| Lowland dry acid grassland | | The Nightjar |
| The Woodlark | | Tower Mustard |
| The Silver-studded blue | | The Adder or Northern viper |
In contrast to the Lowland
Hay Meadows (White Admiral 53,) our Lowland Dry Acid Grassland has not
been so badly lost to agriculture due to the low fertility of the soils of the
Brecklands and Sandlings. Happily, much semi‑natural habitat is still to
be found in both of these areas, and special measures are being taken to
preserve their natural character, where the dry acid grassland exists in mosaic
alongside lowland heathland (a BAP habitat in its own right; see White Admiral 42). The Brecklands support a variety of unusual
moths like the Grey Carpet, and wildflowers
such as Tower Mustard, as well as woodlark, nightjars and stonecurlews,
whilst the Sandlings are home to a dozen small colonies of the Silverstudded
Blue butterfly and the rare antlion Euroleon nostras (Suffolk Natural History Vol 37, p57).
Both areas incorporate
substantial Sites of Scientific Interest, and the sandy soils accommodate
interesting lichens as well as adders and thousands of rabbits ‑ the
unpaid managers of the grassland. The following pages present the action plans
for some of the BAP species to be found here, and incorporate some objectives
that now look unlikely to be achieved by the 2004 target date. The Sandlings
Group and the Brecks Project exist to further the aims of these plans, and the RSPB
MoD and FE are playing important
roles as major landowners.
Lowland dry acid grassland
Acid grassland occurs on the nutrient‑poor, freely‑draining soils with a pH ranging from 4 to 5.5. It is found mainly in the Sandlings and Breckland areas of Suffolk.
1 Definition
This plan includes all the acid grassland which occurs in Suffolk as an integral part of the Sandlings and Breckland heathland landscape. Smaller areas of acid grassland can also be found on stretches of vegetated shingle along the coast.
Acid grassland is characterised by a species‑poor plant community dominated by sheep's fescue, sheep's sorrel and common bent. Other species which are often present in the sward include sand sedge, wavy hair grass, tormentil, and heath bedstraw. The summer parched soils in Suffolk often support stands of acid grassland which are rich in both mosses and lichens. In addition, acid grassland in Suffolk is noted for a number of rare and nationally scarce spring annual plants.
These include several clovers e.g. clustered and suffocated, mossy stonecrop and in the Breckland area, a number of early flowering plants such as spring and breckland speedwells.
Birds of conservation concern which are associated with acid grassland include woodlark, stone‑curlew and nightjar.
Any of the invertebrates occurring in acid grassland are species which do not occur elsewhere. Ground dwelling and burrowing invertebrates particularly favour the open acid grassland swards which typically contain bare sandy areas.
Current status
2.1 Local
The loss of unimproved acid grassland mirrors the loss of other unimproved grassland types in Suffolk. Agricultural intensification, particularly the use of agrochemicals and irrigation has resulted in a substantial loss of acid grassland in the county. Extensive afforestation in the Sandlings and Breckland has also contributed to the drastic loss of the habitat. Further losses can be attributed to an increase in urban development particularly around Ipswich. Recent assessments of the county's resource of this habitat are 820 ha (2.7% of the national resource).
2.2 Natural Areas
Suffolk Coast and Heaths, Breckland and the Fens, East Anglian Plain.
3 Current factors affecting the habitat in Suffolk
Agricultural
improvements through ploughing and reseeding, liming, irrigation, fertiliser
and herbicide applications.
Reduction
in the rabbit population leading to an encroachment of open acid grassland
heath with self‑sown pines, birch and bracken.
Afforestation.
Mineral
extraction.
Other
development including airbases, housing, roads, golf courses.
Atmospheric
pollution, the effects of which have not been fully assessed.
4 Current action
A
number of Special Protection Areas (SPAs)
in Suffolk e.g. Minsmere ‑Walberswick Heaths and Marshes contain
stands of acid grassland where they form part of a complex mosaic of important
habitats.
Significant
areas of acid grassland are designated as SSSI or nonstatutory sites (County
Wildlife Sites).
