Management Plan for Silchester Common

2011-2016

Summary

Silchester Common lies between the villages of Silchester and Pamber Heath and is part of a large Site of Special Scientific Interest (SSSI), which covers 306 hectares in total. This extensive and diverse area is of great value for the high quality heathland found on the site.

It is designated as an SSSI by virtue of the habitat it provides for rare species, such as the Dartford Warbler and the Silver Studded Blue butterfly.

Location

Site name: Silchester Common

SSSI name:PamberForest and Silchester Common SSSI

Date SSSI notified:1951, in relation to the 1949 Act

County: Hampshire

Borough: Basingstoke and Deane

Planning Authorities:HampshireCounty Council

Basingstoke and Deane Borough Council

Total area of HLS:63.32 hectares

Map reference:OS map 1:50,000 - no.175

Access:Open access through common land status

and via one public right of way

History

Silchester Common is one of a few surviving tracts of heathland in the ThamesValley region of North Hampshire. It is an endangered habitat: since the end of the 18th century approximately 90% of the heathland in north Hampshire has been destroyed. The area covered by Basingstoke and Deane Borough Council has lost 98% of its former heaths. Due to the endangered status of heathland habitat, it has been targeted for support by the Department of Food, Environment and Rural Affairs (DEFRA).

Although local residents remember the Common as being an area of open land in the 1930’s, by the late 1980’s it was predominately scrub of birch and gorse. In 1989 a management committee of local people and specialist advisors was formed in order to recover the Heathland area of Silchester. In 1992, the Parish Council, who own the land, entered into the Countryside Stewardship scheme and funding from this and subsequent schemes has been essential in the continued reclamation and maintenance of the common. The aim now is to maintain the complex mosaic of vegetation and thus provide a range of suitable habitats for the diverse flora and fauna now found there. In April 2011 the Parish Council entered a new agreement: the Higher Level Stewardship (HLS). This five year plan relates to the HLS agreement. Silchester Common is managed by the Parish Council, together with interested local people, forming the Commons Management Committee.

Silchester Common has Common Land status and a number of residents of Silchester village hold rights, including mast, estovers and pasture, however, these are rarely exercised.

Description of Area

Geology and soils

The soil of the northern part of Silchester Common is composed of podsols, which are free draining sandy Reading and Bagshot beds, the flat northern part is plateau gravel of the Reading beds and in turn underlain by clay beds of the Bagshot series. The small area in the south of the site has clay at the surface. The top plateau is typical of the heathland areas in this part of the ThamesValley and the flora and fauna is well adapted to the resulting acidity and low nutrient levels of the soils.

Hydrology

There are a series of springs in the northern part, caused by the underlying clay. These run into small south flowing streams, all of which dry up in the summer. The wet areas give rise to an increased range of flora. There are also a number of ephemeral ponds, which are caused by previous gravel extraction.

Topography

The whole area ranges in altitude between 107 metres in the north and 76 metres in the south. The site is well within the maximum altitude at which lowland heaths occur in Britain (250-300m). The northern part is predominately flat with three shallow valleys dropping down to the thin southerly strip. Within the north area there are a number of shallow pits, the result of previous gravel extraction.

Habitat

Silchester Common, together with Tadley Common, represents the largest remnants of the once extensive north Hampshire heathland to the west of the River Loddon. Together, these areas provide the best remaining example of the full transition from dry to wet heathland communities in the area.

Lowland heathland is a rare and threatened habitat, much of it having been lost due to mineral extraction, agricultural practices, forestry activity and building developments. Since 1800 about 80 to 85% of England’s heathland has been lost, with the remaining area of lowland Heathland in the United kingdom now standing at 58,000 hectares. This is about 20% of the total international area.

The habitat of Lowland heathlands are created primarily through human actions of cutting, burning and grazing with stock. Once left untended, the open quality tends to disappear as the area becomes lost under scrub and then secondary woodland. With the encroachment of trees and scrub and, where there is a lack of grazing, the range of vegetation species becomes greatly reduced. Hence maintenance is an on-going task and there will be variation from year to year in terms of the observable habitat.

Rare species

The SSSI status is specifically related to the presence of the Dartford Warbler and the Silver Studded Blue butterfly. Other birds of note, though rare, are the Woodlark and the Nightjar. There are a number of moth species which are found on the site, including the Light Orange Underwing and the White-barred Clearwing.

Site of Special Scientific Interest (SSSI) - Objectives for the Area

The whole area of Silchester Common is designated as SSSI land and there are legal requirements which have to be adhered to in order to maintain this SSSI status.

The SSSI objectives form part of the Higher Level Stewardship agreement and summarised below are some of the main points relating to the flora of the Common.

While favouring the heathland, the aim for the site as a whole is to maintain a mosaic over the area which includes:

  • Dry heathland
  • Wet heathland
  • Acid grassland
  • Mire, which is species-rich
  • Scrub
  • Woodland.

