Arabis glabra (L.)

Tower mustard, Bwllpwllblod y ffwch SYN.: glabra (L.), perfoliata Lam.

Status: Vulnerable Lead partner: Plantlife International Status in Europe: Not threatened 28 10-km squares post 1987 UK BAP Priority Species since 1998

UK Biodiversity Action Plan: The following are the current targets following the 2001 Targets Review:

T1 - Maintain the natural range of this species in Britain. T2 - Establish populations at five sites within its historic range by 2008. T3 - Establish an ex-situ programme to protect genetic diversity, create a reserve population and to provide experimental material.

Progress on targets as reported in the UKBAP 2002 reporting round can be viewed by selecting this species and logging in as a guest on the following web page: http://www.ukbap.org.uk/2002OnlineReport/mainframe.htm.

The full Action Plan for Arabis glabra can be viewed on the following web page: http://www.ukbap.org.uk/UKPlans.aspx?ID=106.

Contents

1 Morphology, Identification, & Genetics ...... 2 1.1 Morphology & Identification ...... 2 1.2 Taxonomic Considerations ...... 2 1.3 Genetic implications ...... 3 2 Distribution & Current Status ...... 3 2.1 World ...... 3 2.2 Europe ...... 3 2.3 ...... 5 2.3.1 ...... 6 2.3.2. Northern Ireland, Scotland & Wales ...... 9 3 Ecology & Life Cycle ...... 9 4 Habitat Requirements ...... 11 4.1 The Landscape Perspective...... 11 4.2 Communities & Vegetation ...... 11 4.3 Summary of Habitat Requirements ...... 12 5 Management Implications...... 14 6 Threats/ Factors leading to loss or decline or limiting recovery...... 14 7 Current Conservation Measures...... 14 1

7.1 In Situ Measures...... 14 7.2 Ex-Situ Measures ...... 15 7.3 Research Data ...... 16 7.4 Monitoring Arabis glabra and the Common Monitoring Standard...... 16 8 References ...... 16 9 Acknowledgments ...... 17 10 Contacts ...... 17 11 Links ...... 18

1 Morphology, Identification, Taxonomy & Genetics

1.1 MORPHOLOGY & IDENTIFICATION Tufted biennial; stems erect to 1m, pubescent below, glabrous above; basal leaves entire to sinuate-lobed; flowers numerous; petals pale yellow (Stace, 1991). Seedpods are straight, four-angled siliquas with brown seeds in single rows under each valve (see Figures 1 & 2).

Figure 1 – Arabis glabra flowers and Figure 2 – Close-up of Arabis glabra seedpods (Photograph by S. stem (Photograph by S. Williams). Williams).

1.2 TAXONOMIC CONSIDERATIONS None.

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1.3 GENETIC IMPLICATIONS No studies on genetic diversity within this species have been carried out. Such a study would be desirable to elucidate relationships between populations, especially in the Brecklands.

2 Distribution & Current Status

2.1 WORLD In Europe, N. Asia, North America and Africa; introduced in Australia (Clapham et al, 1987), as illustrated in Figure 3 below.

Figure 3 – The world distribution of Arabis glabra (Hulten & Fries, 1986). Reproduced with kind permission of Koeltz Scientific Books.

2.2 EUROPE Throughout Europe to 70o N in Norway (Clapham et al, 1987). Status in Europe - Not Threatened.

Where known, the status of Arabis glabra in each country in Europe is given in Table 1.

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Table 1 - Country by country status of Arabis glabra across Europe (*Country codes are taken from Flora Europaea as of 1964 with red data book listings where available [Definitions of the red list categories]).

COUNTRY* IUCN STATUS NOTES SOURCE(S) LISTING Al ALBANIA Au AUSTRIA WITH LIECHTENSTEIN Az AZORES Be BELGIUM WITH LUXEMBOURG Bl ISLAS BALEARES Br BRITAIN INCL ORKNEY, VU Has declined strongly across Wigginton ZETLAND & ISLE OF MAN most of its British range, and is (1999). now known from only six sites in southern England, twelve in West Norfolk and a few in the West Midlands. Bu BULGARIA Co CORSE Cr KRITI WITH GAVDHOS KARPATHOS, & KASOS Cz CZECHOSLOVAKIA Bures et al Absent (2001). Da DENMARK Fa FAEROER Fe FINLAND INCLUDING Not listed Kotiranta et al AHVENANMAA (1998). Ga FRANCE Not listed Olivier et al (1995). Ge GERMANY Not listed Ingelog et al (1993). Gr GREECE EXCLUDING Not listed Phitos et al KRITI & ISLANDS OUTSIDE (1995). EUROPE Hb IRELAND BOTH NORTHERN IRELAND & THE REPUBLIC OF IRELAND He SWITZERLAND Not listed Antonietti (1991). Ho NETHERLANDS Hs SPAIN WITH GIBRALTAR & ANDORRA, EXCL BL Is ICELAND It ITALY Not listed Conti et al (1997). Ju YUGOSLAVIA Stevanović SERBIA Not listed (1999). Lu PORTUGAL No NORWAY Po POLAND Not listed Kaźmierczakowa & Zarzycki (2001). 4

