Although much reduced in size during the 20th Century, Grouville Marsh, also known as Les Maltières]]. lies inland from the Royal Bay of Grouville and Grouville Common. It is the island's second most important wetland area after St Ouen's Pond.
The area is in the hands of a number of landowners and now enjoys a much greater degree of protection from further development than used to be the case. The fields which are of greatest importance for bird and plant life are now owned by the National Trust for Jersey.
Water lies on the surface of at least part of the marsh at most times of the year, and after periods of heavy rainfall the area under water can enlalrge dramatically. Many migrating birds return to the marsh every year and it is known as an ornithologist's paradise.
Grouville Marsh is the best habitat of its type in Jersey and probably the whole of the Channel Islands. The centre of the marsh is thick with reed beds and not generally accessible. However, many of the best birds which visit, are viewable in the flooded fields around the perimeter.
Many duck species visit, including Wigeon, Shoveler and Teal. Bean, Whitefront, Greylag, Brent and even Egyptian Geese have been seen here in recent years. Rare birds recorded here have included Bittern, White Stork, Night Heron, Black Kite, Yellow browed and Dusky Warbler. Cetti’s Warblers occasionally breed.
From the States of Jersey website Grouville Marsh is one of the most important remaining areas of low-lying wet meadow in Jersey and was designated as a Site of Special (Ecological) Interest in 2009. It supports a large number of plant species, including many that are typical of wet habitats and many that are locally rare or of restricted distribution. A large variety of birds visit the site throughout the year. It is jointly owned by various bodies including the National Trust for Jersey who have an interest in its ecological management.
Wetlands, particularly low-lying ones are under considerable threat. Pressure to release the land for agriculture and other developments through drainage has already been the cause of the loss of the large majority of the Island's marshes. Those areas that remain are, therefore, of great importance as the last refuges for wetland flora and fauna. Natural history
Grouville Marsh supports a wide variety of species, many of which are characteristic of wet meadows. A central feature of Grouville marsh is its large area (3.7 hectares) of reeds 'Phragmites australis'. This habitat is not common on the Island, the only other extensive areas being at St Ouen’s Pond and Les Pres Dormants.
The site is also one of the most important for birds. Ducks and waders winter there in good numbers. During the summer the areas of reed-bed and willow carr support breeding species such as reed warbler 'Acrocephalus scirpaceus' and cetti’s warbler 'Cettia cetti'. The nature and variety of habitats of the marsh combined with its geographical position result in very large numbers of migrating birds passing through the site.
Grouville Marsh supports a large number of invertebrate species, including butterflies and dragonflies such as the wide-bodied chaser 'Libellula depressa', which is a rare species on Jersey as it is more-or-less restricted to areas of open wetland.
Most of Jersey's wet meadows are a product of traditional farming practices; typically low intensity summer grazing. Management for conservation of these areas now seeks to emulate this tradition, avoiding, in addition, intensive practice and the use of fertilisers or herbicides.
The potential for a site like Grouville, if appropriately managed, is considerable. The result is not only an area rich in wildlife, but a site that is attractive to visitors and an education to those who wish to know more about Jersey's rich natural heritage.
From the National Trust for Jersey website Les Maltières (named after a malting which once existed nearby), is a complex of marshland, wet meadows and carr (wet woodland). The National Trust for Jersey owns 21 vergees (3.8 hectares) of the marsh.
The holding consists of reed-bed, carr and wet meadow, with a small area of drier grassland. The remainder of the marsh, which is in several ownerships, consists mostly of willow carr and grazed and mown grassland. Water from a wide surrounding area drains into the marsh, and a stream, the Gorey Brook, flows alongside the eastern boundary of the Trust’s land.
The habitats present at Les Maltières have changed dramatically over time. About 6,000 years ago, when much of Jersey would have been covered in woodland, the site was dominated by willow and alder carr. At least part of the area then turned into saltmarsh as sea levels rose, and it remained as such for a further 2,000 years. Freshwater conditions returned as sea levels fell again, and it is likely that at least parts of the site were used for grazing domestic cattle and for making hay.
After 1900, grazing slowly began to decline, and parts of the marsh reverted to carr woodland. Hay was still being made on part of what are now National Trust for Jersey owned reed-beds as late as 1949, but this practice ceased shortly afterwards. The land presumably became wetter as drainage was neglected, and the reeds took over. Trees, mainly willows, rapidly grew up on other parts of the site.
During the German Occupation extensive rock quarrying and sand excavation took place in the area, and the remains of a German-built shed are still visible within the National Trust’s part of the marsh. Peat was also dug for fuel. After the Occupation, parts of the marsh were used as the parish refuse dump, and attempts were made to drain some other areas. The Trust purchased the land in 1979.
Flora and fauna
The Trust’s holding was originally farmed as four fields, three of which now consist mainly of reed-bed, giving way to carr along the eastern edges near the brook. A track flanked by lombardy poplars divides these from the remaining field, which is wet pastureland grazed by cattle. Some of the site’s original hedgerows can still be identified, although these are now very overgrown. Apart from the brook, there is little permanent open water on the site, although much of the area may be flooded for long periods over the winter months.
Besides Common Reed, a good variety of other wetland plants occur at the site, including Water Mint, Hemp Agrimony, Great Hairy Willowherb, Gypsywort, Yellow Flag and Pendulous and Cyperus Sedges, the last species occurring at only one other site on Jersey. The main trees that can be seen in Les Maltieres are Crack Willow, Goat Willow (Salix caprea), Osier, Alder and Grey and Black Italian Poplars, all of which are associated with wet conditions.
Grouville Marsh also supports a rich insect fauna; no less than 282 beetle species (25 per cent of the Jersey total), have been recorded here, for example. The abundance of willows attracts a wide range of moths, such as the Pink-barred Sallow, and butterflies are also numerous on sunny summer days; 9 different species were observed on one visit in 2002. Dragonflies seen in 2002 included the Emperor and the Broad-bodied Chaser. The site is also notable for crickets; 5 species are known to occur, including the Great Green Bush Cricket and the Long-winged Conehead. Small mammals, such as the Jersey Vole, are abundant at Grouville Marsh, although the site is undoubtedly best known for its birdlife.
Extensive bird-ringing has been undertaken at the site by Mr Eddie Buxton and his sons since 1974, during which time 112 species have been recorded. Honey Buzzard, Hoopoe, Corncrake, Hen Harrier, Little Bittern and Thrush Nightingale are just a selection of the more notable birds recorded at Grouville Marsh over this period. Breeding species include the Reed Bunting, Cetti’s, Reed and Garden Warblers (Acrocephalus scirpaceus), Blackcap, Short-toed Treecreeper, Long-tailed Tit and Moorhen. During the winter months, a Woodcock may be flushed from the dense, tangled carr woodland, the elusive Water Rail skulks within the reed-beds and Snipe may be seen feeding on the wet pastureland.
Grouville Marsh is primarily a wildlife reserve, and it is not normally open to visitors. Access to the site is poor, and the terrain is hazardous, especially in winter when much of the area may be flooded. Visits for scientific purposes, such as recording or photographing flora and fauna, may be permitted provided the National Trust for Jersey is notified beforehand.