The SuffolkArgus
July 1998
Bracken for Butterflies
This ancient Royal Forest is one of the largest areas of mature woodland in England, the main trees being Oak, Birch and Alder. It is quoted as being a "textbook
exampleof woodlandmanagement".
by JamesMann It has been widely accepted that the decline of many of our Fritillaries has been as result of changes of woodland management such as abandonment of coppicing. If these butterflies cannot find alternative habitats they will die out. Butterfly Conservation have produced a leaflet 'bracken for butterflies' the opening statement of which is:- The presence of bracken in habitats ranging from open hillside to woodland can be important for many forms of wildlife, bur is especially vital for four highly threatened Fritillary butterflies, the High Brown Fritillary, the Pearl-bordered Fritillary, the Small Pearlbordered Fritillary and the Dark Green Fritillary. For these species, suitable habitats occur in open, sheltered situations often where there are mosaics of grass, bracken and scrub. The bracken fronds act like a woodland canopy for the Violet foodplants and bracken litter provides a warm microclimate for development of the immature stages. Although we know longer have these Fritillaries in Suffolk and cannot hope for them to return by themselves there is no reason for us not to attempt to identify potentially suitable bracken habitats for Fritillaries. If we find areas of bracken habitat that also support violets it is important to pinpoint the location to enable further investigation and possible
12
Dark Green Fritillary by DouglasHammersley management as these may become suitable sites for reintroduction in the future. The easiest method is to search for key areas in Spring before the bracken fronds have unfurled. Bracken stands which are sheltered and south facing ate those most likely to be suitable for Fritillaries. In Spring, Pearl-bordered Fritillary and High Brown Fritillary bracken habitats are characterised by violets growing through a shallow (under 15cm) bracken litter. Suitable mosaics are typically 1/3 grass to 2/ 3 bracken. In contrast, Small Pearl-bordered Fritillary bracken habitats may have abundant purple moor-grass or tufted hair grass, with Dark Green Fritillary bracken mosaics frequently consisting of I /3 bracken and 2/3 grass. The Sandlings certainly supported High Brown Fritillaries in some areas until the 1960' s and may well have supported Pearl-bordered Fritillaries. Many of the largest Fritillary colonies occur in managed bracken communities so if we can identify suitable habitats there is no reason for us not to have Fritillaries in Suffolk in the future.
Mike Williams had very kindly arranged for us to be shown a range of habitats, during the afternoon, by one of the local recorders for the area, who duly met us on our arrival. We were then privileged to drive further into the forest to park our cars and it was here that we had our first sighting of another 'target species' the Pearl-bordered Fritillary. Before moving off into the forest we were instructed to 'stay together and keep with the leader', as obviously those unfamiliar with the area could, and do, easily become lost. We took a narrow path leading between tall dark conifers noticing many wood ants crossing the track and their huge nests constructed beneath the trees. This path led into a more open area of bracken, grass and scrub where we were able to observe the Pearl-bordered Fritillary more closely as it was present in good numbers. Leaving this sheltered spot we climbed up through a tree belt where we emerged somewhat hot and breathless onto a wide grassy strip. This corridor which disappeared into the distance, in both directions, is part of the route of the water pipeline to Birmingham. During our walk the following species were seen:- Pearl-bordered Fritillary, Brimstone, Dingy Skipper, Grizzled Skipper (recorded in a new area), Common Blue, Small Copper, Large White, Peacock, Large Skipper, Speckled Wood. Finally to round off a warm and sunny afternoon we saw several Small Pearl-bordered Fritillaries in a grassy hollow close to "Dowis Brook". Thanks to Mike Williams for devoting a whole day to our group, also to our guide for introducing us to a small but fascinating area of the Wyre Forest.
Day2 Taking our leave of the hotel and Great Malvern, the party set off southwards for the journey to the Butterfly Conservation Reserve at Prestbury Hill, near Cheltenham, and a joint meeting with the Gloucestershire Branch, who were to be our hosts. The two areas oflimestone grassland making up this reserve are high up on the Cotswold scarp slope to the N.E. of Cheltenham, with superb views across the Severn Vale and beyond. The southern half of the reserve, known as the "Bill Smyllie Reserve" and where we were to spend the morning, extends southwards as a narrow valley and until recently traditionally managed by the grazing of cattle. The steep escarpment edge has also protected most of the reserve from ploughing and intensive agriculture. This has resulted in habitats ranging from she!tered valleys through to open grassland, woodland edge, abandoned quarries and low scrub, attracting over thirty species of butterfly, the most abundant being the Marbled White. On leaving our cars just off the minor road which runs along the top of the ridge, we were met with a strong N.E. wind which did not augur well for butterfly spotting! However, once having dropped down into the valley all was well and we soon
~
. . . . . . . . . . . . "'-~ Small Pearl-bordered Fritillary, Wyre Forest by BerylJohnson
r']
9