COUNTRY* IUCN STATUS NOTES SOURCE(S) LISTING Rm ROMANIA Rs(N) NORTHERN Not listed Kotiranta et al DIVISION (1999). Rs(B) BALTIC Environmental DIVISION Protection Estonia Department of Latvia Not listed the Republic of Lithuania Lithuania (1992). Rs(C) CENTRAL DIVISION Rs(W) SOUTH- WESTERN DIVISION Rs(K) KRYM (CRIMEA) Rs(E) SOUTH-EASTERN DIVISION Sa SARDEGNA Sb SVALBARD (SPITSBERGEN BYORNOYA, JAN MAYEN) Si SICILIA Su SWEDEN Not listed Gärdenfors (2000). Tu TURKEY Not listed Ekim et al (2000).

2.3 UNITED KINGDOM OVERVIEW The British distribution of Arabis glabra is shown in Figure 4. Arabis glabra was formerly locally widespread in southeast England, the Midlands and East Anglia, with sites northwards to the Scottish Borders. Historic centres of distribution were in Yorkshire, the Midlands, East Anglia and the Thames Basin, and the current range reflects this, although no sites have been recorded in Yorkshire since 1972. Sites in Scotland and others in the north of England are considered to have been non-native, although the basis of this distinction is not known. Arabis glabra was extinct at all of these northern sites by 1900. The only site recorded in Wales was in Monmouthshire where it was last seen in 1900.

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Figure 4 - British distribution of Arabis glabra.

The total number of 10km squares from which Arabis glabra has been recorded is 133 (110 native and 23 non-native). This declined to 28 between 1987 and 1999 (26 native, 2 non- native), (Preston et al, 2002). The species was only recorded from 29 native sites in 20 10km squares during intensive survey work between 1996 and 1999 (Wheeler, 1999). The current area occupied by this species is only 15% of its total historic area. Stewart et al classed Arabis glabra as a Nationally Scarce species in 1994. It is now included on the priority list of the UK Biodiversity Action Plan (UK Biodiversity Steering Group, 1995), and is classified as a Vulnerable species in the UK, i.e. facing a high risk of extinction in the wild in the medium-term future, in the 3rd edition of the British Red Data Book of Vascular (Wiggington, 1999).

2.3.1. ENGLAND (Based on English Nature’s Natural Areas)

Arabis glabra appears to have declined considerably during the 20th century (see Table 2), although this is difficult to quantify precisely due to the seed bank that is thought to be very long-lived, and its habit of persisting for only short periods at some sites. A closer analysis of the records may show that it has been less abundant in the past than the distribution maps suggest. The great majority of losses from vice-counties occurred in the 19th century 6

and the first half of the 20th century (Wheeler, 1999), but losses from within its range have continued to the present day.

The majority of extant sites are within the Breckland and Severn & Avon Vales Natural Areas. The major centre of distribution is in the East Anglian Breckland Natural Area. In this area it occurs largely in the rides and clearings associated with commercial forestry plantations established on former open heath and grassland in the early 20th century. It still grows on open sites such as Barnham Cross Common and Berners Heath, and it is likely that it would have been more widespread in such situations before afforestation. Within the afforested area the populations fluctuate and sometimes disappear entirely depending on recent management. Plants appear where heavy machinery has recently been used, persisting until the perennial vegetation of the rides re-establishes. One unusual site for Arabis glabra at a Forest Enterprise depot is regularly sprayed with the broad-spectrum herbicide Atrazine. Atrazine suppresses the surrounding vegetation but allows the poorly competitive Arabis glabra to thrive. Arabis glabra has disappeared from much of the rest of its former East Anglian distribution, presumably as a result of agricultural intensification, but it still persists in two sites, one on a road verge near Ipswich, and the second in an abandoned sand pit north of Norwich. Both of these sites are in the East Anglian Plain Natural Area.

