Pulsatilla_vulgaris_Plantlifedossier_FINAL_Apr11.pdf

8/20/2019 Pulsatilla_vulgaris_Plantlifedossier_FINAL_Apr11.pdf

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Pasque Flower, Pulsat i l l a vulgar is Miller

RANUNCULACEAE

SYN.: Anemone pulsat i l la L.

Status: All British populations belong to subsp. vulgaris which is classified as ‘vulnerable’(IUCN Criterion A2ac; Cheffings & Farrell, 2005), and listed as a UK BAP Priority Species in2007. It is currently confined to 18 sites in 19 10km squares in England. In this accountPulsatilla vulgaris refers to subsp. vulgaris unless otherwise stated.

In partnership with:

Pulsatilla vulgaris (L.) Mill.


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Contents

1 Morphology, identification, taxonomy and genetics1.1 Morphology and identification1.2 Taxonomic considerations1.3 Genetic implications

1.4 Medicinal properties

2 Distribution and current status2.1 World2.2 Europe2.3 United Kingdom2.3.1 England2.3.1.1 Native populations2.3.1.2 Introductions2.3.2 Northern Ireland, Scotland & Wales

3 Ecology and life cycle

3.1

Life cycle and phenology3.1.1 Flowering phenology3.1.2 Flower biology3.1.3 Pollination3.1.4 Seed production3.1.5 Seed viability and germination3.1.6 Seed dispersal3.1.7 Regeneration3.1.8 Response to competition3.1.9 Herbivory, parasites and disease

4 Habitat requirements

4.1 The landscape perspective4.2 Communities & vegetation4.3 Summary of habitat requirements

5 Management implications

6 Threats/factors leading to loss or decline or limiting recovery

7 Current conservation measures7.1 In situ Measures7.2 Ex situ Measures7.3 Research Data

7.4

Monitoring and the Common Monitoring Standard

8 References9 Contacts10 Links11 Annex 1 – site descriptions13 Annex 2 – changes in population size, 1960-200614 Annex 3 – associates


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1 Morphology, identification, taxonomy and genetics

1.1 Morphology and identificationHemicryptophyte; 2-15 cm, extending to ca. 45 cm in fruit. Rhizome obliquely erect orvertical, branching, black, 2-17 mm thick, eventually decaying to form new plants. New leafrosettes arising from the branches of the rhizome by growth of lateral buds, producing groups

of leaf rosettes connected below ground by an anastomosing rhizome system. The remains ofold leaf bases protect the overwintering buds at the apex of the rhizome. Basal leaves up to11 from each rhizome apex, bipinnatisect, silky-hairy and forming a rosette. Ascending,developing during anthesis and withering in the autumn (occasionally over-wintering). Petioleto 21 cm, blade to 11 × 7 cm, 2- to 4- pinnate. Cauline leaves 2(-4), sessile, 1.7-5.3 cm,smaller and more deeply divided into linear segments (only slightly lobed), white-hairy andreaching the perianth during most of the flowering period. All leaves silky-hairy at leastinitially, the basal with pubescent petioles. On emergence the silky-villose leaves are tightlycurled around the apical growing points. Flowers solitary, terminal, erect at first but droopingafter a few days, and becoming bell-shaped (campanulate) (Fig. 1a). Buds develop during latesummer and become dormant over the winter months when they are protected by a densecovering of silky-villose hairs and the remains of the previous year’s leaves. Pedicel up to 8 cm

and bent over less than 90º at anthesis, elongating to 25 cm in fruit. Perianth-segments 6, 16-42 × 4-17 mm, deep violet-purple in British plants, more blue to violet-blue on the Continent,darker on the inside, paler and silky on the outside (rarely white or pink), subequal, onlyslightly curving outwards apically. Petals fading and becoming bleached after about a week.Stamens numerous, 50-120 per flower, crowded, the outermost shorter, sterile, club-shapedand secreting nectar. Staminodes and fertile stamens not more than half as long as perianthsegments, 15-25 mm; filaments stout at the base, tapering to the adnately attached anthers,which are bright golden-yellow before fading. Styles purple, borne on a flattened, conical,receptacle, 30-90 per flower, each with a single functional ovule. Fruit is an achene, 2-3 mmlong, with a single embryo, covered with simple, silky hairs and with a persistent featherystyle 3.5-5 cm long. The internode between the stem leaves and flower elongates considerablyafter flowering, increasing the height at which the achenes are released (Fig. 1b). Flowers 1-

3(-12) per plant, actinomorphic, hermaphrodite and protogynous in England, pollinated by avariety of insects, especially bees (Apidae: Apis, Bombus).

1.2 Taxonomic considerationsThe common name Pasque Flower has several derivations; one is reputedly from the Latin

pascha, meaning Easter, as Easter eggs were often stained by rubbing the eggs with theflowers and leaves for celebration. Originally the flower was known by the French as the‘passe-fleur’, and then changed by Gerard (who considered it to be a worthy addition to theherbaceous border) to the ‘Pasque Flower’ on account of the flowers appearing around Eastertime (Smith, 1996).


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Figure 1 – Pulsatilla vulgaris: (a) flowers, Knocking Hoe, Bedfordshire, photo by K.J Walker;(b) elongated scape and achenes, Devil’s Dyke, Cambridgeshire, photo by K.J. Walker; (c)illustration by Stella Ross-Craig (1948).

Pulsatilla vulgaris was described by Carl Linnaeus (1753) as Anemone pulsatilla in the firstvolume of his Species plantarum (p. 539)1. The Scottish botanist Philip Miller (1768) changedthe name to Pulsatilla vulgaris in the eight edition of The gardeners dictionary and this wassubsequently retained in Aichele & Schwegler’s (1957) monograph of the genus whichdescribed a number of taxa within the Pulsatilla vulgaris group. As no holotype exists a

lectotype has recently been designated from Linnaeus’ herbarium (Herb Linn. No. 710.5;Jarvis et al., 2005). This herbarium sheet contains a single flowering and two fruiting stemsbut has no collection details and thus its origin is unknown.2

Pulsatilla is a small genus within the large, primitive family Ranunculacae. The division of theLinnaean concept of ‘ Anemone’ into three genera, Anemone sensu stricto, Hepatica and

1 see http://www.biodiversitylibrary.org/page/358106#551

2 see http://www.linnean‐online.org/5012/


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Pulsatilla is now generally accepted based on both morphology and chloroplast DNA (e.g.Hantula et al., 1989). Morphologically Pulsatilla taxa are distinguished by the styleselongating greatly and becoming feathery in fruit and the presence of nectar-secretingstaminodes (both absent in Anemone sensu stricto; Akeroyd, 1993). The current worldwideclassification scheme of the Angiosperm Phylogeny Group (APG III) considers theRanunculaceae to be among the most basal of the derived Eudicots clade (Hill & Preston,

2002):APG Clade: EUDICOTSAPG Order: RanunculalesAPG Family: RanunculaceaeSubfamily: RanunculoideaeGenus: Pulsatilla Species: Pulsatilla vulgaris Mill.

The genus Pulsatilla contains around 38 species worldwide all of which occur in the NorthernHemisphere, mainly in Europe and Asia with two species in North America. Nine species occurin Europe (Akeroyd, 1993). Five of these are restricted to the montane regions of southwest,central-south and southeast Europe (P. alba, P. alpina, P. halleri, P. montana, P. rubra); the

remaining four taxa are more widespread in the lowlands of northern, central and easternEurope extending from the Atlantic to Eurasia (P. patens, P. pratensis, P. vernalis, P.vulgaris).

Pulsatilla vulgaris is told from all other Pulsatilla species by its sessile cauline leaves, deeplypinnatisect basal leaves with 7-9 primary segments that wither in the autumn and erectflowers (nodding in anthesis). It is a very variable species for which a number of poorlydefined infraspecific taxa have been described in the past. These, however, appear torepresent the more distinct of the numerous isolated populations and probably represent a‘dissected continuous’ type of variation caused by post-glacial climatic changes and theintolerance of the species to ploughing, shade and bad drainage (Akeroyd, 1993).Consequently infraspecific taxa do not often appear to fall into the geographical pattern

characteristic of subspecies. The smaller and more isolated populations, particularly towardsthe edge of the range of the species, are fairly homogeneous (as in Britain), but in other areasthere is considerable variation within populations. While it is likely that most populations areseparable from one another, there is a large amount of overlap between them andintermediates occur frequently.

