Habitat account - Sclerophyllous scrub (matorral)
5130 Juniperus communis formations on heaths or calcareous grasslands
Background to selection
|Distribution of SACs/SCIs/cSACs with habitat 5130 Juniperus communis formations on heaths or calcareous grasslands. Click image for enlarged map.|
Description and ecological characteristics
The relationship between juniper Juniperus communis stands and other types of vegetation is complex. In some cases the stands have no characteristics to separate them from typical examples of heath or calcareous grassland vegetation, except for the abundance of juniper. These are often relatively recent stands. However, at some sites, particularly where the juniper has been present for a longer period, a more distinctive assemblage of species occurs. Here the juniper is associated with other shrubs, shade-tolerant herbs, grazing-sensitive tall herbs, bryophytes and ferns.
The main ecological variation occurs between stands on calcareous substrates (principally chalk and limestone but sometimes calcareous drift) and those found on acid substrates. Calcareous types are mainly found in the southern part of the UK, while acid types are mainly found in northern areas. However, both calcareous and acid types can be found on the same sites in northern England and Scotland.
In northern England and Scotland juniper is found on a wide range of acidic substrates supporting acidophilous plant communities. In many instances these are simply stands of heathland or acidic grassland that have become invaded by juniper. However, at sites where the juniper has been established for longer, the community corresponds to NVC type W19 Juniperus communis ssp. communis – Oxalis acetosella woodland. Such vegetation is typically dominated by juniper, with downy birch Betula pubescens and rowan Sorbus aucuparia often scattered throughout. The understorey is rich in acidophilous species, such as bilberry Vaccinium myrtillus, wood-sorrel Oxalis acetosella, heath bedstraw Galium saxatile and hairy wood-rush Luzula pilosa. Species with a northern distribution, including chickweed wintergreen Trientalis europaea, twinflower Linnaea borealis and lesser twayblade Listera cordata, occur locally. There is usually a well-developed layer of pleurocarpous mosses and ferns. On lower slopes with flushing and on more base-rich substrates the flora is enriched by species that reflect an increased base-status, such as common dog-violet Viola riviniana, dog’s mercury Mercurialis perennis and northern bedstraw Galium boreale.
In southern England juniper scrub may develop on a range of calcareous grassland types on thin chalk soils. More closed juniper stands with a rich scrub flora correspond to NVC type W21d Crataegus monogyna – Hedera helix scrub, Viburnum lantana sub-community, formerly called ‘southern mixed scrub’. Where juniper is not dominant the scrub contains a rich assemblage of other shrubs, mainly of the family Rosaceae. Further north, at higher altitude on limestone, juniper scrub is often associated with limestone pavements and calcareous cliffs and screes. Beyond the distribution range of many rosaceous shrubs and often in heavily grazed situations, such scrub may be relatively poor in specialist scrub species. In such circumstances the vegetation has affinities to the species-poor juniper scrub more usually found on acidic substrates.
Juniper stands occur in juxtaposition with a wide range of other vegetation types. Stands of juniper formerly occurred on lowland heathland, but as a result of burning and lack of management, only scattered specimens now survive at a few sites. In the Scottish Highlands there are stands that are transitional to H91C0 Caledonian forest and birch woodlands. Some southern stands are transitional to beech woodlands. In upland areas, specifically the Cairngorms, stands are still found in an apparently natural context at the upper limit of tree development and extend up above the woods into the dwarf-shrub heaths of the alpine zone. Elsewhere, stands occur that are transitional to calcareous grassland, heath, acidic grassland, rock outcrops, 8240 Limestone pavements, scree and cliffs. A range of juniper scrub types may occur within individual sites, and these may include both calcareous and acidic forms, altitudinal variations and transitions to a range of habitats.
Patches of Juniperus – Oxalis woodland within stands of W18 Pinus sylvestris – Hylocomium splendens woodland are referable to Annex I type H91C0 Caledonian forest. H15 dwarf juniper Juniperus communis ssp. alpina heath is referable to Annex I type 4060 Alpine and Boreal heaths.
European status and distribution
This is a widespread but very local habitat type that is unevenly distributed in the EU.
UK status and distribution Click to view UK distribution of this habitat
Juniper scrub has a scattered and patchy distribution across the UK. It occurs mainly in the eastern parts of northern Scotland, and more locally in the Southern Uplands of Scotland, northern England and southern England. The habitat is not present in Northern Ireland, and occurs only as fragmentary examples in Wales.
Site selection rationale
Site selection has taken account of the patchy geographical distribution of the habitat type and its wide range of ecological variation. Sites with the largest expanses of juniper have been favoured. Site selection has been strongly influenced by the variety of ecological situations in which juniper scrub is found, and the range of transitions to other habitat types. For example, the selected sites include examples on chalk in southern England, and both acidic and more base-rich variations of the northern scrub type; both long-established and more recent stand types have been selected.
