Changes in the vascular plant floras of England and Scotland between 1930–1960 and 1987–1988: The BSBI Monitoring Scheme

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Biological Conservation 75 (1996) 217-229 Copyright © 1996 Elsevier Science Limited Printed in Great Britain. All rights reserved 0006-3207/96/$15.00+.00

CHANGES IN THE VASCULAR PLANT FLORAS OF E N G L A N D A N D SCOTLAND BETWEEN 1930-1960 A N D 1987-1988: THE BSBI MONITORING SCHEME T. C. G. R i c h & E. R. W o o d r u f f

Biological Records Centre, ITE Monks Wood, Abbots Ripton, Huntingdon PE17 2LS, UK (Received 28 February 1995; accepted 28 May 1995)

Abstract The BSBI Monitoring Scheme was a sample hectad (10 km × 10 km square) survey of Britain and Ireland during 1987 and 1988 set up to assess changes in the vascular plant flora since 1960. To assess change, records were compared against data collected for the Atlas of the British flora (1930-1960) for England and Scotland. At least 24% of the flora was found to have changed significantly in England, and at least 12°A in Scotland. Tables showing species which have changed in frequency and selected maps are presented. The major trends suggest that plants of grasslands, heathlands, aquatic and swamp habitats and arable weeds have declined, whilst introduced species have increased.

frequencies of each species in the surveys to see if they have increased, decreased, or remained unchanged after applying a correction for recording effort. Only the results for England and Scotland are presented here. The data for the Channel Islands, Wales and Northern Ireland were difficult to interpret due to marked increases in recording effort and small sample sizes, and data for the Republic of Ireland will be published elsewhere. Full details of the data and problems of interpretation are given by Rich and Woodruff (1990, 1992). Maps updated from Rich and Woodruff (1990) are given in Palmer and Bratton (1995), and the analysis has been updated to include the results of an analysis of recording by Rich and Smith (1996). Nomenclature follows Stace (1991).

Keywords: England, Scotland, monitoring, flora. METHODS

INTRODUCTION

Selection of sample squares One in every nine (11% sample) of the hectads of the national grid were sampled systematically (Fig. 1) as volunteers find a regular grid simple to work with. The distribution of species is unaffected by the position of the national grid and no species shows periodicity in distribution with a lag of three hectads (or a multiple thereof) comparable to the sampling system. The sample variances from systematic grids are often lower than those of random samples (Smartt & Grainger, 1974).

In order to determine priorities and policies for conservation, it is essential to have relevant, up-to-date information on which to make decisions. The Atlas of the British flora (Perring & Waiters, 1962) (hereafter referred to as the Atlas) has been a basic reference source for plant geography and conservation in Britain for the last 30 years, but it is now out of date as it was largely based on records collected between 1954 and 1960 (Rich & Woodruff, 1990; Stewart et al., 1994; Palmer & Bratton, 1995). The BSBI Monitoring Scheme 1987-1988 was therefore set up to assess the current status of the flora, and to provide a more detailed means of monitoring changes in the future. The scheme was a sample hectad (10 km × 10 km square) survey of Britain and Ireland, organised through the Botanical Society of the British Isles (BSBI) and was based at the Biological Records Centre (BRC), Monks Wood. The aim of this paper is to summarise the changes in the flora by comparing the records obtained for the Atlas with those obtained for the Monitoring Scheme. As the surveys were carried out in different ways (because they were designed for different purposes), the differences between them are first set out. Changes in the floras are then established by comparing the

Distribution of species 1930-1960 Details of how the records were collected for the Atlas were given by Perring and Walters (1962). Essentially, botanists visited every hectad in the country and recorded species present until they felt the records were reasonably comprehensive or they ran out of time. A database was compiled for the sample squares from BRC records dated between 1930 and 1960, with updates from the BSBI Vice-county Recorders. Re-compiling the records was surprisingly difficult due to poor documentation and unavailability of some data. Records were not abstracted from the Atlas directly as additional data were known to exist in the BRC databank. The re-compiled data were checked for accuracy and a subsample was compared with the records (i.e. 'dots') published in the Atlas (lst edition):

Correspondence to T. C. G. Rich. Present address: The Annexe, Newgale Farm, Priory Road, Forest Row, RHI8 5JD, UK. 217

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another database, checked and data returned to the Vice-county Recorders for a third check. The average error rate was estimated to be about 0.25% (a detailed breakdown of error sources is given by Rich and Woodruff, 1990). The records represented about 164,000 hectad records (an average of 395 species per square), and 2660 taxa. Full documentation was deposited with the cards at BRC upon completion of the project in 1990.

Comparison of the two data sets The differences between the two data sets were eliminated, minimised or corrected for as follows.

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Fig. 1. Hectads sampled for the Monitoring Scheme.

9.75% of the records were additional to the Atlas and 2.4% of the Atlas records were not represented in the database (some of which are errors). The re-compiled records were considered more representative of the flora than the Atlas due to the additional data, but had an average error rate of about 1%. The Atlas database contained about 225,000 individual records representing about 144,000 hectad records (or 'dots') from the sample squares, and 2006 taxa. The average number of taxa per square is 362, which is well below the 400 overestimate by Perring and Waiters (1962). There are records for 410 of the 429 sample squares (95.5% coverage).

