports particularly good examples of wet heath and many of its sub-communities and associated species such as White Beak-sedge (Rhynchospora alba). The Ramsar includes some of the transition to grazed grassland on the floodplain of the River Frome. There are important assemblages of rare, vulnerable and endangered species including Dorset Heath (Erica ciliaris), Marsh Gentian (Gentiana pneumonanthe) Bog Orchid (Hammarbya paludosa), Brown Beak-sedge (Rhynchospora fusca), Pillwort (Pilularia golobulifera), Marsh clubmoss (Lycopdodiella inundata) and the moss Spagnum pulchrum. The valley mires and wetland areas are particularly rich for their invertebrate fauna including Large Marsh Grasshopper (Stethophyma grossum), Scarce Chaser Damselfly (Libellula fulva) and Southern Damselfly (Coenagrion mercuriale).

These two Ramsars cover much of the same land as the SPAs, 7,605 ha within Purbeck, 16% of the Wild Purbeck area.

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Wild Purbeck AONB, NNR and World Heritage Site

Over half the Wild Purbeck area falls within the Dorset Area of Outstanding Natural Beauty. This is a landscape scale designation and the AONB partnership is focussed on conserving and enhancing the natural beauty of the Dorset countryside. This includes landform, geology and landscape features as well as wildlife, our built heritage and the historical record of human civilisation.

Wild Purbeck includes six National Nature Reserves. These are: Arne Reedbeds, , Heath, Holton Heath, Morden Bog, Durlston and Studland & Godlingston Heath. They cover 1,474 ha or 3% of the Wild Purbeck area. NNRs are declared by Natural and there are currently 224 in England with c. 0.6% land cover.

The Dorset and East Coast World Heritage Site – is the first natural WHS in England. It covers 95 miles of coastline from in Devon to in Dorset. Throughout its range 185 million years of the Earth’s history can be seen in the exposed rocks through the Triassic, Jurassic and Cretaceous periods. It is a place of ‘outstanding universal value’ selected by United Nations Educational, Scientific and Cultural Organization (UNESCO).

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Wild Purbeck Sites of Special Scientific Interest

A Site of Special Scientific Interest is the land notified as an SSSI under the Wildlife and

Countryside Act (1981), as amended. There are 42 SSSIs within the Wild Purbeck area encompassing the majority of the heathland resource, part of the Purbeck Ridge and almost the entire length of coast including the cliffs and the coastal habitats around Poole Harbour. They cover 10,585 ha, nearly 23% of the the Wild Purbeck area. For the whole of Dorset, only 7.5% is covered by SSSI, illustrating again the recognised importance of Purbeck for its outstanding wildlife and geology.

Information on the condition of the SSSIs is available. Each Site Management Unit (SMU) is judged against strict critera to ascertain if it is in favourable condition. The results for SSSI in Purbeck (January 2012) are as follows:

Compartment condition No. SMU % SMU Favourable 212 33 Unfavourable recovering 294 45 Unfavourable no change 97 15 Unfavourable declining 46 7 Part destroyed 2 0 Destroyed 0 0 Total number SMU in Wild Purbeck area 651

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Wild Purbeck Site of Nature Conservation Interest

Sites of Nature Conservation Interest are selected for their habitat or species interest by a panel including representatives of Dorset Wildlife Trust, Dorset Environmental Records Centre, Natural England, Dorset County Council and Dorset AONB. The project has been running since 1989 and has generated a huge amount of useful and interesting data. More recently sites have been assessed so that their ongoing condition can be monitored. The results for January 2012 are as follows:

Condition No. % sites Maintained Improving Declining sites Good 89 39 80 0 9 Fair 33 14 17 4 12 Poor 2 1 2 0 0 Not assessed 104 46

There are 228 SNCIs that fall all or partly within the Wild Purbeck area, covering 2,290 ha or 5% of the NIA. Most are small but they include remnants of heathland outside the SSSI, woodlands, calcareous grassland along the Ridge, reedbeds, road verges and many other habitats.

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Wild Purbeck Local sites

In addition to SNCIs there are numerous other sites that are important to different interest groups.