Significant
areas of acid grassland are in coastal areas and being regenerated in
Breckland.
Agri‑environment
schemes in Suffolk i.e the Environmentally Sensitive Areas scheme and the
Countryside Stewardship scheme provide the main financial incentives to
encourage appropriate management of unimproved grassland.
The
Sandlings, Suffolk Coasts and Heaths and the Breckland projects manage
extensive areas of heathland which include a significant proportion of the acid
grassland resource.
Project
Officers also provide landowners with advice on conservation management and
grant aid where appropriate.
5 Action plan objectives and targets
Maintain
extent of ecologically valuable acid grassland.
Secure
restoration management for all significant stands of acid grassland with the
aim of achieving favourable status by 2010.
Seek
to promote the establishment of acid grassland through agrienvironment schemes
or wherever feasible as part of new developments such as industrial or housing
estates.
Nightjar (Caprimulgus europaeus)
The Nightjar is a summer migrant that utilises heathland and Young conifer plantations as nesting and
feeding habitat. Its range declined drastically over the last century, but has
now begun to increase in numbers. The nightjar has a very fragmented and
localised range.
1 Current status
1.1 National
The nightjar has been declining in numbers and range for much of this century, reaching a low point of 2,100 males in 1981, with a decline in range of 52% between 1968‑72 and 1992. There has been a partial recovery in the population which reached 3,400 males in 1992. The species now breeds mainly in southern England. Lowland heathland and young forestry plantations are now the most important habitats. An increase in forestry clear‑fells as a result of major storms and forest management have assisted recent increases, with over 50% of the total population found in this habitat in the 1992 survey.
1.2 Local
Between 1981 and 1992, the population of males in Suffolk increased by 157% to 308. The number of sites where these individuals were found has also increased at a similar rate. Forest clear‑fells and Breckland heaths (Norfolk and Suffolk) support about 10% of the UK population. The Breckland population may have increased since the start of afforestation.
Between the two Atlas periods, the nightjar disappeared from five 10 km squares in Suffolk. In the Provisional Suffolk Breeding Bird Atlas (1993), 25 2km tetrads (3% ) had records of nightjars, 20 with breeding records.
1.3 Natural Areas
Breckland, Suffolk Coast & Heaths.
1.4 Protection
The nightjar is protected under the Wildlife and Countryside Act, and is listed on Annex 1 of the EC Birds Directive and Appendix 11 of the Bern Convention.
2 Current factors causing loss or decline
· The area of heathland in the UK has undergone a dramatic reduction during the course of this century due to agricultural land claim, afforestation and development. It is estimated that 40% of England's lowland heathland has been destroyed since the 1950s.
Where
heathland lacks appropriate management,
it will become unsuitable as nesting habitat due to invasion by bushes and
trees.
Nightjars
require extensive areas of suitable feeding habitat, especially uncultivated
land. The loss of such habitats within a few kilometres of the nesting area may
result in a decline in the number of birds.
It
is possible that a decline in the availability of large insects caused by
changes in agriculture (such as the indirect effects of pesticides) and/or
climatic change, may have affected nightjar populations.
In
commercial forests, nightjars nest in the young stages of plantations, while
there is still bare ground between trees. If no other suitable habitat becomes
available in other new or young stands, local population declines could occur
as the recently planted blocks mature.
Although
the recent increase in nightjar numbers in this region is dramatic, a long term
decline is noted from the early part of this century The causes of the decline
nationally are also the most likely candidates for local decline in this
period. The recent upturn in numbers could be attributed to the clearing of
forests and the subsequent creation of wide rides and glades, or equally, to
the October 1987 storm which destroyed large areas of forestry in the Suffolk
Coastal Forest. Here, the increases in numbers may be reversed when the
plantations reach an age unsuitable for nightjars.
3 Current action
Detailed
research into the ecology of nightjars nesting in Thetford Forest has been carried out by the RSPB with
FC help. FE's forestry practice is now
aimed at maintaining a constant area of young plantation as good habitat for
breeding nightjars (included in the Thetford
Forest Design Plan).
