- Marsh Fritillary
- Narrow-Bordered Bee Hawk-Moth
- Double Line Moth
- Silver-Studded Blue
- Pillwort
- Marsh Clubmoss
- Three-Lobed Water-Crowfoot
Marsh Fritillary Butterfly (Euphydryas aurinia)
The Marsh Fritillary has undergone a dramatic decline in recent years, with a 66% loss in Marsh Fritillary populations nationally since 1990. In Cornwall there are currently 22 known populations. The Mid Cornwall Moors is a significant area for the Marsh Fritillary supporting some of the larger populations in Cornwall. Habitat management over a number of sites, such as the Mid Cornwall Moors, is necessary for maintaining populations of this butterfly.
The Marsh Fritillary breeds on the wet grassland of the Mid Cornwall Moors where it's principal food plant, Devil's-bit Scabious, is abundant. The butterfly lays its eggs in large batches on the food plant where the caterpillars live as a group inside a conspicuous silken web. These are easily observed during August and September and are a useful indicator of population size for surveys and monitoring.
The Marsh Fritillary is listed as a threatened European species under the EC Habitats and Species Directive and is a priority species in the UK Biodiversity Action Plan.
Narrow Bordered Bee Hawk-Moth (Hemaris tityus)
The narrow-bordered bee hawk-moth (Hemaris tityus) occurs on a wide range of unimproved grasslands (e.g. wet, acidic grassland and chalk downland), acid bogs, peat cuttings and drier heathland, sometimes in association with marsh fritillary (Eurodryas aurinia). The larval foodplant is devil`s-bit scabious (Succisa pratensis). The adult moth requires a supply of nectar and visits a variety of plants such as red campion (Silene dioica). Narrow-bordered bee hawk-moth has declined severely in Britain and is now most common in southern and western England, parts of Wales and on the west coast of Scotland. It is widespread in Cornwall with scattered records from Crousa Downs to Marsland, but with strongholds in wet heath and grassland on Bodmin Moor (e.g. at Ninestones), the Culm grasslands of north Cornwall and historic records from the mid-Cornwall moors. In good years it can be found a long way from suitable habitat; however, it is probably under-recorded in Cornwall, partly because it is a very fast flyer and difficult to spot. There are 7 post-1980 records. It has not been recorded on Goss Moor since the 1960s since 1950, but may still be present on the site.
Double Line Moth (Mythimnia turca)
The double line (Mythimnia turca) moth is largely confined to southern Wales and south west England, although it is also known from a very few sites in south east England. It is widespread in Cornwall, occurring from Kenidjack in the west to Sheviock and Marsland in the east, with at least 19 post-1980 sites. The main centres of population include Bodmin Moor (where its habitat is acid grassland with bracken) and the mid-Cornwall moors (where it is associated with sheltered open woodland areas). It also occurs in open parkland and on Culm grassland and woodland rides. The main foodplant in Cornwall appear to be common bent (Agrostis capillaris), although it may also feed on cock's-foot (Dactylis glomerata) and creeping soft-grass (Holcus mollis); a key habitat requirement is shelter, provided either by trees or scrub, especially bracken. Double line has largely disappeared from open woodland in south east England, due to changes in woodland management resulting in the shading out of woodland rides and glades, but Cornwall remains one of the UK strongholds for this species.
There is no evidence of decline in Cornwall, probably due to its preference for bracken scrub and scrubby woodland, habitats which are widespread in Cornwall.
Double line is present in the Breney Common and Goss and Tregoss moors cSAC, and in the Welcombe and Marsland Nature Reserve. It also occurs on NT land at Kenidjack and Duchy land at Greenscoombe Wood. The actions identified in Cornwall Local BAP for this species plan will be achieved by securing sympathetic management of sites known to support populations, especially sites with bracken scrub. Research should focus on undertaking surveys to determine the current status of the double line moth in Cornwall, together with monitoring the effects of habitat management at Goss Moor and Breney Common.