The other centre of distribution is in the west Midlands in the Severn & Avon Vales Natural Area, where it is currently known from seven sites in and two in . This area appears to be very different to the Breckland, but they have in common well-draining sandy soils and a dry climate, the Severn Vale being in the rain shadow of the Welsh mountains (White & Smith, 1982). It is possible that the present distribution represents the relics of a past system of land management, and this is due to be investigated as part of the current PhD research. In this area, all recent sites are on road verges and beside tracks.

The remaining current sites appear to show little geographical correlation. When these are examined in an historical context however, they are seen to be relics of a former centre of distribution on acidic sandy soils in the London Basin and on the Wealden Greensand of the Surrey/Hampshire border. The six remaining sites are in a variety of habitats including road verges, the edges of a heavily managed common, hedge bottoms, the edges of a car park and unimproved grassland. The only other extant site is on the edge of a minor road crossing a common on greensand in North Wiltshire. It has been known there since 1650, although it is currently of erratic appearance.

Table 2 - Present & former distribution of Arabis glabra in England by vice-county (Wheeler, 1999).

TOTAL NUMBER OF V-C NO. VICE-COUNTY EXTANT SITES % DATE & PLACE(S) OF (POST 1990) / DECLINE LAST RECORD EXTINCT SITES 6 North Somerset 0/1 100 Bath 1796 7 North Wiltshire 1/1 0 Chittoe 1994 12 North Hampshire 2/12 86 Kingsley & Woolmer Forest 2002 13 West Sussex 0/4 100 Southwick 1925 15 East Kent 0/2 100 Stourmouth 1899 16 West Kent 0/5 100 Leybourne Wood 1964 7

TOTAL NUMBER OF V-C NO. VICE-COUNTY EXTANT SITES % DATE & PLACE(S) OF (POST 1990) / DECLINE LAST RECORD EXTINCT SITES 17 Surrey 1/4 80 Milford Common 2002 18 South Essex 0/1 100 High Beech? 19 North Essex 0/3 100 Weeley 1945 20 Hertfordshire 0/37 100 Waterford Tip 1976 21 Middlesex 1/3 75 Stain Hill Reservoirs 2002 22 Berkshire 1/4 80 Woodley, Dinton Pastures LNR 2002 23 Oxfordshire 0/4 100 ? 1970 24 Buckinghamshire 1/5 83 Hedgerley, Gerrards Cross, 1999 25 East Suffolk 1/20 95 Claydon 2001 26 West Suffolk 4/13 76 Barnham Cross Common 2002 27 East Norfolk 1/20 95 Bylaugh 2002 28 West Norfolk 8/12 60 Ickburgh 2003 29 Cambridgeshire 1/0 0 Gamlingay 1995 31 Huntingdonshire 0/1 100 Buckden 1904 32 Northamptonshire 0/1 100 ? 1960 34 West 2/1 33 Bromsberrow Heath and Gloucestershire M50 2002 35 Monmouthshire 0/1 100 Newport, Alexandra Dock 1900 37 Worcestershire 7/17 71 Several sites 2002 38 Warwickshire 0/5 100 Stoneleigh 1891 39 Staffordshire 0/6 100 Three sites 1901 40 Shropshire 0/8 100 ? 1970 54 North Lincolnshire 0/1 100 Sibsey 1897 55 Leicestershire 0/4 100 Three sites 1933 56 Nottinghamshire 0/6 100 Barrow Hills 1904 57 Derbyshire 0/4 100 Deepdale 1985 59 South Lancashire 0/2 100 Two sites 1932 62 North-east 0/8 100 Two sites 1972 Yorkshire 63 South-west 0/3 100 Auckley-Finningley 1888 Yorkshire 65 Mid-west Yorkshire 0/10 100 West Tanfield 1981 66 Durham 0/2 100 ? 1947 67 South 0/4 100 Jesmond 1934 Northumberland 69 Westmorland 0/6 100 Cliburn 1983 70 Cumberland 0/5 100 ? 1900 77 Lanarkshire 0/1 100 Partick 1891 80 Roxburghshire 0/2 100 Heavyside 1860 82 East Lothian 0/2 100 North Berwick 1894 87 West Perth 0/1 100 Glen Devon 1875 88 Mid Perth 0/3 100 Three sites 1898 89 East Perth 0/1 100 Killiecrankie 1898 8

TOTAL NUMBER OF V-C NO. VICE-COUNTY EXTANT SITES % DATE & PLACE(S) OF (POST 1990) / DECLINE LAST RECORD EXTINCT SITES 90 Angus 0/1 100 Kinnaird 1848 99 Dumbarton 0/1 100 Glasgow, Bowling Bay Green 1900

[NOTE: Arabis glabra is still extant in the vice-counties highlighted in bold.]