There are six Local Nature Reserves in the Wild Purbeck area: Thorncombe Wood in the far west; Eight Acre Wood at Wool; plus four around the Poole conurbation (Ham Common, Turlin Moor, Pinesprings, Luscombe Valley).

Dorset Wildlife Trust has eleven DWT reserves plus the Purbeck Wildlife Marine Reserve. The largest sites are on the edge of Poole, and Winfrith Heath. There are several other reserves: heathland sites at Coombe Heath, Higher Hyde Heath and Tadnoll; Meadow, renowned for its Green-winged Orchids; Townsend, grassland on an old limestone quarry; East Stoke Fen, with reedbed and wet woodland; and Kilwood Coppice & Meadow and Stonehill Down on the Purbeck Ridge.

Conservation verges are usually selected for their varied botanical interest. They may have specified management to enhance their interest, for example later cutting times to allow flowers to seed. The project is managed by the Dorset Wildlife Trust and there are 34 conservation verges within the Wild Purbeck area.

The Royal Society for the Protection of Birds has four RSPB reserves covering over 1000 ha. The largest are at Arne and Wareham Meadows with Grange Heath and Stoborough Heath completing the set.

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Wild Purbeck Ancient Woodland and Veteran Trees

Ancient woodlands are those which have had continuous woodland cover since at least 1600 AD. Some sites have been managed with the understorey, often coppiced hazel, being cut on rotation and the standards cut for timber when mature. This continuity of woodland cover has allowed a greater diversity of species and the sites have provided a refuge for species that cannot tolerate disturbance. Data on Ancient Woodland has come from an update to the provisional Dorset Atlas (NCC 1988). The mapping distinguishes between Ancient semi-natural woodlands (ASNW) and plantations on ancient woodland sites (PAWS). There are 119 sites in the Wild Purbeck area covering 1,387 ha with a relatively even split between ASNW (710 ha) and PAWS (676 ha). Sites smaller than 2 ha have not been mapped.

In 2005 DERC mapped 40 key Veteran Tree Sites in the county, 17 of these are within the Wild Purbeck area. They include some ancient woodland sites but also deer parks, pasture woodlands, wooded commons and hedgerow trees. Park is one of the few remaining examples of an ancient deer-park. The trees have been pollarded encouraging longevity of individual trees, which has allowed a very rich epiphytic fauna to develop.

The Greenwood Tree Project is a county-wide survey run by Dorset Wildlife Trust. Members of the public have been encouraged to report ancient and veteran trees. The results include many trees outside of the ancient woodlands and veteran sites mentioned above.

Despite their importance, none of these sites or trees have automatic protection under planning law.

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Wild Purbeck Regionally Important Geological Sites

Regionally Important Geological Sites are selected by the RIGS group primarily for their conservation and education value. There are 18 sites within the Wild Purbeck area and many of them are old quarry sites and chalk pits where the geology can still be seen.

Other sites include include the Agglestone at Studland, a huge, isolated block of sandstone; and there are three RIGS along the shores of Brownsea Island illustrating the sedimentary clays and sand.

RIGS can include geomorphological features and was selected as a rare example of a twin water gap in a chalk ridge. Here in Purbeck it created the mound on which the castle sits.

The largest RIGS in Wild Purbeck is Giant’s Trencher at Ulwell. This dry, steep-sided valley is 100 m deep and 500 m long. There is a dramatic change in the direction of the valley part way along. It is likely that the original valley was formed by structural weaknesses in the chalk exploited in pre-glacial times and later over-deepened by peri glacial spring meltwaters.

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PRIORITY HABITATS

Priority Habitats have been selected for one or more of the following reasons: the habitat is at risk; the UK has international obligations to protect it; they are functionally important for species inhabiting wider environments; or they are important for species of particular conservation concern.

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Wild Purbeck Habitats: Lowland Heathland, Mire, Fen and Acid Grassland

Lowland Heathland is a key habitat within the Wild Purbeck area. The heathland is recognised as being of international importance and is the main reason behind many of the designations already mentioned. There has been a lot of conservation effort to enhance, re-create and re-connect much of the heathland habitats including the removal of conifers and scrub. These are minor gains however compared with the historical losses of heathland in Dorset from 365,000 ha to less than 6,000 ha.