Silver Studded Blue (Plebejus argus)
In Britain, the silver-studded blue (Plebejus argus) occurs mainly on lowland heathland and calcareous grassland; in Cornwall, it is associated with heathland and sand dunes. Extensive colonies occur on three sand dune systems in north Cornwall, where the larval foodplant is common bird's-foot trefoil (Lotus corniculatus). Extensive populations occur on maritime heathland from the Lizard peninsula, around Land Õs End to St Agnes, where the larval foodplant is heather (Calluna vulgaris); these populations are linear and it can be difficult to separate colonies. Five to six inland heathland colonies are known, where the larval foodplant is heather, except at Wheal Busy where common bird's-foot trefoil is preferred. Some colonies can be very small (occupying less than 1 hectare). The silver-studded blue occurs on the Breney Common and Goss and Tregoss Moors cSAC.
The larvae require a warm microclimate at ground level on bare soil or in short vegetation so that sparse heathland or marram (Ammophila arenaria) dominated semi-fixed dune with abundant bare ground provide ideal habitats. The larvae are tended by ants, most often Lasius alienus, L. psammophilus or L. niger, so habitat conditions have to be suitable for one or other of these species. Cornwall is one of the national strongholds for this species. The silver-studded blue has undergone a severe decline in range this century, especially on heathland sites where, in the absence of traditional management, suitable conditions on heathlands are short-lived, perhaps lasting 5-10 years. In Cornwall, the silver-studded blue has disappeared from some inland heathland sites, especially isolated areas. Most colonies (especially on the coast) are linked to form meta-populations; isolated inland heathland populations are most vulnerable to local extinction. The silver-studded blue is a sedentary butterfly, but females may travel some distance (e.g. 0.6-1.0km) to colonise new areas.
Pillwort (Pilularia globulifera)
Pillwort (Pilularia globulifera) is a small fern found in open, muddy areas at the edges of ponds, worked out flooded china-clay pits, ditches, and on wet tracks on heathland. Its distribution is concentrated around two main areas in Cornwall: the Lizard Peninsula in west Cornwall and mid-Cornwall. Scattered sites occur outside these two areas in both east and west Cornwall.
Pillwort does not look like a typical fern Ð it has linear fronds that arise at intervals from creeping, stoloniferous shoots usually anchored in mud or a similar substrate, with only the unfurling curls at the tips (croziers) pointing to a fern. When growing with grasses, the fine-leaved form of bulbous rush (Juncus bulbosus var. fluitans) or floating club-rush (Eleogiton fluitans), it can be difficult to separate from the tangle of vegetation, especially if the vegetation in luxuriant.
Pillwort has benefited from Cornwall's legacy of tin-streaming, mining and china clay extraction, exploiting open areas that have been created as a result of these extractive industries. It is important that these brownfield sites are not only valued for their populations of pillwort, but for the associated wildlife that has colonised these areas.. Pillwort exploits limited disturbance (shallow pond creation, periodic track poaching) and this should form part of the management of existing sites.
Marsh Clubmoss (Lycopodiella inundata)
Marsh clubmoss (Lycopodiella inundata) is a species found in open areas of heathland and bog where competition from other vegetation is limited. Always rare in Cornwall, it has only been recorded at a few sites since 1950 from west and mid-Cornwall; these include Goss Moor, Carbis Moor, Carvear Moor and Retire Common. It is now only found at Retire Common where a large patch exists in an area of open wet heathland.
The last remaining site, Retire Common, is now managed by the Retire Commoners Association under a management agreement with English Nature. Management of the site includes summer grazing and controlled burning. This combination will hopefully create open areas which new plants can colonise.
Three-Lobed Water-Crowfoot (Ranunculus tripartitus)
Three-lobed water-crowfoot grows in shallow, muddy pools, in poached mud, and in winter-wet depressions in trackways and shallow, water-filled ditches. Fluctuating water levels throughout the year are generally thought beneficial, and many of its sites are dry in summer. Its seed is long-lived so the potential for re-establishment at former sites is good if habitat restoration takes place.
In Cornwall it has disappeared from many former sites except on the Lizard where it is still frequent. In mid Cornwall it has been found recently in a wet track on Bokiddick Downs, part of Breney Common SSSI/cSAC. It thrives in heavily disturbed, shallow muddy pools over base- and nutrient-poor substrates, and is intolerant of competition from other vascular plant species. R. tripartitus hybridises with R. omiophyllus, which makes identification difficult and this factor may affect the long term viability of the species at sites where both parents occur.
Habitat destruction or reduced disturbance have led to the gradual decline of this species from the end of the 19th century onwards. The cessation of grazing and associated disturbance, combined with the invasion of scrub, particularly willow carr, has resulted in losses at many sites.
