Acid Grassland a nationally important habitat in London Acid Grassland? What is In the UK there are many Lowland acid grassland develops on kinds of grassland, each with low-nutrient, acidic soils (pH 4 to 5.5) different characteristic
overlying acidic rocks or on the free- e v e e
species of grasses, wild R Lowland Acid draining, gravelly and sandy soils found l e g i
flowers and other wildlife. N Grassland in many parts of London. It often © is an important habitat for These differences depend on occurs as an integral part of lowland nature conservation throughout factors like the nature of the heath landscapes, commons and the Greater London area. soil, altitude and land-use; parklands. Grazing (or cutting) is needed both now and in the past. to prevent invasion by scrub and trees. Areas of infertile soil, unsuitable for growing crops, were often used by our ancestors as common grazing land, The supporting a mixture of heath main picture and acid grassland rich in shows acid OTHER GRASSLAND grassland in Bushy wildlife. Park with well- TYPES developed ant hills. Other types of grassland in A diversity of grasses London that are also Today, some of these areas and wild flowers, such
important for wildlife e v
as germander speedwell e e
remain as commons and R
(blue) and heath conservation include the l e g i
parklands, but the vast majority bedstraw (white), ‘chalk grassland’ found on N can be seen in © Chalk grassland have been developed, converted spring. alkaline (high pH) soils or on into sports pitches and other soils of medium pH, amenity grasslands, or they wildflower-rich ‘neutral grassland’. When either have been neglected and these grasslands or acid allowed to develop into scrub t
grassland are degraded by t e l w and woodland. nutrient enrichment or bad e H n a management, so-called ‘rank’ J © The few remaining areas of grassland develops. The Neutral grassland heath and acid grassland in delicate fine grasses and wild flowers are replaced by London are now under serious coarse grasses like threat – we need everyone to cocksfoot, rye grass, common understand and support efforts couch, Yorkshire fog and e
other plants like thistles, v
to conserve this precious e e R l
common nettle, dock, broad- e g
habitat for the future. i leaved plantain and rosebay N Rank grassland © willowherb. Main photo © Nigel Reeve. Insets © Piers Eley and Why is Acid Grassland important? Nigel Reeve
Wimbledon Common and Putney Heath (main picture) is a Site of Special Scientific Interest which supports the most extensive area of wet heathland in Greater London, with important areas of dry heath and acid grassland.
Acid grassland is a nationally important habitat Acid grassland species you may see G Lowland Acid Grassland is a include (clockwise from above): mat grass, UK Biodiversity Action Plan wavy hair grass, heath speedwell and Essex habitat and as such is a top skipper butterfly priority for wildlife conservation nationally. G Several plant, invertebrate and bird species found in acid grassland are protected under the Wildlife and Countryside Act 1981. G In England and Wales there are 271 Sites of Special Scientific Interest (SSSIs) that Acid grasslands are have this habitat as a principal important in London reason for notification. G G A number of Special Areas of In London there are an estimated 1,300 Conservation (SAC) are hectares of lowland acid grassland, which contributes about 4% to the national resource. designated under the G European Habitats Directive. The acid grasslands of Greater London, south These include Epping Forest, Essex and north west Kent are an important Wimbledon Common and home for a distinctive community of insects and Insects in spiders – many of which are nationally scarce. Richmond Park, all of which the Thames Terrace Invertebrates group include the bee-wolf wasp This community is collectively known as the include substantial areas of (above left) and many solitary bees London’s acid grasslands. and wasps. The bee above is feeding ‘Thames Terrace Invertebrates’. on mouse-ear-hawkweed Introducing the plants of Acid Grassland foot d’s If you look closely, you will see that acid Bir grassland contains a diversity of fine- leaved grasses. These include common bent, red and sheep’s fescues, mat grass and others.Alongside the grasses grow wild flowers like sheep’s sorrel, heath bedstraw, tormentil, harebell, bird’s foot, common stork’s-bill, heath milkwort and bird’s foot trefoil. w tra ds be th ea Nationally scarce plants H found in London’s acid grassland include clustered clover, upright chickweed and autumn squill. Heath milkwort
In areas that are less Harebell well drained, you will see tussocky grasses, along with a range of sedges and rushes. On the soil surface you may find a range of mosses and lichens.