The
nightjar has benefited from heathland
management encouraged
by
the Breckland ESA (Tiers 1 and 2 where heathland is promoted with suitable grazing regimes, ‑a
site specific Management Plan is drawn up taking local factors into account)
and Countryside Stewardship Scheme.
The
1997 survey of forest plantations in Norfolk and Suffolk up to 12 years of age
produced an estimate which suggested an increase in the number of pairs since
the 1992 survey. This study concluded that the creation of a more diverse age
class structure will help the nightjar.
Specific
management work in the Suffolk Sandlings
at Minsmere (RSPB) has
demonstrated the potential benefit for nightjars of restoring heathland
management in ways appropriate to the location.
A
survey of nightjars in Thetford Forest is being conducted as part of a PhD
studentship with UEA.
FE
have re‑established 80 ha of heath from forest on the Suffolk
Sandlings and are currently involved in
improving the state of this heath. FE are also committed to re‑establish
300 ha of heath in Thetford Forest as
part of the HLF Tomorrow's
heathland Heritage project.
4 Action plan objectives and targets
1 Maintain a local population of at least 308 churring males in Suffolk.
2 In line with national targets, aim to increase the Suffolk population by 18% to at least 364 churring males and increase the range by 5% to at least 26.2km tetrads.
Woodlark (Lullula arborea)
The woodlark is a species historically associated with heathland. More recently woodlarks have colonised
farmland and felled forestry plantations. This species has suffered a historic
decline in numbers and range, but has increased substantially in the last 10
years.
1 Current status
1.1 National
The woodlark was formerly found across Britain, south from Yorkshire, but is now largely restricted to five core areas: Devon, east Dorset / south Hampshire (including the New Forest), the Surrey / Hampshire border, Breckland and the Suffolk coast. The number of 10km squares occupied in the breeding season decreased by 62 / (from 198 to 73 10km squares) between 1968‑72 and 1988‑91. However, since 1986 (when the population was estimated to be around 250 pairs) the population has increased with up to 620 pairs breeding in 1993, and around 1,500 pairs in 1997. The nesting habitats are varied and include farmland, recently felled forestry plantations (mainly in East Anglia) and heathland. in southern England and the Suffolk coast. Results from the 1997 survey suggest that around 50% of breeding pairs across the country are now nesting on set‑aside and other weedy fields. The recent increase in the population has resulted largely from new plantation habitats within the core areas. Little is known of the woodlark's winter requirements and distribution, though there appears to be some movement southwards within England and to the continent.
1.2 Local
The 1997 national survey found between 403 and 457 breeding pairs in Suffolk (30% of the UK population). Nearly 340 pairs were
found in Thetford Forest (Norfolk and Suffolk) and so represents a substantial proportion of the local (and national) population. The Suffolk Sandlings held around 16% of the national total, and Brecklands held around 30% of then national total.
The woodlark has disappeared from three 10km squares between the two Atlas periods in Suffolk. However, it has been found in 2 previously empty 10 km squares. Recent RSPB / FE research (1997) has shown the woodlark population to be increasing on all surveyed sites (except two, where there was no change) within Thetford Forest, and on surrounding heath.
The 1987 storm destroyed a large proportion of forestry plantings in the Suffolk Coastal Forest, which has subsequently been restocked, although some areas have been retained as open space specifically to retain woodlark in the long term. However, large areas of suitable habitat will soon become too densely covered to support the current woodlark population, and the number of breeding pairs may decline in the future.
The woodlark populations in East Anglia utilise those plantations with trees up to 4 years old, or up to 6 years when ploughing between rows of 3‑6 year old conifers is included. This means that regular clear‑felling and re‑planting is required for a healthy population.
1.3 Natural Areas
Suffolk Coast & Heaths, Breckland.
1.4 Protection
The woodlark is protected under Schedule 1 of the Wildlife and Countryside Act 1981 and listed on Annex 1 of the EC Birds Directive and Appendix II of the Bern Convention.
2 Current factors causing loss or decline
An
estimated 40% of England's lowland heathland has been lost since the 1950s (for
example 80% of the Suffolk Sandlings heathland has been lost in less than 100
years, and the remaining land is often highly degraded). This has led to a loss
of feeding and nesting habitats for woodlarks.
