Pulsatilla vulgaris (L.) Mill. - Plantlife

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Pulsatilla vulgaris (L.) Mill. - Plantlife

Pulsatilla vulgaris (L.) Mill.

Pasque Flower, Pulsatilla vulgaris Miller

RANUNCULACEAE

SYN.: Anemone pulsatilla 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 in

2007. It is currently confined to 18 sites in 19 10km squares in England. In this account

Pulsatilla vulgaris refers to subsp. vulgaris unless otherwise stated.

In partnership with:

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Contents

1 Morphology, identification, taxonomy and genetics

1.1 Morphology and identification

1.2 Taxonomic considerations

1.3 Genetic implications

1.4 Medicinal properties

2 Distribution and current status

2.1 World

2.2 Europe

2.3 United Kingdom

2.3.1 England

2.3.1.1 Native populations

2.3.1.2 Introductions

2.3.2 Northern Ireland, Scotland & Wales

3 Ecology and life cycle

3.1 Life cycle and phenology

3.1.1 Flowering phenology

3.1.2 Flower biology

3.1.3 Pollination

3.1.4 Seed production

3.1.5 Seed viability and germination

3.1.6 Seed dispersal

3.1.7 Regeneration

3.1.8 Response to competition

3.1.9 Herbivory, parasites and disease

4 Habitat requirements

4.1 The landscape perspective

4.2 Communities & vegetation

4.3 Summary of habitat requirements

5 Management implications

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

7 Current conservation measures

7.1 In situ Measures

7.2 Ex situ Measures

7.3 Research Data

7.4 Monitoring and the Common Monitoring Standard

8 References

9 Contacts

10 Links

11 Annex 1 – site descriptions

13 Annex 2 – changes in population size, 1960-2006

14 Annex 3 – associates

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1 Morphology, identification, taxonomy and genetics

1.1 Morphology and identification

Hemicryptophyte; 2-15 cm, extending to ca. 45 cm in fruit. Rhizome obliquely erect or

vertical, branching, black, 2-17 mm thick, eventually decaying to form new plants. New leaf

rosettes 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 of

old leaf bases protect the overwintering buds at the apex of the rhizome. Basal leaves up to

11 from each rhizome apex, bipinnatisect, silky-hairy and forming a rosette. Ascending,

developing during anthesis and withering in the autumn (occasionally over-wintering). Petiole

to 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 and

reaching the perianth during most of the flowering period. All leaves silky-hairy at least

initially, the basal with pubescent petioles. On emergence the silky-villose leaves are tightly

curled around the apical growing points. Flowers solitary, terminal, erect at first but drooping

after a few days, and becoming bell-shaped (campanulate) (Fig. 1a). Buds develop during late

summer and become dormant over the winter months when they are protected by a dense

covering 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, only

slightly curving outwards apically. Petals fading and becoming bleached after about a week.

Stamens numerous, 50-120 per flower, crowded, the outermost shorter, sterile, club-shaped

and secreting nectar. Staminodes and fertile stamens not more than half as long as perianth

segments, 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 mm

long, with a single embryo, covered with simple, silky hairs and with a persistent feathery

style 3.5-5 cm long. The internode between the stem leaves and flower elongates considerably

after 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 a

variety of insects, especially bees (Apidae: Apis, Bombus).

1.2 Taxonomic considerations

The 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 the

flowers 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 the

herbaceous border) to the ‘Pasque Flower’ on account of the flowers appearing around Easter

time (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 first

volume of his Species plantarum (p. 539) 1 . The Scottish botanist Philip Miller (1768) changed

the name to Pulsatilla vulgaris in the eight edition of The gardeners dictionary and this was

subsequently retained in Aichele & Schwegler’s (1957) monograph of the genus which

described 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 stems

but 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 the

Linnaean 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 styles

elongating greatly and becoming feathery in fruit and the presence of nectar-secreting

staminodes (both absent in Anemone sensu stricto; Akeroyd, 1993). The current worldwide

classification scheme of the Angiosperm Phylogeny Group (APG III) considers the

Ranunculaceae to be among the most basal of the derived Eudicots clade (Hill & Preston,

2002):

APG Clade: EUDICOTS

APG Order: Ranunculales

APG Family: Ranunculaceae

Subfamily: Ranunculoideae

Genus: Pulsatilla

Species: Pulsatilla vulgaris Mill.

The genus Pulsatilla contains around 38 species worldwide all of which occur in the Northern

Hemisphere, mainly in Europe and Asia with two species in North America. Nine species occur

in 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 eastern

Europe 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, deeply

pinnatisect basal leaves with 7-9 primary segments that wither in the autumn and erect

flowers (nodding in anthesis). It is a very variable species for which a number of poorly

defined infraspecific taxa have been described in the past. These, however, appear to

represent the more distinct of the numerous isolated populations and probably represent a

‘dissected continuous’ type of variation caused by post-glacial climatic changes and the

intolerance 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 towards

the edge of the range of the species, are fairly homogeneous (as in Britain), but in other areas

there is considerable variation within populations. While it is likely that most populations are

separable from one another, there is a large amount of overlap between them and

intermediates occur frequently.

Today three subspecies are usually accepted. Subspecies vulgaris, to which all English

populations belong, is the most widespread taxon extending from 61º N in Sweden to c. 45º N

in the Bordeau region of France and from Gloucestershire in England to near to Poznan in

western Poland where it is replaced by subsp. grandis (Lindell, 1998). Subsp. vulgaris is

distinguished by the greater degree of lobing in the leaves (>100;


1.3 Genetic implications

The chromosome base-number of the genus is 8. Pulsatilla vulgaris is tetraploid (2n = 32) and

may 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 has

indicated 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 geographic

range of Pulsatilla vulgaris in England (Barton Hills, Knocking Hoe, Rodborough Common,

Devils Dyke, Therfield Heath), suggesting that overall genetic variation is low, although there

were 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 overall

fitness, population size and degrees of geographical isolation.

Similar work has been undertaken in Germany on 11 populations ranging from 50 plants to

7300 plants (Hensen et al., 2005) and found a significant positive relationship between genetic

diversity 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 loss

of diversity as populations have become smaller and fragmented following rapid land-use

change (i.e. the chance of alleles being lost from one generation to another has been greater

in smaller populations).

Hensen et al. (2005) also found a high level of within population variability which was

attributed to life-history traits likely to preserve variability, namely allogamous pollination, a

long life span and vegetative reproduction. Interestingly there was only weak, albeit

significant differentiation between populations which was correlated to the geographical

distance. This suggests that genetic drift has been the major force driving differentiation

between German populations as the former larger population became fragmented. The

weakness of this relationship suggests that the loss of genetic variability through drift has

been, to some extent, balanced by gene flow between closer populations. Since seed dispersal

in 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 as

populations become smaller and more isolated. However, even if pollinators forage over

several kilometres it seems very unlikely that they would travel between English populations

given their small size and degree of isolation.

1.4 Medicinal properties

Pulsatilla 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 the

plant is dried (Plants for a Future, 2010). Small doses are taken internally in the treatment of

pre-menstrual syndrome, inflammations of the reproductive organs, tension headaches,

neuralgia, insomnia, hyperactivity, bacterial skin infections, septicaemia, spasmodic coughs in

asthma, whooping cough and bronchitis. Externally, it is also used to treat eye conditions such

as diseases of the retina, senile cataract and glaucoma. In homeopathy, extracts are used to

treat measles as well as minor complaints such as nettle rash, toothache, earache and bilious

indigestion (Plants for a Future, 2010).

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2 Distribution and current status

2.1 World

Pulsatilla 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 Europe

Pulsatilla vulgaris belongs to the European Temperate element (Preston & Hill, 1997) with the

core 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 the

plant in Europe and consequently it was not listed as a priority species for conservation in the

most recent assessment of the French flora (unlike P. vernalis; Olivier et al., 1995). In

comparison 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 2000

plants now survive in 23 sites (Franz, 2005), and Switzerland where it is very rare (Pfeifer et

al., 2002) and classed as Endangered under IUCN threat criteria (Moser et al., 2002). In

Belgium it is confined to two small areas in the southern province of Wallonia, where its

habitat (limestone grassland) is under pressure from extensive tree planting (Quentin Groom,

pers. comm.). In Luxembourg it is classified as Endangered under IUCN criteria having

declined from 28 to 5 localities with population sizes now ranging from two to more than 7000

genets (Colling, 2005). It appears to be extinct in Finland, where it has not been seen since

the 1930s (Rassi et al., 2001) and Holland. It’s status in Poland is unknown although recent

maps (e.g. Fig. 2) show it to be very rare. Recent records for Norway all appear to be of

casual escapes (Jonsell, 2001).