Distribution of species 1987-1988 Recording for the Monitoring Scheme was organised in essentially the same way as for the Atlas with two exceptions. First, volunteers were asked to concentrate on three selected 2 km × 2 km squares (tetrads) within each hectad, and to make at least three visits to provide more detailed data for monitoring in the future. However, they did also visit the remainder of the hectad (especially for known rarities) with the aim of making the lists as comprehensive as possible. Secondly, they were asked to follow the Excursion flora (Clapham et al., 1981) which was the most up-to-date, widely available flora at the time. Additional guidance on selected groups was provided by Rich and Rich (1988). The response to the Monitoring Scheme was outstanding. Nearly one million records were collected by over 1600 volunteers in 425 out of the 429 hectads (>99% coverage). Completed record cards were first checked by the appropriate BSBI Vice-county Recorder or other nominated botanist and then compiled into

Inclusion~exclusion of hectads Only hectads recorded for both surveys were included in the analysis to avoid localised bias, and some squares with very unrepresentative data were also excluded (e.g. data for some coastal squares with only a small area of land were incorporated with adjacent squares for the Atlas; Perring & Waiters, 1962). Squares simply underworked were included as they are part of the continuum of variation in recording. Data for 157 out of 169 squares in England and 107 out of 120 in Scotland were included in the analysis. Inclusion~exclusion of species Some qualitative differences between the Atlas and Monitoring Scheme data occurred at a national scale. Introduced species and critical taxa were more widely recorded for the Monitoring Scheme than for the Atlas (8% and 6% of the hectad records for introductions and 10% and 6% for critical taxa respectively), largely due to updated recording practices. To minimise bias, critical taxa and aliens not widely recorded during the Atlas period were (with a few exceptions) eliminated from the statistical comparison. Species with provisional maps in the Atlas (Perring & Waiters, 1962) and those known to have corrupted historic data (e.g. Kickxia spp.) were also excluded. Records of native species at introduced sites were not separated due to incomplete historical data. Duration of surveys Species whose population size varies with time or which are unpredictable in occurrence (e.g. Lotus angustissimus; Le Sueur, 1985) are likely to be less well recorded in the 2 years of the Monitoring Scheme compared to the 31 years Atlas period. Some alpine species were underrecorded in Scotland due to wet summers in 1987 and 1988. These two factors may have affected the coverage obtained for a few species but can generally be ignored as, first, the bulk of the Atlas field work was carried out between 1954 and 1960 (Rich & Woodruff, 1990), and secondly, the difference in recording effort during the surveys (see below) is probably of greater importance than time. Concentration of effort on selected tetrads For the Monitoring Scheme attention was focused on

BSBI Monitoring Scheme the three selected tetrads, and the records are more representative of these tetrads than the hectad as a whole, especially in areas with few botanists (e.g. Scotland). This effect can be quantified using the species-area relationship (Dony, 1963); assuming (falsely) that the tetrads are contiguous, the equation predicts that the three tetrads will contain 62.5% of the flora of each hectad. As the areas are not contiguous, the prediction is increased to 65% because the tetrads selected are separated geographically and consequently are likely to contain more of the taxa present in a hectad (precise predictions are unavailable for this model; J. G. Dony, pers. comm.). The average number of taxa recorded in the selected tetrads for the Monitoring Scheme was 74% of the total number of species found in the hectad, confirming that the selected tetrads were more comprehensively recorded than the rest of the hectad. For the Atlas, botanists themselves selected areas within each hectad to visit, and many of the records are more representative of small, species-rich, interesting areas than the whole hectad. These differences may affect the records for individual squares, but are likely to cancel out overall.

Differences & amount of recording effort There were differences in the amount of recording 'effort' between the surveys (time spent recording, number and expertise of botanists, number and season of visits, areas recorded, etc.), which would be expected significantly to affect any comparison of the data. Figure 2 shows how the number of taxa recorded was related to time spent recording. On a local scale, individual botanists were key factors in determining the quantity and quality of records available for each survey. Rich and Smith (1996) found

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that the major source of variation between recording visits to the same tetrad was the quality of individual recorders, and that an average of only 38% of taxa were recorded in common by different pairs of recorders. However, overall, the number of records for each species increased proportionally with the amount of recording effort irrespective of the recorders. These results indicated that although the records may locally reflect the activities of individuals, the differences should even out after correction for effort. After elimination of records subject to recording bias, there were 4% more hectad records in England for the Monitoring Scheme than for the Atlas and 5% more in Scotland. Overall, there were 8.5% more hectad records for the Monitoring Scheme, with significant regional variations (e.g. 40% more records for Northern Ireland).

Adequacy of sampling The adequacy of sampling (i.e. percentage of total species present recorded) was estimated by comparing the average Atlas and Monitoring Scheme hectad totals with the predicted hectad total using Dony's (1963, 1976) species-area relationship. Provisional estimates were 49% coverage for the Atlas and 56% coverage for the Monitoring Scheme. Dony's relationship was derived for contiguous areas in Bedfordshire and Hertfordshire, both southern counties with fairly rich floras, and thus needs to be applied with caution to the sample squares and the British Isles as a whole. Nonetheless, the analysis indicates the general order of magnitude of coverage, and demonstrates that only about half the species expected to be present in a hectad were recorded in either survey. Also, only 54% of the records were for the same species in the same hectad for both surveys (Rich & Woodruff, 1990).

