Historical Background and Conservation Management
Date posted
18 October 2013
1 INTRODUCTION
Silchester Common lies between the villages of Silchester and Pamber Heath and is
part of a large Site of Special Scientific Interest which covers 306 ha. This extensive
and diverse area is of great value for the recreation of local residents and has long
been recognised for its rich flora and fauna. The varied habitats of the area support
a corresponding variety of plant and animal life, with many rare species present,
making this one of the best sites of its size in Hampshire.
Silchester Common itself is 56 ha in total and is one of a few surviving tracts of
heathland in the Thames Valley region of North Hampshire. It is owned and looked
after by Silchester Parish Council. An internationally endangered habitat,
approximately 90% of the heathland in north Hampshire existing at the end of the
18th century has been destroyed. The area covered by Basingstoke and Deane
Borough Council has lost 98% of its former heaths and currently half of the
remaining 160 ha are now severely degraded by abuse or neglect. In an attempt to
recover from this position a management committee of local people and specialist
advisors has been formed to ensure that a programme of work required to restore
the common is carried out.
The culmination of extensive research, planning and consultation started in 1989
resulted in the entry of the Parish Council into a Countryside stewardship scheme
with MAFF and the formation of a ten year management plan . This was extended in
1992 with a further 10 year Stewardship agreement with Defra and a five year
Wildlife Enhancement Scheme with English Nature. In 2011 we entered a five year
Higher Level Stewardship agreement with Natural England.
Full details of the background to this work are covered the report entitled “
Background Report to Silchester Common Grazing Proposals 1992” also on this
website.
2 GENERAL SITE INFORMATION
Site Name: Silchester Common Grid Reference: SU 620 623
Map Coverage: OS Sheets 175 (1: 50000)
District Council: Basingstoke and Deane Parish Council: Silchester
Status: Part of the SSSI including Upper and Lower Inham’s Copse, Pamber Forest
and Lordswood. Total area 306.8 ha. First notified in 1951. Last notified, 22.10.93.
Confirmed 17.6.94
Site Area: 56 ha (Boundaries shown on Figure 1)
Ownership: Silchester Parish Council
Funding: Previously major funding has come from from Defra Countryside
Stewardship Scheme, English Nature and Silchester Parish Council with additional
funding from other organisations. Our current main funding is from Natural
England.
3 SITE DESCRIPTION
3. i. Physical Features
3.i.a. Soils
Geologically, Silchester Common lies in the Thames Valley of north Hampshire. Most
of the Common lies on an outcrop of Plateau gravel but the lower part off the
Common lies on the Lower Bagshot Beds. The Bagshot beds comprise of clays,
acidic sands and poor soils and like the plateau gravel provide only limited nutrients.
The drainage qualities of these sands and the limiting nutrient availability support an
open Birch-Oak woodland community with an understorey dominated by heathland
vegetation. Where the clays are exposed drainage is impeded which gives rise to
wet heathland and mire communities.
3.i.b. Topography
Silchester Common covers 56 ha the highest point of which lies around the 100m
contour line. The Bagshot Beds characteristically form a hardpan through a capping
of gravel and various other factors. The resulting topography is that of several
plateaus varying in size but all with the ground falling away sharply, especially on
southern slopes.
3.i.c. Hydrology
There are three mires on Silchester common that drain into two streams that run
southwards to join Silchester Brook below Lords Wood. The topography and geology
are such that the plateaus of the north part of the site are fast draining into the
streams below them. The southern end of the site, from Lords Wood to Silchester
Road, is very wet underfoot. This is due to a combination of the drainage north of
this area and the higher clay content observed in this part of the site.
3.ii. Biological Features
3.ii.a. Habitats
Silchester Common is dominated by a variety of heathland habitats which cover
most of the 56 ha. The remainder comprises of alder carr, mire and a border of
open woodland and scrub. The heathland area is one of the best examples of the full
transition from dry to wet heathland habitats around the Hampshire-Berkshire
border. It is also one of the last few remaining remnants.. The northern part of the
Common is dominated by birch and Common gorse scrub, which gives way to dry
heathland which makes up the majority of the common. The dry heath graduates
into humid then wet heath towards the streams. In the middle of the site, adjacent
to the narrowing at the south end of Lords wood, birch and common gorse again
predominate and the southern narrow strip of the site is dominated by oak
woodland. A complete National Vegetation Classification (NVC) survey was carried
out in 1992 and little has changed since this survey was carried out, with the
exception of the birch encroachment in the north and other smaller areas of Sallow
scrub. The heathland communities on the common are excellent examples of their
kind and recent management has preserved their value for conservation.
