DHBlog036 · Inspiring sights from two locations near Sherborne
Dorset plays host to a fascinating mix of landscapes and for the botanist, there is much to learn in studying the flora of each and the wildlife that it supports. In the north-west around Sherborne, there are ridges and steep slopes formed from oolitic limestone and overlain with shallow, free-draining calcareous soils. The semi-natural habitats that have evolved within such landscapes are richly biodiverse and yet, lowland calcareous grassland has undergone such a decline over the last 100 years or so that it is now an S41 Priority Habitat in England. And so, on 1st June 2024, a small party from the Dorset Flora Group met to explore two grassland sites in this region. We were guided knowledgeably by Nigel Spring (Director of EuCAN CIC and Chair & Reserves Manager of Butterfly Conservation Dorset Branch) and Sarah Warren (Milborne Port Climate and Nature Action) who have a long association with the sites.
The morning was spent on East Hill near Milborne Port, just over the border in Somerset. The steep slopes of the hill lie on private land but a good length of public footpath provides some useful access to the general public.
In recent years, the balance of the site has suffered due to encroachment by bramble, gorse and blackthorn scrub but ongoing conservation work by EuCAN volunteers has sought to redress this, removing significant areas of scrub along with ragwort and thistle, some of it carried out by hand and some with brushcutters.
In addition, four ponies – the first grazing animals on site since 2009 – have recently begun to bring the sward back into better condition and it was interesting to see the differences between grazed and ungrazed parts.
We found that the historic lack of grazing had led to a profusion of Upright Brome (Bromopsis erecta) but many downland herbs were still present beneath. Notable species included Horseshoe Vetch (Hippocrepis comosa), Hairy Violet (Viola hirta), Common Rock-rose (Helianthemum nummularium), Devil's-bit Scabious (Succisa pratensis), Wild Marjoram (Origanum vulgare), Wild Thyme (Thymus drucei), a vast Field Maple (Acer campestre) and in areas where scrub has recently been cleared, we enjoyed large stands of Common Gromwell (Lithospermum officinale) busy with bumble bees.
Devil's-bit Scabious is also notable as a food plant for larvae of the vulnerable Marsh Fritillary (Euphydryas aurinia) and we were lucky to see five of these stunning butterflies during our visit.
In the afternoon we moved on to Terrace Meadow, a limestone grassland with varying topography skirting the Terrace Playing Fields at Dancing Hill on the southern edge of Sherborne. Open to the public and owned by Sherborne Town Council, the upper reaches comprise Terrace Meadow SNCI while the lower reaches form a narrow, non-SNCI belt alongside the road.
Since 2012, EuCAN has worked with the town council to safeguard the grassland flora of all parts of the site. Practical conservation of the SNCI has involved cutting and removing scrub and hay with targeted removal of Common Ragwort (Jacobaea vulgaris) and Hogweed (Heracleum sphondylium) after flowering to prevent their spread while retaining their value to invertebrates. Yellow-rattle (Rhinanthus minor) has been encouraged to multiply and we were treated to a spectacular yellow carpet over large areas.
The balance of plant species at Terrace Meadow has altered during this time. Suppression of the rank grasses has led to a marked increase in herbs such as Common Valerian (Valeriana officinalis) and Ribwort Plantain (Plantago lanceolata).
Amongst the sea of Yellow-rattle, we also found Pyramidal and Bee Orchid (Anacamptis pyramidalis; Ophrys apifera), Common Spotted-orchid (Dactylorhiza fuchsii), Fairy Flax (Linum catharticum), Common Broomrape (Orobanche minor), Yellow-wort (Blackstonia perfoliata) and Welted Thistle (Carduus crispus).
Invertebrates have benefitted noticeably, as reflected in recent sightings of a number of interesting bumble and solitary bees and a diverse array of butterflies and moths including Marbled White (Melanargia galathea), Forester (Adscita statices), Small Eggar (Eriogaster lanestris) and a form of Five-spot Burnet where the spots are confluent (Zygaena trifolii f. minoides) (Nigel Spring, pers. commun.).