Today three subspecies are usually accepted. Subspecies vulgaris, to which all Englishpopulations belong, is the most widespread taxon extending from 61º N in Sweden to c. 45º Nin the Bordeau region of France and from Gloucestershire in England to near to Poznan inwestern Poland where it is replaced by subsp. grandis (Lindell, 1998). Subsp. vulgaris isdistinguished by the greater degree of lobing in the leaves (>100;


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1.3 Genetic implicationsThe chromosome base-number of the genus is 8. Pulsatilla vulgaris is tetraploid (2n = 32) andmay have arisen following hybridization between P. patens (2n = 16) and P. pratensis (2n = 16)(Böcher, 1934). Spontaneous hybrids between subsp. vulgaris and P. pratensis and P. patens are known from Northern Europe (Akeroyd, 1993) and work on Swedish populations hasindicated that hybridization barriers are weak between subspecies of Pulsatilla vulgaris, and

between P. vulgaris and P. halleri (Lindell, 1998).

Bailey (1996) found a low percentage of polymorphic loci in five sites across the geographicrange of Pulsatilla vulgaris in England (Barton Hills, Knocking Hoe, Rodborough Common,Devils Dyke, Therfield Heath), suggesting that overall genetic variation is low, although therewere significant differences for individual primers between some of the sites examined.Further work is needed to more fully assess these differences, and in relation to overallfitness, population size and degrees of geographical isolation.

Similar work has been undertaken in Germany on 11 populations ranging from 50 plants to7300 plants (Hensen et al., 2005) and found a significant positive relationship between geneticdiversity and both population size and seed mass (per population). Genetic diversity was

significantly lower in smaller populations than in larger ones, suggesting that genetic drift(random change of allele frequency within a population) has been the main cause of the lossof diversity as populations have become smaller and fragmented following rapid land-usechange (i.e. the chance of alleles being lost from one generation to another has been greaterin smaller populations).

Hensen et al. (2005) also found a high level of within population variability which wasattributed to life-history traits likely to preserve variability, namely allogamous pollination, along life span and vegetative reproduction. Interestingly there was only weak, albeitsignificant differentiation between populations which was correlated to the geographicaldistance. This suggests that genetic drift has been the major force driving differentiationbetween German populations as the former larger population became fragmented. The

weakness of this relationship suggests that the loss of genetic variability through drift hasbeen, to some extent, balanced by gene flow between closer populations. Since seed dispersalin Pulsatilla vulgaris is limited it was concluded that the foraging radius of pollinators,currently thought to be in the order of several kilometres for honeybees (Steffan-Dewenter &Kuhn, 2003) and bumblebees (Osborne et al., 2008), is critical in offsetting genetic drift aspopulations become smaller and more isolated. However, even if pollinators forage overseveral kilometres it seems very unlikely that they would travel between English populationsgiven their small size and degree of isolation.

1.4 Medicinal propertiesPulsatilla vulgaris is unpalatable and poisonous to humans and animals due to the presence of

the glycoside ranunculin in the leaves and roots which is converted to anemonine when theplant is dried (Plants for a Future, 2010). Small doses are taken internally in the treatment ofpre-menstrual syndrome, inflammations of the reproductive organs, tension headaches,neuralgia, insomnia, hyperactivity, bacterial skin infections, septicaemia, spasmodic coughs inasthma, whooping cough and bronchitis. Externally, it is also used to treat eye conditions suchas diseases of the retina, senile cataract and glaucoma. In homeopathy, extracts are used totreat measles as well as minor complaints such as nettle rash, toothache, earache and biliousindigestion (Plants for a Future, 2010).


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2 Distribution and current status

2.1 WorldPulsatilla vulgaris subsp. vulgaris is endemic to Western and Central Europe and is not known

to have been introduced to other parts of the world.

2.2 EuropePulsatilla vulgaris belongs to the European Temperate element (Preston & Hill, 1997) with thecore of its distribution in the lowlands of western and central Europe (Fig. 2).

Its current status in Europe is given in Table 1. France appears to be the stronghold for theplant in Europe and consequently it was not listed as a priority species for conservation in themost recent assessment of the French flora (unlike P. vernalis; Olivier et al., 1995). Incomparison it appears to be threatened throughout the rest of its range. In Denmark,Germany and Southern Sweden it is still relatively widespread, but appears to have declined,especially in Sweden, where it is now classified as Vulnerable using IUCN threat criteria (A2ac;

Gärdenfors, 2010), and Germany, where it’s populations are now small and highly fragmented(Hensen et al., 2005). Similar trends have been reported for Austria, where only around 2000plants now survive in 23 sites (Franz, 2005), and Switzerland where it is very rare (Pfeifer etal., 2002) and classed as Endangered under IUCN threat criteria (Moser et al., 2002). InBelgium it is confined to two small areas in the southern province of Wallonia, where itshabitat (limestone grassland) is under pressure from extensive tree planting (Quentin Groom,pers. comm.). In Luxembourg it is classified as Endangered under IUCN criteria havingdeclined from 28 to 5 localities with population sizes now ranging from two to more than 7000genets (Colling, 2005). It appears to be extinct in Finland, where it has not been seen sincethe 1930s (Rassi et al., 2001) and Holland. It’s status in Poland is unknown although recentmaps (e.g. Fig. 2) show it to be very rare. Recent records for Norway all appear to be ofcasual escapes (Jonsell, 2001).


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Figure 2 - Distribution map of Pulsatilla vulgaris subsp. vulgaris in Northwest and CentralEurope, reproduced from Hensen et al. (2005). Small filled circles are individual site records

from 1950 onwards. Small empty circles are individual site records older than 1950 oroccurrences reported as extinct. Atlas Florae Europaeae data from Jalas & Suominen (1989)are also shown (large filled grey circles) to indicate 50 × 50 km squares from which noindividual occurrence data were available. The doubtful two easternmost records from Polandare given by EUNIS (2004) but not by Wojtowicz (2001).

Table 1 – The status of Pulsatilla vulgaris in Europe.

Country IUCN Status Reference

Austria ? Declined to 2000 plants in 23 sites Franz, 2005Belgium ? Very rare and decliningDenmark ? UnknownFinland EW Formerly one site Rassi et al., 2001

France ? Not threatened? Olivier et al., 1995Germany ? Widespread but declining Hensen et al., 2005Holland EW ExtinctLuxembourg EN Declined from 28 to 5 localities Colling, 2005Norway - Casual escape Jonsell, 2001Poland ? UnknownSweden VU Ca.30% reduction in past 100 years Gärdenfors, 2010Switzerland EN Marked decline Pfeifer et al., 2002; Moser et


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al., 2002UK VU Declined from ca.130 to 18

localitiesCheffings & Farrell, 2005

2.3 United Kingdom 2.3.1 England

2.3.1.1 Native populationsSince its discovery near to Oxford in 1551 (Druce, 1886) Pulsatilla vulgaris has been recordedfrom around 130 sites in 19 English vice-counties (Table 2) but is now confined to 18 sites injust ten vice-counties (Table 3). Former strongholds include the Cretaceous chalk downlandand ancient earthworks of Bedfordshire, Berkshire, Buckinghamshire, Cambridgeshire,Hertfordshire and Oxfordshire and the Jurassic limestone grasslands of Gloucestershire,Northamptonshire and Lincolnshire (Fig. 3). It was also formerly widespread in Magnesianlimestone grasslands in northern England, extending as far north as Piercebridge in CountyDurham (Baker, 1906) but it is now restricted to a single site near to Wakefield (Abbott,2005). Small clusters of populations also occurred in North Essex, Leicestershire, West Norfolkand West Suffolk but it has not been seen in any of these counties since 1888, 1992, 1914 and

1978 respectively (Table 4).

Table 2 – The number of Pulsatilla vulgaris populations recorded in English vice-counties.†Extinct.

Population size (2000-10 period)

VC Vice-county nameExtinc

t1-10

11-50

51-200201-1000

>1000

Total

no.

%extinc

t

19 North Essex† 2 2 100

20 Hertfordshire 7 1 8 88

22 Berkshire 12 1 13 92

23 Oxfordshire† 4 4 100

24 Buckinghamshire 2 1 3 6726 West Suffolk† 3 3 100

28 West Norfolk† 1 1 100

29 Cambridgeshire 7 1 8 88

30 Bedfordshire 2 2 2 6 33

31 Huntingdonshire† 1 1 100

32 Northamptonshire 7 1 8 88

33EastGloucestershire

17 1 2 1 1 22 77

34WestGloucestershire

4 1 5 80

53 South Lincolnshire 16 1 1 18 8954 North Lincolnshire† 5 5 100

55 Leicestershire† 5 5 100

63South-westYorkshire†

6 6 100

64 Mid-west Yorkshire 7 1 8 88

66 Durham† 1 1 100

Total 109 6 3 3 1 5 127 86


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Of the 10 vice-counties with surviving populations, seven only have single colonies.Bedfordshire and East Gloucestershire have the most with 4 and 5 populations respectively.Half the English populations support less than 100 plants, including one site (Ledsham, Mid-west Yorkshire) with a single individual (known since 1984). Only five sites (28%) support inexcess of 1000 plants (Fig 4a). Although total population sizes are difficult to estimate, recent

counts on these sites suggest the following totals: 20,000 at Barnack Hill and Holes, 75,000 atBarnsley Wold, 5,000 at Barton Hills, 1,000 at Knocking Hoe and 60,000 at Therfield Heath(Tarpey, 1999; see Annex 2 for details). These five sites account for 99.3% of the total Britishpopulation. Of the eighteen surviving populations 4 appear to be declining and are threatenedwith extinction, 9 are stable and 5 appear to be increasing due to improvements in grazingregimes (Table 3; see Annex 2 for details).

