RHÔS PASTURE HABITAT IDEAL RHÔS PASTURE HABITAT FRITILLARIES AS INDICATORS OF A DARTMOOR IN LATE SUMMER IN LATE SUMMER HEALTHY ENVIRONMENT are very sensitive and react rapidly to changes in their environment.

Aim for a range in height between 10-30cm Healthy populations of specialist (4-12”) high at the end of the summer butterflies, like the Fritillaries on Scrub is important for such as Reed Dartmoor, are associated with the Bunting and Dormouse; scrub species should occurrence of other specialist species, cover a maximum of 5-10% of the total area Rush patches can be a natural component of the areas of high and habitat habitat, but if they start to dominate they can be quality. Habitat management for the controlled through cutting, preferably in September Devil’s-bit Scabious is an important Fritillary butterflies therefore benefits to avoid disturbance to ground-nesting birds source for many in late summer a wide range of other species Fritillary Butterflies associated with Rhôs pastures Ideal uneven structured sward with and habitats, and thriving tussocks and with abundant host plants populations of the Fritillaries indicate Devil’s-bit Scabious and Marsh Violet a healthy natural environment. of Dartmoor

RESTORATION OF SITES Light grazing in the period May- September with hardy Many sites where Fritillaries breeds such as South Devon cattle or Dartmoor ponies used to occur have declined due to lack of management.

Coarse grasses in Rhôs pastures Unmanaged Rhôs pastures suffer and dense Bracken in Bracken habitats Green Hairstreak from encroachment of coarse grasses tend to dominate and out compete the and scrub, leaving the habitat unsuitable. Marsh Fritillary web host plants that are so important for the However, these areas can be restored on Devil’s-bit Scabious butterflies. Scrub encroachment, left SCRUB WORKS FURTHER HELP through burning, grazing and cutting to continue, will result in the loss of Regular scrub management AND ADVICE An uneven tussocky structured sward (height range Marsh Violet, the host plant of the Small grassland to scrub and woodland. is often necessary in Fritillary For further information and 10-30cm-4-12”) with frequent flowering plants Pearl-bordered Fritillary in wet grassland habitats. However, scrub is advice, please contact such as Devil’s-bit Scabious and Marsh Violet If you are planning to restore important for many species, Conservation below. management to a site, contact such as Green Hairstreak, one of the organisations listed under Yellowhammer, Dormouse, Financial support may be available further help and advice. In general, Reed Bunting and other insects. through Environmental Stewardship re-introduce grazing management gradually and when cutting or burning Scrub should therefore never be to enable sympathetic management WET GRASSLANDS WHAT YOU CAN DO TO HELP areas, avoid tackling more than 1/3 eradicated; levels of 5-10% across of environmental features on your holding. This grant scheme is The unimproved, wet valley On Dartmoor the Marsh Fritillary To manage your Rhôs pasture I Occasional cutting or burning in of the habitat in any one year. This the site are desirable. When carrying bottoms and poorly draining, can be found on this type of wet to benefit a wide range of late winter (January-early March) is especially important if populations out scrub control, avoid damage to administered by Natural England. shallow slopes away from the grassland. The butterfly flies during characteristic species, including might be useful in areas of the site of important species like the the habitat by heavy machinery. open moor on Dartmoor are May and June and lays its eggs on the Marsh Fritillary and Small that are ignored by the livestock Fritillaries are still present. Visit www.naturalengland.org.uk known as Rhôs pasture or Purple the underside of large leaves of the Pearl-bordered Fritillary, aim for: and if a litter layer has built up; Always remove cut materials from or contact your local office for Moor-grass and Rush pasture. host plant, Devil’s-bit Scabious. avoid burning or cutting more the site, or burn cut materials in more information. Another characteristic butterfly is I An uneven, tussocky, structured than 1/3 of the site in any year. a few designated areas, preferably on galvanised iron sheets so that They are rich in wildlife with the Small Pearl-bordered Fritillary. sward at the end of the grazing Dartmoor National Park Authority upper Emsworthy Mire the nutrient-rich ash can be easily characteristic plants such as Adults fly from May until the end of season (normally end of September) Please avoid: also has management agreements lower Pearl-bordered Fritillary I Extensive poaching or over-grazing removed from the site. Treat stumps Thistle, Heath Spotted July and the female lays her eggs between 10-30 cm high (4-12”). on some Fritillary areas and can Orchid, Saw-wort and Devil’s-bit singly on or near the host plant Marsh