Woodlarks
require a mosaic of bare ground or short vegetation for feeding, and tussocks
of vegetation with disturbed ground for nest sites, and up to 3 ha can be
needed for a single territory. Lack of appropriate management can lead to sites
becoming, unsuitable for the species. Rabbits play a key role in creatingbare
ground and short grass (less than 5 cm) for feeding at many sites, and their
decline following myxomatosis in the 1950s may have played a significant part
in the decline of the woodlark.
Severe
winter weather and, in particular, snow cover has had an adverse impact on
winter survival. The hard winters of 1962/63 and 1981/82 had a considerable
impact on woodlark populations on the southern heathlands. The East Anglian
populations do not seem to be influenced as much as the southern populations.
In
Suffolk, the woodlark utilises restocked forestry plantations, and as such the
preferred habitat is not under threat of destruction in this area, but
management decisions may affect the population {e.g. spacing of trees and after
planting management). Increasing tree planting density may lead to closing of
the canopy 1‑2 years earlier and fewer 'holes' in older crops. This could
lead to 5% fewer woodlark in the forest.
3 Current action
41.4%
of the UK population {1997 survey) is found on SSSI sites.
Woodlarks
occur on a number of heathland nature reserves that are managed partly for
their benefit. The RSPB reserve at Minsmere {Suffolk) has recently been
colonised by woodlarks after heathland restoration.
Research
has been carried out by RSPB and FC on the habitat use of woodlarks in
restocked conifer plantations in Breckland. This has allowed the impact of
changes in the age structure of forests to be predicted, enabling Design Plans
in Thetford Forest to be modified and so maintain good numbers of woodlarks.
The
work of the Suffolk Sandlings Group has assisted this species on a number of
heathland sites.
The
woodlark has also benefited from heathland management encouraged by the
Breckland ESA (Tiers 1 and 2 promote the suitable management of heathland with
grazing regimes which match the local needs of wildlife, Tier 4 provides winter
stubble which is used by woodlark).
The
woodlark has also benefited incidentally from the provision of set‑aside
(see 1.1).
Countryside
Stewardship has aided the recreation of heathland at Minsmere (RSPB), and can
be used for aid in management of heathland.
The
recent survey (1997) revealed detailed information relating to the woodlark in
this region. The results appear to be very encouraging, reporting large
increases in populations at known sites.
FE
have produced Endangered Habitat Plans, including one for Suffolk Forests. This
includes proposals for the management of heath areas which have become
overgrown with birch and gorse. Clearing of trees and bracken has started in
some areas, and bare areas will be maintained by rotovation / ploughing.
FE
set aside six woodlark management areas totalling 80ha within the Sandlings
Forest following the 1987 storm. This was done specifically with the objective
of managing the areas optimally for woodlarks once the bulked of the restocked
area has become unsuitable. The aim is to maintain a viable population within
the forest in the long term. Optimum management has commenced. In Thetford
Forest FE are committed to re‑establishing 300ha of heath on former
forestry land as part of the HLF Tomorrow's Heathland Heritage project.
· The RSPB is currently assisting FE with a study on changes torestocking practice in Thetford Forest on woodlark populations.
4 Action plan objectives and targets
1 Maintain as a mininium a population of between 403 and 457 breeding pairs within Suffolk in the existing range of 1110 kin squares.
2 By increasing the area of suitable heathland (through initiatives like ESA, and FE's commitment to recreate heath), increase the possible breeding and feeding areas for the woodlark, and so provide scope for further population expansion in the region. B y offering winter stubble options in ESA, wintering populations may be aided.
Tower mustard (Arabis glabra)
This plant is a biennial of light nutrient‑poor, sandy soils,
usually over chalk. Although its seeds appear to be viable for many years, they
are dependent on open areas for germination. These conditions occurred in
Breckland and the Sandlings as a result of traditional management such as
extensive grazing and occasional cultivation, but these are often no longer
practical today.
1 Current Status
1.1National
Formerly fairly widespread in East Anglia and along the chalk ridge from Bedfordshire down to Hampshire and in Central England, it has suffered a severe decline since 1970, occurring in only about 15 1Okm. squares in recent years.