Historical losses appear to have been high in all vice-counties especially East Gloucestershire,South Lincolnshire and Berkshire where 77%, 89% and 92% of populations have gone extinct(Table 2). The rate of loss appears to have been increased consistently since 1750 from around1.8 populations per decade to 6.0 since 1950 (Fig. 4b) although these figures presumablyunderestimate rates for earlier periods as fewer ‘extinction events’ are likely to have beendetected by eighteenth century botanists (as fewer populations were then known).Consequently the total number of populations has displayed a consistent downward trend (Fig.4c). However, since 1960, the first period when we have detailed information on the size of

Figure 3 – The hectaddistribution of Pulsatillavulgaris in Britain and Ireland.Solid black circles are hectadswhere P. vulgaris has beenrecorded since 2000; solid greycircles, recorded 1987-1999;open circles, recorded before1987; X, introduced.


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English populations, the overall number of plants has increased considerably from anestimated 60,000 to over 160,000 individuals largely due to improvement in grazing regimeson four of the best sites (Barnack Hills and Holes, Barnsley Wold, Barton Hills, TherfieldHeath; Fig. 4d). Despite these losses new populations continue to be found including a smallpopulation of around 15 plants in Swinstead Valley (South Lincolnshire) discovered in 2009(Jefferson & Walker, 2010).

Table 3 – Details of extant populations of Pulsatilla vulgaris in England.

Site VC 10-km Geology/managementSize/trend

Cons.Design

.Therfield Heath 20 TL33 Chalk, winter grazing E↑ SSSI

Aston Upthorpe Down 22 SU58Chalk, ungrazed exclosure, occ.mown

B(r)↓ SSSI

Steps Hill 24 SP91 Chalk, intermittent grazing B↓ SSSI

Devil's Dyke 29TL56/

66Chalk, some areas grazed/mown C≈

SSSI

Barton Hills 30 TL03 Chalk, grazed excluding Jan-Mar D↑ NNR

Ravensburgh Castle 30 TL02 Chalk, ungrazed B↓ SSSI

Deacon Hill 30 TL12 Chalk, some areas grazed A≈ SSSI

Knocking Hoe 30 TL13 Chalk, grazed D↑ NNR

Barnack Hills and Holes 32 TF00Limestone, grazed excluding Mar-Sep

E↑ NNR

Barnsley Wold Warren 33 SP00Limestone, grazed excluding Mar-May

E↑ SSSI

Beaumonts Hay 33 SP12 Limestone, irregular grazing A≈ SSSI

Bourton Down 33 SP13Limestone, grazed excluding Apr-Aug

C≈ SSSI

Hornsleasow Roughs 33 SP15

Limestone, grazed excluding Mar-

May C≈

SSSI

Taylor’s Hill 33 SP01 Limestone, grazed C≈ -

Rodborough Common 34 SO80 Limestone, light mowing/grazing B↓ SSSI

Ancaster Valley 53 SK94 Limestone, winter grazed B(r)≈ SSSI

Swinstead Valley 53 TF02 Limestone, summer grazed A≈ SSSI

Ledsham 64 SE43 Limestone, winter grazed A(r) ≈ SSSI

Code for population sizes and trends: A, 1-10; B, 11-100; C, 101-1000; D, 1001-10000; E,10000-100000; (r), includes reintroduced plants. ↑, population increase; ↓, populationdecline; ≈ population stable.

Table 4 – Vice-counties in which Pulsatilla vulgaris is now extinct with reason for loss

VC Vice-countyname Last recorded site Lastrecord Probable reason for loss

19 North Essex Bartlow Hill 1888 Scrubbed-over23 Oxfordshire Upton Down 1883 Ploughed-up26 West Suffolk Newmarket Heath 1978 Grassland altered by horse

training28 West Norfolk Sporle & Tulip Hills 1914 Scrubbed-over31 Huntingdonshire Stibbington 1926 Possibly an error for sites in

VC32?


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54 NorthLincolnshire

Broughton FarWood

1969 Scrubbed over; last plant ‘dug-up’

55 Leicestershire Shacklewell Hollow 1992 Dumping of rubble63 South-west

YorkshireSmeaton CragPastures

1870 Quarrying/mining

66 Durham Cliffe Wood 1906 Landscaping of parkland

Although there is no fossil evidence of the occurrence of Pulsatilla vulgaris in Europe it wasprobably much more widespread during the early post-glacial in dry, steppe grassland beforeretreating to open refugia, with shallow soils and low competition, following the spread ofdeciduous woodland (Hensen et al., 2005). Woodland clearance from the Neolithic onwards,however, is speculated to have created much new habitat enabling spread from refugia,although ‘barriers’ to migration would have been present in some regions. For example,woodland is thought to have restricted its colonisation of the southernmost chalk in England(Pigott & Walters, 1954; Rose, 1957) although its absence from Late Glacial refugia such asthe Avon Gorge and centres of Neolithic farming activity, such as Salisbury Plain, suggests amuch more complex phytogeographical history in Britain, or at least one that is impossible toreconstruct from modern records alone.

Figure 4 – The number and size of populations of Pulsatilla vulgaris in England: (a) size ofextant populations; (b) number of populations lost per decade; (b) the number of populations


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surviving in each year, and (c) the total number of populations and plants recorded since1960. In (c) all populations were assumed to have been present in 1750 even if they were onlydiscovered much later.

2.3.1.2 IntroductionsThere are around a dozen deliberate or casual introductions known in England (Table 5), with

most resulting from ‘tipping’ of garden waste by roadsides or in old quarries. There have alsobeen six deliberate introductions to either re-establish populations on sites where it becomeextinct (Copper Hill Quarry, Southorpe Paddock), bolster extant populations (Aston Upthorpe,Ancaster, Ledsham) or create entirely new populations for the purposes of research(Hartslock) (see Table 11 for details). The most contentious site, however, is the smallpopulation that straddles the border of Dorset and South Wiltshire on Martin Down whichinterestingly appears to have increased since its discovery in 1983 (seehttp://www.hantsplants.org.uk). Both Bowen (2000) and Brewis et al. (1996) suggest it mightbe native given the typical nature of the habitat (ancient species-rich grassland on anearthwork). However, in view of its isolation from other native populations and late discovery,which is surprising given its close proximity to a path, it is probably best treated as anintroduction unless convincing evidence is produced for it being of natural occurrence

(Preston et al., 2002; Edwards & Pearman, 2004).

Table 5 – Known casual records of Pulsatilla vulgaris in England. Details of translocations aregiven in Table 11.

VC VC name Details

7 North Wiltshire Planted on Morgan’s Hill in 1939 from where it possibly colonisedCherhill Down by 1941 (Grose, 1957) but this seems unlikely.

8/9 SouthWiltshire/Dorset

Known from Martin Down since c.1983 where two smallpopulations grow on either side of the vice-county boundary onancient species-rich chalk banks (SU0518, SU0418). Likely tohave been planted given the distance to the nearest native

populations (Edwards & Pearman, 2004).13/14

West & EastSussex

No details; presumed planted.

20 Hertfordshire Discovered on road verges at two sites (TL1226; TL2426) whereit was presumed to have been planted (T James, pers. comm.).

21 Middlesex No details; presumed planted.24 Buckinghamshire Discovered in 1998 (SP8405) but assumed to have been planted.29 Cambridgeshire In 1994 a few plants originating from a garden were planted on

an area of downland reverting from arable (L Evans, pers.comm.).

30 Bedfordshire Recorded in a quarry where it had presumably been planted (CBoon, pers. comm.).

2.3.2 Northern Ireland, Scotland & WalesPulsatilla vulgaris does not occur in Northern Ireland, Scotland or Wales.

3 Ecology & life cycle

3.2 Life cycle and phenologyPulsatilla vulgaris is a monoecious, long-lived, polycarpic hemicryptophyte which appears toreproduce mainly vegetatively by growth of adventitious buds on the branched rhizome. These


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produce several daughter rosettes close to the parent plant each year. Although new flowerbuds are produced during late summer the whole plant is dormant during the winter months(August to March). The tightly furled leaves appear in March and unfurl at or after floweringand wither in the autumn or after the first frosts.

Plants of Pulsatilla vulgaris are very difficult to age due to the production of new ramets from

the branched rhizome (‘type C perennials’ sensu Grubb, 1990). However, observations inEngland suggest that large plants with rhizomes 15-20 mm long may be at least 20 years old(Wells & Barling, 1971) although individual genets are potentially much longer-lived with half-life of more than 50 years (Grubb, 1990). Plants grown from seed will flower in pots in 1.5-2.5years but in the wild this is likely to be 4-5 years.

