A revision of the Alopecurus pratensis - Sanguisorba officinalis (MG4) grassland community of the NVC 2014

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1 A revision of the Alopecurus pratensis - Sanguisorba officinalis (MG4) grassland community of the NVC 2014 Mike Dodd

2 Lowland floodplain meadows are recognised as a threatened habitat in the EU, being listed in Annex I of the EU Habitats Directive under category 6510 Lowland Hay Meadows (Alopecurus, Sanguisorba.) In the UK, the definition of the habitat has been taken to coincide with the Alopecurus pratensis - Sanguisorba officinalis meadow foxtail - great burnet grassland (MG4) of the British National Vegetation Classification (NVC), Rodwell The original description of this community by the NVC was based on a relatively restricted number of samples and the need for a full review of all the vegetation communities of damp meadows in Britain was highlighted by Rodwell et al. (2000), together with a reassessment of their placement within a broader European context (Rodwell et al. 2007). Aims of the Study To describe the variation within the Alopecurus-Sanguisorba community in Britain; by proposing subcommunities and examining their tolerances to different environmental variables. Methods The analysis involved 2503 quadrats from 48 sites. Quadrats were 1x1 m 2 and all vascular plants and bryophytes were listed. Species abundance was recorded using visual estimates of percentage cover. Data were classified using the modified version of Twinspan in the Juice software package. Four distinct noda were identified. Environmental differences between the noda were tested using water-regime tolerances (Silvertown et al., 1999) and mean Ellenberg F and N values of the species in each quadrat. ph and available phosphorus values were included for a subset of the quadrats.

3 The Outcomes As a result of this work the estimated area for the MG4 community in England and Wales is found to be between 1200 and 1350 ha. This equates to approximately 0.6% of the unimproved and semi-improved neutral grassland in the two countries (Countryside Survey, 2000). Within this general classification, four subcommunities are proposed. These are divided according to their fertility and hydrological tolerances and the findings have been submitted as a paper (Prosser et al, 2014, in review). MG4d MG4c MG4b Increasing tolerance to water logging MG4a Increasing fertility Fig. 1. Proposed subcommunities of MG4 separate out along hydrological and fertility gradients.

4 Four subcommunities are proposed, divided according to their fertility and tolerance of flooding. NVC Code subcommunity MG4a Dactylis glomerata Common name Species richness (mean no. species/m 2) Cocksfoot Species rich (25 m -2 ) especially forb rich Tolerance of flooding Rarely flooded Lowest Fertility (Olsen available P (mg/kg)) mean (range) fertility of MG4 units 7.6 ( ) MG4b Typical Typical Species rich Occasionally (22 m -2) flooded MG4c Holcus lanatus Yorkshire fog Species poor (16 m -2 ) Grass-dominated Frequently flooded Low fertility, 9.4 ( ) More fertile 12.5 ( ) MG4d Agrostis stolonifera Creeping bent Species poor (15m -2 ), flood tolerant species dominant Long duration flooding Highest fertility, 16.2 ( )

5 The species of the broad MG4 community that are constant across all of the subcommunities are listed below: Species found in all subcommunities Species preferential to the Dactylis and Typical subcommunities (i.e. highest Great burnet Common sorrel Meadow vetchling Red fescue Meadow buttercup Sanguisorba officinalis Rumex acetosa Lathyrus pratensis Festuca rubra Ranunculus acris frequencies found in these subcommunities) Red clover Trifolium pratense Perennial rye grass Lolium perenne Crested dogs tail Cynosurus cristatus Dandelion Taraxacum officinale agg. Common knapweed Centaurea nigra Ribwort plantain Plantago lanceolata White clover Trifolium repens Self heal Prunella vulgaris Common bent grass Agrostis capillaris Smooth brome Bromus racemosus Common mouse ear Cerastium fontanum Snakeshead fritillary Fritillaria meleagris

6 Map 1. All MG4 sites described in England and Wales

7 Map 2. All known locations for MG4a: the Dactylis subcommunity in England and Wales. Map 3. All known locations for MG4b: the Typical subcommunity in England and Wales. Map 4. All known locations for MG4c: the Holcus subcommunity in England and Wales. Map 5. All known locations for MG4d: the Agrostis subcommunity in England and Wales.

