An Inventory of Vascular Plants Identified on the Sefton Coast

1 An inventory of vascular plants identified on the Sefton Coast Philip H. Smith November 2005 Unpublished report to Sefton Coast Partnership Introduction & Methods Five years ago, a provisional inventory of vascular plants (species, sub-species and hybrids) identified on the Sefton Coast, Merseyside, was drawn up (Smith 1999a). It listed a total of 971 taxa within the Sefton Coast Management Scheme (now Sefton Coast Partnership) area, of which 881 (90.7%) were recorded in the sand-dune system and 733 (75.5%) in the candidate Special Area of Conservation (cSAC). Some 290 taxa (29.9%) were thought to be non-native to the area and only 14 (1.4%) were considered extinct. Intensive field-work in recent years (and especially in 2004 and 2005) for the proposed new Flora of South Lancashire (vice-county 59) has resulted in a large number of new records, including many garden-escapes, and it was therefore felt appropriate to produce an up-to-date inventory on similar lines to the earlier one. However, since the boundaries of the cSAC have recently been redrawn to include most of the dune system, including dune-heath areas previously excluded, it was decided not to produce a separate list for the cSAC. In addition to sources utilised in the provisional inventory (e.g. Savidge et al. 1963, the 1988 Sefton Coast N.V.C. survey, Ainsdale Sand Dunes and Cabin Hill NNR vascular plant lists, the New Atlas survey data and the Environmental Advisory Service data-base) much use has been made of the v.c. 59 tetrad records currently stored on CD, which forms part of the forthcoming new Flora of South Lancashire. The BSBI vice-county Recorder, D.P. Earl, and a previous Recorder, Ms V. Gordon were consulted and important records were also received from Ms S.E. Edmondson, P.S. Gateley and M.P. Wilcox. Determinations and/or confirmations were obtained from BSBI referees where necessary. In general, nomenclature follows the New Flora of the British Isles (Stace 1997) but other sources were used in a very few cases, for example Phillips & Rix (1989) for some alien shrubs. Non-native or introduced native taxa are indicated by an asterisk; these include both archaeophytes and neophytes as shown in the New Atlas of the British & Irish Flora (Preston et al. 2002).. Notable taxa are also indicated (Nationally Rare, Nationally Scarce, Endangered, Vulnerable, Near Threatened and Species of Conservation Importance in North West England), making use of nationally agreed criteria and data published by the Regional Biodiversity Group for North West England (1999) The current report also includes brief details on the status and main habitats of all the taxa (Appendix 1). 2 Results A total of 1177 taxa was recorded in the Sefton Coast Partnership area, representing an increase of 206 (21.2%) on the 1999 study. Similarly, the new total for the sand-dune system is 1055 taxa, 174 (19.8%) more than the earlier report (Table 1). Quite a high proportion of this increase is due to alien plants, especially garden-escapes, the total of non-native taxa having risen by 145 (50.0%) from 290 to 435. For the coast as a whole, the proportion of alien taxa is now 37.0%, compared with 29.9% in 1999. The proportion for the sand-dune system is 33.0%, as opposed to 29.9% previously. Nineteen additional sub-species were identified on the coast, while the number of hybrids has soared (by 67%) from 67 to 112, of which 97 occur in the dunes (Table 1). Table 1 also shows that 177 notable taxa (11 introduced) were recorded. These comprise 15 Nationally Rare, 13 Nationally Scarce, 3 Endangered, 17 Vulnerable, 15 Near Threatened (some in more than one category) (Table 2) and 120 Species of Conservation Importance in North West England not included under other criteria.. In addition, two taxa found recently on the Sefton Coast are apparently new to the British Isles. Artemisia campestris ssp. maritima from Crosby dunes in 2004 is a Nationally Rare British native but only as ssp. campestris; Cotoneaster hurusawanus, a neophyte recorded at Birkdale Sandhills in 2003, has not been seen previously “in the wild” in Britain.. The identity of these plants was confirmed by BSBI referees. A list of 39 taxa (8 introduced) considered to be extinct is shown in Table 3. This figure represents 3.3% of the coastal flora and is lower than in 1999 as 10 species thought to be lost have been rediscovered in the last six years. Some of the larger genera are well represented in the study area. Particular efforts have been made to record Cotoneaster (14 taxa), Epilobium (16) and Salix (29), the diversity of the latter genus being quite remarkable and possibly unprecedented elsewhere in a similar area of lowland Britain. As studies are ongoing, other willows could soon be added. Also