3.1.1 Flowering phenologyTemperature appears to be a very important cue that regulates the timing and rate of flowerand fruit development (Widén & Lindell, 1996). Flowering commences when temperatures riseabove 12-15°C (Kratochwil, 1988; Widén & Lindell, 1996), usually in the first week of April,reaching a peak between 4-5 weeks later, and continues to the end of June (Fig. 4; Wells(1994) gives the main flowering period as the 6 April to 20 May). However, the onset of

flowering and flower production does vary from year to year depending on climatic conditions.For example, flowering and fruit maturation is known to be higher in warmer years (e.g. 1988;Widén & Lindell, 1996) and for cultivated plants exposed to full sun light either in thegreenhouse (Widén & Lindell, 1996) or under experimental shading conditions (Fig. 5; Walkeret al., in press). In large populations, however, the behaviour of individuals is variable, someplants flowering in successive years whilst others remain vegetative (Wells & Barling, 1971). Inaddition, drought in one summer may affect flowering the following year as primordia areinitiated in late summer (Rich, 1997).

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Weeks from 1st March

N u m b e r o f s i t e r e c o

r d s

Figure 4 – Phenology of Pulsatilla vulgaris in England based on the number of historicalrecords for sites held in the Vascular Plants Database, regardless of location, year & recorder.

3.1.2 Flower biologyEach plant produces 1-3(-12) bell-shaped flowers with numerous carpels with long purplestyles (30-150) and bright yellow stamens, the outer smaller, sterile and secreting nectar (Fig.1a). These are produced on very short stalks and face the sky for about 48 hours after firstopening, only closing at night or during rain (Wells & Barling, 1971). Flowers arehermaphrodite and markedly protogynous with the female reproduction organs reaching


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maturation before the male (andro- and gyno-monoecious and dioecous forms have beenreported from the continent but are likely to be rare). Both stamens and styles continue togrow during anthesis increasing the distance between the anthers and stigmatic papillae(Jonsson et al., 1991). On cultivated plants the obligate female phase (the time from thebeginning of anthesis to the opening of the first pollen sac) lasts just over a day whereaspollen is produced for about 4 days and remains viable for 7-8 days (Jonsson et al., 1991). The

obligate female phase appears to be much shorter late in the flowering season and is directlycorrelated with an increase in temperature (Kratochwil, 1988; Jonsson et al., 1991). In mostpopulations the length of the obligate female phase is likely to be sufficient for some cross-pollination to take place since the great proportion of flowers receive pollen before the onsetof the male phase (Jonsson et al., 1991). However, geitonogamous pollination is probably alsocommon as most populations include plants with 2 or more flowers, including flowers onidentical (daughter) genets growing close-by (Warden, 2001).

Figure 5 – Effects of experimental shading on (a) the % survival and (b) floweringperformance of Pulsatilla vulgaris grown at Monks Wood Experimental Station,Cambridgeshire, 1970-80 (Walker et al., in press). Plants were planted in a chalk subsoil to adepth of 1 m and exposed to three levels of shading (dense, medium, light) simulated usingblack gauze screens erected over each plot. Each plot consisted of 12 regularly spaced plants25 cm apart. Three replicates of each treatment and a control (no shade) were arranged in arandomised latin square and the survival of transplants and flowering performance recorded inApril and May of each year. The plots were fenced to exclude rabbits and weeded to removecompetition.

3.1.3 PollinationThe flowers of Pulsatilla vulgaris are insect-pollinated mainly by aculeate Hymenoptera andbees (Apidae: Apis, Bombus). Many other insects have been recorded visiting flowers inEngland and on the continent but appear not to contribute significantly to pollination (e.g.flies, beetles, Lepidoptera, non-Apoidea Hymenoptera; Wells & Barling, 1971; Kratochwil,1988; Warden, 2001). Experiments with exclusion of pollinators showed that Pulsatilla vulgaris is mainly an outbreeding plant due to the absence of spontaneous selfing (index of self-incompatability (ISI)


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populations has shown that dichogamy is incomplete, since artificial selfing produces a smallamount of fertile seed although selfed flowers produced fewer seeds than those that cross(Jonsson et al., 1991; Lindell, 1998). Seed set from self-pollination is variable with reportedvalues of 18% in England (Warden, 2001) and 31-50% in Sweden (Lindell, 1998). Insects seem tobe necessary even for self-fertilisation as enclosed flowers do not set seed automatically(Wells & Barling, 1971; Kratochwil, 1988; Widén & Lindell, 1996) and early flowering plants

and those in small populations have lower seed-set due to pollinator-limitation (Widén &Lindell, 1996).

3.1.4 Seed productionBetween 30-90 carpels are borne on a flattened, conical receptacle, each containing a singleembryo which when fertilised develops into an achene 2-3 mm long with a persistent featherystyle (3-5 cm) borne on stems that elongate after anthesis (Fig. 1b). Achenes ripen 4-5 weeksafter the flowers open and fruits may be ripe from mid May to mid June. There is considerablevariation in the number of achenes produced per flower and total achene production perplant. For example, Wells & Barling (1971) found 23-74 achenes per flower in five Englishsites, with an average of 46, though not all may have been fertile (Rich, 1997) whereasWarden (2001) found an average of 62 at Aston Upthorpe in Berkshire of which ca.30-35 were

viable (‘filled’). In Sweden Widén & Lindell (1996) found a similar average of 18 and 28 viable(undamaged) seeds per flower at two sites excluding achenes damaged by seed-boring insects.

In Germany Kratochwil (1988) found fruit set to exceed 70% over four years, even though onlya few hours of favourable conditions occurred in most years. However, intermediate floweringplants appear to be more fecund than earlier or late flowers, because early flowers encountera paucity of pollen vectors and suffer from early frosts whereas late flowers suffer fromgreater predation and may have to compete with developing leaves for resources (Widén &Lindell, 1996; Warden, 2001). Later-flowering plants also appear to develop seeds morerapidly due to higher temperatures (Widén & Lindell, 1996). Flowers in most populationsproduce infertile achenes containing no embryo, usually towards the centre of the flower;these weigh about 0.6 mg whereas fertile achenes weigh 3 mg (Wells & Barling, 1971)

although seeds containing no embryo can sometimes weigh more than those that are viable(Bailey, 1996). The cause of this infertility is unknown but is presumably caused by cold,inclement weather at the time the flower is produced and the abundance of flying insects.(e.g. 1996 in England; Bailey, 1996).

3.1.5 Seed viability and germinationThe viability of fresh seeds is generally high with reported germination values at roomtemperature of 47% for Swedish material (Widén & Lindell, 1996) and 59% (Bailey, 1996), 75%(Warden, 2001) and 90% (Wells & Barling, 1971) for English material. Under more controlledlaboratory conditions 80% germination was been achieved on 1% Agar solution at 20°C, 8/16hours light and dark and 95% at 21°C, 12/12 hours light and dark (RBG Kew, Wakehurst Place).In comparison, only 16% of seeds germinated in a field germination trial increasing to 29%

when seeds were covered with 3 mm of soil (Wells & Barling, 1971).

Tests on the viability of seed stored at room temperature have shown variable declines withage. Wells & Barling (1971) found between 15-65% germination after 8-9 months with nogermination occurring after 2.5 years. However, only a small decreases in viability has beenreported for seed stored at 4°C for one year (Warden, 2001) and dried to low moisturecontents and stored for 13 years (RBG Kew, Wakehurst Place). Germination appears to beunaffected by light levels or storage at temperatures as low as -7°C (Wells & Barling, 1971).


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3.1.6 Seed dispersalAchenes of Pulsatilla vulgaris are adapted for wind-dispersal by modification of the style intoa feathery pappus and the elongation of the fruiting stems (by a process of cell elongation),increasing the height at which the ripe seeds are released to above the general level of thesurrounding vegetation (Fig. 1b). For example Wells & Barling (1971) give a mean scape height

at fruiting of 18.4 cm for 50 plants at Barnsley Wold in 1966 as opposed to 4 cm for thesurrounding grassland. Despite these adaptations, long-distance dispersal is most probablyabsent or very rare (Tackenberg et al., 2003). Observations in England suggest that seedsdisperse less than 20 cm from parent plants often because the entire head remains intact orthe feathery tail becomes entangled in the surrounding vegetation (Wells & Barling, 1971;Warden, 2001). In addition simulations of aemochorous dispersal showed that 90% of the seedsland within the mother population with only 0.05% of seeds being dispersed over a distance ofmore than 100m (Tackenberg, 2001). According to Röder & Kiehl (2006) Pulsatilla seeds alsohave a high potential for epizoochory, including dispersal on machinery, which might be amore important strategy for long distance dispersal in modern landscapes. Establishment ofnew populations in this way is likely to be rare, but may have occurred at one site inCambridgeshire where a new population was discovered 300 m from the nearest population

(Leslie, 2004; see Devil’s Dyke, Annex 1). Dispersal by machinery is the most likely vector atthis site as the new colony occurs on a mown road verge inaccessible to livestock.