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Assessment of change Ideally, change should be assessed for each species from a comparison of frequency of occurrence in hectads collected using standardised recording effort. However, no independent estimate of effort (e.g. time spent recording) is available for the Atlas, and the greater amount of recording effort for the Monitoring Scheme would result in apparent increases in some species simply due to the increased effort. Thus the records cannot be compared directly, and the frequency for the Atlas survey had to be corrected to a relative value for comparison with the frequency in the Monitoring Scheme. The relative frequency of occurrence in hectads for the Atlas (R) was obtained by correcting for country variations in recording effort, and for relative species commonness or rarity (this is necessary as increasingly more effort is required to record species in areas where they are rare), using the following equation: A2

R = CA + (l-C).h-where A -- original number of hectads recorded for the

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Fig. 3. Maps of selected species showing increases, decreases or no change between 1960 and 1987-1988 (Copyright JNCC). (a) Fallopia japonica. The increase of this introduction continues in all areas. (b) Gnaphalium sylvaticum. A large decrease in this uncommon species of heaths, open woods and moorland, possibly because of habitat loss. (c) Hydrocotyle vulgaris. A significant decline of this plant of wet meadows, fens and marshes in England, probably because of drainage of agricultural land. (d) Oenanthe crocata. No significant change in this plant of wet woods, riverbanks, damp coastal habitats, etc. The symbols on the maps are enlarged so that they are clear to read and must not be taken to imply comprehensive coverage. O, Recorded only for the Atlas between 1930 and 1960 (or before 1960 in Ireland); O, Recorded for both the Atlas and the Monitoring Scheme; +, Recorded only for the Monitoring Scheme (1987-1988).

Atlas database, n -- number of 10-km sample squares analysed in the country, and C -- a country effort correction factor (constant) specific to the area under consideration (for both England and Scotland C -- 1-1; other values need to be applied elsewhere). Values for the country effort correction factor were found such that the corrected total number of Atlas database records for the area under consideration equalled the

total number of Monitoring Scheme records. The correction gives an approximate linear increase for rarer species and a progressively smaller proportional increase for c o m m o n species. The applicability of this model has been demonstrated by Rich and Smith (1996). The corrected, relative Atlas frequencies (R) were tested for significant increases or decreases against the

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Fig. 3. (Continued) Monitoring Scheme frequencies using a two-tailed test of the equality of two percentages (Sokal & Rohlf, 1969) with 95% confidence limits. For example, Fallopia japonica (Fig. 3(a)) was recorded in 57 out of 157 hectads between 1930 and 1960 in England (-- A), and 121 out of 157 in 1987-1988. This 1930-1960 figure (A) was corrected as R -- 62-7 + (-4).1) × 3249/157 = 60.6 hectads. The test statistic b was then calculated as (38.4-61.39)/3-234 --7.11, which gives a probability of p<0.05. RESULTS Species which show significant changes in frequency in England and Scotland are summarised in Tables l ~

together with the species' typical habitat derived from field experience and floras. Some changes which may be due to recording bias are indicated. Of the 1535 taxa analysed in England 174 (11%) have increased significantly and 195 (13%) have decreased significantly. In Scotland, of the 1159 taxa analysed 86 (7%) have increased and 50 (4%) have decreased. These indicate changes in the frequency of approximately one in every four species in England, and one in every eight in Scotland. A simple breakdown of changes by habitat is given in Table 5. The major changes in England are a decline in plants of wet, calcareous and unimproved grassland, open habitats, heathlands and acidic grassland, aquatic and swamp habitats, and arable weeds. In contrast, species of general grassland (often nitrophiles)and

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Fig. 3. (Cont&ued) species of anthropogenic habitats (casuals, garden escapes) have increased. In Scotland, the main changes are losses of plants of unimproved grassland and arable weeds, and a massive increase in introduced species. These differences between the two countries largely reflect differences in habitats and the pressures upon them. Maps of four species showing typical patterns of increase, decrease and no change are given in Fig. 3. All records for the British Isles are included on the maps, but the changes noted only apply to England and Scotland (preliminary analyses for Wales and Ireland are given in Rich and Woodruff, 1990). On the maps a predominance of open circles suggests a decline since 1960, and a predominance of pluses, an increase. Very few cases of changes in distribution without a change in

frequency were observed. Changes in individual squares cannot be taken to indicate local change because of variations in recording, and similarly analysis of turnover (i.e. percentage in common between the surveys) or persistence in individual hectads would be inappropriate; Nilsson and Nilsson (1983) found that sampling error accounted for two-thirds of the estimated turnover of species on islands in Sweden. DISCUSSION The main problem encountered in the comparison of the records was the greater recording effort for the Monitoring Scheme. This would introduce a substantial bias if the absolute numbers of squares recorded for

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Fig. 3. (Continued) each survey were compared, and, as no independent measures of recording effort were available, the species hectad frequencies had to be corrected relative to each other. The problem of correcting for differences in recording effort will be common to all other surveys unless standardised recording procedures are adopted. For monitoring change in the long term, it is better to use purpose-designed, site-specific surveys (e.g. Barr et al., 1993), or monitor individual species (e.g. Foley, 1992). Recording schemes should be directed at gleaning considerably more recording information from recorders (e.g. time spent recording) which is vital if the records are to be used for anything more than simple distribution mapping.