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Figure 2 - Distribution map of Pulsatilla vulgaris subsp. vulgaris in Northwest and Central

Europe, 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 or

occurrences 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 no

individual occurrence data were available. The doubtful two easternmost records from Poland

are 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, 2005

Belgium ? Very rare and declining

Denmark ? Unknown

Finland EW Formerly one site Rassi et al., 2001

France ? Not threatened? Olivier et al., 1995

Germany ? Widespread but declining Hensen et al., 2005

Holland EW Extinct

Luxembourg EN Declined from 28 to 5 localities Colling, 2005

Norway - Casual escape Jonsell, 2001

Poland ? Unknown

Sweden VU Ca.30% reduction in past 100 years Gärdenfors, 2010

Switzerland EN Marked decline Pfeifer et al., 2002; Moser et

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UK VU Declined from ca.130 to 18

localities

2.3 United Kingdom

2.3.1 England

al., 2002

Cheffings & Farrell, 2005

2.3.1.1 Native populations

Since its discovery near to Oxford in 1551 (Druce, 1886) Pulsatilla vulgaris has been recorded

from around 130 sites in 19 English vice-counties (Table 2) but is now confined to 18 sites in

just ten vice-counties (Table 3). Former strongholds include the Cretaceous chalk downland

and 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 Magnesian

limestone grasslands in northern England, extending as far north as Piercebridge in County

Durham (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 Norfolk

and 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)

Tota %

VC Vice-county name

Extinc

t

1-10

11-

50

51-200

201-

1000

>1000

l

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 67

26 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

33

East

Gloucestershire

17 1 2 1 1 22 77

34 West

Gloucestershire

4 1 5 80

53 South Lincolnshire 16 1 1 18 89

54 North Lincolnshire† 5 5 100

55 Leicestershire† 5 5 100

63

South-west

Yorkshire†

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, Midwest

Yorkshire) with a single individual (known since 1984). Only five sites (28%) support in

excess 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 at

Barnsley 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 British

population. Of the eighteen surviving populations 4 appear to be declining and are threatened

with extinction, 9 are stable and 5 appear to be increasing due to improvements in grazing

regimes (Table 3; see Annex 2 for details).

Figure 3 – The hectad

distribution of Pulsatilla

vulgaris in Britain and Ireland.

Solid black circles are hectads

where P. vulgaris has been

recorded since 2000; solid grey

circles, recorded 1987-1999;

open circles, recorded before

1987; X, introduced.

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 around

1.8 populations per decade to 6.0 since 1950 (Fig. 4b) although these figures presumably

underestimate rates for earlier periods as fewer ‘extinction events’ are likely to have been

detected 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

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English populations, the overall number of plants has increased considerably from an

estimated 60,000 to over 160,000 individuals largely due to improvement in grazing regimes

on four of the best sites (Barnack Hills and Holes, Barnsley Wold, Barton Hills, Therfield

Heath; Fig. 4d). Despite these losses new populations continue to be found including a small

population 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/management

Size/

trend

Cons.

Design

.

Therfield Heath 20 TL33 Chalk, winter grazing E↑ SSSI

Aston Upthorpe Down 22 SU58

Chalk, ungrazed exclosure, occ.

mown

B(r)↓

SSSI

Steps Hill 24 SP91 Chalk, intermittent grazing B↓ SSSI

Devil's Dyke 29 TL56/

66

Chalk, 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 TF00

Limestone, grazed excluding Mar-

Sep

E↑

NNR

Barnsley Wold Warren 33 SP00

Limestone, grazed excluding Mar-

May

E↑

SSSI

Beaumonts Hay 33 SP12 Limestone, irregular grazing A≈ SSSI

Bourton Down 33 SP13

Limestone, 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; ↓, population

decline; ≈ population stable.

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

VC Vice-county Last recorded site Last Probable reason for loss

name

record

19 North Essex Bartlow Hill 1888 Scrubbed-over

23 Oxfordshire Upton Down 1883 Ploughed-up

26 West Suffolk Newmarket Heath 1978 Grassland altered by horse

training

28 West Norfolk Sporle & Tulip Hills 1914 Scrubbed-over

31 Huntingdonshire Stibbington 1926 Possibly an error for sites in

VC32?

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54 North

Broughton Far 1969 Scrubbed over; last plant ‘dug-

Lincolnshire Wood

up’

55 Leicestershire Shacklewell Hollow 1992 Dumping of rubble

63 South-west Smeaton Crag 1870 Quarrying/mining

Yorkshire Pastures

66 Durham Cliffe Wood 1906 Landscaping of parkland

Although there is no fossil evidence of the occurrence of Pulsatilla vulgaris in Europe it was

probably much more widespread during the early post-glacial in dry, steppe grassland before

retreating to open refugia, with shallow soils and low competition, following the spread of

deciduous 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 as

the Avon Gorge and centres of Neolithic farming activity, such as Salisbury Plain, suggests a

much more complex phytogeographical history in Britain, or at least one that is impossible to

reconstruct from modern records alone.

Figure 4 – The number and size of populations of Pulsatilla vulgaris in England: (a) size of

extant 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 since

1960. In (c) all populations were assumed to have been present in 1750 even if they were only

discovered much later.

2.3.1.2 Introductions

There 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 also

been six deliberate introductions to either re-establish populations on sites where it become

extinct (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 small

population that straddles the border of Dorset and South Wiltshire on Martin Down which

interestingly appears to have increased since its discovery in 1983 (see

http://www.hantsplants.org.uk). Both Bowen (2000) and Brewis et al. (1996) suggest it might

be native given the typical nature of the habitat (ancient species-rich grassland on an

earthwork). 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 an

introduction 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 are

given in Table 11.

VC VC name Details

7 North Wiltshire Planted on Morgan’s Hill in 1939 from where it possibly colonised

8/9 South

Wiltshire/Dorset

Cherhill Down by 1941 (Grose, 1957) but this seems unlikely.

Known from Martin Down since c.1983 where two small

populations grow on either side of the vice-county boundary on

ancient species-rich chalk banks (SU0518, SU0418). Likely to

have been planted given the distance to the nearest native

populations (Edwards & Pearman, 2004).

No details; presumed planted.

13/1 West & East

4 Sussex

20 Hertfordshire Discovered on road verges at two sites (TL1226; TL2426) where

it 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 (C

Boon, pers. comm.).

2.3.2 Northern Ireland, Scotland & Wales

Pulsatilla vulgaris does not occur in Northern Ireland, Scotland or Wales.

3 Ecology & life cycle

3.2 Life cycle and phenology

Pulsatilla vulgaris is a monoecious, long-lived, polycarpic hemicryptophyte which appears to

reproduce mainly vegetatively by growth of adventitious buds on the branched rhizome. These

13


produce several daughter rosettes close to the parent plant each year. Although new flower

buds 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 flowering

and 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 in

England 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 halflife

of more than 50 years (Grubb, 1990). Plants grown from seed will flower in pots in 1.5-2.5

years but in the wild this is likely to be 4-5 years.

3.1.1 Flowering phenology

Temperature appears to be a very important cue that regulates the timing and rate of flower

and fruit development (Widén & Lindell, 1996). Flowering commences when temperatures rise

above 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 the

greenhouse (Widén & Lindell, 1996) or under experimental shading conditions (Fig. 5; Walker

et al., in press). In large populations, however, the behaviour of individuals is variable, some

plants flowering in successive years whilst others remain vegetative (Wells & Barling, 1971). In

addition, drought in one summer may affect flowering the following year as primordia are

initiated in late summer (Rich, 1997).

Number of site records

60

50

40

30

20

10

0

1 2 3 4 5 6 7 8 9 101112131415161718192021

Weeks from 1st March

Figure 4 – Phenology of Pulsatilla vulgaris in England based on the number of historical

records for sites held in the Vascular Plants Database, regardless of location, year & recorder.

3.1.2 Flower biology

Each plant produces 1-3(-12) bell-shaped flowers with numerous carpels with long purple

styles (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 first

opening, only closing at night or during rain (Wells & Barling, 1971). Flowers are

hermaphrodite and markedly protogynous with the female reproduction organs reaching

14


maturation before the male (andro- and gyno-monoecious and dioecous forms have been

reported from the continent but are likely to be rare). Both stamens and styles continue to

grow 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 the

beginning of anthesis to the opening of the first pollen sac) lasts just over a day whereas

pollen 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 directly

correlated with an increase in temperature (Kratochwil, 1988; Jonsson et al., 1991). In most

populations the length of the obligate female phase is likely to be sufficient for some crosspollination

to take place since the great proportion of flowers receive pollen before the onset

of the male phase (Jonsson et al., 1991). However, geitonogamous pollination is probably also

common as most populations include plants with 2 or more flowers, including flowers on

identical (daughter) genets growing close-by (Warden, 2001).

Figure 5 – Effects of experimental shading on (a) the % survival and (b) flowering

performance 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 a

depth of 1 m and exposed to three levels of shading (dense, medium, light) simulated using

black gauze screens erected over each plot. Each plot consisted of 12 regularly spaced plants

25 cm apart. Three replicates of each treatment and a control (no shade) were arranged in a

randomised latin square and the survival of transplants and flowering performance recorded in

April and May of each year. The plots were fenced to exclude rabbits and weeded to remove

competition.