A significant part of the resource occurs in north-east Scotland, where a diverse range of stand types is found, and therefore six of the sites selected are from this area.
|Aston Rowant||Berkshire, Buckinghamshire and Oxfordshire|
|Aston Rowant represents Juniperus communis formations near the northern edge of the habitat’s range on the chalk of southern England where it is rare and declining. The juniper population has been estimated to be between 1,000 and 2,000 individuals of various age-classes. It is one of the best remaining examples in the UK of lowland juniper scrub on chalk.|
|Cairngorms||Highlands and Islands, North Eastern Scotland|
|The Cairngorms has the third-largest extent of juniper Juniperus communis formations in the UK and is one of several sites representing the habitat type in north-east Scotland. The site is exceptional for the wide range of ecological situations in which juniper occurs. Creag Fhiaclach is unique in having the most natural altitudinal tree-line in the UK. At around 640 m there is mixed tree-line woodland with stunted Scots pine Pinus sylvestris and juniper, giving way at higher altitude to alpine juniper scrub. The alpine juniper scrub is developed extensively and often occurs in a stunted form transitional between ssp. communis and ssp. nana. On most of the site juniper occurs on acidic granite, while at Inchrory juniper occurs on both neutral and calcareous soils. Juniper also occurs at the margins and as part of the understorey of 91C0 Caledonian forest within the site.|
|Dam Wood||Highlands and Islands|
|Dam Wood represents the most northerly example of Juniperus communis formations in the SAC series. This is one of the few remnants of juniper scrub on the Black Isle and occurs within the largest remaining fragment of lowland Calluna heath that once characterised the central part of the Black Isle. Associated habitats include grasslands and lime-rich seepages. The habitat is in good condition and the juniper is regenerating well.|
|Glenartney Juniper Wood||Eastern Scotland|
|Glenartney holds the largest extent of Juniperus communis formations in Tayside at the southern edge of the Scottish Highlands. The juniper occurs widely at moderate altitude within a wide range of habitat mosaics, including acidic heaths, rush-pasture, bracken Pteridium aquilinum and grasslands, and is regenerating well. The NVC type is W19 Juniperus communis – Oxalis acetosella woodland.|
|Green Hill of Strathdon||North Eastern Scotland|
|Green Hill of Strathdon represents an unusual form of Juniperus communis formations in the eastern Scottish Highlands with a species-rich basiphilous flora influenced by the underlying serpentine rocks. Juniper scrub is associated both with Calluna-dominated heaths and grassland. There are many junipers scattered over a large area, especially in the Calluna heath, but smaller, denser stands also occur in both heath and, unusually, in species-rich grassland.|
|Ingleborough Complex||North Yorkshire|
|Ingleborough represents upland Juniperus communis formations on a calcareous substrate in northern England. It occurs here at its highest altitude on limestone in the UK. Amid stands of calcareous grassland it has the only large stands of juniper on 8240 Limestone pavements at high altitude in the UK. The scrub is of the relatively species-poor type typical of these situations.|
|Lake District High Fells||Cumbria|
|The Lake District High Fells represents Juniperus communis formations on upland acid substrates in north-west England. Three of the component upland SSSIs have extensive areas of juniper Juniperus communis, whilst scattered juniper occurs on many of the inaccessible cliffs and slopes throughout the complex. The NVC type is W19 Juniperus communis ssp. communis – Oxalis acetosella juniper woodland. Birk Fell supports the most extensive stand of juniper in the Lake District. The juniper is associated with open silver birch Betula pendula woods with scattered rowan Sorbus aucuparia, ash Fraxinus excelsior, bird cherry Prunus padus, holly Ilex aquifolium, hawthorn Crataegus monogyna and dog rose Rosa canina. Bracken Pteridium aquilinum or fescue – bent grassland with bryophytes and wood sorrel Oxalis acetosella predominate over the woodland floor, although locally there are richer areas. There are good transitions to upland oak woodland and upland habitats such as dry heath and blanket bog. Helvellyn and Fairfield and Skiddaw Group support extensive stands of juniper. Associated species here include ash F. excelsior, sessile oak Quercus petraea, birch B. pendula and rowan S. aucuparia. The ground flora is either Nardus – Festuca – Agrostis grassland or dry heath.|
|Moor House - Upper Teesdale||Cumbria, Tees Valley and Durham|
|This site represents Juniperus communis formations on a more acidic substrate in north-east England. It has the second most extensive area of juniper scrub in UK and the largest south of Scotland. The main area of juniper scrub grows on the igneous whin-sill, at moderately high altitude. In Upper Teesdale the juniper has developed mainly on heath and is of the W19 Juniperus communis – Oxalis acetosella type. There are transitions to dwarf-shrub heath, acidic grasslands and whin-sill cliffs. Small patches of juniper scrub also occur on calcareous soils, including the sugar limestone grassland for which this site is famous. Palaeo-environmental evidence indicates that juniper scrub has been present continuously since the last glacial period.|