1.2 Local
A significant colony was discovered in 1998 on a roadside bank in Claydon Village, and there are a number of other earlier records, mainly from the Ipswich area, all of which are believed to be extinct. A Breckland species, it has been recorded at more than one site in Suffolk recently. Sporadic appearances may be due to its persistence in the seed bank.
1.3 Natural Areas
Breckland.
1.4 Protection
Classified as Vulnerable in 1999 Red Data Book. It has only general protection from uprooting under the Wildlife and Countryside Act.
2 Current factors causing loss or decline
The following changes in land management were largely responsible for the decline of Tower mustard and are now providing constraints on recovery.
· Habitat decline due to agricultural intensification.
Destruction
of heathland for housing, industry, airfields, forestry and agriculture.
Habitat
neglect, resulting in loss of open areas for regeneration.
Overgrazing
by rabbits, sheep, deer and cattle.
3 Current action
· Regular monitoring of Breckland site.
· Establishment of a Roadside Nature Reserve to protect its vulnerable urban site in Claydon, followed by regular monitoring.
Further
new sites may be found as a direct result of the county‑wide survey in
progress for Atlas 2000 and a new Suffolk Flora
4 Action plan objectives and targets
1 Maintain current sites and increase awareness.
2 Increase knowledge of former sites.
3 Investigate means of establishing the species at former sites.
Silver‑studded blue (Plebejus argus)
This is a butterfly characteristic of lowland heathland that was once
widespread across the UK, but is now confined to southern England with outposts
in East Anglia and Wales. As a caterpillar it feeds on heathers and gorse and
has a complex relationship with black ants. Adults can occur at large density
in favourable years on suitable patches of heathland.
1 Current status
1.1 National
The Silver‑studded blue was widely distributed in England at the turn of the century, but has become extinct in all counties except those in the south and south‑west, small parts of East Anglia (Norfolk and Suffolk), Wales and the west midlands. It is now common only in Dorset and Hampshire. It is absent from 65% of 10km squares that were occupied before
1940.
1.2 Local
The species was abundant in the Suffolk Brecklands, especially between Brandon and Tuddenham, as little as 50 years ago, but the last record was made in 1965. It is now confined to the Sandlings and here it was also formerly widespread, occurring on most heaths between Lowestoft and Ipswich. Colonies now occur only on the extensive heathlands of Westleton and Minsmere in the north and on a few heaths close to Ipswich and Hollesley in the south. Most are small by national standards and occupy patches of heathland of less than 2ha. Two sites were established by introductions in 1986; one is now the largest colony in the county and has stimulated the colonisation of nearby heathland.
1.2Natural Areas
Suffolk Coast & Heaths (also formerly in Breckland).
1.3 Protection
The Silver‑studded blue is listed on the Wildlife and Countryside Act 1981 with
respect to sale only.
2 Current factors causing loss or decline
· The species requires heathland on light sandy soils in an early stage of development after disturbance or burning that is characterised on the Sandlings by the presence of Bell heather (Erica cinerea), patches of loose soil and short turf conditions, once attained, can be prolonged by intense rabbit or sheep grazing or occasionally by mowing, but eventually soils will either grass or moss over andstabilise, or Ling (Calluna vulgaris) dominates, excluding large nests of the ants on which it depends (Lasius niger and L. alienus). Most colonies in Suffolk are on previous burns or areas of disturbance.
· Colonies in Suffolk are largely adequately managed and there are few factors causing further loss of colonies. However, management of many current colonies is seldom harsh enough to encourage fresh conditions for the butterfly and there is a general succession trend on many colonies. The small size of colonies restricts this type of management at many sites.
· The following have been implicated in the historical loss of colonies and may become important again in the future. They are similar to factors afflicting the lowland heathland habitat as a whole.
Destruction
of heathland habitat through industrial, housing or recreational development.
Destruction
of heathland for agriculture or forestry (the latter was probably largely
responsible for the loss of the Breckland population).
Decline
in traditional management such as grazing by livestock, cutting and burning
that maintained heathland and prevented succession.