A hectad presence/absence survey is relatively crude. No change would be noted if a species was lost from all localities in each hectad except one. This suggests the real picture of change may be much more dramatic than indicated by simple changes in frequency at a hectad level. Despite this lack of sensitivity, the BSBI Monitoring Scheme has shown significant changes in the frequency of one-quarter of the species in England (24%) and one-eighth of the plants in Scotland (12%). A number of major ecological trends were detected (Table 5): (a) there were widespread losses of grassland taxa (especially species of wet, unimproved, calcareous and open pastures), which may be because of drainage, fertilizers and herbicides;

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T. C. G. Rich, E. R. Woodruff Table 1. Species which have shown a sign.kant decrease in frequency between 1930-1960 and 1987-1988 in England

Species

General habitat

Species

Adonis annua Agrimonia procera Agrostemma githago Aira caryophyllea Aira praecox Allium oleraceum Anagallis minima Anthemis arvensis Anthemis cotula Apium graveolens Apium inundatum Arabis glabra Arabis hirsuta Atriplex hortensis Arena strigosa Baldellia ranunculoides Briza media Bromus lepidus Bupleurum tenuissimum Butomus umbellatus Calluna vulgaris Caltha palustris Calystegia soldanella Carduus tenuiflorus Carex caryophyllea Carex digitata Carex nigra Carex panicea Carex pilulifera Carex vesicaria Carex vulpina Carlina vulgaris Centaurea cyanus Centaurea melitensis Centaurea scabiosa Centaurea solstitialis Centaurium littorale Cerastium arvense Chenopodium bonus-henricus Chenopodium urbicum Chichorium intybus Chrysanthemum segetum Cirsium dissectum Coeloglossum viride Conringia orientalis Coriandrum sativum Cuscuta epithymum Cynoglossum officinale

Arable weed Unimproved grassland Arable weed Open places Open places Unimproved grassland Damp, open places Arable weed Arable weed Saltmarshes Aquatic Heathland edges Calcareous grassland Casual Arable weed Swamps Unimproved grassland Unimproved grassland Saltmarshes and coastal grassland Swamps Heathland Marshes Sand dunes Sand dunes and coastal grassland Unimproved grassland Calcareous woodland Wet grassland and swamps Wet grassland and mires Acidic grassland and heaths Swamps Swamps Calcareous grassland Arable weed Casual Calcareous grassland Arable weed Sand dune slacks Unimproved grassland Near habitation Arable weed Roadsides Arable weed Fens Calcareous grassland Casual Casual Heathland and sea cliffs Calcareous grassland and sand dunes Fens Acidic grassland and heaths Unimproved grassland Unimproved grassland Casual Calcareous grassland and sand dunes Aquatic Swamps Heathland Wet heathland Open places Coast Arable weed Unimproved grassland Open places

Filago vulgaris Fragaria vesca Frangula alnus Galeopsis angustifolia Galium pumilum Galium tricornutum Galium uliginosum Galium verum Genista anglica Genista tinctoria Geranium phaeum Geranium robertianum Geum rivale Gnaphalium sylvaticum Groenlandia densa Gymnocarpium dryopteris Hordelymus europaeus Hydrocharis morsus-ranae Hydrocotyle vulgaris Hyoscyamus niger Hypericum humifusum Hypericum montanum Hypochaeris glabra Jasione montana Knautia arvensis

Dactylorhiza traunsteoleri Danthonia decumbens Dianthus armeria Dianthus deltoides Dipsacus sativus Echium vulgare Elatine hexandra Eleocharis acicularis Erica cinerea Erica tetralix Erodium cicutarium Erodium moschatum Euphorbia exigua Euphrasia spp. Filago minima

General habitat

Open places Hedges, grassland, etc. Heaths, scrub Arable weed Calcareous grassland Arable weed Marshes Unimproved grassland Heaths Unimproved grassland Garden escape Hedges, etc. Damp grassland and woods Heaths Aquatic Woodland Calcareous woodland Aquatic Marshy grassland Casual Heaths, woodland rides, etc. Calcareous grassland Open acidic grassland Acidic grassland and heaths Unimproved grassland, hedges, etc. Koeleria macrantha Calcareous grassland Lathyrus aphaca Casual and arable weed Lathyrus linifolius Hedges, rocky woods, etc. Lepidium campestre Casual Lepidium heterophyllum Open places Linum catharticum Grassland Listera ovata Woodland and grasslands Lithospermum arvense Arable weed Lolium temulentum Arable weed Marshy grassland L ychnis flos-cuculi L ycopodium clavatum Heaths, acidic grassland and uplands Lythrum salicaria Swamps Malva moschata Unimproved grassland and hedges Marrubium vulgare Unimproved grassland, often introduced Medicago minima Open grassland Medicago polymorpha Open grassland Medicago sativa subsp, sativa Roadsides, etc. Melica nutans Rocky woodlands Casual Melilotus indica Mentha pulegium Wet grassland Mentha suaveolens Unimproved grassland Menyanthes trifoliata Swamps Mertensia maritima Shingle Myosotis ramosissima Open places Aquatic Myriophyllum verticillatum Nardus stricta Acidic grassland and heaths Neottia nidus-avis Woodlands Aquatic Oenanthe aquatica Swamps Oenanthe fistulosa Ononis spinosa Unimproved grassland Woodlands and grassland Orchis mascula Orchis morio Unimproved grassland Orchis ustulata Calcareous grassland Calcareous grassland Origanum vulgare Acidic grassland and heaths Ornithopus perpusillus Orobanche alba Calcareous grassland (Contimwd)