3,657 ha or 6% of England’s remaining lowland heathland resource is within the Wild Purbeck area.

Heathland usually forms a complex with other habitats including fen, mires and acid grassland and the Wild Purbeck area encompasses much of the Dorset resource for these habitats including: 64 % Dorset heathland, 80% of Dorset Fens, 42% of the Dorset acid grassland.

In Purbeck there are some extensive areas of acid grassland notably at Corfe Common; areas at Greenland and Godlingston restored through natural reversion; and Fitzworth on the edge of Poole Harbour. Just under 8% of acid grassland in the SW is found within Wild Purbeck.

The fens and mire systems within the heathlands bring increased diversity to the sites. It is an important habitat for many invertebrates including the Large Marsh Grasshopper (Stethophyma grossum).

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Wild Purbeck Habitats: Lowland Calcareous Grassland, Lowland Meadows and Purple Moor Grass & Rush Pasture

The lowland calcareous grassland is found along the Purbeck Ridge and along stretches of the coast with one large inland site at East Chaldon. Part of the Ridge and much of the coast is Limestone grassland with significant areas at and Cap. Calcareous grassland can be very species rich and an important habitat for butterflies and invertebrates. The Lulworth and Purbeck chalk support at least 25 breeding species of butterfly. This area is a national stronghold for the Lulworth Skipper and a good site for Adonis Blue. Other rare and notable invertebrates include Grey Bush Cricket, Cistus Forester and Large Crysalis Snail. 948 ha of Lowland Calcareous Grassland has been recorded, 29% of the Dorset resource.

The largest areas of purple moor-grass and rush pasture are confined to the floodplain around Wareham but there are additional sites at Corfe Common, scattered along the edges of Poole Harbour and the heathland and on the . 203 ha has been recorded, 48% of the Dorset resource.

There are few Lowland Meadow sites in this area, the largest falling within the MOD land. 84 ha has been recorded, 13% of the Dorset resource.

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Wild Purbeck Habitats: Coastal habitats and Floodplain Grazing Marsh

The coastal and floodplain grazing marsh along the Rivers Frome and Piddle provides important habitat for over-wintering birds and the extensive ditches, particularly in the lower reaches, include some interesting plant species.

Poole Harbour is one of the largest harbours in the UK and particularly important for estuarine habitats in Dorset. The saltmarsh covers 408 ha, 86 % of the saltmarsh in Dorset. There are also several large areas of reedbed around the harbour covering 182 ha, 63% of the Dorset resource. These habitats are particularly important for invertebrates and the many birds which feed upon them.

97 % of Dorset’s sand dunes are on the Studland peninsula forming part of an interesting complex of habitats. The acid heath found here is the only example of this Priority EU habitat on the south coast and one of the most extensive in England supporting 8% of the UK resource.

Along the south coast, between Ringstead and St Alban’s Head, there are areas of maritime cliff and slope. Here, areas of bare ground provide important habitat for specialist invertebrates and several rare plants.

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Wild Purbeck Habitats: Lowland Mixed Deciduous Woodland, Wet Woodland and Wood Pasture & Parkland

Priority Habitat Woodland in Wild Purbeck is very scattered with few large sites. The majority is lowland mixed deciduous woodland (792 ha). Most of this lies away from the coast with some interesting strips of woodland running along the Purbeck ridge.

Within the Wild Purbeck area there is 130 ha of wet woodland, 28 % of the Dorset resource. Wet woodland often forms part of a larger woodland site, making it difficult to map and, probably, under-recorded. In Britain much wet woodland has been lost as land has been cleared and drained so remaining wet woodland should be valued. Wet woodland can provide an extremely rich invertebrate habitat if managed to retain water levels, structural diversity and dead wood.

Wild Purbeck includes several key parkland sites notably Creech and Lulworth Park. The main interests on these sites are their veteran trees and important assemblages of key lichens.

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Wild Purbeck Professor Good Archive

Professor Good's stands Between 1931 and 1939 Prof. Good recorded plant species at 7575 stands (sites) across Dorset. The results of Good's survey were published as A Geographical Handbook of the Dorset Flora (1948).