Other typical species include where the sward is grazed tightly; with an appropriate herbicide provide advice on management. Scabious usually growing amongst Violet. This butterfly can also be found Dormouse, Snipe, Reed Bunting I Frequent flowering plants present this leaves the habitat unsuitable to prevent re-growth immediately vegetation dominated by Purple in Bracken habitat, where other and Grasshopper Warbler. The such as Devil’s-Bit Scabious, Marsh for species that are dependent on the Marsh Fritillary caterpillar web on after cutting. contact 01626 832093 Moor-grass and Sharp-flowered species of violet are used as host plant. habitat is also used by Barn Owls Violet and Heath Spotted Orchid. Also shelter provided by a tussocky sward. the host plant Devil’s-bit Scabious. Rush. The habitat typically occurs and Short-eared Owls for hunting. dwarf shrubs like Cross-leaved Heath. as part of a patchwork with wet A typical moth species associated with I Under-grazing that leads to heath, drier grassland, wet Rhôs pastures is the Narrow-bordered Many species associated with I Scrub species covering a maximum encroachment of coarse grasses; woodland and scrub habitats. Bee Hawk-moth. This beautiful day Rhôs pasture have declined rapidly. of 5-10% of the total area. a dead litter layer will build up This leaflet has been part-funded by Natural England and has been produced as part of the Two Moors Threatened Butterfly Project funded by: flying moth, that resembles a large The primary cause has been loss of their smothering the flowering plants Butterfly Conservation, Dartmoor National Park Authority, Environment Agency, Exmoor National Park Authority, Natural England, bumblebee, has undergone a habitat; damp grasslands have been This is best achieved by: and scrubby species will rapidly Dartmoor Sustainable Development Fund, Exmoor Sustainable Development Fund, Esmée Fairbairn Foundation and the Exmoor Trust. substantial decline. Dartmoor Rhôs drained, fertilised and stocked more I Light grazing in the period May- invade the site. pastures are one of the remaining heavily. More recently, populations are September with cattle (eg. Galloway, strongholds for this species. being lost because these agriculturally South Devon) and/or hardy ponies Because of natural variation in site A practical guide to marginal areas are no longer grazed. (eg. Dartmoor). conditions and grazing preferences This results in encroachment of coarse of stock it might not be feasible grasses and scrub, leaving the habitat I Check the site regularly; a rough to achieve ideal habitat conditions HEAD OFFICE t 0870 774 4309 managing Bracken and unsuitable for the butterflies and many guideline is 1 cow or pony per across the whole site all of the time. Manor Yard, East Lulworth, e [email protected] of the other associated species. hectare (2.5 acres) for 3 months, However, aim to maximise the amount Wareham, Dorset BH20 5QP www.butterfly-conservation.org Devil’s-bit Scabious but stocking rates may need to of ideal habitat by adjusting stocking vary according to site conditions; levels and the grazing period to Rhôs pasture habitats it may be necessary to move the the site conditions during that year. Meadow Thistle in Rhôs pasture Butterfly Conservation is a registered charity and a non-profit making company, limited by guarantee. Registered in England No. 2206468 - Registered Charity No. 254937. stock off early in a dry year, or If necessary, encourage grazing Photographs by: Jim Asher, Norman Baldock, Alan Barnes, Anja Borsje, Caroline Bulman, Peter Burgess, Sam Ellis, Martin Warren and Robert Wolton. to stock later in a wet year of under-grazed areas by burning Illustrations by Mike Langman. Written by Anja Borsje and Caroline Bulman. Designed and produced by cellcreative 01942 681648. for Fritillaries on Dartmoor (September-November) to or cutting. Narrow-bordered Bee Hawk-moth achieve suitable habitat conditions. THE DARTMOOR LANDSCAPE This leaflet describes PEARL-BORDERED MARSH FRITILLARY BRACKEN HABITAT IDEAL BRACKEN HABITAT the habitats in which these This butterfly is one of the FRITILLARY The Marsh Fritillary flies from threatened butterfly species most rapidly declining species This is the earliest Fritillary to be mid-May until the end of June. DARTMOOR IN SPRING IN SPRING The beautiful Dartmoor landscape occur and explains how in the UK and there is huge seen flying and can be found from Eggs are laid in large batches on potential for conserving this April until the end of May, although the host plant Devil’s-bit Scabious. your land can be managed species on Dartmoor. occasionally second broods occur, The spin a protective that we see today is the product to safeguard these species. The butterfly flies from mid June web over their host plant. The movement has resulted in tracks with adults flying in August. and broken up Bracken litter, creating to August with eggs being laid singly webs are conspicuous by