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Table 1. (Caatiaaed)

Species

General habitat

Species

General habitat

Orobanche minor Orobanche rapum-genistae Papaver argemone Paris quadrifolia Pedicularis palustris Pedicularis sylvatica Phalaris minor Phyteuma orbiculare Pilosella officinarum Platanthera bifolia Poa palustris Polygala vulgaris Polygonum viviparum Potamogeton acutifolius Potamogeton compressus Potamogeton friesii Potamogeton praelongus Potentilla argentea Potentilla erecta Pulsatilla vulgaris Radiola linoides Ranunculus arvensis Ranunculus auricomus Ranunculus circinatus Ranunculus flammula Ranunculus parviflorus Ribes spicatum Rumex rupestris Ruppia maritima Sagina nodosa Salix repens Sambucus ebulus Scandix pecten- veneris Scleranthus annuus Scutellaria galericulata Sedum rosea* Sempervivum tectorum

Grassland, often recent Unimproved grassland, scrub Arable weed Woodland Marshes Damp grassland Casual Calcareous grassland Unimproved grassland Grassland and woods Wet places Calcareous grassland Uplands Aquatic Aquatic Aquatic Aquatic Acidic grassland and heaths Acidic grassland and heaths Calcareous grassland Open places Arable weed Woodland Aquatic Marshes Arable weed and sea cliffs Rocky woodlands Coat Aquatic Wet grassland Acidic grassland and heaths Near habitation Arable weed Arable weed and open places Swamps Uplands Near habitation

Senecio aquaticus Senecio sylvaticus Sherardia arvensis Silene gallica Silene noctiflora Silene vulgaris Sium latifolium Spergula arvensis Spergularia rubra

Wet grassland Acidic grassland and heaths Arable weed and open places Arable weed Arable weed Calcareous grassland Swamps Arable weed Acidic grassland and woodland rides Calcareous grassland Arable weed Calcareous grassland and open woods Woodland and hedges Aquatic Wet grassland Acidic grassland and heaths Calcareous grassland Arable weed Arable weed Cultivated Arable weed Mires Marshes Arable weed Arable weed and sand dunes Acidic grassland and heaths Marshes Weed Acidic grassland and heaths Heaths Arable weed Calcareous grassland Damp woodland rides and grassland

Spiranthes spiralis Stachys arvensis Stachys officinalis Stellaria holostea Subularia aquatica Succisa pratensis Teesdalia nudicaulis Thlaspi perfoliatum Torilis arvensis Torilis nodosa Trifolium incarnatum Turgenia latifolia Vaccinium uliginosum Valeriana dioica Valerianella dentata Valerianella locusta Veronica officinalis Veronica scutellata Vicia parviflora Viola canina* Viola lactea Viola tricolor Vulpia unilateralis Wahlenbergia hederacea

*Changes which may be related to recording or sampling bias.

(b) there were large declines in arable weeds, probably because of herbicides and seed screening; (c) there were declines in species of heathland and acidic grassland in England, probably because of land reclamation for agriculture; (d) aquatic and swamp species have declined in England, possibly resulting from eutrophication of water, drainage and habitat reclamation (the increases in Scotland may be related to increased sampling); (f) there were huge increases in introduced species such as garden escapes, weeds and planted trees and shrubs, which may be related to disturbance of the countryside (e.g. Hodgson, 1986b). There were a few changes in coastal species in England, but there was virtually no change in the uplands. Change was most marked in central England and least in the montane areas, again suggesting man as a primary, causal factor. Gross habitat change at the landscape scale (e.g. Nature Conservancy Council, 1984; Barr et al., 1993) is almost certainly the primary cause of the changes.

Recording bias (Rich & Woodruff, 1992) has been minimised as far as possible. It is tempting nevertheless to attribute unexpected changes to recording bias (e.g. the increase in Anthoxanthum odoratum), but some changes may be real. Indeed, it would be surprising if some general changes had not occurred, as the flora is continually changing naturally through the processes of migration, succession and extinction. There are no other studies of a similar scale against which to compare the results, but they are broadly comparable with previous findings noted in local floras (e.g. Dony, 1976, 1977; Hall, 1980; Hodgson, 1986a,b; Wells, 1989; Lavin & Wilmore, 1994). The survey has shown considerable changes in the flora of England and Scotland since 1960. A detailed baseline has also been established against which to monitor changes in the future, but before the tetrad survey is repeated there must be more research into the most effective recording techniques for monitoring change (e.g. Rich & Smith, 1996), A broader, multivariate analysis of the whole data set may well reveal further trends; there is plenty of scope for further

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Table 2. Species which has shown a significant increase in frequency between 1930-1960 and 1987-1988 in England Species