3.1.3 Pollination

The flowers of Pulsatilla vulgaris are insect-pollinated mainly by aculeate Hymenoptera and

bees (Apidae: Apis, Bombus). Many other insects have been recorded visiting flowers in

England 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 selfincompatability

(ISI)


populations has shown that dichogamy is incomplete, since artificial selfing produces a small

amount 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 reported

values of 18% in England (Warden, 2001) and 31-50% in Sweden (Lindell, 1998). Insects seem to

be 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 production

Between 30-90 carpels are borne on a flattened, conical receptacle, each containing a single

embryo which when fertilised develops into an achene 2-3 mm long with a persistent feathery

style (3-5 cm) borne on stems that elongate after anthesis (Fig. 1b). Achenes ripen 4-5 weeks

after the flowers open and fruits may be ripe from mid May to mid June. There is considerable

variation in the number of achenes produced per flower and total achene production per

plant. For example, Wells & Barling (1971) found 23-74 achenes per flower in five English

sites, with an average of 46, though not all may have been fertile (Rich, 1997) whereas

Warden (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 only

a few hours of favourable conditions occurred in most years. However, intermediate flowering

plants appear to be more fecund than earlier or late flowers, because early flowers encounter

a paucity of pollen vectors and suffer from early frosts whereas late flowers suffer from

greater predation and may have to compete with developing leaves for resources (Widén &

Lindell, 1996; Warden, 2001). Later-flowering plants also appear to develop seeds more

rapidly due to higher temperatures (Widén & Lindell, 1996). Flowers in most populations

produce 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 germination

The viability of fresh seeds is generally high with reported germination values at room

temperature 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 controlled

laboratory conditions 80% germination was been achieved on 1% Agar solution at 20°C, 8/16

hours 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 with

age. Wells & Barling (1971) found between 15-65% germination after 8-9 months with no

germination occurring after 2.5 years. However, only a small decreases in viability has been

reported for seed stored at 4°C for one year (Warden, 2001) and dried to low moisture

contents and stored for 13 years (RBG Kew, Wakehurst Place). Germination appears to be

unaffected by light levels or storage at temperatures as low as -7°C (Wells & Barling, 1971).

16


3.1.6 Seed dispersal

Achenes of Pulsatilla vulgaris are adapted for wind-dispersal by modification of the style into

a 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 the

surrounding 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 the

surrounding grassland. Despite these adaptations, long-distance dispersal is most probably

absent or very rare (Tackenberg et al., 2003). Observations in England suggest that seeds

disperse less than 20 cm from parent plants often because the entire head remains intact or

the feathery tail becomes entangled in the surrounding vegetation (Wells & Barling, 1971;

Warden, 2001). In addition simulations of aemochorous dispersal showed that 90% of the seeds

land within the mother population with only 0.05% of seeds being dispersed over a distance of

more than 100m (Tackenberg, 2001). According to Röder & Kiehl (2006) Pulsatilla seeds also

have a high potential for epizoochory, including dispersal on machinery, which might be a

more important strategy for long distance dispersal in modern landscapes. Establishment of

new populations in this way is likely to be rare, but may have occurred at one site in

Cambridgeshire 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 at

this site as the new colony occurs on a mown road verge inaccessible to livestock.

3.1.7 Regeneration

Despite the production of viable, highly germinable seeds, establishment of new individuals

from seed appears to be rare (seedlings observed at only one site by the author) and most

regeneration, is probably achieved by the disintegration of the branched rootstock (Wells &

Barling, 1971). Plants reproduce vegetatively by growth of adventitious buds on the rhizome 2

cm 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 has

revealed as many as seven distinct rosettes from a single rootstock, the younger plants being

clustered 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, well

managed 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 seed

reaches the soil surface hygroscopic movement of the style may help bury the seed, but this

has not been observed. Germination is epigeal, the green cotyledons expanding 3-6 mm above

the soil surface. The slender primary root of the seedling grows vertically downwards reaching

a depth of 15 cm within 6 months of germination by which time it has formed an extensive

root system. At this stage the underground stem is ca.2 mm long with 2 or 3 leaves arising

from axillary buds at the apex of the rootstock.

The establishment of new plants appears to be a rare event as seedlings have only been

observed a few times in recent decades. For example seedlings were found on only one site

during 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 at

or on near the soil surface (see Fig. 9k).

Soil moisture appears to be critical for establishment as seedlings only appear to survive in

wet summers (Wells, 1994; Rich, 1997). For example, Wells & Barling (1971) showed that

17


higher germination occurred where seeds were covered with a thin layer of soil but that all

seedlings suffered high mortality due to physical disturbance and herbivory. In addition,

seedling development was extremely slow and even after two years plants were still very

small.

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 the

rarity 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 competition

Pulsatilla vulgaris occurs at highest density where soils are shallowest and above ground

competition (biomass) is low (Fig. 7a). Flower production also decreases as competition from

tall 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 been

attributed to the smothering effect of leaf litter of Bromopsis erectus and increased

competition from tall grasses. For example, Mitchley (1988) showed a positive correlation

between 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 project

their leaves into the upper canopy thereby reducing the amount of photosynthetically active

radiation 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 vegetation

by physically restricting the growth of surrounding species, especially low-growing

hemicryptophytes such as Pulsatilla vulgaris (Campbell et al., 1992). Attempts to simulate

these effects through shading have shown significant decline in longevity, survivorship and

flowering performance at increasing levels (Fig. 5). Likewise transplants of Pulsatilla vulgaris

have significantly greater survivorship and performance (number of leaves) when competition

from surrounding vegetation is removed (Warden, 2001). These findings highlight the critical

role of above-ground competition plays in restricting the amount of light reaching the base of

18


the sward and thereby determining the relative abundance of hemicryptophytes such as

Pulsatilla vulgaris.

(a) (b)

Figure 7 – The effects of competition on Pulsatilla vulgaris. (a) The relationship between

depth 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 between

sward height and the % of Pulsatilla vulgaris plants in flower in a grazing exclosure at Barton

Hills, Bedfordshire. Each dot represents a year with overall numbers increasing from 138

following the withdrawal of grazing 1964 to 654 in 1969. Both figures adapted from Wells &

Barling (1971).

3.1.9 Herbivory, parasites and disease

Pulsatilla vulgaris is a plant of sheep and rabbit grazed downland and is well adapted to

grazing by herbivores. The plant is dormant during the winter, and at other times the

vegetative 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 flower

or part of it are eaten by caterpillars, pheasants (Bowen, 1997) or small mammals (wood

mouse Apodemus sylvaticus, field vole Microtus agrestis) (Carter, 1967). Although the leaves

contain anemonin they are eaten by sheep, rabbits, slugs and snails. Caterpillars of two leafmining

moths of the genus Cnephasia have also been recorded on leaves in the UK (Database

of Insects and their Food Plants, accessed August 2010). At least two other leaf-mining insects

have been reported on the continent and nematode worms of the genus Meloidogyne have

been 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 flies

belonging to two Diptera families, the Agromyzidae and Cecidomyiidae, and are a potentially

serious 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 has

so far been observed (Warden, 2001). Parasites on Pulsatilla vulgaris include Cuscuta

epithymum, which has been recorded on plants at Barnsley Wold. The fungal rust

Coleosporium 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

19


In England Pulsatilla vulgaris is confined to moderately steep south to southwest facing slopes

where 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 Jurassic

limestone (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. Ravensburgh

Castle, 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 facing

northwards (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 or

bottom. For example, Wells & Barling (1971) recorded densities of 7.5 plants m -1 where the

soil was 5 cm deep but only 1.2 plants m -1 at soil depths greater than 100 cm (Fig. 7a).

(a) (b)

Figure 8 – The aspect (a) and slope (b) of Pulsatilla vulgaris populations in England. The

figures include values for the 29 populations included in Wells & Barling (1971) and five

populations 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 relatively

high surface soil pH (average 7.5; range 7.1-7.8; Table 6). These soils are very friable and

porous 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 (320-830

mg 100g -1 dry soil) with other mineral nutrients, especially phosphorous, occurring at low

levels (Table 6). The clay/silt/sand fractions of these soils is also low (


Table 6 – Chemical and mechanical analysis of soil from Pulsatilla vulgaris sites in England and

five sites on sandy soils in Sweden for comparison. These summarise data presented for 10

sites in Table 1 of Wells & Barling (1971).