the end Encroaching scrub and dense Bracken; areas Eggs are laid singly on dead Bracken germination sites for violets of centuries of traditional land-use, There are five species of Fritillary on dead leaves or Bracken stems. near violets. The caterpillars hibernate of August, and the caterpillars can like this can be restored to suitable habitat butterfly for which Dartmoor is The species over-winters as an egg, and re-emerge in spring, basking in be found basking on the surface. important and they can be found hatching in early spring. The caterpillar the warmest and driest habitats, and The caterpillars hibernate and can be Areas with Bluebells indicate deeper soils & damp creating a landscape rich in wildlife. in two different types of habitat: can be found basking on Bracken litter feeding on the leaves and flowers of seen again in early spring, when they conditions - unsuitable for the Fritillary butterflies in the spring, but they are well violets. Dartmoor is an important area bask on dead leaf litter. This species is I Bracken stands containing camouflaged, resembling dead for this butterfly and it is found more declining across and Dartmoor The future of the characteristic abundant violets. Bracken fronds. They pupate widely in Bracken habitats compared is one of the few strongholds for the under dead Bracken or leaves. to the High Brown, but despite this, butterfly in Britain. Broadleaved woodland encroachment I is still suffering massive declines. Dartmoor wildlife is strongly Rhôs pastures (the local Paths encourage animal movement across the site up the valley sides can quickly result name for Purple Moor-grass in loss of habitat and Rush pastures). linked to the continuation of Patches of grass encourages animal movement One of the most important areas traditional farming practices. of Bracken habitat for the Fritillaries Some scattered scrub is important for species such is the Dart valley, where cattle and as Green Hairstreak, Stonechat and Yellowhammer ponies graze extensive areas of acid Recently, changes in the economics of agriculture have grassland and Bracken in late winter led to the cessation of management within land that is and summer to benefit the High Brown, Extensive grazing by hardy cattle and ponies marginal to the farm business. It is exactly these areas Pearl-bordered, Small Pearl-bordered and . like Bracken slopes and Rhôs pastures that are vital Ideal egg laying sites for Pearl-bordered and for the Fritillary butterflies of Dartmoor, as they have One of the typical Rhôs pasture areas High Brown Fritillary are found where violets grow through a thin layer of Bracken litter escaped previous major agricultural improvements. where the Marsh Fritillary and the Small Mosaic of Bracken & grass with abundant violets Pearl-bordered Fritillary are found is the sheltered, wet valley system in the Cessation of management quickly leads to these enclosed farmland between King Tor areas becoming unsuitable for the Fritillaries and and Easdon Tor, west of the village many other species of and plants. As a result, of North Bovey. Here, landowners are grazing their Rhôs pastures in summer SILVER WASHED many species are declining dramatically and urgent with cattle and ponies to create ideal DARK GREEN FRITILLARY SMALL PEARL- Adults fly from June to August, BORDERED FRITILLARY FRITILLARY habitat conditions for these butterflies I Small amounts of mineral action is needed to save them. and eggs are laid singly on dead This species flies in June and July, and The Silver-washed Fritillary also BRACKEN HABITATS WHAT YOU CAN DO TO HELP and other species such as Narrow- Bracken is very common on Within Bracken habitats, each Fritillary Many Fritillary colonies in Bracken To manage your Bracken habitat supplements & hay can be used plant material, or on violets. can be found in both Bracken habitats occurs on Dartmoor, but as it is Dartmoor covering about 5000 species occupies a distinct patch that habitat are under threat as a result to benefit a wide range of species to encourage stock to move through bordered Bee Hawk-moth, Snipe Eggs hatch in summer, but the and Rhôs pastures. Eggs are laid predominantly a woodland species, hectares. Most of it is found in reflects the temperature requirements of the decline or abandonment including the Fritillaries, aim for: areas of dense Bracken, in particular and Reed Bunting. caterpillar immediately hibernates. singly near violets on dead vegetation. it is beyond the scope of this leaflet. exposed areas that are unsuitable of the caterpillar. of grazing, unsympathetic Bracken in late winter, but please rotate feed PRIORITY AREAS FOR FRITILLARIES ON DARTMOOR They begin feeding in spring on The caterpillars feed until September, for Fritillary butterflies. However, control and occasionally over-grazing. I A mosaic of Bracken interspersed areas to avoid poaching and move violets, and bask on the vegetation. when they hibernate. These