8 MG4a: Dactylis (Cocksfoot) subcommunity. This is the richest of the four subcommunities with 25 species m -2 on average. It is characterised by flooding intolerant species, grading into MG5 and/or CG2a on drier ground and to richer expressions of MG1 on infrequently cut areas. Extensive stands are found on North Meadow and Clattinger Farm (Wiltshire), at Yarnton Mead near Oxford, and Woodside Meadow near Bicester. Alopecurus pratensis is often sparse and patchy in this vegetation. Differential species i.e. species found only in this subcommunity Goat s beard Lesser hawkbit Fairy flax Cowslip Black medick Tragopogon pratensis Leontodon taraxacoides Linum carthaticum Primula veris Medicago lupulina Preferential species i.e. highest frequencies found in this subcommunity Cocksfoot Yellow oat-grass Ladies bedstraw Quaking grass Meadow brome Rough hawkbit Oxeye daisy Dactylis glomerata Trisetum flavescens Galium verum Briza media Bromus commutatus Leontodon hispidus Leucanthemum vulgare

9 MG4b: Typical subcommunity. This represents those stands closest in their species composition to the constancy table of Rodwell There are no species found only in this subcommunity (differential species) however the table lists those species found at their most frequent. Preferential species Meadow buttercup Common sorrel Field wood-rush Sweet vernal grass Meadow fescue Ranunculus acris Rumex acetosa Luzula campestris Anthoxanthum odoratum Festuca pratensis

10 MG4c: Holcus lanatus (Yorkshire fog) subcommunity. This unit has a generally higher cover of grass species and is more widespread than the Agrostis subcommunity. It was found at 35 of the 58 sites in this analysis. It is less species rich than MG4a and b with on average 16 species m-2. The vegetation is separated from other units by the absence or scarcity of species common to the Dactylis and Typical subcommunities (Table 1, column 2). In general the Holcus and Agrostis stolonifera subcommunities feature species of more fertile substrates than those of the Dactylis and Typical subcommunities. Preferential species Tufted hairgrass Couch grass Deschampsia cespitosa Elytrigia repens

11 MG4d: Agrostis stolonifera (Creeping bent) subcommunity. The Agrostis stolonifera subcommunity is the least species rich (15 species m-2) and it is especially characteristic of the Derwent Ings, Yorkshire. Again lacking those species that characterise the Dactylis and Typical subcommunities, it shares with the Holcus subcommunity the high frequency and cover of meadow foxtail Alopecurus pratensis. It is the unit most tolerant to waterlogged soils. Preferential species Creeping bent grass Cuckoo flower Brown sedge Slender tufted sedge Meadowsweet Creeping jenny Amphibious bistort Differential species Agrostis stolonifera Cardamine pratensis Carex disticha Carex acuta Filipendula ulmaria Lysimachia nummularia Persicaria amphibia Sneezewort Small-flowered forget-me-not Marsh stitchwort Achillea ptarmica Myosotis laxa Stellaria palustris

12 Why does it matter? Understanding the community assemblages enables improved understanding of soil-water levels and soil fertility at a site. Understanding the subtle differences in plant community at a site will help to alert site managers to potential changes in soil water, fertility and management; enabling action to be taken to reverse any negative changes. References Prosser, M., Wallace, H.L., and Gowing, D.J. (2014). Floristic variation within the Alopecurus pratensis-sanguisorba officinalis community in England and Wales; the role of soil hydrology. Submitted to Phytocoenologia. In review Rodwell, J.S. ed British Plant Communities. 3 Grasslands and Montane communities. Cambridge, CUP. Rodwell, J.S., Dring, J.C., Averis, A.B.G., Proctor, M.C.F., Malloch, A. J.C., Schaminée, J.H.J. and Dargie, T.C.D Review of coverage of the National Vegetation Classification. JNCC Report 302, JNCC Peterborough. Rodwell, J.S., Morgan, V., Jefferson, R.G. and Moss, D The European context of British Lowland Grasslands. JNCC Report 394, Peterborough. Silvertown, J., Dodd, M., Gowing, D.J. and Mountford, J.O. (1999) Hydrologically defined niches reveal a basis for species richness in plant communities. Nature, 400: Accounting for Nature: assessing habitats in the UK countryside. Countryside Survey Department of the Environment, Transport and the Regions; London). Acknowledgements We would like to thank Hilary Wallace and Mike Prosser (Ecological Surveys (Bangor)) for their hard work in pulling this report together. We would also like to thank those people who allowed access to sites, helped with data provision and commented on the final submitted paper. In particular thanks must go to John Rodwell and Owen Mountford. This work was funded by the Floodplain Meadows Partnership and thanks must go to the Esmee Fairbairn Foundation for their continued support to this project.