Chalk a

Limestone

b

Mean Range

Calc.

sand c

Sweden

pH 7.6 7.4 7.5 7.1-7.8 5.2 5.0

Organic

(%)

matter

15 11

13 8-22

8.5

8

Nitrogen (%) 0.5 0.4 0.5 0.3-0.7 0.2 0.3

K (mg 100g -1 ) 18 21 19 11-31 0.9 18

Ca (mg 100g -1 ) 654 492 582 320-830 170 44

Mg (mg 100g -1 ) 13 11 12 7-17 12 6

P (mg 100g -1 ) 1.5 1.0 1.3 0.6-2.3 0.8 1.1

CaCO3 (%) 71 62 67 34-91 0.8


Figure 9 – Habitats of extant populations of Pulsatilla vulgaris in England (arrows mark the

position of small populations): (a) Anglo-Saxon earthwork, Devil’s Dyke, Cambridgeshire; (b)

shallow limestone quarry workings, Hornsleasow Roughs, Gloucestershire; (c) Knocking Hoe

and ‘Spiranthes Bank’, Bedfordshire; (d) Ravensburgh Castle Iron Age hill fort, Bedfordshire;

(e) Ledsham Banks, Mid-west Yorkshire; (f) Steps Hill (Incombe Hole), Buckinghamshire.

22


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) Church

Hill, Therfield Heath, Hertfordshire.

4.2 Communities & vegetation

In England Pulsatilla vulgaris is almost entirely confined to short, herb-rich Bromion grasslands

on calcareous soils derived from the Chalk or Oolitic Limestone (Rodwell, 1992). The main

23


National Vegetation Classification (NVC) grassland type on both chalk and limestone is Bromus

erectus grassland (CG3), including grazed species-rich and ungrazed species-poor subcommunities

(CGa-b and CG3d respectively) (Fig. 10a). It occurs less frequently in Bromus

erectus-Brachypodium pinnatum (CG5) and Brachypodium pinnatum (CG4) grasslands, mainly

on limestone (Rodwell, 1992). These three communities form the core alliance of the

Brometalia in western Europe and are broadly characterised by the grasses Brachypodium

pinnatum, Bromopsis erectus, Helictotrichon pratense, Koeleria macrantha and a wide range

of 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 and

rabbits has reduced the cover of Bromopsis erectus to very low levels. In all these

communities the vegetation is typically very diverse (23 species m -2 ) with a high cover of

broad-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) National

Vegetation Classification (NVC) grassland types; and (b) ordination plot (Detrended

Correspondence Analysis) showing overall variation in species composition. Both plots include

quadrat data for 30 sites including all 29 visited by Wells & Barling (1971) plus Swinstead

Valley discovered in 2009. Twenty-nine of these quadrats were recorded in 1964-1968 and 27

recorded since 2000. * includes sub-communities 2a & 2d; ** includes sub-communities 3a, 3b

and 3d.

Overall there is remarkably little variation between the composition of these grasslands on

chalk or limestone (Fig. 10b), the main difference being the almost complete replacement of

Brachypodium 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 the

ordination plot, are Hildersham Furze and Unhill Bottom. Both were rank, species-poor swards

dominated 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 glacial

sands and gravels, although the vegetation was distinctly calcicolous due to the presence of

free calcium. Pulsatilla vulgaris occurs on soils with a similar pH in Sweden and Denmark, but

these are much more base-poor and consequently the vegetation is dominated by acidophiles

such 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.

24


Cavenham Heath) support extensive areas of Festuca ovina–Agrostis capillaris–Rumex

acetosella acid grassland (Erodium cicutarium-Teesdalia nudicaulis U1c sub-community), a

species-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 long

periods 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 that

in taller swards competitive exclusion by coarse grasses eventually leads to an overall decline

in plant numbers (Fig. 11a). Consequently taller swards lead to a reduction in overall species

diversity (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 the

open conditions favoured by Pulsatilla vulgaris.

Figure 11 –Differences in (a) sward height (cm), (b) species diversity and (c) % cover of

Bromopsis erectus (± 1 SE) on extant Pulsatilla vulgaris sites in England (n = 14) in relation to

population 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 requirements

A number of habitat features are important to Pulsatilla vulgaris in England and these are

summarized in Table 7.

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

Type Description

Physical and • Lowland (


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 reproduces

vegetatively, and rarely from seed. It is a poor competitor and therefore unable to persist in

ungrazed, closed swards or amongst scrub where the general height of the vegetation exceeds

15 cm and there is a build-up of litter from coarse grasses, especially Bromopsis erectus and

Brachypodium pinnatum. Its survival is therefore dependent on grazing, although short-term

fluctuations in grazing intensity or short-term neglect are unlikely to be critical in the longerterm.

For example, one of the largest populations in England survived 100 years of sheep

grazing, 13 years of very heavy sheep grazing, 22 years of no grazing including a severe fire

during the flowering season (Wells, 1968).

Management should aim to produce a sward of ca.5(-10) cm during the flowering period with

up 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 season

appears to have no ill-effect. All its current sites are also subject to moderate to high levels

of rabbit grazing throughout the year and, although this can cause localized extinction where

severe, it has probably been vital in maintaining open conditions on sites with intermittent or

low levels of stock grazing. It has also survived a variety of cutting treatments ranging from

cutting once a year in spring, summer or autumn, to three times a year as well as annual

burning (‘swaling’) in February or March to reduce the dominance of coarse grasses such as

Bromopsis erectus and Brachypodium pinnatum. On some sites it has also benefited from

occasionally burning and trampling by humans which appears to stimulate the development of

the deep-seated adventitious root buds.

On some sites where over-grazing, mainly by rabbits, is perceived to be a problem fencing

exclosures have been erected although this appears to have been detrimental due to the

build-up of coarse grasses.

Given the poor dispersal ability of Pulsatilla vulgaris and the high degree of isolation of many

populations the movement of livestock and cutting machinery between extant and potentially

suitable sites is likely to be critical in promoting gene-flow and in enabling colonization to

take place.

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

In England Pulsatilla vulgaris has undergone a rapid and dramatic range contraction over

recent millennia and its current distribution now represents just 27% and 14% of its former

range at the 10-km and site-population scales respectively. A similar magnitude of decline has

been 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;

26


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 grew

together 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 least

1750 (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 by

the Cambridgeshire botanist Charles Babington (1860), who noted that “Until recently (within

60 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 its

peculiar plants mostly confined to small waste spots by road-sides, pits, and the very few

banks which are too steep for the plough.” Although this probably over-states its former

abundance, 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 urban

population. During the same period many populations were also lost to quarrying and mining

activities 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 and

2000. % loss figures are based only on localities where the cause of loss is known and therefore

exclude ‘Unknown’ and ‘Possible error/duplicate record’.

Reason for loss

1750-

1800

1801-

1850

1851-

1900

1901-

1950

1951-

2000

Total

(%)

Ploughing

Lack of grazing/scrub

2 8 10 7 1 28 (42)

encroachment

Quarrying/mining/mineral

1 1 1 14 17 (25)

extraction 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 36

Possible error/duplicate record 2 3 5

Total 9 12 31 26 30 108

Rate of loss per decade 1.8 2.4 6.2 5.2 6.0 4.3

27


Figure 12 – Sites where Pulsatilla vulgaris is now extinct (all photos taken 2003-2006; year of

last 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).

28


Losses to ploughing and quarrying continued into the twentieth century and by the 1960s only

29 populations remained (Wells & Barling, 1971). Losses since then have mainly been caused

by increased above-ground competition, particularly with Bromopsis erectus, as a result of

under-grazing (Walker et al., in press). Ironically this was first observed in grazing exclosures

that 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, mowing

or burning (Table 9). These include small areas of grassland on earthworks or steep banks that

are now completely isolated within arable landscapes and are now partly or completely

scrubbed-over (e.g. Fleam Dyke, Fig. 12a; Honnington Camp, Fig. 12d), small exclosures

erected to exclude livestock, deer and rabbits on over-grazed sites (e.g. Aston Upthorpe

Down, Fig. 13a) and privately managed nature reserves where resources for management have

been limited (e.g. Ancaster Valley, Fig. 13).

This decline of grazing frequency and intensity on many sites has been due to the reduced

profitability of livestock farming in arable areas since the 1950s which has made it difficult to

sustain appropriate grazing management on unproductive sites (Nisbet & Shere, 2006). On

mixed 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 increased

transport and infrastructure costs. Even on livestock farms these problems have prevented the

grazing of small fragments of semi-natural grasslands perceived to be unproductive and/or

difficult to manage. In addition, there has been a decline in rabbit grazing since the spread of

myxomatosis in 1953 which is known to have caused dramatic successional changes, especially

on 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.

Extant

Management since 1968

1. Winter + some spring/summer/autumn

Increas

e

Stable Decline

Extinc

t

Total

grazing 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 and

reseeded 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 more

recently at Barton Hills (M. Gurney, pers. comm.). In addition, the last known plants were

dug-up at two former sites (Broughton Far Wood, Fleam Dyke; Marren, 1999) although other

factors 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 on

the last Leicestershire colony. More recently there has also been concern, but no direct

evidence, that atmospheric nitrogen deposition may be adversely affecting some populations

through eutrophication of infertile grassland (Crawley, 2005; Rich et al., 1993).