|Morecambe Bay Pavements||Cumbria, Lancashire|
|Morecambe Bay Pavements represents Juniperus communis formations on 8240 Limestone pavements at low to intermediate altitude in north-west England. In contrast to most other areas in northern England, these are ungrazed or grazed at low intensity and have affinities to southern mixed scrub, owing to the presence of species such as wild privet Ligustrum vulgare and burnet rose Rosa pimpinellifolia. Other stands occur on 6210 semi-natural dry grassland dominated by blue moor-grass Sesleria caerulea.|
|Morrone Birkwood||North Eastern Scotland|
|Morrone Birkwood is one of several sites representing juniper Juniperus communis formations in north-east Scotland. It has the most extensive and diverse example of a transition between woodland and juniper scrub in the UK. The site contains examples of juniper developed both on limestone drift soil and on contrasting acidic soils. The stands on lime-rich soils are the largest and most diverse in Scotland. The flora is species-rich, with a well-developed northern component. This includes rare species usually associated with Scots pine Pinus sylvestris woods, such as twinflower Linnaea borealis, serrated wintergreen Orthilia secunda and interrupted clubmoss Lycopodium annotinum. Nodding mellick Melica nutans, globeflower Trollius europaeus and northern bedstraw Galium boreale also occur. Juniper is actively regenerating on the open slopes above the wood. Pollen analysis indicates that the wood has not altered floristically since the post-glacial period. Other habitats associated with the limestone include 6210 Semi-natural dry grasslands and scrubland facies on calcareous substrates, 7220 Petrifying springs with tufa formation, 7230 Alkaline fens and 7240 Alpine pioneer formations of the Caricion bicoloris-atrofuscae.|
|Morven and Mullachdubh||North Eastern Scotland|
|Morven and Mullachdubh is one of several sites representing Juniperus communis formations in north-east Scotland. It has the largest known area of juniper scrub in the UK, about double the extent occurring at any other site. The juniper is developed amongst dry heath and acidic grasslands. The ground flora beneath the juniper is locally rich in ferns, including oak fern Gymnocarpium dryopteris and hard-fern Blechnum spicant. Common woodland herbs, such as wood-sorrel Oxalis acetosella and hairy woodrush Luzula pilosa are widespread. Wood anemone Anemone nemorosa and moschatel Adoxa moschatellina also occur. Of particular interest is the extensive development of juniper up to high altitude, where there is a transition to lichen-rich alpine heaths.|
|North Pennine Moors||Cumbria, North Yorkshire, Northumberland and Tyne and Wear, Tees Valley and Durham|
|The North Pennine Moors includes one major stand of juniper scrub in Swaledale as well as a number of small and isolated localities. The Swaledale site grades into heathland and bracken Pteridium aquilinum but the core area of juniper is of W19 Juniperus communis – Oxalis acetosella woodland with scattered rowan Sorbus aucuparia and birch Betula spp.|
|Salisbury Plain||Gloucestershire, Wiltshire and Bristol/Bath area, Hampshire and Isle of Wight|
|Salisbury Plain represents Juniperus communis formations near the southern edge of the habitat’s range on chalk in southern England, where it is particularly rare. This site is the best remaining example in the UK of lowland juniper scrub on chalk. The juniper is juxtaposed with extensive 6210 semi-natural dry grassland and chalk heath. In some cases the scrub has developed recently by invasion of open chalk grassland and contains few typical shrub species. However, most of the scrub is of the southern mixed scrub type and is enriched by roses Rosa spp., wild privet Ligustrum vulgare, dogwood Cornus sanguinea, wayfaring tree Viburnum lantana and other species characteristic of the type.|
|Tayvallich Juniper and Coast||Highlands and Islands|
|Tayvallich represents an important and extensive outlier of Juniperus communis formations on the west coast of Argyll. This is the only representation in the SAC series of the habitat in western Scotland. The juniper formations occur in an extremely varied habitat mosaic – dry wooded ridges grade into heathland and grassland, with flushes, valley mires and open water transition communities. The juniper is regenerating locally.|
|Tynron Juniper Wood||South Western Scotland|
|Tynron is the only site representing Juniperus communis formations in the Southern Uplands. The juniper occurs at low altitude and is associated with dry, acid grassland, W25 Pteridium aquilinum – Rubus fruticosus underscrub and, where the juniper casts a dense shade, a moss-dominated ground layer. Much of the juniper scrub is tall and dense, with both narrow and columnar and broad and spreading growth forms of juniper occurring. Juniper is also present in the understorey of a small area of broad-leaved woodland.|
SACs/SCIs/cSACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection
|Hill of Towanreef||Highlands and Islands, North Eastern Scotland|
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