2.3.2. NORTHERN IRELAND, SCOTLAND & WALES Arabis glabra is not now found in these countries.

3 Ecology & Life Cycle The ecology and population dynamics of Arabis glabra are the subject of a PhD research project being carried out by Jo Nightingale at the University of Sussex (Nightingale, 2002). The research includes Dianthus armeria, a species believed to have a similar ecology, and it should answer many questions of immediate relevance to the conservation management of both species. Additional research into seed biology and germination ecology is being carried out by Dave Watson at Bath Spa University College, and an experiment designed to investigate the response of a population of Arabis glabra to different cultivation regimes is underway in Breckland. This dossier will be updated with the results of these as they become available. This information will also be synthesised to form a Biological Flora account for publication in the Journal of Ecology.

There is little existing information on the ecology of Arabis glabra, but there is some anecdotal information upon which some working hypotheses can be based to enable some educated guesses to be made about methods for conservation management.

Arabis glabra appears to behave largely as a species with a biennial lifecycle - the seedlings germinate during the early spring; develop into rosettes during the first summer and then over-winter. These rosettes can be easy to find at sites with large populations. The flowering stem begins to elongate in the following spring, with flowers appearing from the end of May onwards, most flowering being over by the end of July by which time the flowering stem can be as tall as 1.5m (see Figure 5). Seedpods begin to ripen from mid June onwards, but seeds are retained in the pods, being released gradually, and some can still be found in pods in the following February. A life cycle of this sort is not unusual in biennial species, the seeds having an innate dormancy that requires exposure to cold conditions to break, germination occurring in response to increasing temperature in the spring. This is similar to the behaviour of Dianthus armeria (D Watson, pers comm.).

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Figure 5 – Arabis glabra towering in flower (Photograph by S. Williams).

Other observations suggest that things are not this simple however. Collected seed has been germinated immediately on sowing in the autumn (Wheeler, 1999), but it is not known whether these seedlings flowered in the following summer or required a longer period to accumulate sufficient energy reserves to produce flowers. Neither is it known what proportion of the seeds germinated at this time, and it is possible that even more seedlings would have emerged in the following spring. Plants can be induced into prolonging their lives by damage, for instance by rabbit grazing. In one area at Stain Hill Reservoir, rabbits had eaten the flowers. Most of these plants had then produced secondary flower spikes that still had unripe pods in November, and many plants had produced vegetative growth from their bases, suggesting that they were about to over-winter again to flower in the following year. Dianthus armeria also has a flexible strategy with up to 5% of plants in large populations having an annual lifecycle, and a few plants being able to flower in more than one year (Wilson, 2002). The related species Arabis hirsuta, which grows in similar habitats, is thought to be a short-lived perennial “or rarely a monocarpic semi-rosette hemicryptophyte”, germinating largely in the autumn (Grime et al, 1988).

The results from observations of marked plants are awaited for full elucidation of the life cycle of this species (Nightingale, 2002).

In terms of established strategy (Grime et al, 1988), Arabis glabra is probably best classified as a stress-tolerant ruderal. The related Arabis hirsuta has no mycorrhizal associates (Harley & Harley, 1986).

It appears likely that Arabis glabra has a persistent seed-bank. This is a very important adaptation for a short-lived that relies on unpredictable site conditions, and means that it can survive for periods during which these are unsuitable. The length of time for which the seed can persist is unknown, but such information is very important when considering the suitability of sites for restoration management. The presence of persistent seed banks can give the impression of a mobile species capable of forming extensive metapopulations (eg Ickburgh Fields), but in fact it is more likely that Arabis glabra is simply reappearing from the seed-bank as management becomes suitable. Preliminary results suggest that Arabis glabra seed can be dispersed by wind, but the distances are not known (J Nightingale, pers comm.). 10