3.1.7 RegenerationDespite the production of viable, highly germinable seeds, establishment of new individualsfrom seed appears to be rare (seedlings observed at only one site by the author) and mostregeneration, is probably achieved by the disintegration of the branched rootstock (Wells &Barling, 1971). Plants reproduce vegetatively by growth of adventitious buds on the rhizome 2cm or more below ground level, producing a small rosette of leaves close to the parent plant.Two or three new rosettes may be produced each year and excavation of groups of plants hasrevealed as many as seven distinct rosettes from a single rootstock, the younger plants beingclustered around the parent plant. Consequently, the density of flowering stems can reach up

to 67 plants m-2, although an average of ca.4 plants is probably more typical in short, wellmanaged grassland (Wells & Barling, 1971).

Pulsatilla vulgaris appears to have a short-lived, transient seed bank (Thompson et al., 1997)and so most recruitment is likely to occur shortly after the seed is dispersed. Once the seedreaches the soil surface hygroscopic movement of the style may help bury the seed, but thishas not been observed. Germination is epigeal, the green cotyledons expanding 3-6 mm abovethe soil surface. The slender primary root of the seedling grows vertically downwards reachinga depth of 15 cm within 6 months of germination by which time it has formed an extensiveroot system. At this stage the underground stem is ca.2 mm long with 2 or 3 leaves arisingfrom axillary buds at the apex of the rootstock.

The establishment of new plants appears to be a rare event as seedlings have only beenobserved a few times in recent decades. For example seedlings were found on only one siteduring a recent survey of all extant British populations (Fig. 6). At this site (Bourton Down)seedlings were confined to bare soil in very open grassland with abundant limestone rubble ator on near the soil surface (see Fig. 9k).

Soil moisture appears to be critical for establishment as seedlings only appear to survive inwet summers (Wells, 1994; Rich, 1997). For example, Wells & Barling (1971) showed that


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higher germination occurred where seeds were covered with a thin layer of soil but that allseedlings suffered high mortality due to physical disturbance and herbivory. In addition,seedling development was extremely slow and even after two years plants were still verysmall.

These factors, combined with low seed production and frequent dessication in drought-prone

soils, probably explain the apparent inability of this species to spread to new sites and therarity of seedlings in the wild.

Figure 6 – Seedlings of Pulsatilla vulgaris recorded at Bourton Down in Gloucesterhire on 30 th April, 2005.

3.1.8 Response to competitionPulsatilla vulgaris occurs at highest density where soils are shallowest and above groundcompetition (biomass) is low (Fig. 7a). Flower production also decreases as competition fromtall grasses increases, with a sharp fall occurring when the surrounding vegetation reaches 10-15 cm (Fig. 7b). This was first observed in grazing exclosures (Wells, 1968) and has beenattributed to the smothering effect of leaf litter of Bromopsis erectus and increasedcompetition from tall grasses. For example, Mitchley (1988) showed a positive correlationbetween interference ability and mean height of the rosette leaves in Bromopsis erectus grassland. This was attributed to the ability of dominant species such as B. erectus to projecttheir leaves into the upper canopy thereby reducing the amount of photosynthetically activeradiation able to reach lower levels (Mitchley & Willems, 1995). Bromopsis erectus is also

known to generate high ‘shoot thrust’, enabling it to attain early dominance in the vegetationby physically restricting the growth of surrounding species, especially low-growinghemicryptophytes such as Pulsatilla vulgaris (Campbell et al., 1992). Attempts to simulatethese effects through shading have shown significant decline in longevity, survivorship andflowering performance at increasing levels (Fig. 5). Likewise transplants of Pulsatilla vulgaris have significantly greater survivorship and performance (number of leaves) when competitionfrom surrounding vegetation is removed (Warden, 2001). These findings highlight the criticalrole of above-ground competition plays in restricting the amount of light reaching the base of


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the sward and thereby determining the relative abundance of hemicryptophytes such asPulsatilla vulgaris.

Figure 7 – The effects of competition on Pulsatilla vulgaris. (a) The relationship betweendepth of soil and above-ground biomass on the density of Pulsatilla vulgaris at Barnsley Wold,Gloucestershire. Means based on 50 samples at each soil depth. (b) The relationship betweensward height and the % of Pulsatilla vulgaris plants in flower in a grazing exclosure at BartonHills, Bedfordshire. Each dot represents a year with overall numbers increasing from 138following the withdrawal of grazing 1964 to 654 in 1969. Both figures adapted from Wells &Barling (1971).

3.1.9 Herbivory, parasites and diseasePulsatilla vulgaris is a plant of sheep and rabbit grazed downland and is well adapted tograzing by herbivores. The plant is dormant during the winter, and at other times thevegetative and floral buds and leaves are generally at ground level and therefore not readily

available to grazing animals. Occasionally whole flowers are grazed by rabbits, or the floweror part of it are eaten by caterpillars, pheasants (Bowen, 1997) or small mammals (woodmouse Apodemus sylvaticus, field vole Microtus agrestis) (Carter, 1967). Although the leavescontain anemonin they are eaten by sheep, rabbits, slugs and snails. Caterpillars of two leaf-mining moths of the genus Cnephasia have also been recorded on leaves in the UK (Databaseof Insects and their Food Plants, accessed August 2010). At least two other leaf-mining insectshave been reported on the continent and nematode worms of the genus Meloidogyne havebeen reported to cause root galls in the Netherlands caused by (Wells & Barling, 1971).

In Sweden achenes are attacked by the larvae and pupuria of a range seed-boring fliesbelonging to two Diptera families, the Agromyzidae and Cecidomyiidae, and are a potentiallyserious factor reducing seed production by up to 36% (Widén & Lindell, 1996). Many small flies

have been reported visiting flowers of Pulsatilla vulgaris but no evidence of attack of seed hasso far been observed (Warden, 2001). Parasites on Pulsatilla vulgaris include Cuscutaepithymum, which has been recorded on plants at Barnsley Wold. The fungal rustColeosporium pulsatilla has also been recorded on Pulsatilla species on the Continent (Aichele& Schwegler, 1957), but it is not known if hosts include Pulsatilla vulgaris.

4 Habitat requirements

4.1 The landscape perspective

(a) (b)


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In England Pulsatilla vulgaris is confined to moderately steep south to southwest facing slopeswhere insolation is high, soils are shallow and competition from other species is restricted(Fig. 8). Most populations are confined to escarpment grasslands of Chalk and Jurassiclimestone (Fig. 9c, 9e-g, 9i-l) but it also occurs in similar grasslands in old quarries (e.g.Hornsleasow Roughs, Fig. 9b) and on ancient earthworks such as hill-forts (e.g. RavensburghCastle, Fig. 9d) and Anglo-Saxon dykes (e.g. Devil’s Dyke, Fig. 9a). In old quarries and on

earthworks plants tend to occur on relatively shallow slopes on a greater range of aspects,although even on these plants are generally found on more southerly aspects than those facingnorthwards (Wells & Barling, 1971). Plants usually occur at greatest density on the steepest(mid) part of the slope where soils are shallowest, rather than on deeper soils at the top orbottom. For example, Wells & Barling (1971) recorded densities of 7.5 plants m -1 where thesoil was 5 cm deep but only 1.2 plants m -1 at soil depths greater than 100 cm (Fig. 7a).

Figure 8 – The aspect (a) and slope (b) of Pulsatilla vulgaris populations in England. Thefigures include values for the 29 populations included in Wells & Barling (1971) and fivepopulations discovered since then.

With the exception of Hildersham Furze Hills (see below), Pulsatilla vulgaris occurs on shallow(5-15(25) cm) drought-prone calcareous rendzinas over chalk and limestone with relativelyhigh surface soil pH (average 7.5; range 7.1-7.8; Table 6). These soils are very friable andporous with high contents of calcium carbonate (mean 67%; range 34-91%), organic matter(mean 15%; range 8-22%) and total nitrogen (mean 0.5%; range 0.3-0.7%) (Wells & Barling,1971). All are base-saturated with calcium being the most abundant cation present (320-830mg 100g-1 dry soil) with other mineral nutrients, especially phosphorous, occurring at lowlevels (Table 6). The clay/silt/sand fractions of these soils is also low (


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Table 6 – Chemical and mechanical analysis of soil from Pulsatilla vulgaris sites in England andfive sites on sandy soils in Sweden for comparison. These summarise data presented for 10sites in Table 1 of Wells & Barling (1971).