3.ii.b. Plant Species
The wide range of habitat types found on Silchester Common is reflected in the high
number of plant species found there. Of the heathland habitats in northeast
Hampshire over 30% of the true heathland plant species are to some degree
categorised as rare. This proportion of rarities is also reflected in the animal groups,
which makes heaths such as Silchester Common a high priority for conservation
management. Information from the NVC survey and other records indicates that the
Common supports over 320 species of higher plant, 29 bryophytes and 75 fungi.
3.ii.c. Animal Species
The diversity of habitats is also reflected in the fauna found on Silchester Common.
There is a very diverse Aranae and insect fauna. Hymenoptera are well represented
including a nationally scarce solitary wasp which thrives on the bare ground found in
heathland habitats. Lepidoptera are well documented and there are over 200 species
listed for Silchester Common alone.
There is an extensive list of over 100 bird species recorded on or near the common
which includes several Nationally Scarce Species and three Red Data Book species
associated with heathland; Caprimulgus europaeus, Nightjar, Lullua arborea,
Woodlark, Sylvia undata, Dartford Warbler. Refer to the list at the end of this report.
The other significant vertebrate fauna are the reptiles. Four of the six native species
are found on the Common, which provides the ideal habitat for them. They are
Lacerta vivipara, Common Lizard, Anguis fragilis, Slow worm, Natrix natrix, Grass
snake and Vipera berus, Adder. Of the larger vertebrates Oryctolagus cuniculus,
rabbit, Vulpes vulpes, fox and Capreolus capreolus, Roe deer are present.
3.iii. Cultural Features
3.iii.a. Common land status
Silchester Common has common land status and The rights of the Common are
registered under the Commons Registration Act, 1965, for 29 properties on or
beside the Common. The majority of these rights are for grazing but they also
include Estovers, Turbary and Gravel extraction. However, the previous lack of
interest and practice is part of the reason for the initial decline of the common.
Gravel extraction and the digging of peat (Turbary) created ponds and wet areas
whilst grazing controlled the dominant and invasive plant species, thus the habitat
diversity of the common was maintained.
3.iii.b. Public Access and Use
There are only two official Rights of Way through Silchester Common, a bridleway
and a footpath, however there is easy public access from a boundary path and other
points around the site. A survey of local residents commissioned in 1992 showed
that the establishment of a fence in accordance with grazing proposals provided
adequate access.
3.iii.c. Past Management
During the 1980’s until 1990 scrub clearance was regularly carried out by volunteer
groups and the Manpower Services Commission. This combined with uncontrolled
heath fires helped to maintain open heath. However, in the long term fires have
served to encourage birch and bracken invasion. Since 1992 scrub clearance, stump
treatment and bracken spraying have been carried out by contractors according to
the previous management plan. A three year consultation process was begun in the
early 1990’s and the Common was fenced and a grazing regime introduced in
February 1995. Woodland thinning, boardwalk construction and scrub clearance
have also been organised by Silchester Parish Council.
4 MANAGEMENT OBJECTIVES
4.i. Short-term Management
4.i.a. Rationale
Although scrub clearance and uncontrolled fires have kept much of Silchester
Common open, invasion by scrub species is still a major issue. Birch is the main
problem which as a pioneer species has a very effective seed dispersal mechanism
and can readily produce thick scrub in the absence of natural check such as grazing.
The worst of the scrub is in the north of the site resulting from severe fire damage
in earlier years. Fires exacerbate the problem as burnt sites are ideal for birch and
bracken invasion. Invasion of open areas like heathland by scrub species such as
birch, gorse and sallow is part of the natural process of succession. This process also
acts on a smaller scale in the wetland areas where purple moor-grass accumulates
in large tussocks that smother the wet areas and eventually dry them out. The
cattle have proved beneficial in relation to the purple moor grass by breaking it
down with their hooves as they graze the area. The task of bringing the succession
process under control on Silchester Common is an ongoing one. To maintain a
rolling mosaic of different habitats is a continuous process and the grazing regime is
part of the scrub control process.
4.i.b. Scrub Clearance
The majority of scrub to be cleared from Silchester Common is birch. Unfortunately
birch coppices readily and therefore stump treatment is required to prevent
regrowth. Where the cleared birch trees are very small the herbicide treatment is
carried out in the following summer by application to the leaves. Treatment of
stumps of leaves adds to the clearance costs, but these methods have proved very
effective.