4 Habitat Requirements

4.1 THE LANDSCAPE PERSPECTIVE Arabis glabra was probably once a species of open grassland that experienced occasional disturbance from erosion or the actions of herbivorous animals. Much of the decline of this species has probably been due to the loss of such habitats through the enclosure of commons, agricultural improvement of pastures, urban development and forestry. There are still some sites in Breckland where it occurs in such habitats, but the great majority of extant sites are in track and roadsides, forestry rides, sand pits, car parks and other marginal habitats that may represent the final vestiges of suitable habitat within its former range (Table 3). Its existence in such fragments is tenuous, depending on its persistent seed-bank and haphazard disturbance from such factors as the passage of vehicles, rabbit digging, forestry management and even herbicide application. Deliberate conservation management is now probably the most important factor in the survival of Arabis glabra in Britain.

The soils on which Arabis glabra grows are almost always sandy and freely draining. In the Breckland the soils are sandy glacial drift over chalk, while in Worcestershire they are derived from Triassic sandstones. Soil chemistry is unknown, but evidence of the surrounding vegetation suggests that soils are largely neutral. Its apparent preference for sandy soils probably reflects the slow development of perennial vegetation on these nutrient-poor soils, and the persistence of the effects of disturbance for more than a single season. Arabis glabra appears to have a preference for well-illuminated sites, and if the site slopes it is usually to the south or west.

Table 3 - Habitat types in which Arabis glabra is found in Britain.

HABITAT TYPE NUMBER OF SITES Track and roadsides 14 Unimproved grassland 4 Forest rides 7 Sand pits 3 Reservoir banks 1 Hedgebanks 1

4.2 COMMUNITIES & VEGETATION A considerable amount of vegetation data has been collected during the course of Plantlife International's Back from the Brink project for Arabis glabra (Stagg, 1998; Wheeler, 1999; Wilson, 2002). This has however not yet been fully analysed. The following comments are a subjective assessment only. All community names refer to the National Vegetation Classification (NVC), (Rodwell, 1992).

The typical vegetation of road and trackside sites is MG1 Arrhenatherum elatius grassland, ungrazed but subjected to periodic cutting and disturbance. This is normally a relatively species-poor community dominated by tussock-forming grasses including Arrhenatherum elatius, Dactylis glomerata, Holcus lanatus and Festuca rubra. Other abundant perennial species include Plantago lanceolata, Achillea millefolium, Agrostis capillaris, Silene latifolia and Glechoma hederacea. Much of this vegetation in which Arabis glabra occurs shows the effects of disturbance, with other biennial and annual species including Crepis capillaris, Vicia sativa, Bromus hordaceus and Heracleum sphondylium. Frequent ruderal perennials include Artemisia vulgaris, Urtica dioica and Convolvulus 11

arvensis. Scrub species including Rubus fruticosus, Crataegus monogyna and Prunus spinosa are also prominent in some stands, but are kept under control by disturbance and cutting.

Grassland sites in the Breckland that may represent a semi-natural habitat for Arabis glabra have vegetation approaching SD8 or SD10 inland sand-dune grassland. Festuca rubra and Agrostis capillaris are dominant with frequent Carex arenaria, Galium verum, and annual and biennial species including Echium vulgare, Erodium cicutarium, Geranium molle, Reseda luteola, Trifolium arvense, Plantago coronopus etc. Grasslands in the Breckland forestry rides are mesotrophic variants of this community, but where these have been recently disturbed ruderal species become abundant.

More open disturbed sites such as those at Stain Hill Reservoir and Dinton Pastures are rich in ruderal species including Vulpia bromoides, Crepis capillaris, Poa trivialis, Artemisia vulgaris, Medicago lupulina and Daucus carota. At Stain Hill, part of the population grows on the steeply shelving, west facing concrete embankments of the reservoir in mats of Tortula ruralis, Brachythecium albicans and Bryum spp, with other plants growing in crevices in a brick wall.

In summary, Arabis glabra is found in a range of vegetation types. These are characterised by occasional disturbance, and are open with patches of exposed soil. They range from well- established SD8 grasslands with natural disturbance from erosion and rabbits in the Breckland, through roadside stands of MG1 in Worcestershire and elsewhere, to stands of disturbed vegetation on artificial substrata at some sites including Stain Hill Reservoir and Dinton Pastures. Some stands have been invaded by scrub, and scrub species persist where clearance has been carried out.

4.3 SUMMARY OF HABITAT REQUIREMENTS Habitat features important to Arabis glabra in Britain have been summarised in Table 4.