Acid grasslands are also important for l i t
their fungi, in particular various n e m r
coloured waxcaps (below) – but o T e v
e conditions are rarely good enough e Waxcap fungi R l e g i for these in the N © d a London area. e r p s s i h t n Grasses and rushes, like dense-headed heath woodrush (left) are o s o t typical of acid grassland. However, a huge range of tiny, yet o h p spectacularly beautiful, wild flowers thrives in the acid grassland l l A habitat. If you look carefully, you will often be rewarded by finding delicate blooms like those on these pages. yer me nke Bla nne usa © S
structure Rabbits have Habitat exposed the The infertile acidic soil means earth (below), providing a that the grasses and flowers are welcoming warm-up generally small and grow close patch for to the ground. common lizard (right)
Patches of bare soil are very e
important because they warm v e e R l e
up quickly in the sun, which is g i N good for a range of insects, © spiders and reptiles.
Although invasion by scrub and trees is a serious threat to our acid grassland, occasional patches of scrub, including e v e e
R gorse and heather, add l e g i e N v
structure and valuable diversity e © e R l e g to the habitat – providing i N shelter as well as pollen and © nectar for insects. e r u t a N h s
Grazing animals do a much i l g n E / y
better job of maintaining an e K r e g
ideal structure than the use o Common green grasshopper R of mowing machines.Their trampling and browsing helps to control scrub and creates a natural patchwork of plant heights and bare areas.
Highland cattle (right) are hardy grazers that control scrub and bracken, create Wolf spider e
structure in the vegetation and help to v with her eggs e e R
Dwarf gorse adds to restore grasslands l e g i
acid grassland habitat N © Meadow brown (top left) and small copper (top right) butterflies, the bee-wolf wasp (below left) and many species of tiny solitary bee are What animals might I see? among acid grassland’s residents. A huge array of animals can be found in acid grassland...
G Small mammals such as shrews, mice and voles (above right) forage in dense grass.
G Common lizards may bask in sun- warmed patches of bare soil.
G Kestrels (top left) and tawny owls (left) hunt many of these creatures as prey.
G The large range of invertebrates attracts many other birds such as the green G Characteristic butterflies include the small woodpecker, meadow heath, meadow brown, small copper, small, p s a w pipit and skylark. large and Essex skippers. f l o w - e e b
t G p e G The Thames Terrace Invertebrates include c x
e In undisturbed areas, e v
e many species of burrowing bees and wasps. e
R meadow ants create l e g i The red-banded sand wasp is a flagship species N e
t distinctive mounds (ant i © a s for acid grassland in London. The mining bee o W t e o k h i hills) among the grass p Andrena florea M l
l and the bee-wolf wasp are A © (right). endangered and nationally scarce species found in London’s acid grassland. What can we do to conserve it? The conservation of acid Ideally acid grassland is maintained skylarks, meadow pipits and others. grassland depends on appropriate by carefully-managed low-intensity It is generally best to delay cutting management and the co-operation grazing with livestock; usually hardy for as long as possible into the of visitors to the sites. Neglect breeds of cattle, sheep or ponies. autumn, although the availability of allows the habitat to become However, if grazing is really the appropriate machinery and wet invaded by scrub and woodland impractical, as it is in some urban weather may mean that timing has so that it loses its special wildlife areas, a programme of cutting and to be flexible.Whenever the cut value.The addition of nutrients by scrub control is necessary. occurs, it is best to remove all the fertilisers, dog-fouling or from cuttings to avoid putting the atmospheric pollution from The time of cutting is also nutrients back into the soil. vehicles, are all very damaging; as important. A summer cut may Sometimes an acid grassland or is the use of lime either to remove food from some insect heath in poor condition requires ‘improve’ the grassland or in species at a critical time. Cutting radical treatment such as major stone chippings used in car parks before the end of July may also scrub clearance, or the removal of and paths.Tree planting, even just affect ground nesting birds like an area of secondary woodland. one tree in the wrong place, will increase shade and can cause Scraping a living significant destruction of this for wildlife vulnerable habitat. One effective remedial treatment is to scrape off An important aim of grassland an area of nutrient-enriched topsoil and either remove it, bury it or pile it into a bank. Rather management is to ensure a than re-seed, the site is usually left bare to continuity of cover and food recolonise naturally, so the area may look a bit supply for wildlife throughout the bare for a while. year. For example, many insects The area above was scraped clear of rich topsoil Low-intensity grazing by hardy traditional (above). Seventeen months later, the ground was breeds of livestock like Welsh ponies spend the winter as eggs or being re-colonised by pioneering acid grassland (above) and placid Longhorn cattle (below) larvae in standing dead plant plants and animals (left). is ideal for acid grassland wildlife. stems. So it is vital never to cut The ground can look a bit ugly to the general or graze an entire area, but to public and may lead to complaints. However, the bare ground will be colonised by specialist leave a percentage untouched in pioneer species, the acid grassland habitat will each parcel of land as a wildlife recover to a better standard than before and the refuge. wildlife of the site will benefit greatly in the long term. All photos © Nigel Reeve. How you can help – a user’s guide G Always observe the bylaws of will allow scrub to take over. creatures we are trying to removing trees that are the sites you visit and respect G Please do not drop matches conserve. threatening the habitat. the needs of wildlife and other or have a barbeque on these G Please avoid disturbing wildlife G Why not enquire about visitors. grassland sites. They are very and do not pick, uproot or conservation volunteering? G Please clear up after your dog easy to set fire to in dry damage plants and fungi. There may be opportunities to – otherwise you are adding weather and burning is very G Support land managers join in with everything from nutrients to the soil and these damaging. carrying out conservation practical land management encourage the growth of G Please keep to pathways. management, whether this is work to helping with coarse grasses, dominant Moving off paths can result in bringing-in grazing, mowing, education and interpretation. weedy plants and eventually the trampling of many of the scraping, scrub clearance or All photos © Nigel Reeve.