Whilst controlling the birch scrub is the main priority on the Common it is important
to remember that birch is of great value for invertebrate fauna and therefore it is
desirable to retain some on the Common. There are many insectivorous bird species
that feed in birch as well as predatory insects. Birch is the third best species in
terms of the number of invertebrate species it supports and open heathland is a
situation that appears to benefits many of them. Mature birch trees provide habitat
for various species of Fungi and make attractive landscape features but it is
important to retain a diversity of ages to benefit the widest group of associated
species. Sallow is another species that needs to be controlled especially in the mires
and wet areas.
4.i.c. Bracken Control
Bracken invasion has become a widespread problem right across the country in
recent decades. The problem is exacerbated on areas such as heathlands where
uncontrolled fires are common. In the absence of management it forms dense
stands which not only shade out other species but secrete toxic root exudates which
other species cannot tolerate. Bracken also forms a dense litter layer which
smothers other plant species and hence reduces floral diversity. Large bracken
stands also present a public health issue, the spores can be a problem for those
suffering from asthma. As with birch, however, bracken does have a wildlife value.
It provides excellent cover and on heathlands this is often used by snakes and
lizards although heather is just as good and a more appropriate species for the
heathland community. There are over 40 insect species that are able to feed on
Bracken despite it’s toxic nature e.g. the larvae of the Brown Silver-line Moth,
Petrophora chlorosata, which has been recorded on Silchester Common. The
greatest wildlife value of bracken is in woodland and sheltered glades and therefore
bracken control should be concentrated on the areas of heathland whilst part of the
stands in the south of the Common are retained. Currently, European legislation is
being debated regarding the continuing use of Asulox, the herbicide treatment used
for bracken.
4.i.d. Gorse Restoration
Gorse is widespread across Silchester Common and much of it is young and healthy,
however there are a few stands where it is becoming over mature to the point of
being degenerate. At this stage the plant becomes leggy and comprises mostly of a
woody stem with little foliage. Gorse is of great value to many species for food and
shelter and so it is of benefit to bring most of the gorse stands under management
to prevent them reaching the degenerate stage and losing value for wildlife.
Effective management is easy and can be incorporated in to general scrub control
but without stump treatment. In degenerate stands not all cut stumps will regrow
because of their age but those that do will be rejuvenated. Some degenerate bushes
should be left to enhance structural diversity providing they do not constitute a fire
risk. A rolling programme of gorse clearance results in a mosaic of gorse of different
stages and heights which are beneficial to a variety of bird species. Dwarf Gorse,
Ulex minor, is also present much of the Common but does not require management.
4.i.e. Restoration of Ponds and Wet Areas
The flora and fauna of heathland ponds, as with most, benefit from plenty of
sunlight, however, most of the ponds on the common were surrounded by dense
scrub. The removal of this scrub will greatly improve the conditions in the ponds by
reducing leaf fall into the pond and reducing the shade cast on the water. Again it is
important to retain structural diversity, so a small amount of vegetation can be
retained on the northern edges of ponds. Tall and emergent vegetation is valuable
for emerging Dragonflies and Damselflies which in turn provide a food source for
birds.
Another problem in the ponds and wet areas on the Common is the development of
large tussocks of Purple moor-grass, Molinia caerulea. These smother and dry out
the ground and need to be grazed or removed manually. Sallow encroachment is
another problem in wet areas and one that needs careful treatment.
Non-native aquatic species can be particularly aggressive and have a devastating
effect on aquatic communities. It is important to maintain vigilance to prevent the
establishment of plants such as New Zealand swamp stonecrop or the introduction
of fish.
4.ii. Long-term Management
4.ii.a. Rationale
As with any managed site it is important to have a long-term management regime
to preserve and enhance the quality of habitat achieved by restoration work. The
long term regime should be one of maintenance rather than any repetition of costly
initial tasks. Such a regime should have three main objectives:



To create maximum habitat diversity, thereby ensuring that the full range of
species can survive, with specific management targeted at particular rarities
as required.
To keep nutrient levels in the ecosystem low, which is essential for the
continued vigour and survival of the heathland plant communities.
To prevent the succession of scrub and Bracken and the subsequent loss of
open heathland habitats and their wildlife.
These three objectives are usually compatible with each other but as with any long
term management it is important to monitor the effect of such management
techniques to avoid over use and potential damage to any part of the heathland
community. The most commonly used management techniques are considered
below.