The main plants of note are:

  • Calluna vulgaris (common heather) and Ulex minor(dwarf gorse) on the dry heathland
  • Erica tetralix(cross-leaved heath), Salix repens (creeping willow) and Sphagnum compactum(sphagnum moss) in the wet heath
  • Narthecium ossifragum (bog ashphodel) and Sphagnum papillosum(sphagnum moss) in the valley mire.

The current SSSI objectives provide detail relating to the vegetation species, including those listed below:

  • Dwarf shrubs are characteristic of heathland and the aim is to have at least three species of dwarf shrub, including: Calluna vulgaris, Erica cinerea (bell heather), Vaccinium myrtillus (bilberry), Ulex minor. Both the Calluna vulgaris and the Erica cinerea are of food value to the Silver Studded Blue butterfly.
  • Ulex spp. (common and Europena gorse). These gorse species support a range of invertebrate and vertebrate life, however they can become too invasive, therefore the aim is to maintain cover of these at below 20%. A range of ages of gorse is beneficial to the Dartford Warbler, who uses different stages of growth for different purposes.
  • Grasses are a necessary component of the mosaic. The aim is to have at least one species with frequent cover and two species with occasional cover, however dominance of the grasses would be detrimental to heathers and heaths. It is important to have less than 50% cover of Molinia caerulea (purple moor grass) and for Deschampsia flexuosa (wavy hair grass)to be no more than occasional.
  • Sward composition should include a range of plants and notable species present include Danthonia decumbens (heath grass), Agrostis capillaries (fine bent), Briza media (quaking grass), Carex pallescens (pale sedge), C. caryophyllea (spring sedge), C. hostiana (tawny sedge), Melampyrum pratense (common cow-wheat) and Dactylorhiza maculate (heath spotted orchid). There should also be, from the following list, two species occurring frequently and four occasionally: Anemone nemorosa (wood anemone), Centaurea nigra (black knapweed), Conopodium majus (pignut), Galium saxatile (heath bedstraw), G. verum (lady’s bedstraw), Genista tinctoria (dyer’s greenweed), Lathyrus linifolius (bitter vetch), Leontodon hispidus/saxatilis (rough / hairy hawkbit), Leucanthemum vulgare (oxeye daisy), Lotus corniculatus/uliginosus (bird’s foor trefoil), Pilosella officinarum / Hieracium pilosella (mouse-ear hawkweed), Polygala spp. (milkworts), Potentilla erecta (tormentil), Silaum silaus (pepper saxifrage), Stachys officinalis (common betony), Succisa pratensis (devil’s bit scabious).
  • Undesired species in the sward, to be less than 5% of the cover, include the following: Cirsium arvense (creeping thistle), Cirsium vulgare (spear thistle), Rumex crispus (curled dock), Rumex obtusifolius (broad leafed dock), Senecio jacobaea (common ragwort), Urtica dioica(stinging nettle).
  • Pteridium aquilinum(bracken) can be of benefit for a range of invertebrates and it also provides habitat for reptiles. However, to maintain it at a suitable level of cover it should be controlled, such that there is no more than 10% cover of bracken (where present as a dense canopy) in the heath and grass mosaic.
  • Treesand scrub on the lowland heathprovide suitable habitat for bird species such as the woodlark, which require a mosaic of short ground vegetation, bare patches and clumps of trees and scrub. To maintain the lowland heath though, the tree and scrub cover will be kept to a maximum of 15% (excluding the Ulex species).
  • Broadleaved woodland area, within the site there are areas of broadleaved trees, including Quercus (oak), Corrylus (hazel), Alnus(alder), Populus tremuloides (aspen). Within the woodland areas the aim is to retain a varied mosaic of vegetation, including understorey and canopy of different ages, denser areas as well as sunny open spaces, along with standing and fallen dead wood as habitat for invertebrates. The Polulus tremuloides is of particular importance to the Light Orange Underwing moth, while the larvae of the White-barred Clearwing moth feed on the Alnus and Betula.

CurrentState of the Area

Prior to the setting up of the management committee in 1989, Silchester common was dominated by Betula pendula (silver birch) and Ulex spp. (gorse). The Betula spreads rapidly by seed, therefore, to maintain this species as a vital component of the mosaic, rather than a dominating feature, constant input is required. The Betula and Ulex are generally maintained at a suitable level of cover by paid contractors and by regular work parties of volunteers in the autumn and winter months. At present there are a number of areas requiring reduction in the birch cover.

The accompanying Map details the works which are to be carried out over the five year period. For ease of understanding, the total area is described below in the divisions used within the HLS agreement.

Field no. 0907

Hectares: 54.60

This covers the main body of the Common and most of the area is fenced in and grazed all year round by a herd of pedigree Dexter cattle. The northerly part includes: lowland heath, including grass species and dwarf shrubs; scrub of birch and gorse; alder carr; and areas of mire, where springs emerge. On the south eastern side of theCommon there is a small area of approximately 0.75 hectares of broadleaved woodland, which is outside the fence line. The southerly part is a thin strip of woodland pasture. On the northern plateau there are a number of ephemeral ponds, the result of previous gravel extraction. There is one bridle way across the area, however there are a large number of paths, as the area is open access and widely used by the local community for recreation purposes.