Chalka Limestone

b Mean Range

Calc.sandc

Sweden

pH 7.6 7.4 7.5 7.1-7.8 5.2 5.0

Organic matter(%) 15 11

13 8-228.5

8

Nitrogen (%) 0.5 0.4 0.5 0.3-0.7 0.2 0.3K (mg 100g-1) 18 21 19 11-31 0.9 18Ca (mg 100g-1) 654 492 582 320-830 170 44Mg (mg 100g-1) 13 11 12 7-17 12 6P (mg 100g-1) 1.5 1.0 1.3 0.6-2.3 0.8 1.1CaCO3 (%) 71 62 67 34-91 0.8


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Figure 9 – Habitats of extant populations of Pulsatilla vulgaris in England (arrows mark theposition of small populations): (a) Anglo-Saxon earthwork, Devil’s Dyke, Cambridgeshire; (b)shallow limestone quarry workings, Hornsleasow Roughs, Gloucestershire; (c) Knocking Hoeand ‘Spiranthes Bank’, Bedfordshire; (d) Ravensburgh Castle Iron Age hill fort, Bedfordshire;(e) Ledsham Banks, Mid-west Yorkshire; (f) Steps Hill (Incombe Hole), Buckinghamshire.


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Figure 9 continued. Habitats of Pulsatilla vulgaris in England: (g) Beaumonts Hay,Gloucesterhire; (h) Barnack Hill and Holes, Northamptonshire; (i) Barnsley Wold,Gloucestershire; (j) Barton Hills, Bedfordshire; (k) Bourton Down, Gloucestershire; (l) ChurchHill, Therfield Heath, Hertfordshire.

4.2 Communities & vegetationIn England Pulsatilla vulgaris is almost entirely confined to short, herb-rich Bromion grasslandson calcareous soils derived from the Chalk or Oolitic Limestone (Rodwell, 1992). The main


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National Vegetation Classification (NVC) grassland type on both chalk and limestone is Bromuserectus grassland (CG3), including grazed species-rich and ungrazed species-poor sub-communities (CGa-b and CG3d respectively) (Fig. 10a). It occurs less frequently in Bromuserectus-Brachypodium pinnatum (CG5) and Brachypodium pinnatum (CG4) grasslands, mainlyon limestone (Rodwell, 1992). These three communities form the core alliance of theBrometalia in western Europe and are broadly characterised by the grasses Brachypodium

pinnatum, Bromopsis erectus, Helictotrichon pratense, Koeleria macrantha and a wide rangeof herbs (Rodwell et al., 2007). It occasionally occurs in other calcareous grasslands,especially Festuca ovina (CG2) grasslands on chalk, usually where heavy grazing by sheep andrabbits has reduced the cover of Bromopsis erectus to very low levels. In all thesecommunities the vegetation is typically very diverse (23 species m -2) with a high cover ofbroad-leaved herbs (44 % m-2) and constant associates include Bromopsis erectus, Carex

flacca, Cirsium acaule, Festuca ovina, Helianthemum nummularium and Sanguisorba minor and associated (see Annex 3).

Figure 10 – Grassland communities in which Pulsatilla vulgaris occurs in England: (a) NationalVegetation Classification (NVC) grassland types; and (b) ordination plot (DetrendedCorrespondence Analysis) showing overall variation in species composition. Both plots includequadrat data for 30 sites including all 29 visited by Wells & Barling (1971) plus SwinsteadValley discovered in 2009. Twenty-nine of these quadrats were recorded in 1964-1968 and 27recorded since 2000. * includes sub-communities 2a & 2d; ** includes sub-communities 3a, 3band 3d.

Overall there is remarkably little variation between the composition of these grasslands onchalk or limestone (Fig. 10b), the main difference being the almost complete replacement ofBrachypodium pinnatum by Bromopsis erectus on nearly all the sites on the chalk (Wells &

Barling, 1971). Two notable exceptions, positioned to the extreme left of the first axis of theordination plot, are Hildersham Furze and Unhill Bottom. Both were rank, species-poor swardsdominated by Festuca rubra by the time of the 1964-68 survey. At one of these sites,Hildersham Furze Hills, Pulsatilla vulgaris formerly grew on an acidic soil derived from glacialsands and gravels, although the vegetation was distinctly calcicolous due to the presence offree calcium. Pulsatilla vulgaris occurs on soils with a similar pH in Sweden and Denmark, butthese are much more base-poor and consequently the vegetation is dominated by acidophilessuch as Calluna vulgaris and Deschampsia flexuosa (Wells & Barling, 1971). Pulsatilla vulgaris probably once grew in similar acid communities in Breckland as a few former sites (e.g.


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Cavenham Heath) support extensive areas of Festuca ovina–Agrostis capillaris–Rumexacetosella acid grassland (Erodium cicutarium-Teesdalia nudicaulis U1c sub-community), aspecies-rich types with close affinities to calcareous grassland (Rodwell, 1992).

Pulsatilla vulgaris tends to grow in short swards (7.5 ± 0.7 cm) though it can persist for longperiods in taller grassland (>20 cm) in the absence of grazing, cutting or burning. However,

recent population trends suggest that a sward height of between ca.5-10 cm is ideal and thatin taller swards competitive exclusion by coarse grasses eventually leads to an overall declinein plant numbers (Fig. 11a). Consequently taller swards lead to a reduction in overall speciesdiversity (Fig. 11b) and an increase of in the dominance of Bromopsis erectus (Fig. 11c).Bailey (1996) provides a useful list of species positively and negatively associated with theopen conditions favoured by Pulsatilla vulgaris.

Figure 11 –Differences in (a) sward height (cm), (b) species diversity and (c) % cover ofBromopsis erectus (± 1 SE) on extant Pulsatilla vulgaris sites in England (n = 14) in relation topopulation trends, 1968-2006. Means with the same latter are not significantly different from

one another (Walker et al., in press).

4.3 Summary of habitat requirementsA number of habitat features are important to Pulsatilla vulgaris in England and these aresummarized in Table 7.

Table 7 - A Summary of habitat features important to Pulsatilla vulgaris in England.Type DescriptionPhysical andtopographical

• Lowland (


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microsites for seed germination and seedling establishment• Transfer of seed between sites by herbivores and/or mowing

machinery• Transfer of pollen between populations by insects

Chemical • Soils with pH ca. 7.5 (formerly 5)• Infertile soils with high calcium carbonate content

5 Management implications

Pulsatilla vulgaris is a long-lived polycarpic perennial herb which mainly reproducesvegetatively, and rarely from seed. It is a poor competitor and therefore unable to persist inungrazed, closed swards or amongst scrub where the general height of the vegetation exceeds15 cm and there is a build-up of litter from coarse grasses, especially Bromopsis erectus andBrachypodium pinnatum. Its survival is therefore dependent on grazing, although short-termfluctuations in grazing intensity or short-term neglect are unlikely to be critical in the longer-term. For example, one of the largest populations in England survived 100 years of sheepgrazing, 13 years of very heavy sheep grazing, 22 years of no grazing including a severe fireduring the flowering season (Wells, 1968).

Management should aim to produce a sward of ca.5(-10) cm during the flowering period withup to 30% bare ground although there is much flexibility in how this can be achieved (Rich,1997). The preferred management is sheep grazing from August to April (< 5 sheep ha -1),although low intensity grazing, including by cattle or horses, during the flowering seasonappears to have no ill-effect. All its current sites are also subject to moderate to high levelsof rabbit grazing throughout the year and, although this can cause localized extinction wheresevere, it has probably been vital in maintaining open conditions on sites with intermittent orlow levels of stock grazing. It has also survived a variety of cutting treatments ranging fromcutting once a year in spring, summer or autumn, to three times a year as well as annualburning (‘swaling’) in February or March to reduce the dominance of coarse grasses such asBromopsis erectus and Brachypodium pinnatum. On some sites it has also benefited fromoccasionally burning and trampling by humans which appears to stimulate the development ofthe deep-seated adventitious root buds.

On some sites where over-grazing, mainly by rabbits, is perceived to be a problem fencingexclosures have been erected although this appears to have been detrimental due to thebuild-up of coarse grasses.

Given the poor dispersal ability of Pulsatilla vulgaris and the high degree of isolation of manypopulations the movement of livestock and cutting machinery between extant and potentiallysuitable sites is likely to be critical in promoting gene-flow and in enabling colonization totake place.

7

Threats/factors leading to loss or decline or limiting recovery

In England Pulsatilla vulgaris has undergone a rapid and dramatic range contraction overrecent millennia and its current distribution now represents just 27% and 14% of its formerrange at the 10-km and site-population scales respectively. A similar magnitude of decline hasbeen reported for Pulsatilla vulgaris in central Germany (Hensen et al., 2005), Austria (Franz,2005), Switzerland (Pfeifer et al., 2002) and Luxembourg (Colling, 2005) and for Pulsatilla

patens in Finland where 60% of populations have been lost since the 1930s (Uotila, 1996;


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Kalliovirta et al., 2006). There are also striking similarities with the decline of Orchis ustulata in England (Foley, 1992), which might be expected given that the two species formerly grewtogether on a number of sites (and still do at one site in Bedfordshire).