4.ii.b. Gorse Management
Common gorse is widespread on Silchester Common and is present in stands of
varying ages due to previous management and uncontrolled fires. This provides
wide structural diversity in the stands but mature gorse bushes provide the best
combination of food and shelter and are particularly important for Dartford Warblers
during the winter. Coppicing on a 12-15 year rotation is the best way to maintain
good quality mature gorse stands. It is best carried out at the end of the winter with
all the debris removed. The coppicing regime should aim to maintain a minimum of
50% of the gorse on the site as mature bushes in any one year. However, the
impact of uncontrolled fires must be taken into consideration as they will have the
same effect as coppicing. It may also be necessary to stump treat some gorse along
the paths to help prevent the spread of a fire and keep paths open.
4.ii.c. Grazing
Following a three year consultation process, Silchester Common was fenced in the
winter of 1994/95 and grazing by a mixed herd of 25 cattle began in February 1995.
In the following years the grazing stock has changed including New Forest Ponies,
Dexter Cross cattle and Highland cattle. Annual surveys were carried out in the early
years of the grazing to assess the impact of the grazing regime on the flora of the
Common. A number of exclosures were erected in different plant communities
across the common and surveys of the flora within six of them and adjacent to them
were carried out. The resulting reports have highlighted benefits and disadvantages
which point to a continuation of the grazing regime but with some changes.
Behavioural observations of the cattle and ponies on the site revealed that the
ponies tended to spend most of their time in the wooded and improved areas whilst
the Highland cattle tended to stay in the wet areas.
Cattle were observed to browse on all three kinds of heather on the Common with a
tendency to concentrate on the young growth on the plant tips. This will encourage
further new growth and will be of benefit to the Silver-studded butterfly, Plebejus
argus, which relies on it as a food source as a caterpillar. Some trampling damage
occurred to the woody stems of the mature Calluna plants but this too has it’s
benefits by creating small patches of bare ground which are used by a wide group of
species. Invertebrates utilise bare ground for basking, hunting, burrowing and
mating whilst reptiles and ground nesting birds also benefit aswell as pioneer plant
species.
The preferred grazing areas of the Highland cattle were the wet mire areas which
has both advantages and disadvantages. Trampling and grazing in these areas has
broken down the Purple moor-grass tussocks that were smothering the mires and
drying them out. However this is a species that needs control not eradication as the
tussocks it produces provide important hibernation sites for reptiles and
invertebrates. Another disadvantage of the reduction in Purple moor-grass is ability
of tree saplings to germinate in the newly created open ground. The cattle do eat
some of the seedlings but there are so many that it is impossible for the problem to
be kept under control by the present stock numbers. Increasing the numbers of
livestock alone is not a viable option as trampling damage is already adversely
affecting the Sphagnum in the mires and overgrazing is also a problem for some
species. The most notable example of this is Bog asphodel ,Narthecium ossifragum,
which has had a marked decline.
Generally the presence of livestock on the Common is having a beneficial effect.
Grazing is removing large amounts of combustible material and the presence of
livestock may act as a deterrent to those thinking of starting a fire. The movement
of livestock around the site is creating new micro habitats as discussed earlier and
the diversity of age and structure in the heathland areas is increasing .
Since 2001 pure bred Dexter cattle have grazed the Common. These small, hardy
animals are well suited to year round grazing without the need to remove them from
the Common. Their small size reduces the damage to the wet bog areas and they
have less of tendency towards these areas, regularly grazing across the whole of the
fenced-in area.. In addition, the use of a separately fenced meadow, part of Pamber
Forest Nature Reserve, permits summer grazing which, in turn, reduces the
pressure from grazing on summer flowering species.