29


The current range of Pulsatilla vulgaris in England is characterised by a high level of

fragmentation, since numbers and size of populations have declined considerably over the

past 40 years. During this time the average distance between neighbouring populations has

increasing from 8 km to 22 km. Most significantly eight populations are now separated by more

than 10 km, five by more than 35 km and the most isolated site, Ledsham in Yorkshire, by 102

km. 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 local

extinction 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 in

central Germany, as well as a number of other European grassland species that have suffered

similar 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 characters

Pulsatilla vulgaris may have maintained higher levels of genetic variation than would be

expected for a declining species, although small populations are likely to display lower levels

of genetic variation than larger ones, even where gene exchange is occurring between sites in

close proximity. As the distance between half of English populations is well beyond the

foraging radius of most pollinators (>10 km) we would expect to see a significant

differentiation between isolated or outlying populations, both in terms of genetic variation

and reproductive performance. Further work is needed to test these hypotheses.

7 Current Conservation Measures

7.1 In Situ Measures

Pulsatilla vulgaris is currently classed by as Vulnerable using IUCN criteria but is not currently

included in Schedule 8 of the Wildlife and Countryside Act, 1981 (Cheffings & Farrell, 2005). It

was also included as a priority Biodiversity Action Plan species in 2007 (NERC Act 2006) and is

listed as one of 47 priority Crop Wild Relatives in the UK for which action plans have been

produced (Maxted et al., 2007).

With the exception of Taylor’s Hill, Gloucestershire, all extant populations of Pulsatilla

vulgaris occur on SSSIs or NNRs (Table 10). Seven sites appear to be in favourable condition

from the perspective of Pulsatilla vulgaris (but not necessarily for other designated site

features), with some form of grazing management to maintain calcareous grassland features

of interest including Pulsatilla vulgaris. Populations have therefore increased in size or

remained stable over the past 40 years. Seven sites appear to be in poor condition or are

recovering from poor condition due to the introduction of management. These include sites

that were under-grazed for a long period and have recently been cleared of scrub and grazing

re-introduced. The most dramatic example is Ancaster Valley, South Lincolnshire (Fig. 13). By

1981 dense Ulex europaeus scrub had eradicated most of the Pulsatilla vulgaris population (as

well as Carex ericetorum) and only a few plants remained. Since then the scrub has been

completely removed and the condition of the grassland improved through winter sheepgrazing.

A similar project to stock-proof and reintroduce grazing to the Devil’s Dyke in

Cambridgeshire is also benefiting Pulsatilla vulgaris largely through the reduced dominance of

Bromopsis erectus (Fig. 14d). The recent re-introduction of grazing is also having positive

results at Rodborough Common (cattle) and Deacon Hill, where a ‘flying flock’ of Hebridean

sheep 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

30


.

(a) Sites in good condition, grazing regime ideal

Barnack Hills and NNR Good condition, population temporary fenced to reduce

Holes

disturbance

Barnsley

Warren

Wold SSSI Good condition

Barton Hills NNR Good condition, flowering poor in some years due to overgrazing

Bourton Down SSSI Good condition, seedlings present

Hornsleasow

Roughs

SSSI Good condition, some parts under-grazed

Knocking Hoe NNR Good condition, severe rabbit disturbance in some years

Therfield Heath SSSI Good condition, some parts under-grazed

(b) Sites in poor condition or recovering from poor condition

Ancaster Valley SSSI Scrub clearance and grazing reintroduced

Deacon Hill SSSI Under-/over-grazed in the past; severe rabbit disturbance

Devil's Dyke SSSI Under-grazed but grazing introduced to some areas

Beaumonts Hay SSSI Grazing irregular

Taylor’s Hill - Grazing irregular

Rodborough

Common

SSSI Under-grazed

Swinstead Valley SSSI Under-grazed, encroachment by Brachypodium pinnatum

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

Aston

Down

Upthorpe 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 extinct

Steps Hill SSSI Undergrazed, threatened by scrub encroachment

As noted above, exclosures have been erected at a few sites to protect populations from overgrazing

(e.g. Aston Upthorpe, Knocking Hoe, Pitstone Hill) but in general these had lead to

declines due to increased growth of Bromopsis erectus. At Aston Upthorpe annual mowing has

been 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 to

ensure that areas containing Pulsatilla vulgaris are grazed appropriately. At Barnack Hills and

Holes single strand fencing is used to reduce disturbance by visitors during the flowering

period (Fig. 14b). At the most recently discovered site, Swinstead Valley, a temporary grazing

exclosure erected during the flowering period led to an increase from 4 flowers in 2009 to 18

in 2010.

31


1981 1992

1999 2006

Figure 13 – The restoration of Pulsatilla vulgaris habitat at Ancaster Valley, South

Lincolnshire. The extant population is located on the left hand slope covered in Ulex

europaeus 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

plan

ts

%

surviv

al

Source

of seed

Details of translocation attempt

Aston Upthorpe, 1999 87 56 Aston Augmentation of existing colony.

Berkshire

(2009) Upthorp Plants protected within exclosure

e but few flower due to predation by

rabbits or voles.

Hartslock,

1998 78 80 Barnack Experimental introduction to

Oxfordshire

(2008)

investigate translocation

techniques (Warden, 2001).

Southorpe

1999 12 0 Barnack Re-introduction to a former site.

Paddock,

Plants failed to survive more than 2

Northamptonshir

e

years.

Ancaster, South 1992- 68 32 Ancaster Augmentation of existing colony.

Lincolnshire 2002

(2005)

Plants protected by wire cages

during the flowering period.

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

32


Quarry, Ancaster 1996 Most scratched out by rabbits and

pheasants within a few days of

planting. Four plants survived for

Ledsham, Midwest

Yorkshire

two years.

2000 1 0 Barnack A single plant was introduced to

encourage cross-pollination of the

sole remaining plant in northern

England. This died within a couple

of years.

In England attempts to re-introduce Pulsatilla vulgaris to former sites or augment existing

populations have been carried out at six sites with variable success (Table 11). Transplants

have survived at Aston Upthorpe, Ancaster and Hartslock plants within protective exclosures

where the surrounding vegetation has been removed to reduce competition (Fig. 14c) and the

surrounding vegetation has been mown or grazed. However, at both Aston Upthorpe and

Hartslock 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 surviving

plant 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

33


educe trampling by visitors, Barnack Hills & Holes, Northamptonshire; (c) cages to protect

transplants from rabbits (note clearance of vegetation from around the plant), Ancaster

Valley, 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 situ Measures

Plants of wild origin are known to be cultivated in the Oxford Botanic Garden and Kew’s

garden at Wakehurst Place. Plants originating from Barnack Hills and Holes were also grown by

Terry Wells at Monks Wood Experimental station between 1970 and 1980 for the purposes of

research, some of which were transferred to his garden in Upwood. Many plants originating

from wild British populations are likely to be cultivated in other private gardens. A small

amount 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 from

Barnack Hills and Holes, with the intention of growing on plants for reintroduction to the wild

site, but without success (A. Headley, pers. comm.).

7.3 Research Data

Research is urgently required to assess genetic variation within English populations and the

extent to which small population size, limited gene-flow (due to extreme population

fragmentation), genetic drift and inbreeding depression are affecting the performance of

English populations. Likewise studies that assess dispersal and pollination mechanisms, in

particular the potential for dispersal via livestock and machinery, may provide valuable

insights into gene-flow and how best to conserve Pulsatilla vulgaris in the future. Studies on

the genetic relationships between British and continental populations would also be useful

help to inform European conservation priorities.

Research on the regeneration niche of Pulsatilla vulgaris is needed in order to establish the

optimum 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 Hills

and Holes, Northamptonshire. Data supplied by Chris Gardner (Natural England).

34


7.4 Monitoring and the Common Monitoring Standard

Traditionally Pulsatilla vulgaris has been monitored by simple counts of flowering ‘crowns’ or

estimates based on densities in small areas (e.g. Tarpey, 1999). These provide an overall

assessment 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 total

count 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 sites

where livestock are present during the flowering period. Third, such counts do not take into

account the life-stage structure of the population or whether recruitment is taking place

through the production of seed, presence of juveniles, etc.

Possible alternative approaches include counts within fixed plots as has been carried out at

Barnack Hills and Holes in Northamptonshire since 1975 (Fig. 15). This should preferably

include a number of demographic parameters, including the individuals in different lifestages,

flowering performance, seed production etc., and relate these environmental

variables such as sward height, % cover of bare ground, ‘hits’ on dominant grasses, etc. Simple

counts of rosettes rather than flower stems is probably a more preferable performance

parameter 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 a

more accurate assessment of the size of populations (Bailey, 1996). However, all these

approaches are likely to be time consuming to carry-out and therefore dependent on available

expertise, time and resources.

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Anemone pulsatilla and A. pratensis (Ranunculaceae). Symbolae Botanicae Upsaliensis

31, 145-158.

