This is the text of the SSSI, the Site of Special Scientific Interest notification. In summary it says that Walthamstow Marsh is one of the last areas of semi-natural wetlands in London and there are some unusual types of flora and fauna (insects and birds). It seems to cover the area from the reservoirs to the line of Black Poplars. The light green area, Horseshoe Thicket, is the only part of the SSSI that is performing as it should. Natural England's web site, with its report on this SSSI, can be found by clicking this link. Natural England's main finding can also be seen on this table. It is surprising that the paddock is not included in this area.
Most of the SSSI is assessed as "unfavourable declining". One of the problems may be that the whole concept is flawed since it is based on the idea that there were horses and cattle on the marsh (horses were banned and the evidence suggests that rather than cows there were sheep, and these animals graze in a very different way to cows). See A V Roe on the marsh in 1909.
See also:SSSI contact in 2012.appalling condition report in plan
Status: Site of Special Scientific Interest (SSSI) notified under Section 28 of the Wildlife and Countryside Act 1981.
Local Planning Authority: Waltham Forest
National Grid Reference: TQ 352875 Area: 36.7 (ha.) approx 90.7 (ac.) approx
Ordnance Survey Sheet 1:50,000: 177 1:10,000: TQ 38 NW & TQ 38 NE
Date Notified (Under 1949 Act): Date of Last Revision: -
Date Notified (Under 1981 Act): 1985 Date of Last Revision: -
Other Information: New site: adjoins Walthamstow Reservoirs SSSI.

Reasons for Notification: Walthamstow Marshes are one of the last remaining examples of semi-natural wetland in Greater London. They contain a variety of plant communities typical of a former flood plain location, such as a range of neutral grassland types, sedge marsh, reed swamp, sallow scrub and areas of tall herb vegetation. Associated with this diversity of habitat are several species of plant and insect which are uncommon in the London area. Traditionally, Walthamstow Marshes were managed as 'Lammas Land': they were shut up for hay from early April to mid August and then opened up for grazing by commoners' horses and cattle. With the decline of this traditional management earlier this century it seems likely that the taller more aggressive plants were favoured. Although there are several areas of tall herb, tall grass or tall fen communities, shorter plants continue to survive. One of the more interesting species is adder's tongue fern Ophioglossum vulgatum, and its presence is considered to be indicative of the ancient origin of the grassland communities.

The areas of relatively dry grassland are dominated by a variety of common grasses, with bents Agrostis species and clovers Trifolium species co-dominating in the shortest, driest turfs. Herbs associated with this community include burnet saxifrage Pimpinella saxifraga, bird's-foot-trefoil Lotus corniculatus and common agrimony Agrimonia eupatoria. The wetter areas of grassland are often characterised by single species stands of reed grass Phalaris arundinacea, tufted hair grass Deschampsia cespitosa, brown sedge Carex disticha, and great hairy willowherb Epilobium hirsutum or clumps of comfrey Symphytum species or michaelmas daisy Aster species. Adder's tongue fern is scattered throughout this community, and also present are ragged robin Lychnis flos-cuculi, square-stemmed St John's wort Hypericum tetrapterum and meadowsweet Filipendula ulmaria. The latter species is common over much of the marsh and forms dense stands in a number of places.

In the lower lying areas sedges are common and the hybrid 'graceful' sedge Carex x subgracilis forms some of the most extensive stands. In total 7 species of sedge and one hybrid are present on the marshes. Reed Phragmites australis tends to dominate the wettest parts of the site and is generally present as single species stands. Sedges, reed grasses, and reedmace Typha latifolia are well represented in the network of ditches: several of these species are present together with other bankside plants along the Coppermill stream. The main ditch of the 'Triangle' also contains a good variety of wetland plants such as water dropwort Oenanthe fistulosa, water plantains Alisma species, water whorl-grass Catabrosa aquatica, gypsywort Lycopus europaeus and marsh bedstraw Galium palustre.

The marshes contain several species of insect with a restricted distribution in the London area such as the Essex skipper butterfly Thymelicus lineola, an uncommon hoverfly Volucella inanis and a pyralid moth Shoeribius micronellus. This latter species is a marshland species and its presence together with that of Roesel's bush cricket Metrioptera roeselii are indicative of the likely antiquity of the marshland habitat. The insect fauna includes other moths as well as flies and a bug of local distribution. The breeding bird community contains several species typically associated with marshland habitats such as reed bunting, reed, sedge and willow warblers. A variety of wintering birds visit the marshes and neighbouring reservoirs while in autumn flocks of finches are to be found feeding on the seeds of the tall herbs.
Lea Marshes

Team - London - SSSI name - Walthamstow Marshes - Staff member responsible for site - Emily Dresner
RegionCountyDistrictMain habitatStaff member responsible for unitUnit numberUnit IDUnit area (ha)Latest assessment dateAssessment descriptionCondition assessment commentReason for adverse condition
LondonGreater LondonWaltham ForestBroadleaved, mixed and yew woodland - lowlandEmily Dresner310051822.8408 Jul 2009FavourableThe unit has maintained its habitat extent. The woodland is dominated by Salix species with elder and hawthorn. Dominant ground flora species are Heracleum sphondylium, Urtica dioica and Symphytum officinale. Varied structure and good regeneration from coppice areas.
LondonGreater LondonWaltham ForestFen, marsh and swamp - lowlandEmily Dresner410051833.4408 Jul 2009Unfavourable decliningLarge patches of dense bramble and abundant thistles, willow herbs and nettles. Patches of swamp and mire are still present at the northern end of the unit. These are assessed as unfavourable due to dense litter cover, lack of positive indicators for M27 and failure in structural diversity (in relation to invertebrates).Inappropriate cutting/mowing, Other - specify in comments
LondonGreater LondonWaltham ForestFen, marsh and swamp - lowlandEmily Dresner5100516931.2508 Jul 2009Unfavourable decliningThere has been siginificant progress in the management of some habitats at Walthamstow Marshes, notably through grazing and cutting of grassland areas. The quantity of Michaelmas daisy has been reduced and the rare Apium repens continues to do well. However, the swamp and mire communities for which the site was notified have failed the condition assessment attributes meaning the is unfavourable due to: - dense litter/thatch cover - lack of positive indicator species - undesirable non-woody species (in reed bed and swamp)Inappropriate css/esa prescription