The data from Good’s maps and diaries can be used as a comparison with more recent data. Many of Good’s sites are within the Wild Purbeck area.

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Wild Purbeck Professor Good stands re-visited by Anne Horfall

Between 1976 and 1987 Anne Horsfall revisited many of the Good stands within the Wild Purbeck area and found the following:

• The habitat had been totally destroyed at 489 sites (27%) • At 211 sites the habitat had been partly destroyed (12%) • The habitat remained unchanged at 1091 sites (60%) • 95 sites (5%) were not revisited

Many of the sites that had been totally destroyed were heathland, but there were also many woodland sites, calcareous grassland, mires and arable margins that had changed significantly.

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Wild Purbeck Habitats: Micro-habitats

From our knowledge of Purbeck and its habitats, DERC has produced the following list of micro- habitats. This is a first attempt to focus on very specific habitats within the scope of Priority Habitats. Micro-habitats are often under-surveyed and may require specific management to be retained but they form an important part of the habitat complex and are vital to the huge diversity of Wild Purbeck’s natural environment. A short definition of each micro-habitat is given.

Lowland mixed Deciduous woodland Coppice woodlands Woodlands traditionally managed by regular cutting of the underwood, typically Hazel. Once widespread in Purbeck it has largely ceased resulting in extinction of several woodland butterflies and decrease in plants and invertebrates.

Ash woods (W8) Ash is an important component of many woodlands in PNIA, and two of the larger blocks of semi-natural woodland, Great Wood and Kings Wood, are dominated by Ash. The fungal pathogen Chalara fraxinea poses a significant threat to Ash trees and associated habitats in the British Isles. Veteran & ancient trees Trees older than the natural age for the species and supporting features such as hollows, wound tracks, dead wood and bracket fungi. Important for specialist (saproxylic) invertebrates and lichens. Purbeck has important concentrations around Lulworth Park and Creech, but little is known about the resource elsewhere in the NIA. Dead wood habitats Standing and fallen dead wood is important for specialist invertebrates and fungi in woodland parkland habitats.

Wet woodland Sphagnum-rich wet Woodland usually on waterlogged acid peats dominated by Downy Birch with a well- woodland developed carpet on bog-mosses in the ground layer. Corresponds to 'Bog woodland' Annex 1 habitat type. Fen-woodland Woodland fed by basic groundwater usually mixed Alder - Ash - Sallow with a diverse ground flora and possibly a specialised invertebrate fauna although little survey work has been carried out here compared to work in .

Parkland & Wood-pasture Dead wood habitats (see above) Veteran & ancient trees Trees older than the natural age for the species and supporting features such as hollows, wound tracks, dead wood and bracket fungi. Import for specialist (saproxylic invertebrates) and lichens. Purbeck has important concentrations around Lulworth Park and Creech.

Lowland dry acid grassland Sandy parched grasslands Short grasslands on well-draining sandy or gravelly soils droughted in the summer (U1 types) characterised by the abundance of early annual plants, particularly clovers. Trackways and bare ground provides habitat for species such as Mossy Stonecrop. Purbeck supports nationally important examples. Herb-rich Bracken Corfe Common is one of the most important acid grassland sites in southern England grasslands (U20a-related) supporting 40ha of herb-rich Bracken stands (U20a). There are smaller stands found on the Lulworth Ranges.

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Lowland calcareous grassland Open and rocky Purbeck supports large areas of both chalk and limestone grassland, but only a very small xerophytic grasslands percentage of it is open with soil pockets, low rock outcrops and terricolous bryophytes and (CG1, CG7, CG4a) lichens. These areas are important for specialist invertebrates and flowering plants particularly small annuals such as Dwarf Mouse-ear, Hairy-fruited Cornsalad and Nit- grass; the chalk ridge is of national importance for lichens associated with chalk pebbles and flints. These species are easily lost through changing management, particularly a reduction in grazing pressure.

Purple Moor-grass and Rush-pasture Molinia meadows (M24) Seasonally damp or flushed grasslands with abundant Purple Moor-grass often rich in sedges and herbs and characterised by the presence of Meadow Thistle. Important examples are found on Corfe Common, Lulworth Ranges and Tadnoll. Corresponds to the 'Molinia meadows on calcareous, peaty or clayey silt-laden soils' Annex 1 habitat type.