Wójtowicz, W. 2001. Pulsatilla vulgaris Mill. Sasanka zwyczajana. In: Kazmeirczakowa, R. &

Zarzycki, K. (eds), Polska czerwona ksiega roslin. Polska Akademia Nauk, Krakow,

pp.138-139.

39


9 Contacts

Botanical Society of the British Isles

97 Dragon Parade

Harrogate

North Yorkshire

HG1 5DG.

Plantlife International

The Wild Plant Conservation Charity

14 Rollestone Street

Salisbury

Wiltshire

SP1 1DX.

Tel: 01722 342730

10 Links

Kevin Walker - kevinwalker@bsbi.org.uk

Tim Wilkins - tim.wilkins@plantlife.org.uk

� BSBI Maps Scheme: http://www.bsbimaps.org.uk/atlas/main.php

� Records via NBN Gateway: http://www.nbn.org.uk

� Global Biodiversity Information Facility: http://www.gbif.org

� Pasqueflower is a Species of Principal Importance in England (S41 of NERC Act 2006):

http://www.ukbap.org.uk/NewPriorityList.aspx

� The UK list of threatened (red listed) vascular plants is maintained by JNCC:

http://jncc.defra.gov.uk/page-3354

40


11 Annex 1 – site descriptions

Descriptions of the 34 English population of Pulsatilla vulgaris thought to be extant in the

1960s including 29 included in Wells & Barling (1971) and five discovered subsequently. With

the exception of Swinstead Valley (discovered in 2009) all have been resurveyed by Walker et

al. (in press) since 2000. Sites are listed in vice-county and then alphabetical order.

Conservation designations are given in parentheses. † Denotes where Pulsatilla vulgaris is

thought to be extinct.

HERTFORDSHIRE (v.c.20)

Aldbury Nowers (SSSI)†

During the 1960s a few plants were recorded in rank Bromopsis erectus grassland (CG3b) and

scrub overlying chalk adjacent to an Iron Age camp. The site was ungrazed for many years and

consequently scrubbed over (recently cleared) except in a few places where small fragments

of chalk grassland remain. Pulsatilla has not been seen at this site since 1969 despite

repeated searches (Trevor James, pers comm.).

Therfield Heath (SSSI)

The second largest British colony largely confined to very short, rabbit grazed turf on the

steep south to southwest-facing slopes of a narrow chalk spur known locally as ‘Church Hill’

(TL332395). A few plants also occur in rank Bromopsis erectus grassland (CG3a) on the

adjacent Pen Hill (TL332397) and to the east of the tumuli marked on the OS map (TL332399).

All occur on common land in the ‘roughs’ of a golf course which were ungrazed for many

years. Church Hill has a long history of heavy rabbit grazing and in the 1980s small areas were

also mown in late February or early March using a tractor and ‘Flymo’. Since 1986 rotational

winter grazing has been carried out across much of the site using temporary grazing

compartments and, on Church Hill at least, this has led to an increase in overall population

numbers, which now exceed 60,000 and up to 12 rosettes m -2 (Tarpey, 1999). Recreation

pressures include trampling on the spine of Church Hill and the occasional removal of flowers

or whole plants. The population near the tumuli may have originated from seed spread by a

local farmer (W.H. Darling) in 1953/54.

BERKSHIRE (v.c.22)

Aston Upthorpe Down (SSSI)

The sole relic of a once extensive population that stretched along the Berkshire Downs (Druce,

1886; Crawley, 2005). By the 1960s around 300 plants were confined to a northwest-facing

chalk slope although flowering was limited due to heavy grazing by rabbits. As a consequence,

a small exclosure was erected in 1961 with an inner fence to exclude rabbits (repaired 1976

and replaced in 1998). This resulted in a gradual decline in the numbers of Pulsatilla vulgaris

due to increased competition from coarse grasses and the grazing off of inflorescences by

wood mice (Carter, 1967). The population continued to decline into the 1970s and 1980s

despite occasional mowing/burning to control the growth of Bromopsis erectus. Mowing was

re-introduced in 1996 and this led to an increase in flowering performance although by this

time only around 13 plants remained (Warden, 2001). Only a few plants have been recorded

outside this exclosure since 1994 due to very heavy rabbit grazing. Eighty-seven plants grown

from Aston Upthorpe seed were planted inside the new exclosure in October 1999 (Warden,

2001); 55 (63%) were still present in 2004 (Kathy Warden, pers. comm.).

41


Lockinge†

In 1962 two plants were discovered in rough grassland above Lockinge. It has apparently been

seen again since 1987 (Crawley, 2005) but no plants or suitable habitat could be located by

the author in 2005 (SU427846).

Unhill Bottom†

This site was the remnant of an extensive population, possibly totalling over 55,000 plants,

which spread over much of the adjacent chalk downland of Dean’s Bottom (Crawley, 2005).

Much of this area was used for military training during the 1939-45 war and was subsequently

ploughed-up. The population had declined to around 5000 plants by the late 1950s (Bowen,

1968) and then to around 750 plants by 1967 when Pulsatilla was confined to a small area of

ungrazed Festuca rubra grassland (CG6) on a NNW-facing slope. It apparently survived in this

locality till at least 1978 but eventually disappeared when the grassland was improved and

intensive sheep grazing was introduced (Warden, 2001).

BUCKINGHAMSHIRE (v.c.24)

Clipper Down (SSSI)†

In the 1960s a few plants were recorded on a steep SSW-facing chalk slope which was being

heavily grazed by sheep from November until April. The intensity of grazing was increased

during the 1970s and 1980s (excluding November to March) leading to deterioration in the

condition of the site (Everett, 1988). The population was fenced (c.1986) for a number of

years until grazing levels were reduced on the surrounding slope. The last reliable record was

in 1976 although there are unconfirmed records of flowering in 1986 and more recently as

vegetative plants (Greves, 1997). No plants have been found in recent years despite repeated

searches during the flowering period (L. Trowbridge, pers., comm.). This site currently falls

within the Ivinghoe Hills SSSI complex and is managed favourably by a tenant farmer for the

National Trust.

Pitstone Hill (SSSI)†

In the 1960s a few plants occurred on the steep S-facing slope of a mediaeval ditch in

relatively short Bromopsis erectus grassland. It persisted in tightly-grazed grassland although

plants were very difficult to locate in the mid-1980s due to heavy grazing pressure. An

exclosure was erected around the site in 1986 and this has led to the build up of coarse

grasses and scrub. The last record was at the top of the S-facing bank in 1996; it has not been

recorded since despite repeated searches.

Steps Hill (SSSI)

In the 1960s over 100 plants were recorded in short, Festuca ovina turf on a steep SW-facing

spur of chalk downland above Incombe Hole. The site was formerly very heavily grazed by

sheep and cattle leading to localised poaching and the removal of most of the flowerheads

during the spring (R. Maycock, pers. comm.). Grazing levels were subsequently reduced and

this led to a gradual increase in Bromopsis erectus (CG3). Sheep now lightly graze the site

from autumn to early spring (Greves, 1997) and as a result vegetation remains fairly rank (>15

cm). In 2005 there approximately 50 plants were located in a limited area (20 × 15-m)

surrounded by hawthorn scrub and many freely regenerating whitebeams.

CAMBRIDGESHIRE (v.c.29)

Devil’s Dyke (SSSI)

42


Historically Pulsatilla has been recorded sporadically along 7 km of an Anglo-Saxon chalk ditch

and bank between Burwell and where the Cambridge-Newmarket railway crosses the dyke to

the SE. The majority of plants are confined to the SW-facing banks particularly where the

grassland has been kept open by rabbits, infrequent mowing or burning. A few plants also

occur on the top of the dyke, where grass growth is reduced by trampling, and on the

adjacent Newmarket Heath which is cut fortnightly, although no plants have been recorded

from the heath since 1984. The dyke itself was not grazed for many decades leading to the

development of a thick sward of Bromopsis erectus. Accidental burning of one section in the

1970s led to a dramatic increase in flowering numbers although numbers subsequently

declined to pre-1970 levels. Since then localised mowing has led to localised increases on

some sections (e.g. adjacent to Newmarket Heath) and in 2003 the introduction of wintersheep

grazing (and stock-fencing) led to increased flowering on the southern section. In the

same year four plants appeared (with Himantoglossum hircinum) on the steep SE-facing bank

of the A14 c. 300m to the N of the nearest plants on the Dyke itself (TL603632; Leslie, 2004).

These presumably established from seed dispersed to the site on mowing machinery.

Fleam Dyke (SSSI)†

In the 1960s a small population was recorded on an ungrazed SW-facing bank of a mediaeval

chalk ditch and bank immediately to the NW of a small tumulus. It was last seen in April 1973

when the plants were dug-up by the farmer in order to reduce the number of botanists visiting

the site (Marren, 1999).

