4 Management of Acid Grassland (Pdf)

04 Kent Wildlife Trust Land Management Advice Series Management of Acid Grassland This advice sheet contains information about the following topics: ● the importance of this habitat in Kent ● species associated with this habitat ● choosing a management regime for your site ● increasing the plant diversity of the site ● choosing livestock and finding a suitable grazier Acid heathland/grassland mosaic at Hothfield Heathlands © Kent Wildlife Trust ● protected species This leaflet is designed to give owners Up until the Second World War, traditional ● dealing with ragwort and other of acid grassland some general grazing practices ensured that grasslands problem plants recommendations on how to manage were grazed in a low intensity, wildlife- ● their land and assumes that the primary friendly manner, resulting in habitats which dealing with scrub objective is to manage the land for were botanically very diverse. ● references and further reading nature conservation purposes. Other ● further advice advice sheets are available and are From the 1940s onwards, more efficient listed in the Further Reading section. farming techniques such as better drainage and chemical inputs, together with farming Acid grassland in Kent subsidies, all contributed to change the way our grasslands were used: many Species-rich acid grassland is mainly areas were either ‘improved’, ploughed up found on the Greensand Ridge, in the for crops, or left ungrazed and gradually High Weald and in parts of the Blean, taken over by scrub and woodland. Other Dartford and Dungeness areas, although areas were lost to development, quarrying, occasional patches occur on sands and road construction and tree planting. Since gravels overlying the chalk in the Downs. then, traditionally managed, wildflower- It is a particularly rare habitat, of which rich grasslands have declined nationally only 512 hectares are left in Kent (ARCH by 97%; their disappearance is thought Kent Habitat Survey 2012) and it is listed to have led to the drastic decline of many as a Priority Habitat in the Kent Biodiversity species including bumblebees, farmland Action Plan. It tends to be associated with birds and wildflowers. It is therefore parkland, old pastures and commons, and important that land managers and it is often found in mosaics with heathland conservationists across Kent work to re- Betony © I.Rickards and woodlands. establish a network of acid grassland. Large print version available by calling 01622 662012 Your living landscape. Your living seas. Keeled skimmer dragonfly © Kent Wildlife Trust Comma butterfly on devil’s-bit Knole Park © C.Blackburn scabious © I.Rickards Female adder © Dr Lee Brady Species associated with Wildflower species found on acid grassland Ground-nesting birds such as skylarks acid grassland in Kent: bell heather, betony, bilberry, and meadow pipits will use this habitat bird’s-foot trefoil, biting stonecrop, bitter- unless it is too heavily grazed or is Acid grassland occurs on free-draining, vetch, blue fleabane, broom, buck’s-horn dominated by trees and tall scrub; nutrient-poor soils such as sandstones and plantain, chamomile, clustered clover, softer, wetter acid grassland can provide gravels. The diversity of plant and animal common centaury, common dog-violet, a source of invertebrates which are species found tends to be lower than on common rockrose, common stork’sbill, essential food for rearing chicks. other grasslands, but these species are devil’s-bit scabious, dwarf gorse, European more specialised and able to cope with a Reptiles such as adder and viviparous gorse, harebell, heath bedstraw, heath lizard are frequently found in this habitat low soil pH of between 3.5 and 6.0 and a speedwell, heather, heath spotted-orchid, and like to bask on the open, warm usually short, open vegetation structure. lady’s bedstraw, lousewort, milkworts, ground (areas with short vegetation and Acid grassland often occurs in a mosaic mouse-ear hawkweed, parsley-piert, patches of bare ground warm up faster with other habitats such as heathland, bog, pignut, rough/lesser hawkbit, saw-wort, than taller grassland areas); however, or along woodland rides. The wildflower sheep’s-bit, sheep’s sorrel, shepherd’s- they rely on nearby cover, such as species listed below provide a rough cress, slender bird’s-foot trefoil, thymes, scrub, for shelter from predators. guide as to plants which are indicative of tormentil, violets, wild strawberry, wood unimproved, species-rich acid grassland, anemone, wood sage. Many species of invertebrate lay their but botanical diversity will depend on eggs on certain species of grass or Lichens, mosses and fungi such as wax many factors including past management, wildflower and overwinter in tussocks; cap are also associated with this habitat. drainage, aspect and stocking density. areas of bare sand and soil are Often areas of acid grassland can look very particularly important