Hedgerows Species-rich / Ancient Hedgerows are an integral part of the landscape, especially on clay soils where many are of hedgerows and stone ancient origin. On the Limestone Plateau stone walls are a particular feature. walls

Lowland heathland Humid and wet heaths Dorset Heath Erica ciliaris is a rare plant in Britain with the Purbeck Heaths supporting the with Dorset Heath Erica largest populations. Some areas have been lost to tree planting and could be restored, ciliaris (H3 & M16) especially in the Remsptone Forest Area. 'Temperate Atlantic wet heaths with Erica ciliaris and Erica tetralix' is a Priority Annex 1 habitat with only c. 400 ha in the UK. Bare sandy ground and Areas of bare sandy substrate often on banks providing breeding sites for reptiles and trackways ground-nesting bees and wasps. Sandy, gravelly and clayey trackways, both dry and damp, provide niches for species of open ground. A small suite of uncommon plants, Allseed, Chaffweed and Yellow Centaury are strongly associated with damp heathland tracks. Abandoned mineral Abandoned sand and gravel workings with regenerating acid grassland and heathland workings habitats. Bare ground, especially vertical exposures are important for invertebrates. Information suggests that many hymenoptera have declined due to sites becoming overgrown. However, there are opportunities to create habitat in recently abandoned workings. Winter-wet hollows on Small hollows on firm peaty ground typically characterised by an abundance of White shallow peat Beak-sedge and supporting uncommon plants such as Marsh Clubmoss, Marsh Gentian and Brown-beak-sedge. Purbeck has nationally important examples which correspond to the Annex 1 habitat ' depressions on peaty substrates'.

Lowland fens Sphagnum-dominated Mires dominated by bog-mosses fed by acid ground water formed over peat in shallow valley mires valleys and around springlines within the wider heathland landscape. Purbeck and the support the best remaining examples in NW Europe. Rich Fens - Short-sedge / Areas fed by basic ground water characterised by small sedges and brown-mosses, usually brown-moss fens (M10- well-grazed. Very rare in lowland England with the only examples in Dorset confined to related) and Cladium Corfe Common, with only 0.10 ha found. Saw-sedge Cladium mariscus is a rare plant in mariscus fens (S2) and southern England and the Wild Purbeck area supports the only extensive stands in the Schoenus nigricans - county, both of which are threatened, one by rising sea levels and the other by scrub Brown-moss runnels encroachment (M14)

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Coastal and floodplain grazing marsh Species-rich ditch systems Ditches and ditch systems supporting diverse wetland plant and invertebrate assemblages, mainly in the lower floodplains of the Frome and Piddle.

Ponds Old ball clay workings Abandoned workings filled with water, very poor in nutrient status, supporting many invertebrates, particularly Odonata, and wetland plants such as Pillwort. Shallow and temporary Shallow pools flooded for only part of the year supporting a distinctive assemblage of nutrient-poor pools plants and invertebrates. There are many such pools on the MoD Ranges at Lulworth, but they also occur elsewhere.

Maritime cliff and Slopes Soft cliffs Actively eroding sand and clay cliffs supporting a diverse range of niches, with a specialised invertebrate fauna and several uncommon plants. Parched cliff edges and Areas of bare ground kept open by exposure and summer parching on cliff edges, bare ground (MC5, important ground nesting invertebrates and terricolous bryophytes and lichens. The MC8b,e) Purbeck limestone coast has very good examples, especially in the abandoned coastal quarries.

Coastal salt-marsh Salt-marsh - freshwater Around the western and southern edges of Poole Harbour there are numerous freshwater transitions incursions into the upper saltmarsh. These produce interesting plant communities and a number of uncommon invertebrates have been recorded. The transitions from saltmarsh to mire and saltmarsh to wet woodland are of particular interest.