Hildersham Furze Hills (SSSI)†

A small population formerly grew (with Dianthus deltoides) on the spine of the easterly (Sand)

hill on a sandy soil (pH 5.2) derived from glacial sands and gravels (Wells & Barling, 1971).

During the 1950s there were never more than 3-4 clumps with 20-30 flowers (Trist, 1988).

Annual rabbit damage was intense, especially during droughts, although this declined

following the advent of myxomatosis in 1954. Three plants survived on the spine of the hill

into the mid-1980s despite the spread of rank grasses and blackthorn scrub (Trist, 1988). By

1990 only one, non-flowering plant remained and it has not been recorded since despite

improvements in the condition of the grassland and the removal of scrub (Compton, 2010

onwards).

BEDFORDSHIRE (v.c.30)

Barton Hills (NNR)

Several large sub-populations occur towards the S end of this reserve in exceptionally rich

chalk downland turf on steep, predominantly S- to SW-facing slopes and spurs where soils are

very shallow and competition from coarse grasses is restricted (Wells, 1968; Welsh, 1983). A

few plants also occur on ancient field systems at the N end of the reserve where grazing is

more variable. Historically the site was heavily grazed by sheep but management was

neglected from 1934 to 1954 resulting in the development of a dense sward of Bromopsis

erectus (Wells, 1968). This was burnt-off in 1954 and sheep grazing re-introduced for nine

months of the year (2-3 ac -1 ), although rabbit grazing declined dramatically due to

myxomatosis. Since the mid-1980s the site has been grazed by rabbits all year (although

populations have increased in recent years) and sheep (0.4 ha -1 ) from May to December

(inclusive) although this has been relaxed in recent years due to a rise in the rabbit population

(Bailey, 1996). This has resulted in an increase in the flowering population to over 5,000

crowns although flowering is suppressed in some years by heavy grazing (G. Bellamy, pers.

comm.). The Barton population of Pulsatilla is well known and attracts many visitors during

43


the flowering period. In the past many flowers were traditionally gathered at Easter, although

this activity it is much less common today. However, in 2006 around 70 plants were illegally

removed (M. Gurney, pers. comm.).

Deacon Hill (SSSI)

Since 1960 small numbers of Pulsatilla have been recorded sporadically from several localities

in the vicinity of Deacon Hill on steep, SW to NW-facing chalk downland slopes and spurs: (1)

the NE slope of Barn Hole (TL119294); (2) narrow spur adjacent to Pegsdon Firs (TL121297);

(3) combe NE of Pegsdon Firs (TL123296); and (4) the celtic field system below Deacon Hill

itself (TL12SP98). Historically the northern half of the site (Deacon Hill) has been heavily

grazed by sheep and rabbits. In contrast, grazing has been much lower in the southern half of

the reserve leading to a decline as a result of scrub encroachment and build-up of coarse

grasses from the 1950s onwards. In recent years, scrub clearance and the reintroduction of

grazing have led to an improvement in the quality of the grassland although no plants have

been found in Barn Hole despite repeated searches.

Knocking Hoe (NNR)

Between 500-1000 plants grow on the SW-facing slope of a small chalk hill (‘the Hoe’;

TL130139) in exceptionally rich calcareous turf with a number of other national rarities

(Hypochaeris maculata, Orchis ustulata, Seseli libanotis and Tephroseris integrifolia). A few

plants also occur on a Celtic field system (within a grazing exclosure) just to the east

(‘Spiranthes bank’; TL131308), and more sporadically within an abandoned exclosure on a

steep S-facing slope to the W of Tingley Wood (TL132306). It was lost from other parts of the

reserve that were ploughed for a short period in 1956 but it has not re-colonised this area.

The site was sheep grazed throughout the nineteenth century although this declined after

1931 and since then it has had periods of heavy and light grazing by sheep, rabbits and cattle

with occasional mowing and raking of cut material to maintain a tight sward. Few plants were

recorded during the 1970s due to the decline in the rabbit population and the growth of

coarse grasses (Bromopsis erectus). However, the population increased dramatically following

the introduction of mowing and the recovery of the rabbit population in the 1980s although

these caused severe localised erosion in places (e.g. Spiranthes Bank) (Bailey, 1996). The Hoe

itself is currently heavily-grazed by rabbits with additional winter sheep grazing and

management is now considered to be ideal with over 1000 flowers counted in 2005 (G.

Stevens, pers. comm.). In contrast, numbers within the two less heavily grazed exclosures

remain low due to greater competition with coarse grasses. The site receives few visitors but

there are reports of over 1000 plants being dug-up in the past (Hope-Simpson, 1948).

Ravensburgh Castle (SSSI)

In the 1960s two sub-populations were recorded from adjacent chalk slopes of an Iron Age hill

fort dating back to 400BC. The smaller of the two populations occurred immediately below

the fort on a steep W-facing slope (TL098295); the larger colony extended eastwards from a Sfacing

spur overlooking the first site (TL097296). Over 300, mainly vegetative plants were

recorded on this slope in 1981 and 30 below the hill fort (Welsh, 1983). In 1964 the grassland

was very rank but by 1980 the vegetation was very short with much bare chalk due to heavy

grazing by sheep and rabbits. It has not been grazed since and is now dense Bromopsis erectus

grassland with scattered hawthorn scrub. As a consequence, no plants have been seen on the

W-facing slope for many years and only a few plants survive on the S-facing spur where the

grassland is more exposed and the soils are very shallow.

Smithcombe Hill (SSSI)†

44


In the 1960s a small population occurred in rank Bromopsis erectus grassland (CG3a)

surrounded by scattered Viburnum lantana scrub on a steep SSE-facing chalk slope. By the

1980s the scrub had become very dense and only a single vegetative rosette could be found

(Welsh, 1983). It has not been recorded since despite scrub clearance and the introduction of

goat grazing.

NORTHAMPTONSHIRE (v.c.32)

Barnack Hills and Holes (NNR)

Many thousands of plants (>20,000) occur over a large area of mediaeval limestone quarry

workings where they are confined to shallow soils on S and SW-facing slopes. Grazing ceased

in 1914 and by the 1960s the grassland was very rank Bromopsis erectus-Brachypodium

pinnatum grassland with a dense layer of leaf litter. Sheep grazing (September to late-

December) was re-introduced in 1978 resulting in a dramatic increase in flowering. Monitoring

in fixed plots showed an increase from 260 in 1978 to 4,727 crowns by 2005. The entire

population is now estimated to exceed 20,000 crowns (C. Gardiner, pers. comm.). The

management is now considered ideal (Rich, 1997) and as a result P. vulgaris has spread to new

areas of the reserve where it may have established from seed (C. Gardiner, pers comm.).

Southorpe Paddock (SSSI)†

In the 1960s a small colony was recorded in rough Brachypodium pinnatum grassland. The site

has received variable amounts of grazing in the past and the last confirmed record was in

1995. In 1999 12 plants originating from Barnack seed were planted out but none survived for

more than a year (C. Gardner, pers. comm.).

Southorpe Roughs (SSSI)†

A few plants formerly occurred in rank Bromopsis erectus-Brachypodium pinnatum grassland

in an area of old quarry workings. The site was not grazed for many years and by the 1980s

plants were very difficult to locate amongst the rank grass and invading scrub. It was

apparently last seen by Franklyn Perring in 1990 (L. Farrell in litt. to T.C.E. Wells). It has not

been seen since despite the recent reintroduction of sheep grazing (2004) and tree felling to

reduce shade.

Sutton Heath†

A single flowering plant was discovered on a small ridge of limestone turf close adjacent to

Sutton Bog in 1972 (Wells, 2003) where it was seen again in 2003. The grassland shows signs of

agricultural improvement and is heavily grazed. No plants have been found since despite

repeated searches, although Astragalus danicus still occurs on the same ridge.

EAST GLOUCESTERSHIRE (v.c.33)

Barnsley Wold Warren (SSSI)

The largest population in the UK with the majority of plants occurring at high density in

exceptionally rich limestone turf on a steep (c.20º) SW-facing slope where soils are very

shallow and there is much bare soil and rubble. Small numbers of plants have also occurred

sporadically on a W-facing slope nearby. Historically the site has been heavily grazed by

sheep, cattle and horses and the vegetation burnt (‘swaled’) in February or March. This

practice was abandoned in 1971; since then the site has been grazed by sheep, at high

density, between February to March and then from June onwards. This management has

45


esulted in an increase from around 50,000 to an estimated 75,000 crowns (D. Barling, pers.

comm.).

Beaumonts Hay (SSSI)

This site forms part of the Brassey Reserve and Windrush Valley SSSI and supports a small

population of Pulsatilla on a relatively steep SW-facing limestone slope. Grazing has been

increased in recent years producing a much shorter, species-rich sward.