as solitary bees short and “devoid” of wildlife; however Species of grass most commonly found and wasps make use of the loose, include sheep’s fescue, common bent many of these patches are rich with moss sandy soil to create burrows and lay grass, heath-grass, wavy hair-grass and and lichens, so make sure these areas are their eggs. purple moor-grass. protected too. Where ponds occur, a particular set of species has evolved to cope with the acidity of the water, such as keeled skimmer dragonfly, which breeds only in acid ponds. Choosing a management regime for your site Under-grazing, or no grazing or mowing at all, results in grassland becoming dominated by coarse grasses and scrub, with the eventual loss of the characteristic acid grassland species. Wavy hair-grass © I.Rickards Devil’s-bit scabious © I.Rickards Meadow pipit © Amy Lewis Lousewort © I.Rickards Harebells © J.Shorter Management of these grasslands is some tussocks and taller grass to remain. to do so, cutting different parts of the therefore very important to maintain their This regime will allow most plants to set grassland at different times of the year species diversity. seed and invertebrates to complete their will create a more diverse mosaic. lifecycles. Do not overgraze. If you have the option to get the site Re-creating acid grassland grazed, then this is preferable to not ● grazing in April/May can be important for It is possible to re-create acid grassland from grazing the site at all: livestock tends control of scrub since this is the period cultivated land, although this is most likely to use parts of a site in different ways when the livestock are most likely to tackle to work where the soils are thin and low in and so creates patches of taller and birch and other woody growth nutrient. Other factors such as weed burden, shorter vegetation. Mowing is a good ● light grazing from July into the autumn will availability of local seed sources, current artificial alternative but will create a very help to reduce dominance of some of the species composition, aspect, choice of seed uniform sward. Remember to factor in rank grasses (purple moor grass) and soft/ mix and drainage will all affect the outcome. rabbit grazing into your plans to manage hard rush. Further advice should be sought from Kent the site – it may be that you do not Wildlife Trust if this is an option you would need livestock. If dwarf shrubs such as like to consider. heather are present, then ensure that you rotate the cutting / grazing so as to Increasing the number of allow stands of different ages to develop. plant species Grassland which has been agriculturally Grazing - the preferred option: Rushes may need to be controlled by grazing © Kent Wildlife Trust ‘improved’ over the decades can slowly have ● for established acid grassland (where nutrient removed through grazing. Numbers the scrub and rough grasses are under of plant species may be very low and it control), exclude livestock from early Mowing (if grazing is not available): will take several years for seed to come in March to July and then graze later in the ● cut once a year in September; the later from adjacent land, assuming that you have year (August – December), depending you leave the cut, the more plants will get species-rich acid grassland nearby. Where on how wet the land is. Aim for a sward a chance to set seed. This is particularly possible, it is always preferable to allow seed height of under 5cm/2 inches but allow important if there is no grazing by livestock to come in naturally or by spreading some or rabbits taking place (or not enough). If green hay (fresh cuttings) from species-rich possible, remove the cuttings since any acid grassland. However, it is possible to dead vegetation (or ‘thatch’) will smother increase the number of plant species by seeds trying to germinate and will also introducing seed or young plants from a local allow nutrients to build up on site. source. The seed source must be of local Do not add fertilizer. provenance to ensure that the seed is of a ● if there are problems with aggressive local genetic strain and therefore well-adapted vegetation (ie. purple moor grass, birch) to the environment (see Further Reading). For Grazing by rabbits may mean that you do not need to do any grazing or cutting © Richard Burkmar then cutting earlier in the year would be small areas, buying single species seed packs beneficial (July-August). If it is practical is often cheaper than buying mixes. Further reading and references Kent Wildlife Trust Land Management Advice Series Control of ragwort, thistles and other problem plants; A brief guide to choosing livestock for conservation grazing; Scrub, its value for wildlife and how to manage it; Management of small pastures. The Grazing Animals Project (G.A.P.) Bracken and birch encroaching on acid grassland © Kent Wildlife Trust Downloadable publications and the G.A.P.

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