Pulsatilla vulgaris (L.) Mill. - Plantlife

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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
Page 1 and 2: Pulsatilla vulgaris (L.) Mill. Pasq
Page 3 and 4: 1 Morphology, identification, taxon
Page 5 and 6: Pulsatilla is now generally accepte
Page 7 and 8: 2 Distribution and current status 2
Page 9 and 10: UK VU Declined from ca.130 to 18 lo
Page 11 and 12: English populations, the overall nu
Page 13 and 14: surviving in each year, and (c) the
Page 15 and 16: maturation before the male (andro-
Page 17 and 18: 3.1.6 Seed dispersal Achenes of Pul
Page 19 and 20: the sward and thereby determining t
Page 21 and 22: Table 6 - Chemical and mechanical a
Page 23 and 24: Figure 9 continued. Habitats of Pul
Page 25 and 26: Cavenham Heath) support extensive a
Page 27 and 28: Kalliovirta et al., 2006). There ar
Page 29: Losses to ploughing and quarrying c
Page 33 and 34: Quarry, Ancaster 1996 Most scratche
Page 35 and 36: 7.4 Monitoring and the Common Monit
Page 37 and 38: Kalliovirta, M., Ryttäri, T. & Hei
Page 39 and 40: Warden, K. 2001. An investigation i
Page 41 and 42: 11 Annex 1 - site descriptions Desc
Page 43 and 44: Historically Pulsatilla has been re
Page 45 and 46: In the 1960s a small population occ
Page 47 and 48: introduced by the National Trust le
Page 49 and 50: 13 Annex 2 - changes in population
Page 51 and 52: Annex 3 continued. All sites Limest

Pulsatilla vulgaris (L.) Mill. - Plantlife

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