There
are factors that currently limit the potential of the species for expansion to
other parts of the Sandlings.
Isolation
of current heathland sites.
Inappropriate
or lack of management on many heathland sites, such as winter burning or
cutting of mature heathers, gorse or other invasive heathland species without
removing the litter layer.
Many
sites could become suitable again through a programme of management that mimics
the effects of summer burning. Topsoil stripping has been shown to be effective
at creating conditions for the species and some sites in Suffolk occur in old
sandpits or other works.
3 Current action
Recovery
plans for the species have been prepared for the Sandlings Group (1996) and
Forest Enterprise (1997), giving details of necessary action to maintain the
species and encourage spread on the Sandlings.
The
Silver‑studded blue is a target species of an HLF project for the
restoration and maintenance of the Sandlings which started in 1999. An HLF bid
is also underway for the Brecks, proposing to create or restore 300ha of
heathland over the next five years.
Most
colonies occur on either heathland nature reserves or SSSIs, although the
largest colony in Suffolk, at Westleton Common, is unprotected.
· The heathland of most colonies is managed.
· Reviews of the effects of management and monitoring of all populations, including those established at introduction sites, has occurred at regular intervals since 1985, but no work on populations sizes or their relation to recent management has been carried out since 1994.
Informal
monitoring of populations is performed by Martlesham, Conservation Group and
the RSPB at Martlesham Heath and within Minsmere respectively, and by Butterfly
Conservation elsewhere on the Sandlings.
The
RSPB are establishing a colony at their reserve at Aldringham Walks.
4 Action plan objectives and targets
1 Enhance the existing population at current colonies through appropriate management.
2 Increase the number of colonies of the Silver‑studded blue on the Sandlings by two by 2004.
3 If feasible establish a population of the species in Breckland by 2004.
Adder or Northern viper (Vipera berus)
The Adder has a wide British distribution, but is found in locally isolated patches in most areas.
It is strongly associated with permeable soils, especially sediments such as
sand, alluvium, chalk, and peaty substrates. Preferred habitats include
heathland, acid and chalk grassland, mires, and coastal dunes. Adders feed largely on voles and other small mammals and
common lizards.
1 Current status
1.1 National
Although widely distributed, the Adder is absent or found only patchily in many areas. The largest colonies tend to be in extensive areas of heath and moorland, often in association with modem forestry plantations. Recent evidence indicates a decline across much of its range, particularly in central and southern England.
1.2 Local
The Adder is almost exclusively found on the Sandlings heaths and associated habitats, the Brecks, and valley mire habitats extending from the Brecks. There are also populations northwest of Lowestoft, and old, unconfirmed reports around Newmarket. The last review of status, in 1988, showed there were 46 known populations, of which most were considered small, isolated and /or vulnerable. Anecdotal evidence indicates a continued decline.
1.3 Natural Areas
Breckland, Suffolk Coast and Heaths, Broadland, East Anglian Chalk, East Anglian Plain.
1.4 Protection
Wildlife and Countryside Act 1981, schedule 5: protection against killing, injury and trade.
2 Current factors causing loss or decline
The following are known to affect Adder sites in Suffolk (in approximate order of perceived severity):
Fragmentation
of habitat by roads and arable farming.
Unsympathetic
habitat management, particularly over‑grazing, mowing and scrub
clearance.
· Agricultural intensification, particularly encroachment into grassland and heathland.
· Damage and disturbance to habitats by public pressure, such as recreational use.
· Persecution by landowners and the public.
· Habitat loss through development.
3 Current action
Criteria for designating Adder sites as County Wildlife Sites have been developed by SWT in conjunction with Froglife.
A minority of populations are actively receiving positive habitat management for Adders.
Some survey and advisory work is undertaken by SARG, Froglife and SWT.
4 Action plan objectives and targets
1 Determine the current distribution and status of Adders in Suffolk.
2 Maintain the range, distribution and viability of existing Adder populations.
3 Restore Adder populations to sites which previously supported them, where feasible, in order to recover the range and density of populations to former levels, and increase connectivity between populations.
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