In order to maintain the current regime of grazing, it will be necessary to undertake extensive repairs to the fencing, which is now over twenty years old.

Field nos. 5240; 6123; 8521; 8638

Hectares: 4.47; 1.29; 2.5; 0.46

These are all unfenced areas to the east of the main area. The vegetation is mainly scrub of birch and gorse, with some small heath areas, which have developed where scrub has been cleared previously. Within area 8521, there has been an issue with invasive species, including Rhus coriaria (sumac) and Laurus nobilis (laurel), as the result of neighbouring residents dumping their garden waste. There are also a number of ephemeral ponds in the areas 5240 and 8521. The areas also contain access paths.

Philosophy for the Management of Silchester Common

The overall aim is to maintain Silchester Common in line with its SSSI status and objectives, as detailed above. Whilst fulfilling these conservation objectives, it is also necessary to ensure that the Common remains as a valuable recreational resource to the community. In order to achieve these aims, a detailed plan has been drawn up, showing the specific management to be carried out in different areas of the common.

Grazing

This will be continued by the herd of pedigree Dexter cattle, which are an integral part of the management scheme for the common. By grazing, the cattle assist in the maintenance of a diversity of species on the common. They are also very beneficial in scrub control, by grazing re-growth after clearance. As a result of the cattle making tracks through the vegetation, they provide natural fire breaks, which are useful in the rare event of an accidental fire. The herd currently has 21 cattle and the aim is to maintain the number between fifteen and twenty four. Necessary replacement /repairs to the fencing will be undertaken as a matter of priority. The day to day management of the cattle is undertaken by a local herdsman, while purchasing replacements is the responsibility of the Commons Management Committee.

Scrub control

Scrub will be controlled by both the regular volunteer work parties and by employing contractors to cut birch and gorse, either by hand or by machine. Where appropriate, approved herbicide will be applied to the stumps of felled trees and saplings, to lessen re-growth. Mechanical weed-wiping of suitable areas may also be undertaken. In order to maintain the overall mosaic of vegetation as attractive habitat for fauna, there will continue to be some areas of scrub cover on the common. The gorse is an important habitat for the Dartford Warbler and in order to retain this there will be a rolling programme of removal of the older gorse to be replaced by gorse of heights suitable for the bird. Over the five year period the intention is to clear 12 hectares of scrub.

Bracken control

There are a number of pockets of bracken over all the areas of the common. In order to keep this at suitable levels, there is a programme to remove 5 hectares of bracken over the five year period. The intention is to use the herbicide Asulox, however, should this become unavailable a suitable alternative will need to be sought.

Mire areas

In order to maintain the variety of species present there will be targeted removal of trees and scrub in these areas. This will ensure that the wet areas remain as such, and can thus support the specific rare plants which survive there.

Footpath clearance

Occasionally it will be necessary for work parties to clear paths which have become overgrown, in order to ease continued public access. To this end, there will also be on-going maintenance of the wooden walkways, which have been built over the low lying wet areas.

Volunteer Work Parties

These are organised throughout the autumn and winter months. They are a vital aspect of the management of the Common, both in terms of the work achieved and the opportunity they provide for people to gain a greater understanding of the conservation of the area.

Control of Invasive Species

Where there are invasive species, such as sumac and laurel, these will be cleared and treated with approved herbicide where necessary.

Proposed work

From April 2011 to March 2013
Field number / Work to be carried out / Hectares / Code on map
0907 / Scrub (birch and gorse) clearance / 1.19 / A1
0907 / Scrub (birch and gorse) clearance / 0.66 / A2
0907 / Scrub (birch and gorse) clearance / 0.51 / A3
0907 / Scrub (birch and gorse) clearance / 0.70 / A4
0907 / Scrub (birch and gorse) clearance / 0.17 / A5
0907 / Scrub (birch and gorse) clearance / 0.53 / A6
0907 / Scrub (birch and gorse) clearance / 0.52 / A7
0907 / Scrub (birch and gorse) clearance / 1.12 / A8
0907 / Scrub (birch and gorse) clearance / 0.60 / A9
Total scrub clearance / 6.00
0907 / Chemical bracken control / 2.50 / P1
0907 / Post and wire fencing / 1183metres / L1 and L2
0907 / Bridle gate / 2 of / P3
From April 2013 to March 2016
Field number / Work to be carried out / Hectares / Code on map
0907 / Scrub (birch and gorse) clearance / 0.95 / A10
0907 / Scrub (birch and gorse) clearance / 0.68 / A11
0907 / Scrub (birch and gorse) clearance / 4.36 / A12
Total scrub clearance / 5.99
0907 / Chemical bracken control / 2.50 / P21
0907 / Post and wire fencing / 1073metres / L3 and L4
0907 / Bridle gate / 2 of / P4

Report Dated: 22nd October 2011

Author: Anne Tynegate (Commons Management Committee)

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