Table 4 - Habitat features important to Arabis glabra in Britain.

Type Physical & topographical A lowland species reaching a maximum of around 80m near Kidderminster. Soils are almost always sandy and freely draining, derived from a range of substrata including artificial ones. Sites are generally flat or gently sloping to the south and west. Sites are unshaded. Processes Arabis glabra needs exposed soil for germination. This is created either by erosion, by rabbit digging or by human activity. Arabis glabra appears to be palatable to herbivores including rabbits, and is frequently grazed off. Few sites are grazed by stock. Vegetation/structural Arabis glabra occurs in open vegetation with exposed soil particularly during the germination and seedling establishment period. It ranges from species-poor dune vegetation through Arrhenatherum elatius grassland to disturbed ruderal vegetation. Chemical Soil chemistry is unknown but in general soils appear to be 12

Type near neutral and deficient in macronutrients.

A preliminary assessment of habitat requirements for Arabis glabra can be made, but these will perforce be modified in the light of the findings of the current experimentation.

Arabis glabra is a short-lived species that has relatively simple requirements. It needs to produce seed regularly and requires gaps in the vegetation for seedling establishment. The seeds germinate readily and need no special treatment other than perhaps low temperatures over winter.

In essence, Arabis glabra needs a sandy, drought-prone soil on which vegetation cover Figure 6 – Arabis glabra at develops slowly. This should be subject to Milford Common, Surrey (S. occasional disturbance to expose soil and Williams) buried seed. Disturbance should not be so frequent however as to destroy germinated seedlings and no disturbance should be carried out during the flowering and seedling period. Plants retain seeds into the winter, so vegetation should not be cut too early, and attention should be paid to the disposal of cuttings.

Management varies between sites. At most sites, there has been a lapse of traditional management in recent years leading to development of dense, tussocky grassland and scrub. Conservation management has started only recently, largely in response to priority listing in the UKBAP and Plantlife International's Back from the Brink project.

Factors that have maintained sites in suitable condition, in the absence of specific conservation management, include soil erosion, rabbit digging and grazing and chance disturbance by forestry vehicles. Where conservation management has been undertaken, successful measures have included radical disturbance by disc cultivation and bulldozing (Breckland sites, N. Gibbons pers comm.), large-scale scrub clearance (Milford Common –see Figure 6), and intensive vegetation control (Broome Road Verge, A. Shepherd pers comm.). Only one site (Berner’s Heath) is known to be grazed at the moment.

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5 Management Implications Some preliminary suggestions for the management of Arabis glabra can be made, but may be modified in the light of results of current research:

Annual cutting of vegetation between January and February, with disposal of cuttings.

Cultivation of the site. Periodicity of this will depend on the speed at which perennial vegetation colonises the site. No more than a third of the site should be cultivated each year. Cultivation should be carried out between December and February.

Grazing. Any grazing should be very extensive. Sheep should not be used.

6 Threats/ Factors leading to loss or decline or limiting recovery Massive changes in the British countryside have combined to cause the large declines in the range of Arabis glabra over the past hundred years. These have included the loss of common land to urbanisation, forestry and agricultural improvement, and the abandonment of traditional management over the areas that are left (see Table 5). These processes, particularly the latter, continue and threaten the few remaining sites.

Table 5 - Threats to the survival of Arabis glabra in the UK.

Type Threat Habitat destruction Agricultural improvement. Afforestation. Industrial/urban development. Mineral extraction. Successional Abandonment of traditional extensive grazing.

Neglect of verge cutting.

Grazing Rabbit grazing can be detrimental to some populations.

7 Current Conservation Measures

7.1 IN SITU MEASURES OVERVIEW Table 6 gives an indication of the number of extant sites for Arabis glabra receiving protection as Sites of Special Scientific Interest (SSSIs). The majority of sites are now being managed favourably (see Table 7), either under informal or statutory agreements.

Table 6 - Number of Arabis glabra sites included in SSSIs.

TOTAL NUMBER OF SITES NUMBER WITHIN % IN SSSIS SSSIS 33 12 36

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Table 7 - Management of Arabis glabra sites.