APPENDIX
Records of Bird Species found on Silchester Common
Table 1 89 species recorded on Silchester Common
Specific Name
Anas crecca
Anas platyrhnchos
Gallinula chloropus
Fulica atra
Accipiter gentilis
Accipiter nisus
Buteo buteo
Falco tinnunculus
Falco subuteo
Circus cyaneus
Falco peregrinus
Alectoris rufa
Perdix perdix
Phasianus colchicus
Vanellus vanellus
Gallinago gallinago
Limosa limosa
Common Name
Teal
Mallard
Moorhen
Coot
Goshawk
Sparrowhawk
Common Buzzard
Kestrel
Hobby
Hen Harrier
Peregrine Falcon
Red Legged Partridge
Grey Partridge
Pheasant
Lapwing
Snipe
Black Tailed Godwit
Scolapax rusticola
Tringa ochropus
Actitis hypoleucos
Columba oenas
Columba palumbas
Streptopelia decaocto
Streptopelia turtur
Cuculus canorus
Tyto alba
Strix aluco
Caprimulgus europaeus
Apus apus
Picus viridis
Dendrocopus major
Dendrocopos minor
Lullula arborea
Alauda arvensis
Turdus merula
Turdus pilaris
Turdus philomelos
Turdus iliacus
Turdus viscivorus
Sylvia communis
Sylvia borin
Sylvia undata
Sylvia atricapilla
Hirundo rustica
Delichon urbica
Anthus trivialis
Anthus pratensis
Motacilla alba
Motacilla cinerea
Troglodytes troglodytes
Prunella modularis
Erithacus rubecula
Luscinia megarhynchos
Saxicola rubetra
Saxicola torquata
Oenanthe oenanthe
Sitta europaea
Certhia brachydactyla
Garrulus glandarius
Pica pica
Corvus monedula
Corvus frugilegus
Corvus corone
Sturnus vulgaris
Passer domesticus
Fringilla coelebs
Phylloscopus sibilatrix
Phylloscopus collybita
Woodcock
Green Sandpiper
Common Sandpiper
Stock Dove
Wood Pigeon
Collared Dove
Turtle Dove
Cuckoo
Barn Owl
Tawny Owl
Night Jar
Swift
Green Woodpecker
Greater Spotted Woodpecker
Lesser Spotted Woodpecker
Woodlark
Skylark
Blackbird
Fieldfare
Songthrush
Redwing
Mistlethrush
Whitethroat
Garden Warbler
Dartford Warbler
Blackcap
Swallow
House Martin
Tree Pipit
Meadow Pipit
Pied Wagtail
Grey wagtail
Wren
Hedge Sparrow
Robin
Nightingale
Whinchat
Stonechat
Wheatear
Nuthatch
Tree Creeper
Jay
Magpie
Jackdaw
Rook
Carrion Crow
Starling
House Sparrow
Chaffinch
Wood Warbler
Chiffchaff
Phylloscopus trochilus
Regulus regulus
Muscicapa striata
Aegithalos caudatus
Parus palustris
Parus ater
Parus montanus
Parus caeruleus
Parus major
Carduelis carduelis
Carduelis spinus
Carduelis cannabina
Carduelis chloris
Acanthis flammea
Loxia curvirostra
Pyrrhula pyrrhula
Emberiza citrinella
Emberiza schoeniclus
Miliaria calndra
Jynx torqullia
Willow Warbler
Goldcrest
Spotted fly catcher
Longtailed Tit
Marsh Tit
Coal Tit
Willow Tit
Blue Tit
Great Tit
Goldfinch
Sisken
Linnet
Green Finch
Redpoll
Crossbill
Bullfinch
Yellowhammer
Reed Bunting
Corn Bunting
Wryneck
Table 2 12 Species recorded overflying Silchester Common
Specific Name
Larus ridibudus
Larus marinus
Larus fuscus
Larus argentatus
Larus canus
Phalacrocorax carbo
Ardea cinerea
Numenius arquata
Numenius phaeopus
Pandion haliaetus
Cygnus olor
Branta canadensis
Common Name
Black Headed Gull
Great Black Back Gull
Lesser Black Back Gull
Herring Gull
Common Gull
Cormorant
Grey Heron
Curlew
Whimbrel
Osprey
Mute Swan
Canada Goose
Table 3 24 Species recorded close to Silchester Common
Specific Name
Aythya fuligula
Tringa totanus
Sylvia corruca
Falco columbarius
Athene noctua
Riparia riparia
Pluvialis apricaria
Alcedo atthis
Anthus campestris
Lymnocryptes minimus
Common Name
Tufted Duck
Redshank
Lesser Whitethroat
Merlin
Little Owl
Sand Martin
Golden Plover
Kingfisher
Tawny Pipit
Jacksnipe
Upupa epops
Motacilla flava
Anthus spinoletta
Locustella naevia
Passer montanus
Coccothraustes coccothraustes
Lanius excubitor
Ficedula hypoleuca
Egretta garzetta
Acanthis flavirostris
Lanius collurio
Phoenicurus phoenicurus
Phoenicurus ochruros
Acrocephalus schoenobaenus
Hoopoe
Yellow Wagtail
Water pipit
Grasshopper Warbler
Tree Sparrow
Hawfinch
Great Grey Shrike
Pied Flycatcher
Little Eagret
Twite
Red Backed Shrike
Common Redstart
Black Redstart
Sedge Warbler