Want to know more? G Ask your site manager about whether there are any nature-trail or information leaflets, guided walks or talks you can attend so that you can learn more about acid grassland, adding to your enjoyment of the sites you visit. G London’s Acid Grassland Habitat Action Plan Use the internet to visit www.lbp.org.uk to see the full The London Biodiversity Partnership (LBP) was established in 1996 acid grassland biodiversity action in response to the UK Biodiversity Action Plan. The LBP aims to Biodiversity Main picture: Hounslow Heath is an extensive plan for London.You can also protect and enhance the capital's habitats and species for the benefit area of acid and neutral grassland. Heathland is download an advisory booklet and enjoyment of future generations. There are now 31 action plans: developing where restoration has encouraged natural regeneration of heather. It is home to Acid Grassland Conservation in 11 habitats, 12 species, plus 8 Generic Action Plans that address broader issues. Each action plan many other special plants and animals that need tackles key issues such as conservation and education and is implemented by a working group heathland and acid grassland to survive in. London (2005) containing more made up of a partnership of public, private and voluntary organisations and also individual Among the common species you may see are the detailed guidance for land field grasshopper (above) and six-spot burnet enthusiasts. moth (below). managers. G Visit www.ukbap.org.uk to see The Acid Grassland Habitat Action Plan Working Group works alongside other action plans for the national plans for acid heathland, chalk grassland, reptiles and others. Our main aims are: grassland (upland and lowland). • To ensure the protection and optimal management of acid grassland in Greater London. G • To improve on existing knowledge of its ecological value in the regional context. Visit the London Wildweb website • To develop a more universal appreciation of the habitat and its wildlife, and secure the for detailed information on involvement of Londoners in its conservation. wildlife sites in London. http://wildweb.london.gov.uk Some Acid Grassland sites you can visit in Greater London Twenty seven London Boroughs out of 33 have some acid grassland. Some key sites for acid grassland conservation in London that you can visit are listed here.
Poor’s Field, Ruislip Woods National Nature Reserve, Ruislip. Hadley Green, Barnet. Contact: London Borough of Contact: London Borough Hillingdon, 01895 250635 of Barnet Greenspaces Map not to scale. Team,020 8359 7825 Position of sites approximate
M25 Wanstead Flats, Redbridge. Hounslow Heath, M1 Contact: City Hounslow. of London, Contact: CIP M11 020 8508 0028 Group, M40 020 8577 3664
M4
Richmond Park National Nature Chislehurst Reserve, M3 Common, Richmond M20 Bromley. upon Thames. Contact: Contact:The Royal M25 M26 Chislehurst Parks, 020 8948 3209 Commons M23 Conservators, 01689 825102 Bushy Park Wimbledon Common, Mitcham Common, Richmond Wandsworth and Merton. Merton. upon Thames. Contact:Wimbledon & Contact: Mitcham Contact:The Royal Putney Commons Common Conservators, Parks, 020 8979 1586 Conservators, 020 8288 0453 020 8788 7655 , s e
Published by the London t a i c
Biodiversity Partnership. o s s Booklet funded by English Nature. A & : t n n i
Biodiversity o r The Royal Parks are the lead 2 p 4 m l 4 d a 7 S n
partner for the London Acid 7 a 8 y r n 4 u g i 8
Grassland Plan. b s 5 a e 1 e S 0 D