General habitat

Species

Acer platanoides Acer pseudoplatanus Agrostis capillaris Agrostis gigantea Allium roseum Allium triquetrum Alnus incana Alopecurus geniculatus Alopecurus pratensis Amsinckia micrantha Angelica archangelica Anisantha sterilis Antirrhinum majus Arabis caucasica Arctium minus agg.* Arrhenatherum elatius* Arum italicum+ Asparagus officinalis subsp. officinalis+ Aster nova-belgii agg. Atriplex halimus Aubrieta deltoidea Arena fatua Avena sterilis Azolla filiculoides Barbarea intermedia Berberis darwinii* Brassica napus* Bromopsis inermis Bromus hordeaceus Buddleja davidii Buxus sempervirens+ Callitriche agg.* Campanula persicifolia Campanula portenschlagiana* Campanula poscharskyana* Cardamine flexuosa Cardamine hirsuta Carex divulsa subsp, divulsa* Carex spicata* Centaurea montana* Cerastium glomeratum Cerastium tomentosum Ceratochloa carinata Chenopodium ficifolium* Chenopodium rubrum Cicerbita macrophylla Colutea arborescens Coronopus didymus Crocosmia x crocosmiiflora Cyclamen hederifolium Dactylorhiza praetermissa* Digitalis purpurea Dipsacusfullonum Dryopteris dilatata* Elodea nuttallii Elytrigia repens Epilobium ciliatum Epilobium hirsutum Escallonia macrantha Euphorbia lathyris Fallopia bauldschuianica Fallopia japon&a Festuca gigantea Festuca rubra* Fuchsia magellanica Galanthus nivalis

Widely planted Casual Grassland Grassland Garden escape Garden escape Widely planted Marshy grassland Grassland Casual Riverbanks Arable weed Garden escape Garden escape Roadsides, waste ground, etc. Grassland Woodlands and garden escape Casual

Galeopsis tetrahit Arable weed, waysides, etc. Galinsoga ciliata Arable weed Gunnera tinctoria Planted Heracleum mantegazzianum Riverbanks, roadsides, etc. Hesperis matronalis Riverbanks Hordeum jubatum Casual Hyacinthoides hispanica Garden escape Iberis umbellata Garden escape Impatiens glandulifera Riverbanks Iris foetidissima+ Woods and coast Juglans regia* Widely planted Juncus bufonius s.1. Damp, open places Lactuca serriola Weed Lagarosiphon major Aquatic Lamiastrum galeobdolon subsp. Garden escape argentatum* Lamium hybridum Arable weed Lamium maculatum Garden escape Lathyrus latifolius Garden escape Laurus nobilis* Planted Leucanthemum x superbum Garden escape Leycesteria formosa Planted Lilium martagon Garden escape Linaria purpurea Garden escape Lobelia erinus* Garden escape Lobularia maritima Garden escape Lonicera japonica Garden escape Lonicera nitida Widely planted Lunaria annua Garden escape Lupinus arboreus Garden escape Lupinus polyphyllus Garden escape Lychnis coronaria Garden escape L ysichiton americanus Planted Lysimachia punctata Garden escape Mahonia aquilifolium Garden escape Matricaria discoidea Arable weed Matricaria recutita Arable weed Meconopsis cambrica+ Garden escape Montia sibirica Riverbanks Muscari neglectum+ Garden escape Mysotis sylvatica+ Woods and garden escape Narcissus agg. Widely planted Nigella damascena Garden escape Oxalis articulata Garden escape Oxalis corymbosa Garden escape Oxalis exilis Garden weed Papaver atlanticum Garden escape Papaver dubium subsp, lecoqi[* Arable weed Papaver somniferum Garden escape Pentaglottis sempervirens Garden escape Persicaria amphibia Aquatic Persicaria campanulata Garden escape Persicaria lapathifolia Weed Persicaria wallichii Garden escape Philadelphus coronarius Garden escape Platanus x hybridus Planted Poa chaixii Garden escape Poa compressa Unimproved grasslands Poa trivialis Woods, hedges, grassland, etc. Polemonium caeruleum+ Garden escape Polygonum aviculare agg. Weed Polystichum aculeatum Woodlands Polystichum setiferum Hedges and woodlands Populus trichocarpa* Planted Potamogeton pectinatus Aquatic Prunus avium+ Planted Prunus cerasifera Planted

Garden escape Casual Garden escape Arable weed Arable weed Aquatic Casual Widely planted Cultivated Casual Grassland Garden escape Widely planted Aquatic Garden escape Garden escape Garden escape Garden escape Gardens and open places Grassland and hedges Unimproved grassland Garden escape Arable weed Garden escape Casual Arable weed Arable weed Garden escape Garden escape Weed Garden escape Garden escape Marshes Woods, heaths and hedges Waysides, etc. Woodlands, hedges Aquatic Grassland Casual weed Swamps Widely planted Weed Garden escape Garden escape Damp grassland and hedges Grassland Widely planted Garden escape

General habitat

*Changes which may be related to recording or sampling bias. +Native species which have increased due to introductions. ¢co,,,,ed)

B S B I Monitoring Scheme

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Table 2. (Continued)