Coastal sand dunes Acid dune heath (H11) Dune-heath is stabilised vegetation dominated by dwarf ericaceous shrubs on acid, nutrient-poor substrates typically sand. The dune system at Studland is the only example of this Priority EU habitat on the south coast and one of the most extensive in England supporting 39% of the resource, and 8% of the UK resource. Open dune slacks Seasonally wet hollows between dunes ridges with areas of bare ground and wet vegetation usually with Creeping Willow. Indications are that the dune slacks at Studland are much more closed than formerly leading to a loss in species diversity. Sandy strandlines Annual vegetation of sandy beaches included several uncommon and declining plants, Frosted Orache, Prickly Saltwort, Sea Rocket. Easily lost through excessive trampling. Older records suggest that these species were once more widespread around the Purbeck coast.

Other habitats Arable field margins Areas of Purbeck still support a diverse arable plant flora, especially between and St Aldhelm's Head. Species-rich road verges Road verges can provide a refuge for grassland and woodland plants in areas of intensive agriculture. Purbeck is known to support important verges, especially around the fringes of the heaths. Species-rich scrub Scrub is an integral part of calcareous grassland, heathland and coastal slopes. Much of it is relatively recent, e.g. Gorse on the Purbeck Ridge, but some stands are more ancient and important for breeding birds, invertebrates and some plants.

Churchyards Churchyards, particularly old and little-disturbed ones, are an important habitat for many different species, particularly lichens. The grassland is often little improved and can support an interesting flora and grassland fungi.

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Wild Purbeck Species: Changes in declining and threatened plants

Extinctions Despite supporting the richest square for vascular plants in the British Isles, SY98, a total of 55 Dorset Rare Plant Register species have become extinct in the Purbeck NIA area; the majority of these, 33, were lost before 1950.

Analysis of the preferred habitats for these lost species show that 14 (25%) were associated with arable and fallow fields and many of these are now very rare (eg Corn Cleavers, Broad-fruited Cornsalad) or extinct (Lamb's Succory) in the British Isles.

Another group associated with heathland, Stag's-horn Clubmoss, Fir Clubmoss, Grass-of Parnassus and Common Butterwort, are largely northern and western species in Britain and are very rare or extinct in the lowlands.

Changes in landscape management, particularly the loss of common grazing, were responsible for the loss of Brown Galingale, Field Gentian and Small Fleabane which survive in the New Forest where traditional grazing has been maintained.

Species Habitat Site and date of last record Alisma lanceolatum Narrow-leaved Water-plantain Aquatic Wareham Common, 1989 Althaea officinalis Marsh Mallow Saltmarsh Poole, <1799 Anthemis arvensis Corn Camomile Arable fields Seacombe, 1933 Arnoseris minima Lamb's Succory Fallow fields Slepe, 1937 Blysmus compressus Flat-sedge Basic flushes , 1880 Bupleurum tenuissimum Slender Hare's-ear Maritime cliffs Tilly Whim, 1900 Centaurea cyanus Cornflower Arable fields , 1937 Chenopodium bonus-henricus Good King Henry Fallow fields , 1957 Chenopodium urbicum Upright Goosefoot Fallow fields Ridge Farm, 1966 Chenopodium vulvaria Stinking Goosefoot Waste ground South Haven, 1900 Clinopodium acinos Wild Basil Calcareous grassland Bindon Range, 1984 Coeloglossum viride Frog Orchid Calcareous grassland , 1953 Colchicum autumnale Meadow Saffron Neutral grassland Creech, <1895 Cyperus fuscus Brown Galingale Common grazing , 1900 Dactylorhiza incarnata subsp. incarnata Early Marsh- Marshes Arne, 1982 orchid Eleocharis parvula Dwarf Spike-rush Aquatic Little Sea, 1935 Epipactis leptochila Narrow-lipped Helleborine Woodland Creech, 1985 Eryngium maritimum Sea Holly Sand dunes & strandlines Brownsea Island, 1970 Euphrasia pseudokerneri Calcareous grassland Round Down, Filago pyramidata Broad-leaved Cudweed Fallow fields Creech 1937 Fumaria bastardii Arable fields Studland, 1960 Fumaria parviflora Arable fields Keysworth, 1961 Galeopsis angustifolia Red Hemp-nettle Arable fields Redcliff, 1991 Galium tricornutum Corn Cleavers Arable fields Worth Matravers, 1920 Gentianella campestris Field Gentian Acid grassland Tadnoll, 1976 Geranium purpureum Little Robin Maritime cliffs Punfield, <1895 Gnaphalium sylvaticum Heath Cudweed Fallow fields Longthorns, 1977 Hordeum marinum Sea Barley Coastal , <1895