noteworthy are Carex (23 taxa), Juncus (18), Rubus (33) and Veronica (18). Habitat analysis (Table 5) shows that by far the largest number and proportion (33.1%) of taxa is dependent on “disturbed ground”. In general, this is land that has been disturbed by human agency, such as trampling, use of motor-vehicles, tipping (especially of garden waste), dereliction and agriculture. Most of the non-native and introduced native plants are associated with this habitat type while the frequent presence of bare soil allows colonisation by ruderal species and annuals. Not unexpectedly, the next most important type is freshwater wetland, represented by dune-slacks, scrapes and ditches (18.7%). Many of the duneland specialists, such as Dactylorhiza incarnata ssp. coccinea, Parnassia palustris and Pyrola rotundifolia ssp. maritima, are associated with this habitat. The fixed-dune habitat is also important (14.5%), both this and humid dune- slacks being Priority Habitats in the EU Habitats Directive. Interestingly, mobile & embryo dunes (1.1%) and the strand-line (1.1%) support the lowest numbers of vascular 3 plants. This is presumably due to the fact that relatively few species have adapted to the severe environmental conditions associated with these habitats. Discussion Stace & Ellis (2004) give the total number of vascular taxa in v.c.59 (South Lancashire) as 2096, though this figure may now be somewhat out-of-date. Thus, in supporting 1177 taxa, the Sefton Coast Partnership area (7825ha) has a remarkable 56% of the entire vice- county vascular flora. The comparable figure for the 2100ha dune system is 50%. The Sefton Coast therefore contributes spectacularly to the vice-county flora, which itself is the most species-rich north of Worcestershire (Stace & Ellis 2004). This species-richness may be attributed to the wide range of habitats present, the abundance of calcareous substrates and also the geographical position of the coast which provides a home to species with both northern and southern distributions in Britain. Unfortunately, the richness of the Sefton Coast is not reflected in data presented in the New Atlas (Pearson et al. 2002). Fig. 6.1 in that publication indicates that fewer species have been recorded since 1970 in the three hectads that represent the coast than in the hectads immediately inland which consist largely of intensively farmed arable land. This seems to be because a great many coastal records have “gone missing” for reasons which are not apparent. At least 149 taxa known by me to have been present on the Sefton Coast since 1970, some commonly, have missing coastal hectad records. While about one third of the coast’s vascular plants is non-native, this is not a particularly high figure in the national context. Thus, Stace & Ellis (2004) show that the average proportion of alien taxa in all British vice-counties is 40%, while in South Lancashire as a whole it is 50%. However, the number of neophytes becoming established on the coast is undoubtedly increasing, largely due to garden-waste dumping (personal observations) and, although the great majority consists of low-impact neophytes, a small number of invasive aliens is causing actual or potential problems (Smith 1999b). The slightly higher percentage of non-natives in the SCP area, as opposed to the dune system (Table 1), was also noted in the previous study and was put down to the greater proportion of ruderal habitat in the former area (Smith 1999a) Only 39 vascular plants are known or are thought to have become extinct on the coast (3.3% of the flora), this being greatly outweighed by the many new taxa recorded in recent years (206 since 1999). The latter figure is all the more surprising in view of the past history of plant recording in Sefton, the dune system having long been a “Mecca” for botanists. However, the data probably reflect an increasing concentration on less well studied groups, such as aliens and hybrids. The high species-richness of the study area is also reflected in the 177 notable taxa listed in the Inventory. The Regional Biodiversity Steering Group (1999) lists 474 notable vascular plants in the whole of North West England (Cheshire, Cumbria, Greater Manchester, Lancashire and Merseyside). The fact that the Sefton Coast supports a remarkable 37% of these reflects its very high conservation status (Smith 1999b). 4 Acknowledgements Grateful thanks are due to D.P. Earl, Ms S.E. Edmondson, P.S. Gateley, Ms V. Gordon, and M.P. Wilcox for contributing records to this survey. P.S. Gateley and, especially M.P. Wilcox, made constructive, detailed and helpful comments on a draft of the manuscript. References Phillips, R. & Rix, M. 1989. Shrubs. The Garden Plant Series. Pan Macmillan. London. Preston, C.D., Pearman, D.A. & Dines, T.D.

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