MANAGEMENT STATUS NUMBER OF SITES Favourable management 19 Management suitable but no agreement 2 Management under negotiation 4 Unsuitable management 5 Unknown 3

CURRENT CONSERVATION SCHEMES A number of countryside conservation schemes offer assistance to land managers conserving grassland and other sites currently or formerly supporting populations of Arabis glabra. Amongst the most appropriate are:

Environmentally Sensitive Areas The ESA scheme aims to maintain and often to enhance the scientific, landscape, historical and cultural values of key environmental areas across England. To date 22 areas have been identified as ESA, and 10,915 agreements signed, encouraging the sympathetic management of 532,000 hectares of land. Agreements typically last for a ten-year period. The whole of the Breckland area is included within an ESA. The scheme is administered by DEFRA.

Countryside Stewardship The Countryside Stewardship scheme is the Government’s principal scheme for the sustainable management of valued areas in the wider countryside, through the payment of grants to enhance, restore and recreate targeted landscapes and sites. It operates outside Environmentally Sensitive Areas. Through the scheme, farmers and land managers enter 10-year agreements to manage land in an environmentally sensitive manner in return for annual payments. Like the ESA programme, this scheme is administered by DEFRA. Tomorrow’s Heathland Heritage This is a £25 million-plus, ten-year programme that seeks to restore and recreate lowland heathland in local communities around the United Kingdom. The programme includes up to 26 separate site-based heathland projects, where scrub/tree clearance, heathland recreation, and reinstatement of traditional management practices is helping to make a significant contribution to the Government’s heathland biodiversity action plan. It may be relevant to three sites for Arabis glabra. English Nature leads the project with the support of over 140 partner organisations. The Heritage Lottery Fund supports the project financially.

1.1.2.1 PROTECTED ROAD VERGES Protected road verges. Many district councils run protected road verge schemes. Six sites for Arabis glabra are listed as protected road verges. In many cases, these schemes offer little more than freedom from the normal cutting regime, but they can give the opportunity to carry out more constructive management programmes. One site on the verge of the M50 in Gloucestershire has a Highways Agency management plan.

For more information about each programme access the appropriate link by clicking on the scheme title.

7.2 EX-SITU MEASURES There are four accessions of Arabis glabra seed in the Millennium Seed Bank as follows: Brettenham; Brettenham Heath; Waterford, near Hertford and Claydon. Plants grow readily from seed and are grown by several botanists, including as part of research projects at Bath

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Spa University College and Sussex University. Arabis glabra is now being grown in the Order Beds at the Royal Botanic Gardens, Kew, and at the Barn Elms Wetlands Centre.

7.3 RESEARCH DATA Although there is currently no experimental data available on Arabis glabra, the results of research being carried out at Bath Spa University College, Sussex University and by Plantlife will become available over the next three years.

7.4 MONITORING Arabis glabra AND THE COMMON MONITORING STANDARD Individual flowering plants of Arabis glabra are relatively easy to distinguish and count. An effort should be made to assess the numbers of non-flowering rosettes, as these indicate the condition of the site for regeneration and the future health of the population. Non- flowering rosettes can be difficult to find, particularly in denser stands of vegetation. Most populations are small, so complete counts should be made.

8 References Antonietti, A. (1991). ? La vegetazione forestale del Cantone Ticino, v. n° 3505. Biodiversity Steering Group (1995). Biodiversity: the U.K. Steering Group report. H.M.S.O., London. Bures, et al (2001). Black and Red List of Vascular plants of the Czech Republic – 2000. Príroda, Praha, 18: 1-166, 2001. Čeřovský, J., Feráková, V., Holub, J., Maglocký, Š. & Procházka, F. (1999). Červená kniha ohrožených a vzácných druhů rostlin a živočichů ČR a SR. Vol. 5. Vyšší rostliny. Príroda a. s., Bartislava. Clapham, A.R., Tutin, T.G. & Moore, D.M. (1987). Flora of the British Isles. 3rd edition. University Press, Cambridge. Conti, F., Manzi, A. & Pedrotti, F. (1997). Liste Rosse Regionali delle Piante d’Italia. Associazione Italiana per il World Wildlife Fund & Società Botanica Italiana, Camerino, Italy. Conti, F., Manzi, A. & Pedrotti, F. (1997). Liste Rosse Regionali delle Piante d’Italia. Associazione Italiana per il World Wildlife Fund & Società Botanica Italiana, Camerino, Italy. Ekim, T. et al (2000). Red Data Book of Turkish Plants. Ankara. Environmental Protection Department of the Republic of Lithuania (1992). Red Data Book of Lithuania: Rare and Endangered Species of Animals, Plants and Fungi. Vilnius, Lithuania. Gärdenfors, U. (2000). Rödlistade arter i Sverige 2000 – The 2000 Red List of Swedish Species. ArtDatabanken, SLU, Sweden. Grime, J.P, Hodgson, J.G. & Hunt, R. (1988). Comparative Plant Ecology. Chapman & Hall, London. Harley, J.L. & Harley, E.L. (1986). A checklist of mycorrhizas in the British flora. New Phytologist, 105: 1-102. Hulten, E. & Fries, M (1986). Atlas of north European vascular plants north of the Tropic of Cancer. II. Koeltz Scientific Books, Konigstein, Germany. Ingelög, T., Andersson, R. & Tjernberg, M. (1993). Red Data Book of the Baltic Region: Part 1 – Lists of threatened vascular plants and vertebrates. Swedish Threatened Plants Unit, Uppsala, Sweden.