In England historical records show that Pulsatilla vulgaris has been declining since at least1750 (Fig. 4; Table 8). The majority of the losses before 1900 (64%) were due to ploughing-up

of common lands following Parliamentary Enclosure awards, mainly between 1750 and 1850(Wells, 1968; Jones, 1969; Wells, 1969). These earliest losses were described most vividly bythe Cambridgeshire botanist Charles Babington (1860), who noted that “Until recently (within60 years) most of the chalk district was open and covered with a beautiful coating of turf,profusely decorated with Anemone Pulsatilla [Pulsatilla vulgaris], Astragalus Hypoglottis [ Astragalus danicus], and other interesting plants. It is now converted into arable land, and itspeculiar plants mostly confined to small waste spots by road-sides, pits, and the very fewbanks which are too steep for the plough.” Although this probably over-states its formerabundance, it was certainly occurring in other parts of southern England (e.g. Druce, 1886,p.xxxii) due to increased demand for home-grown corn fuelled by a rapidly increasing urbanpopulation. During the same period many populations were also lost to quarrying and miningactivities on coal fields in the Midlands and northern England (Table 8).

Table 8 – Reasons for the loss of Pulsatilla vulgaris populations in England between 1750 and2000. % loss figures are based only on localities where the cause of loss is known and thereforeexclude ‘Unknown’ and ‘Possible error/duplicate record’.

Reason for loss1750-1800

1801-1850

1851-1900

1901-1950

1951-2000

Total(%)

Ploughing 2 8 10 7 1 28 (42)Lack of grazing/scrubencroachment 1 1 1 14 17 (25)Quarrying/mining/mineralextraction 3 1 3 7 (10)Improvement/overgrazing 7 7 (10)Building/urban development 2 1 1 1 5 (7)Afforestation 1 1 2 (3)Landscaping of parkland 1 1 (1.5)Unknown 1 1 14 13 7 36Possible error/duplicate record 2 3 5Total 9 12 31 26 30 108Rate of loss per decade 1.8 2.4 6.2 5.2 6.0 4.3


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Figure 12 – Sites where Pulsatilla vulgaris is now extinct (all photos taken 2003-2006; year oflast record indicated): (a) Fleam Dyke, Cambridgeshire (1973); (b) Shacklewell Hollow,Leicestershire (1992); (c) Hildersham Furze Hills, eastern (Sand) hill, Cambridgeshire (1990);(d) Honnington Camp, Lincolnshire (1992); (e) Pitstone Hill, Buckinghamshire (1996); (f)Southorpe Roughs, Northamptonshire (1990).


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Losses to ploughing and quarrying continued into the twentieth century and by the 1960s only29 populations remained (Wells & Barling, 1971). Losses since then have mainly been causedby increased above-ground competition, particularly with Bromopsis erectus, as a result ofunder-grazing (Walker et al., in press). Ironically this was first observed in grazing exclosuresthat were erected to protect populations from over-grazing (e.g. Carter, 1967; Wells, 1971).Of the 20 sites where Pulsatilla vulgaris has either declined or gone extinct since the 1960s,

16 have been ungrazed for over 40 years or have only received intermittent grazing, mowingor burning (Table 9). These include small areas of grassland on earthworks or steep banks thatare now completely isolated within arable landscapes and are now partly or completelyscrubbed-over (e.g. Fleam Dyke, Fig. 12a; Honnington Camp, Fig. 12d), small exclosureserected to exclude livestock, deer and rabbits on over-grazed sites (e.g. Aston UpthorpeDown, Fig. 13a) and privately managed nature reserves where resources for management havebeen limited (e.g. Ancaster Valley, Fig. 13).

This decline of grazing frequency and intensity on many sites has been due to the reducedprofitability of livestock farming in arable areas since the 1950s which has made it difficult tosustain appropriate grazing management on unproductive sites (Nisbet & Shere, 2006). Onmixed farms the conversion of grassland to arable has made farmers less committed to grazing

small areas, whereas their inaccessibility has deterred potential graziers because of increasedtransport and infrastructure costs. Even on livestock farms these problems have prevented thegrazing of small fragments of semi-natural grasslands perceived to be unproductive and/ordifficult to manage. In addition, there has been a decline in rabbit grazing since the spread ofmyxomatosis in 1953 which is known to have caused dramatic successional changes, especiallyon sites with no history of livestock grazing (Sumpton & Flowerdew, 1985).

Table 9 - Management of Pulsatilla vulgaris populations in relation to trends in abundance,1968-2006. 1-5 represent a decline in the intensity of grazing management.

ExtantManagement since 1968 Increas

eStable Decline

Extinct

Total

1. Winter + some spring/summer/autumngrazing 3 2 - - 5

2. Winter grazing (since 1980) 2 1 - - 3

3. Irregular grazing, mowing, burning - 4 2 2 8

4. Over-grazed then under-grazed - - 2 3 5

5. Ungrazed for over 40 years - - - 7 7

6. Improved/destroyed - - - 4 4

7. Unknown - 1 - - 1

Over the last 40 years many grassland sites have also been agriculturally improved andreseeded to increase productivity. Other threats have included the digging-up of plants for

horticulture including over 1000 from Knocking Hoe in 1948 (Hope-Simpson, 1948) and morerecently at Barton Hills (M. Gurney, pers. comm.). In addition, the last known plants weredug-up at two former sites (Broughton Far Wood, Fleam Dyke; Marren, 1999) although otherfactors were more important in causing declines. Other direct threats, including forestry,building developments, etc. have only caused a few losses, including the dumping of rubble onthe last Leicestershire colony. More recently there has also been concern, but no directevidence, that atmospheric nitrogen deposition may be adversely affecting some populationsthrough eutrophication of infertile grassland (Crawley, 2005; Rich et al., 1993).


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The current range of Pulsatilla vulgaris in England is characterised by a high level offragmentation, since numbers and size of populations have declined considerably over thepast 40 years. During this time the average distance between neighbouring populations hasincreasing from 8 km to 22 km. Most significantly eight populations are now separated by morethan 10 km, five by more than 35 km and the most isolated site, Ledsham in Yorkshire, by 102km. Consequently, gene-flow between populations is likely to be very low or none existent

making populations vulnerable to genetic drift and inbreeding depression, and therefore localextinction due to genetic, demographic or environmental problems (Schaffer, 1987; Lande,1988). In these circumstances a decrease in genetic diversity is to be expected (Soulé, 1986)accompanied by a reduction in reproductive performance as shown for Pulsatilla vulgaris incentral Germany, as well as a number of other European grassland species that have sufferedsimilar declines (e.g. Oostermiejer et al., 1995; Ouburg & van Treuren, 1995; Vergeer et al.,2003). The results from the German study suggests that due to life-history charactersPulsatilla vulgaris may have maintained higher levels of genetic variation than would beexpected for a declining species, although small populations are likely to display lower levelsof genetic variation than larger ones, even where gene exchange is occurring between sites inclose proximity. As the distance between half of English populations is well beyond theforaging radius of most pollinators (>10 km) we would expect to see a significant

differentiation between isolated or outlying populations, both in terms of genetic variationand reproductive performance. Further work is needed to test these hypotheses.

7 Current Conservation Measures

7.1 In Si t u MeasuresPulsatilla vulgaris is currently classed by as Vulnerable using IUCN criteria but is not currentlyincluded in Schedule 8 of the Wildlife and Countryside Act, 1981 (Cheffings & Farrell, 2005). Itwas also included as a priority Biodiversity Action Plan species in 2007 (NERC Act 2006) and islisted as one of 47 priority Crop Wild Relatives in the UK for which action plans have beenproduced (Maxted et al., 2007).

With the exception of Taylor’s Hill, Gloucestershire, all extant populations of Pulsatillavulgaris occur on SSSIs or NNRs (Table 10). Seven sites appear to be in favourable conditionfrom the perspective of Pulsatilla vulgaris (but not necessarily for other designated sitefeatures), with some form of grazing management to maintain calcareous grassland featuresof interest including Pulsatilla vulgaris. Populations have therefore increased in size orremained stable over the past 40 years. Seven sites appear to be in poor condition or arerecovering from poor condition due to the introduction of management. These include sitesthat were under-grazed for a long period and have recently been cleared of scrub and grazingre-introduced. The most dramatic example is Ancaster Valley, South Lincolnshire (Fig. 13). By1981 dense Ulex europaeus scrub had eradicated most of the Pulsatilla vulgaris population (aswell as Carex ericetorum) and only a few plants remained. Since then the scrub has beencompletely removed and the condition of the grassland improved through winter sheep-

grazing. A similar project to stock-proof and reintroduce grazing to the Devil’s Dyke inCambridgeshire is also benefiting Pulsatilla vulgaris largely through the reduced dominance ofBromopsis erectus (Fig. 14d). The recent re-introduction of grazing is also having positiveresults at Rodborough Common (cattle) and Deacon Hill, where a ‘flying flock’ of Hebrideansheep are used to graze a number of Pulsatilla vulgaris sites managed by the Wildlife Trust.