Species

General habitat

Species

General habitat

Prunus domestica Prunus lusitanicus Puccinellia distans Pulmonaria officinalis Pyrola rotundifolia subsp, maritima Quercus cerris Quercus ilex Quercus petraea* Quercus rubra Ranunculus lingua*+ Rheum x cultorum Rhododendron ponticum Ribes nigrum+ Ribes rubrum+ Ribes sanguineum Ribes uva-crispa+ Robinia pseudacacia Rorippa austriaca Rosa rugosa Rubus idaeus Rumex conglomeratus Rumex crispus Rumex cristatus Rumex obtusifolius Rumex patientia Rumex sanguineus Salix caprea Salix cinerea Salix fragilis Salix viminalis Saxifraga x urbium

Hedges Planted Saltmarshes and roadsides Garden escape Sand dune slacks Planted Planted Woodlands Planted Marshes and ponds Garden escape Planted Garden escape Garden escape Garden escape Garden escape Planted Casual Garden escape Hedges, roadsides, etc. Grassland Grassland weed Casual Grassland weed Casual Grasslands and woods Scrub, hedges, etc. Scrub, hedges, etc. River banks Often planted Garden escape

Sedum album Sedum rupestre+ Sedum spurium Senecio cineraria Senecio jacobaea Solanum sarrachoides Soleirolia soleirolii Solidago canadensis Solidago gigantea* Sonchus asper Sorbus intermedia Sorbus latifolia agg.+ Sorbus torminalis Spiraea spp. Symphoricarpos albus Syringa vulgaris Taxus baccata Tellima grandiflora Tilia x vulgaris Tolmeia menziesii Trifolium dubium Tropaeolum majus Valerianella carinata Veronica arvensis Veronicafiliformis Veronicahederifolia Veronica serpyllifolia Vicia cracca Viola x wittrockiana Vulpia myuros

Garden escape Garden escape Garden escape Garden escape Grassland Arable weed Garden escape Garden escape Garden escape Weed Planted Hedges, woods, etc., often planted Woodlands Garden escape Garden escape Garden escape Garden escapes and planted Garden escape Planted Garden escape Grassland Garden escape Arable weed and open places Arable weed and open places Garden weed Arable weed Damp, unimproved grassland Hedges, waysides, etc. Garden escape Open places, railways, etc.

*Changes which may be related to recording or sampling bias. tNative species which have increased due to introduction.

Table 3. Species which have shown a significant decrease in frequency between 1930-1960 and 1987-1988 in Scotland

Species

General habitat

Species

General habitat

Alchemilla vulgaris agg. Allium schoenoprasum Alopecurus myosuroides Artemisia vulgaris Astragalus glycyphyllos Bromopsis inermis Bromus lepidus Calendula officinalis Campanula rapunculus Carduus tenuiflorus Centaurea scabiosa Chrysanthemum segetum Cichorium intybus Eryngium maritimum Fagopyrum esculentum Filago minima Galeopsis speciosa Geranium phaeum Gnaphalium sylvaticum Lamium amplexicaule Leucanthemum vulgate Linaria vulgaris Listera ovata Lithospermum arvense Lithospermum officinale

Unimproved grassland Unimproved pasture, sometimes casual Arable weed Waysides, waste ground, etc. Unimproved grassland Casual Unimproved grassland Casual Garden escape Coast Calcareous grassland and railways Arable weed Garden escape Sand dunes Casual Open places Arable weed Garden escape Heaths, woodland rides Arable weed Unimproved grassland Unimproved grassland Unimproved grassland Arable weed Woods, hedges, etc.

Lolium multiflorum Lycopodiella inundata Malva moschata Medicago polymorpha Minuartia verna Oenanthe fistulosa Phalaris canariensis Platanthera chlorantha Primula veris Ranunculus bulbosus* Ranunculus circinatus Raphanus raphanistrum Rumex conglomeratus Sherardia arvensis Silene conica Silene vulgaris Silybum marianum Sinapis arvensis Sonchus arvensis Stachys arvensis Subularia aquatica Tanacetum vulgare Trifolium arvensis Veronica polita Viola tricolor

Arable weed and cultivated Damp heaths Unimproved grassland Casual Uplands Marshes Casual Unimproved grassland Unimproved grassland Unimproved grassland Aquatic Arable weed Grassland Arable weed and open places Casual Unimproved grassland Casual Arable weed Waste places, etc. Arable weed Aquatic Waysides, etc. Open places Arable weed Arable weed and dunes

*Changes which may be related to recording or sampling bias.