Bourton Down (SSSI)

Around 500 plants are restricted to a small area of sheep-grazed, W-facing downland with

extremely shallow soils. Historically the site has been heavily grazed by sheep, although since

1982 stock have been removed from March to late summer in order to allow Pulsatilla to

flower and currently the population appears stable. This management is similar to Barnsley

Wold but with more variable winter grazing (Rich, 1997). In the 1966 two patches of Pulsatilla

were recorded in ungrazed Brachypodium pinnatum grassland about 1 km to the NW of the

reserve (SP132321) but this area is now dense hazel scrub.

Hornsleasow Roughs (SSSI)

At this site Pulsatilla is scattered across a large area of former limestone quarries (“hills and

holes”) that have had periods of heavy (1960s) and light grazing (1970-80), mostly by sheep

but with a few cattle. It is currently lightly grazed by sheep (


introduced by the National Trust leading to a reduction in the cover of Brachypodium

pinnatum and a gradual increase in the numbers of Pulsatilla.

SOUTH LINCOLNSHIRE (v.c.53)

Ancaster Valley (SSSI)

A small colony occurs in lightly grazed limestone grassland (CG3) on an E-facing slope of a

narrow limestone valley. The site was not grazed for many years leading to the development

of rank Brachypodium pinnatum grassland and dense gorse scrub. The latter was removed

during the late 1980s and the site has subsequently been annually winter-grazed by c.30 sheep

(J. Welhan, pers. comm.). Due to improvement in the condition of the grassland 68 plants

(originating from Ancaster seed) were re-introduced to the same slope (in 1992, 1993, 1998

and 2002) where they are protected by wire cages during the flowering period. All plants have

been monitored annually since the early 1990s; in 2005 6 native plants and 22 (32%)

introduced plants remained.

Holywell Mound (SSSI)†

In the 1960s around 200 plants were present in species-rich limestone turf on a SW-facing

slope although few plants flowered due to heavy grazing and the occasional ‘picking’ of

flowers by local school children (J. Gibbons in litt. to T.C.E. Wells). In the 1960s the grassland

was very short, herb-rich Bromopsis erectus-Brachypodium pinnatum grassland (CG5) with

abundant Thesium humifusum. A few plants survived into the 1980s although the site was

subsequently sprayed and partially improved. Pulsatilla has not been recorded for many years

and the grassland is now a species-poor Bromopsis erectus grassland (CG3b) with few herbs.

Honington Camp (SSSI)†

In the 1960s a small colony occurred in rank Bromopsis erectus grassland (CG3d) on the Wfacing

outer embankment of an Iron Age hill fort surrounded by arable land. The site has been

infrequently grazed leading to the development of a thick sward of Brachypodium pinnatum

amongst scattered Crataegus scrub. No plants have been seen since 1992 despite repeated

searches.

Swinstead Valley (SSSI)

On 25 th April 2009, a single flowering plant of Pulsatilla vulgaris was discovered at a new site

by Richard Jefferson and Fiona Hart in Swinstead Valley, South Lincolnshire (Jefferson &

Walker, 2010). Subsequent searches revealed a total of four “plants” in 2009 and 18 in 2010,

following the erection of a temporary grazing exclosure. This population is located on a

moderately steep (c.30º) west-facing slope (280-310ºN) of limestone grassland on the east side

of a narrow valley where the vegetation had been kept very short by rabbit and sheep grazing.

The vegetation is species-rich Brachypodium pinnatum-Bromus [Bromopsis] erectus grassland

(74% fit to CG5a, typical sub-community) with abundant Bromopsis erectus, Festuca ovina,

Helianthemum nummularium, Sanguisorba minor and Thymus polytrichus and Astragalus

danicus growing close-by.

NORTH LINCOLNSHIRE (v.c.54)

Broughton Far Wood (Clap-gate Pit) (SSSI)†

In the 1960s 3-4 plants were recorded amongst ungrazed grassland and scrub in an abandoned

limestone quarry. The plants were last recorded in 1969 when they were dug-up (I. Weston,

pers. comm.).

47


LEICESTERSHIRE (v.c.55)

Shacklewell Hollow (SSSI) †

In the 1960s a small colony was recorded in species-rich limestone grassland (CG5a) on a

shallow SW-facing slope. Three plants were re-discovered at this site in 1992 when the

grassland was very rank due to the lack of grazing. However, the population was subsequently

destroyed when the farmer dumped rubble over the area (D. Isaac, pers. comm.).

MID-WEST YORKSHIRE (v.c.64)

Ledsham (SSSI)

In 1984 a single plant was discovered in heavily grazed limestone grassland (CG4a) on a SEfacing

limestone bank. For many years flower heads were grazed-off and so cages were placed

around the plant to protect it from rabbits. In 1997 the plant was hand-pollinated with pollen

collected (the same day) from Barnack Hills and Holes but the plant failed to set seed due to

predation by slugs. As a result pollen from the Ledsham plant (male parent) was used to crosspollinate

five plants from Barnack (site 4) but without success (A. Headley, pers. comm.). A

single Barnack plant was then translocated to within 4 metres of the Ledsham plant in order

to encourage pollination but disappeared within a couple of years.

48


13 Annex 2 – changes in population size, 1960-2006

Changes in the numbers of Pulsatilla vulgaris on 33 sites included in Walker et al. (in press).

Totals are the maximum number of crowns recorded in any one year for each decade and

were derived from a variety of sources.

Site-population

(a) Increasing

1960-69 1970-79 1980-89 1990-99 2000-06

Barnack Hills and Holes 2000 1300 14200 15000 20000

Barnsley Wold 50000 50000 50000 50000 75000

Barton Hills 1100 685 4000 5000 5000

Knocking Hoe 300 50 460 300 1000

Therfield Heath 1000 2897 ? 60000 60000

(b) Stable

Ancaster Valley 1 6 5 16 11 6

Beaumonts Hay


14 Annex 3 – associates

Vegetation composition and structure of Pulsatilla vulgaris populations in England (in 16 of

the 18 extant populations - Taylor’s Hill & Swinstead Valley not included). For associates

figures are frequency in quadrats (n = 62) with the mean % cover given in parentheses. Species

recorded in 80 % of quadrats)

are highlighted in bold. For composition and structure variables figures are means with ± 1SE

in parentheses. Figures are presented for (a) all 16 sites and for (b) limestone and (c) chalk

sites only (n = 7 and 9 respectively).

All sites Limestone only Chalk only

(a) Associates

Pulsatilla vulgaris V (4.2) V (3.6) V (4.9)

Bromopsis erectus V (24.2) V (24.7) V (23.7)

Festuca ovina V (12.9) IV (8.5) V (17.6)

Sanguisorba minor V (8.8) V (8.7) V (8.9)

Helianthemum nummularium V (6.0) V (7.2) IV (4.7)

Carex flacca V (4.2) V (3.7) V (4.7)

Cirsium acaule V (4.2) V (5.3) V (3.1)

Leontodon hispidus IV (2.8) IV (2.8) IV (2.9)

Pilosella officinarum IV (2.5) IV (3.2) III (1.8)

Briza media IV (1.5) IV (1.9) III (1.0)

Helictotrichon pratense IV (1.3) III (0.6) V (2.0)

Koeleria macrantha IV (1) III (0.6) V (1.4)

Carex caryophyllea IV (0.9) IV (0.9) IV (0.9)

Brachypodium pinnatum III (5.1) V (7.4) I (2.7)

Ctenidium molluscum III (3.6) III (3.4) III (3.7)

Lotus corniculatus III (1.2) III (1.6) III (0.8)

Campanula rotundifolia III (0.9) II (0.9) V (1.0)

Scabiosa columbaria III (0.8) III (1.1) II (0.5)

Plantago lanceolata III (0.7) III (0.7) III (0.6)

Scleropodium purum II (2.0) III (3.5) II (0.3)

Filipendula vulgaris II (1.6) I (0.5) IV (2.9)

Thymus polytrichus II (1.0) III (1.8) I (0.1)

Thymus pulegioides II (1.0) II (1.0) III (1.0)

Centaurea nigra II (0.8) II (0.4) III (1.3)

Plantago media II (0.6) II (0.9) III (0.4)

Polygala calcarea II (0.6) II (0.9) I (0.3)

Hippocrepis comosa II (0.6) I (0.5) III (0.8)

Campyliadelphus

chrysophyllus II (0.5) II (0.2) I (0.9)

Campanula glomerata II (0.5) I (0.2) II (0.8)

Viola hirta II (0.3) III (0.3) II (0.3)

Homalothecium lutescens II (0.3) II (0.4) I (0.1)

Asperula cynanchica II (0.2) II (0.2) II (0.2)

Ranunculus bulbosus II (0.2) II (0.3) II (0.2)

Carlina vulgaris II (0.2) II (0.3) I (0.1)

50


Annex 3 continued.

All sites Limestone only Chalk only

Pimpinella saxifraga II (0.2) II (0.2) I (0.2)

Linum catharticum II (0.1) III (


Written by Kevin Walker, BSBI

Edited by Plantlife International

First draft dated Sept 2010

Last revised 19 April 2011

52

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