caterpillars sunny, sheltered slopes (below The High Brown Fritillary uses the Abandonment and under-grazing with grassy patches and gaps mineral licks regularly. Paths (approx They pupate in a tent of grass do not bask in the spring, but spend their 300m) where there is a patchwork warmest areas of the site. It is usually quickly leads to total domination in the canopy. tractor width) can also be cut through stems held loosely together with time hidden in the vegetation, only coming of grass, Bracken and scrub, restricted to south-facing slopes and by Bracken or scrub encroachment dense Bracken to encourage silk. This is one of the most common out to feed on violets. This species is on south-facing hillsides, often requires the violets to grow through resulting in the loss of plant species I Abundant violets growing through livestock movements. Fritillaries across Dartmoor and the declining nationally but still found widely provide ideal conditions. a thin layer of Bracken litter. Dartmoor on which Fritillaries and other shallow Bracken litter and standing one most likely to be encountered on Dartmoor. In warm summers a is one of the few areas in the country insects depend. trash where there is little or no I If Bracken becomes too dense High Brown Fritillary caterpillar in Bracken habitats. second brood may occur in August. Here, the ground flora contains an where this species survives. cover of grass. and is out-competing other species, in May with characteristic feeding abundance of violets, with a mixture it can be controlled by cutting or damage showing on the violet leaf. of woodland plants such as Wood The Pearl-bordered Fritillary is usually This is best achieved by: bruising (only patches or strips) Bracken habitat at Aish Tor Sage, Bugle, and acid grassland restricted to sites with similar conditions, I Extensive grazing of these acidic during the summer. Where cutting plants such as Tormentil. but can also be found in smaller, more grassland and Bracken habitats or bruising is not safe or appropriate, Please avoid: fragmented sites and woodland fringes. by hardy cattle and ponies. spraying can be an option. However, I Excessive poaching of the habitat Bracken is very important for J FMAM JJASOND The trampling action of the animals the impact should be carefully as this often leads to grassy swards the Fritillaries; during the summer Two other Fritillary butterflies can through Bracken stands, in particular assessed before works should unsuitable for the Fritillaries. it acts like a woodland canopy, helping be found in Bracken habitats; the during winter and early spring commence. When managing to suppress grass growth and favour Small Pearl-bordered Fritillary (usually February to April), is most Bracken, avoid treating more than Because of natural variation in site violets. The dead Bracken litter and and the Dark Green Fritillary. Both important to help break up the 1/5th of the site in any year. conditions and grazing preferences standing trash provides a warm species can breed in cooler vegetation dense standing trash. This also of stock, it might not be feasible microclimate for the caterpillars when and select violets growing in fairly tall, Over-grazing can lead to an increase creates a network of paths running I Areas with a thick Bracken litter to achieve ideal habitat conditions they are feeding on their hostplant grassy vegetation with scattered in grass cover, which is particularly through the Bracken, which provides layer with sparse or no violets can across the whole site all of the time. the violet in early spring. Bracken litter Rhôs pasture habitat near Easdon Tor Bracken. The Dark Green Fritillary is detrimental to the High Brown and germination sites for violets. Light also be burnt or cut in late winter. However, aim to maximise the amount refers to the broken down fragments one of the most widespread Fritillaries Pearl-bordered Fritillaries. Sympathetic pony or cattle grazing in summer However, burning stimulates Bracken of ideal habitat by adjusting stocking FLIGHT PERIOD in contact with the soil surface. Standing and flies from mid-June to Mid-August. management of Bracken, acid grassland helps to open up the Bracken canopy growth, so always follow up with levels if necessary, managing dense OF EACH SPECIES trash refers to the dead, un-degraded The Small Pearl-bordered Fritillary and scrub mosaics will benefit a wide and maintain grazing for stock. further Bracken management, and/or Bracken stands and by implementing remains of fronds and stalks still is also found in wet grassland range of other species, including appropriate grazing levels to produce measures to encourage livestock standing or lying on the ground. habitat where it uses Marsh Violet Whinchat and Lesser Butterfly Orchid. I Cut scrub regularly where it is the right conditions. to move throughout the site. as its host plant. encroaching, but never eradicate it completely from the site.