Environment Report for the Wild Purbeck NIA Dorset Environmental Records Centre Page 26 of 29 Species Habitat Site and date of last record Hottonia palustris Water Violet Aquatic Wareham, 1830 Huperzia selago Fir Clubmoss Heathland Black Hill, <1895 Hydrocharis morsus-ranae Frogbit Aquatic Wareham, 1840 Juniperus communis Juniper Heathland Hartland Moor, 1959 Leersia oryzoides Cut-grass Marshes Wareham, 1975 Lithospermum arvense Field Gromwell Arable fields St Aldhelm's Head, 1986 Lycopodium clavatum Stag's-horn Clubmoss Heathland Wareham Heath, <1799 Monotropa hypopitys Yellow Bird's-nest Woodland Kingston, <1900 Myriophyllum verticillatum Whorled Water-milfoil Aquatic Wareham, <1799 Nepeta cataria Catmint Hedgebanks West Lulworth, 1938 Ophrys insectifera Fly Orchid Calcareous grassland , 1961 Orchis ustulata Burnt Orchid Calcareous grassland Lulworth & Old Harry, <1895 Orobanche rapum-genistae Greater Knapweed Heathland Arne, 1956 Parnassia palustris Grass-of Parnassus Basic flushes Wareham Heath, 1893 Pinguicula vulgaris Common Butterwort Basic flushes Arne-Stoborough, 1865 Polygonum oxyspermum Ray's Knotgrass Sand dunes & strandlines Studland, 1935 Puccinellia rupestris Stiff Saltmarsh-grass Maritime cliffs Swanage, <1900 Pulicaria vulgaris Small Fleabane Common grazing Keysworth, <1895 Ranunculus lingua Greater Spearwort Aquatic Arne, 1937 Ranunculus ophioglossifolius Adder's-tongue Spearwort Aquatic Woodsford, 1914 Ranunculus tripartitus Three-lobed Crowfoot Aquatic The Moors, 1968 Rumex rupestris Shore Dock Maritime cliffs Ringstead, 1968 Seriphidium maritimum Sea Wormwood Saltmarsh Arne, 1968 Silene noctiflora Night-flowering Catchfly Arable fields Arne, 1952 Tephroseris integrifolia Field Fleawort Calcareous grassland , 1908 Valerianella rimosa Broad-fruited Cornsalad Arable fields Rempstone, 1937 Wahlenbergia hederacea Ivy-leaved Bellflower Woodland Bere Wood, <1895

CHANGES IN HEATHLAND SPECIES Heathland is often interpreted as a distinct habitat of dwarf shrubs, but can equally be thought of as a landscape comprising heather dominated areas, Sphagnum bog, acid grassland, scrub, small-scale sand and gravel pits, ponds and trackways. Extensive grazing was the traditional management, along with localised peat digging, turf cutting, Bracken cutting and burning. All this management suppressed succession and kept habitats open providing niches for a specialised flora and fauna.

Damp acid grassland species These species prefer tightly grazed grassland such as commons and village greens and are sometimes found along seasonally wet trackways and around the edges of shallow ponds. Chamomile is a good example requiring tightly grazed, seasonally damp grassland on acid nutrient-poor soils. Once widespread in south-east Dorset it is now restricted to just four sites, three in the NIA. It is still locally frequent on Corfe Common.

As well as the species listed below Pennyroyal and Small Fleabane, both previously found in this habitat, have become extinct in the Purbeck NIA and are very rare now in Britain outside of the New Forest.