T. C. G. Rich, E. R. Woodruff

228

Table 4. Species which have shown a significant increase in frequency between 1930-1960 and 1987-1988 in Scotland Species

General habitat

Species

Acer platanoides Aconitum napellus+ Agrostis gigantea Allium paradoxum Alnus incana Anaphalis margaritacea Anthoxanthum odoratum* Aquilegia vulgaris+ Arctium minus agg. Arena fatua Barbarea intermedia Berberis darwinii* Buddleja davidii Callitriche agg.* Carex rostrata Centaurea montana* Cerastium tomentosum Ceratophyllum demersum Cicerbita macrophylla Convallaria majalis+ Crocosmia × crocosmiflora Diplotaxis muralis Doronicum plantagineum Eleocharis uniglumis Elodea nuttallii Epilobium brunnescens Epilobium ciliatum Equisetum fluviatile* Erinus alpinus Erysimum cheiri Fallopia japonica Festuca rubra* Fuchsia magellanica Lamiastrum galeobdolon subsp, argentatum* Gaultheria shallon Gnaphalium uliginosum Hordeum jubatum Hyacinthoides hispanica x non-scripta Impatiens glandulifera Juncus acutiflorus* Juncus articulatus* Juncus bufonius s.1. Juncus effusus* Lemna gibba Lemna minor

Widely planted Garden escape Grassland and waste ground Garden escape Widely planted Garden escape Grassland Garden escape Hedges, waste places, etc. Arable weed Casual Widely planted Garden escape Aquatic Swamps Garden escape Garden escape Aquatic Garden escape Garden escape Widely planted Casual Garden escape Swamps and saltmarshes Aquatic Uplands Weed Swamps Garden escape Garden escape Garden escape Grassland Widely planted Garden escape

Lemna trisulca Leucanthemum x superbum Leycesteria formosa Lupinus polyphyllus Lysimachia nummularia

Planted Damp open places Casual Garden escape Riverbanks Marshes Marshes Damp, open places Wet grassland Aquatic Aquatic

General habitat

Aquatic Garden escape Widely planted Garden escape Damp grassland and garden escape Lysimachia punctata Garden escape Meconopsis cambrica+ Garden escape Mentha spicata Garden escape Montia fontana Damp grassland and springs, etc Myriophyllum alterniflorum Aquatic Narcissus species Widely planted Petasites japonica Widely planted Peucedanum ostruthium Near habitation Philadelphus coronarius Widely planted Pilularia globulifera Marshes and pond Populus x canescens Widely planted Potamogeton alpinus Aquatic Prunus cerasifera Widely planted Prunus lusitanicus Widely planted Pyrus pyraster Widely planted Rheum × cultorum* Garden escape Rhododendron luteum Widely planted Ribes alpinum+ Garden escape Ribes nigrum+ Garden escape Ribes rubrum+ Garden escape Ribes sanguineum Garden escape Rosa rugosa Garden escape Sagina procumbens* Grasslands Salix daphnoides Widely planted Sambucus racemosa Widely planted Saxifraga x urbium Garden escape Scirpus sylvaticus* Damp woodlands Sedum forsteranum+ Garden escape Sedum rupestre Garden ecape Sedum spurium Garden escape Senecio fluviatilis Garden escape Solidago gigantea* Garden ecape Sparganium angustifolium Aquatic Syringa vulgaris Widely planted Tellima grandiflora Garden escape Tolmeia menziesii Garden escape Triglochin palustris Marshes Veronicafiliformis Garden weed Viola palustris* Wet grassland Zostera angustifolia Marine

*Changes which may be related to recording or sampling bias. tNative species which may be related to recording or sampling bias. Table 5. Crude breakdown of changes by country and major habitats. Species with possible recording bias are excluded Habitat

Woodland, scrub, hedges, etc. General grassland Calcareous grassland Wet grassland Unimproved grassland Open grassland Heathland, acidic grassland, etc. Uplands Aquatics, swamps Coast Arable weeds Introductions Others

Number of species in England

Number of species in Scotland

Decreases

Increases

Decreases

Increases

15 1 22 17 22 12 24 2 24 8 31 17 1

12 10 0 4 5 3 0 0 6 1 13 110 10

1 3 1 1 12 3 2 1 2 2 10 10 4

0 1 0 3 0 2 0 1 11 2 1 65 2

B S B I Monitoring Scheme analysis (e.g. Le Duc et al., 1992; Smith, 1995; Thompson et al., in press) and the data are available at BRC. Finally, there are three major implications of the results for plant conservation in Britain. (1) The problems encountered during comparison of the data suggest that a more rigorous, systematic approach is needed in data collection. (2) It is evident that the Atlas is out of date as an indicator of the status of the flora and a new Atlas of the British and Irish flora is urgently needed (Rich, 1991). (3) The marked decline in species of high-quality habitats for nature conservation such as calcareous grassland indicates priorities for habitat protection at a national scale.

ACKNOWLEDGEMENTS Thanks are particularly extended to the 1600 volunteers, largely members of the BSBI, who contributed to the Monitoring Scheme in 1987 and 1988, to the BSBI Vice-county Recorders and other nominated botanists who have helped co-ordinate and check the recording, and the Country Coordinators, Stan Beesley, Gwynn Ellis, Roger Goodwillie and Henry Noltie. We also wish to thank Chris Preston, Claire Appleby, Julian Dring and Paul Harding for assistance during the work, the late John Dony, Paul Smith and Mark Hill for discussion and Dorian Moss for statistical advice. Penny Angold, Arthur Chater, John Hellawell, Eimear Nic Lughadha, Henry Noltie, Chris Preston and Paul Smith provided many useful comments on draft manuscripts. The work was funded by the Nature Conservancy Council and the Department of the Environment, Northern Ireland. Staff who worked with us at BRC were Paul Smith, Jayne Abblitt, Tina Waterman, Karen Tomblin, John Needham, Stuart Green and Val Burton. Records of scarce and aquatic plants were updated in 1992 with funding from JNCC.

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