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Jalas, J. & Suominen, J. (eds) (1972, 1973, 1976, 1979, 1980, 1983, 1986, 1989, 1991, 1994, 1996). Atlas Florae Europaeae. Vols. 1-11. The Committee for Mapping the Flora of Europe and Societas, Biologica Fennica Vanamo, Helsinki. Kaźmierczakowa, R. & Zarzycki, K. (2001). Polish Red Data Book of Plants. Polish Academy of Sciences, Cracow, Poland. Kotiranta, H., Uotila, P., Sulkava, S. & Peltonen, S.-L. (eds). (1998). Red data book of East Fennoscandia. Ministry of the Environment, Finnish Environment Institute & Botanical Museum, Finnish Museum of Natural History, Helsinki, Finland. Nightingale, J. (2002). Analysis of population dynamics of Arabis glabra and Dianthus armeria in Great Britain. Interim report to University of Sussex and Plantlife. Olivier, L., Galland, J-P. & Maurin, H. (1995). Livre Rouge de la Flore Menacée de France. Tome I: Espèces Prioritaires. Paris. Phitos, D. et al (1995). The Red Data Book of Rare and Threatened Plants of Greece. WWF. Athens. Preston, C.D., Pearman, D.A. & Dines, T.D. (2002). New Atlas of the British & Irish Flora. University Press, Oxford. Rodwell, J.S. (ed). (1992). British Plant Communities, Volume 3, Grasslands and Montane Communities. University Press, Cambridge. Stace, C.A. (1997). New Flora of the British Isles (2nd ed.). University Press, Cambridge. Stagg, P. (1998). The current status of Arabis glabra in England in 1997. Plantlife Report no. 96. Plantlife, London. Stevanović, V. (ed). (1999). Red Data Book of Flora of Serbia, 1: Extinct and critically endangered taxa. Belgrade. Stewart, A,, Pearman, D.A. & Preston C.D. (1994). Scarce Plants in Britain. JNCC, Peterborough. Wheeler, B.R. (2000). Tower mustard (Arabis glabra). Report on work undertaken during 1999. Plantlife Report no. 145. Plantlife, London. White, E.J. & Smith, R.I. (1982). Climatological Maps of Great Britain. ITE, Penicuik. Wiggington, M.J. (ed.) (1999). British Red Data Books 1 Vascular plants. 3rd edition. Peterborough: Joint Nature Conservancy Committee. Wilson, P.J. (2002). Tower Mustard Arabis glabra in 2001. Plantlife Report no. 209. Plantlife, London. 9 Acknowledgments

Thanks are due to previous Arabis glabra project officers Tim Rich, Penny Stagg and Belinda Wheeler, Nick Gibbons of Forest Enterprise, Alan Shepherd of Worcestershire Wildlife Trust, Rosie Clift of Gloucestershire Wildlife Trust and members of the London Biodiversity Partnership.

10 Contacts Plantlife International 14 Rollestone Street Andrew Byfield - [email protected] Salisbury Or Wiltshire Amanda Miller - [email protected] SP1 1DX Tel: 01722 342730 Philip Wilson [email protected]

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11 Links ARKive species web page for Arabis glabra http://www.arkive.org/.

Plantlife International’s Back from the Brink project is supported by English Nature, Scottish Natural Heritage & the Countryside Council for Wales. Plantlife International wishes to acknowledge the financial support of English Nature.

Work on Arabis glabra is supported by:

Original draft by Phil Wilson, Edited by Plantlife International First draft dated February 2003 Last revised 28 April 2004

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