Table 10 - Extant populations of Pulsatilla vulgaris in England.

Site Cons Condition


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.

(a) Sites in good condition, grazing regime idealBarnack Hills andHoles

NNR Good condition, population temporary fenced to reducedisturbance

Barnsley WoldWarren

SSSI Good condition

Barton Hills NNR Good condition, flowering poor in some years due to over-grazing

Bourton Down SSSI Good condition, seedlings presentHornsleasowRoughs

SSSI Good condition, some parts under-grazed

Knocking Hoe NNR Good condition, severe rabbit disturbance in some yearsTherfield Heath SSSI Good condition, some parts under-grazed

(b) Sites in poor condition or recovering from poor conditionAncaster Valley SSSI Scrub clearance and grazing reintroduced

Deacon Hill SSSI Under-/over-grazed in the past; severe rabbit disturbanceDevil's Dyke SSSI Under-grazed but grazing introduced to some areasBeaumonts Hay SSSI Grazing irregularTaylor’s Hill - Grazing irregularRodboroughCommon

SSSI Under-grazed

Swinstead Valley SSSI Under-grazed, encroachment by Brachypodium pinnatum

(c) Sites in poor condition, plant likely to go extinctAston UpthorpeDown

SSSI Most plants in ungrazed exclosure; rest of site overgrazed

Ledsham SSSI Only a single plant; likely to go extinct

Ravensburgh Castle SSSI Ungrazed; likely to go extinctSteps Hill SSSI Undergrazed, threatened by scrub encroachment

As noted above, exclosures have been erected at a few sites to protect populations from over-grazing (e.g. Aston Upthorpe, Knocking Hoe, Pitstone Hill) but in general these had lead todeclines due to increased growth of Bromopsis erectus. At Aston Upthorpe annual mowing hasbeen introduced to counter this and maintain sward heights at the appropriate height (Fig.14a). At Therfield Heath temporary fencing is used to rotationally graze common land and toensure that areas containing Pulsatilla vulgaris are grazed appropriately. At Barnack Hills andHoles single strand fencing is used to reduce disturbance by visitors during the floweringperiod (Fig. 14b). At the most recently discovered site, Swinstead Valley, a temporary grazingexclosure erected during the flowering period led to an increase from 4 flowers in 2009 to 18in 2010.


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Figure 13 – The restoration of Pulsatilla vulgaris habitat at Ancaster Valley, SouthLincolnshire. The extant population is located on the left hand slope covered in Ulexeuropaeus in 1981. The scrub was cleared in the 1980s and winter-grazing reintroduced.

Table 11 – Details of translocations of Pulsatilla vulgaris in England.Site

Year(s)of intro

No.of

plants

%surviv

al

Sourceof seed

Details of translocation attempt

Aston Upthorpe,Berkshire

1999 87 56(2009)

AstonUpthorp

e

Augmentation of existing colony.Plants protected within exclosurebut few flower due to predation byrabbits or voles.

Hartslock,Oxfordshire

1998 78 80(2008)

Barnack Experimental introduction toinvestigate translocationtechniques (Warden, 2001).

SouthorpePaddock,Northamptonshire

1999 12 0 Barnack Re-introduction to a former site.Plants failed to survive more than 2years.

Ancaster, SouthLincolnshire

1992-2002

68 32(2005)

Ancaster Augmentation of existing colony.Plants protected by wire cagesduring the flowering period.

Copper Hill 1994- 68 0 Ancaster Re-introduction to a former site.

1981 1992

1999 2006


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Quarry, Ancaster 1996 Most scratched out by rabbits andpheasants within a few days ofplanting. Four plants survived fortwo years.

Ledsham, Mid-west Yorkshire

2000 1 0 Barnack A single plant was introduced toencourage cross-pollination of the

sole remaining plant in northernEngland. This died within a coupleof years.

In England attempts to re-introduce Pulsatilla vulgaris to former sites or augment existingpopulations have been carried out at six sites with variable success (Table 11). Transplantshave survived at Aston Upthorpe, Ancaster and Hartslock plants within protective exclosureswhere the surrounding vegetation has been removed to reduce competition (Fig. 14c) and thesurrounding vegetation has been mown or grazed. However, at both Aston Upthorpe andHartslock very few plants manage to set seed due to predation by rabbits or voles (Warden,2009). All other attempts have been failures with plants only surviving for one or two years.This included an attempt to translocate a single plant to within 4 metres of the sole survivingplant in northern England (at Ledsham) to encourage cross-pollination (A. Headley, pers.

comm.). Similar high rates of translocation failures have been reported for Switzerland(Pfeifer et al., 2002).

Figure 14 – Examples of in situ conservation work for Pulsatilla vulgaris in England: (a)fencing to exclude livestock, Aston Upthorpe Down, Berkshire; (b) temporary fencing to


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reduce trampling by visitors, Barnack Hills & Holes, Northamptonshire; (c) cages to protecttransplants from rabbits (note clearance of vegetation from around the plant), AncasterValley, South Lincolnshire; and (d) effects of the reintroduction of grazing to the Devil’s Dyke,Cambridgeshire, following the erection of stock-proof fencing.

7.2 Ex si t u Measures

Plants of wild origin are known to be cultivated in the Oxford Botanic Garden and Kew’sgarden at Wakehurst Place. Plants originating from Barnack Hills and Holes were also grown byTerry Wells at Monks Wood Experimental station between 1970 and 1980 for the purposes ofresearch, some of which were transferred to his garden in Upwood. Many plants originatingfrom wild British populations are likely to be cultivated in other private gardens. A smallamount of viable seed is currently stored in the Kew Millennium Seed Bank at Wakehurst Place(Royal Botanic Gardens Kew, 2008).

Pollen from the single Ledsham plant has been used to cross-pollinate five plants fromBarnack Hills and Holes, with the intention of growing on plants for reintroduction to the wildsite, but without success (A. Headley, pers. comm.).

7.3 Research DataResearch is urgently required to assess genetic variation within English populations and theextent to which small population size, limited gene-flow (due to extreme populationfragmentation), genetic drift and inbreeding depression are affecting the performance ofEnglish populations. Likewise studies that assess dispersal and pollination mechanisms, inparticular the potential for dispersal via livestock and machinery, may provide valuableinsights into gene-flow and how best to conserve Pulsatilla vulgaris in the future. Studies onthe genetic relationships between British and continental populations would also be usefulhelp to inform European conservation priorities.

Research on the regeneration niche of Pulsatilla vulgaris is needed in order to establish theoptimum conditions under which field germination and seedling establishment takes place.

Further work is also needed to assess factors controlling the abundance of Pulsatilla vulgaris,in particular the affects of the removal of competitive dominance in grassland swards e.g.responses to environmental perturbations and the removal of dominant species and leaf litter(Bailey, 1996).

Figure 15 – Fluctuations in the number of Pulsatilla vulgaris in fixed plots at Barnack Hillsand Holes, Northamptonshire. Data supplied by Chris Gardner (Natural England).


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7.4 Monitoring and the Common Monitoring StandardTraditionally Pulsatilla vulgaris has been monitored by simple counts of flowering ‘crowns’ orestimates based on densities in small areas (e.g. Tarpey, 1999). These provide an overallassessment of year to year variation but are limited for a number of reasons. First, ‘crowns’do not represent discrete genets due to the production of offshoots close to parents. The totalcount is therefore likely to overestimate the total size of the population possibly by orders of

magnitude. Second, grazing can have a marked influence on estimates especially on siteswhere livestock are present during the flowering period. Third, such counts do not take intoaccount the life-stage structure of the population or whether recruitment is taking placethrough the production of seed, presence of juveniles, etc.

Possible alternative approaches include counts within fixed plots as has been carried out atBarnack Hills and Holes in Northamptonshire since 1975 (Fig. 15). This should preferablyinclude a number of demographic parameters, including the individuals in different life-stages, flowering performance, seed production etc., and relate these environmentalvariables such as sward height, % cover of bare ground, ‘hits’ on dominant grasses, etc. Simplecounts of rosettes rather than flower stems is probably a more preferable performanceparameter given the dramatic fluctuations in the numbers of flowers observed on some sites

(e.g. Fig. 15). These are less affected by seasonal factors and grazing and therefore provide amore accurate assessment of the size of populations (Bailey, 1996). However, all theseapproaches are likely to be time consuming to carry-out and therefore dependent on availableexpertise, time and resources.

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