Three species, Chaffweed, Yellow Centaury and Allseed are characteristic of rutted trackways and hollows in damp grassland, and being annuals are reliant on open ground and periodic disturbance. They have suffered severe declines with the cessation of traditional management practices. Interestingly Chaffweed and Allseed have benefited from the re-introduction of extensive grazing with new populations being discovered on Godlingston Heath, Hartland Moor and Stoborough Heath. However, Yellow Centaury has not shown a similar response and remains a threatened species. Environment Report for the Wild Purbeck NIA Dorset Environmental Records Centre Page 27 of 29

Damp Acid Grassland species analysis A B C D E F Centunculus minimus Chaffweed 40 39 1 98 20 21 Cicendia filiformis Yellow Centaury 25 23 2 92 4 6 Radiola linoides Allseed 88 74 14 84 30 44 Chamaemelum nobile Chamomile 21 19 2 90 1 3 Nardus stricta Mat-grass 35 33 2 94 8 10 Viola canina Heath Dog-violet 37 33 4 89 11 15

Key to tables A = total number of historical sites with records B = numbers of historical sites where species not refound C = historical sites with post-1990 records D = % decline E = sites with post-1990 records but no earlier records F = total number of post-1990 sites

Dry acid grassland species Dry acid grasslands are currently found around the fringes of the heaths and mainly occurred historically where heathland was cleared to create agricultural land. Because of the nutrient-poor free- draining soils the land quickly become unsuitable for agriculture and reverted to grassland which was then maintained by grazing. Interesting areas of acid grassland have developed in more recent times on fields that are being restored to heathland. The species suffered greater declines than the true heathland species, although some such as Clustered Clover, along with Common Cudweed and Hairy Bird’s- foot-trefoil, have survived better on sandy road verges, tracks on military land and in amenity grasslands.

Dry acid grassland species analysis A B C D E F Moenchia erecta Upright Chickweed 26 25 1 96 1 2 Potentilla argentea Hoary Cinquefoil 12 8 4 67 5 9 Trifolium glomeratum Clustered Clover 14 7 7 50 16 23 Sagina nodosa Knotted Pearlwort 23 21 9 91 9 11 Sagina subulata

Heath & mire species By and large species found in the major heathland habitats (dry, humid and wet heath and valley mire) have declined less than those of the more marginal habitats, although they have all suffered declines of 40% or more. Petty Whin is one exception, a species that is more grazing-dependent; another is Marsh Lousewort, an annual of open flushes reliant on grazing animals to disturb the seed bank and with the largest remaining populations now found on Corfe Common.

Heath and mire species analysis A B C D E F Drosera anglica Great Sundew 18 9 9 50 3 12 Hammarbya paludosa Bog Orchid 10 6 4 60 3 7 Lycopodiella inundata Marsh Clubmoss 37 23 14 62 9 25 Gentiana pneumonanthe Marsh Gentian 43 17 26 40 0 13 Genista anglica Petty Whin 40 32 8 80 10 18 Viola lactea Pale Heath-violet 24 13 11 54 7 18 Pedicularis palustris Marsh Lousewort 55 53 8 91 2 10

Coastal habitats

Environment Report for the Wild Purbeck NIA Dorset Environmental Records Centre Page 28 of 29 Along the coast the cliffs, sand dunes and saltmarshes have been less influenced by man and therefore the plants have by large survived better. One habitat where there has been a decline is on strandlines and beaches. This suite of species are very susceptible to continual disturbance and trampling and now are largely confined to Studland and Shell Bay where even here they are very localised. One species that has shown a recent increase is Prickly Saltwort which lives up to its name and is avoided by visitors; it is helping to form embryo dunes in Shell Bay. These species have the ability to re-colonise after long intervals. Sea Stock, for example, has recently appeared after a gap of 100 years.

Coastal species analysis A B C D E F Atriplex laciniata Frosted Orache 8 5 3 63 3 6 Calystegia soldanella Sea Bindweed 7 3 2 43 2 6 Cakile maritima Sea Rocket Elytrigia juncea Sand Couch 8 6 2 75 1 3 Honckenya peploides Sea Sandwort 7 2 5 29 3 8 Polygonum oxyspermum Ray’s Knotgrass 4 0 0 100 0 0 Salsola kali Prickly Saltwort 9 4 5 44 1 6

Environment Report for the Wild Purbeck NIA Dorset Environmental Records Centre Page 29 of 29