We also visited the lower, non-SNCI section of Terrace Meadow near to the road where EuCAN is also working to improve floristic diversity. Here, volunteers are cutting and removing rank grasses, making hay when practical and reintroducing local native species both as seed and as plug plants. This has been challenging as the grasses are vigorous and the local rabbits have good appetites but some of the results have been very promising, including an impressive display of Common Knapweed (Centaurea nigra) and associates on the road verge that was featured by Plantlife in 2021.
We recorded plant species from Terrace Meadow as we went and reached a total of 110 (upper and lower meadows combined), listed here:
While the list includes numerous specialists of impoverished calcareous grassland, it also contains many generalists and species typical of more fertile, mesotrophic conditions. It seems likely that the site has experienced an influx of nitrogen over the years from sources such as atmospheric deposition and the decomposition of vegetation in situ.
Interestingly, the area has been surveyed several times over the past 90 or so years, providing an opportunity to examine changes in the flora over that time. The upper meadow has partial overlap with one of over 7500 stands that contributed to Ronald Good's groundbreaking A Geographical Handbook of the Dorset Flora (Good,1948). Only about a quarter of this stand (G2694) remains as grassland and scrub; historic aerial imagery and Ordnance Survey maps show that in the latter part of the 20th Century, a substantial strip of meadow became infilled by the fringing woodland along the western side of the hill. The stand was surveyed by Good on 17/8/1934 (Good, 1934) and then again by Robin Walls on 21/8/2009 as part of a comprehensive study of changes in Dorset's calcareous grassland flora over the intervening period (Newton et al., 2012). Our species list is annotated to show overlap with these studies.
Notwithstanding differences in the precise areas covered, the total number of species that we recorded (110) was roughly double that recorded in 2009 (51). In seeking an explanation, one cannot overlook that the site is now managed more sympathetically towards grassland species than it was in 2009, at which time it had been identified as a potential SNCI but was not receiving specialised management (Robin Walls and Nigel Spring, pers. commun.). Notable gains include positive indicators such as Hairy Violet and Common Valerian which are not strong competitors and indicate some success in creating a less robust sward. Other additions are varied in nature and less easy to group together but some may be attributable to a few areas of greater disturbance that we covered during our visit. A good number of these are either of an arable or woodland habit and thus may have also benefitted from a reduced sward. We were unable to confirm a few of the species from 2009 including Devil's-bit Scabious, Field Scabious (Knautia arvensis) and Common Centaury (Centaurium erythraea), possibly due to the earlier timing and more relaxed nature of our visit.
We recorded 16 of the 24 species in Good's 1934 survey of G2694, including all of his calcicolous notables. Interestingly, the species overlap included two grasses, Tor-grass (Brachypodium rupestre) and Yellow Oat-grass (Trisetum flavescens), that were not in evidence in 2009, suggesting that recent management has brought the complement of grasses closer to its historical composition. Good's list is surprisingly short; there may be several reasons for this including differences in recording bias and strategy, the time of year and the prevailing strength of grazing or cutting. He described the stand as "unmanaged with substantial scrub blocks" and by comparison, the extant meadow is now managed with the grassland flora much more in mind. Whatever the case, it is clear that – in several different ways – the floristic diversity of Terrace Meadow has increased greatly since 1934.
With the continuing hard work of EuCAN volunteers and the respective landowners, prospects for restoring and maintaining the valuable grassland habitats at both East Hill and Terrace Meadow are most encouraging. We give many thanks to Nigel Spring and Sarah Warren for helping to organise and lead the trip.
This article is an expansion of text and images provided by Wren Franklin. It contains additional contributions from Daniel Holloway, Jean Smith, Tom Smith, Nigel Spring, Robin Walls, Jackie Walsh, Sarah Warren and Mariko Whyte, and was edited by Daniel Holloway.
REFERENCES
Good, R.D. (1934). Vegetation of Dorset 1934. Field Diaries. https://derc.org.uk/the-good-archive/
Good, R.D. (1948). A Geographical Handbook of the Dorset Flora. The Dorset Natural History and Archaeological Society, Dorchester.
Newton, A.C., Walls, R.M., Golicher, D., Keith, S.A., Diaz, A. & Bullock, J.M. (2012). Structure, composition and dynamics of a calcareous grassland metacommunity over a 70-year interval. J. Ecol. 100, 196–209. https://doi.org/10.1111/j.1365-2745.2011.01923.x