Moss Valley SSSI

 ancient, marsh, grazing area, Site of Special Scientific Interest - SSSI (UK), woodland

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The Moss Valley is situated on the eastern side of the Pennines to the south of the
City of Sheffield, and is virtually surrounded by urbanisation and industrialisation
which contrasts sharply with its rural character and semi-natural vegetation. It is a
wide valley of about 10 square km formed by the Moss Brook and its tributaries
which rise at its western end. The Moss Brook is a small, fast-flowing stream of
high quality water. The valley lies on the shales and sandstones of the Lower Coal
Measures of the Upper Carboniferous period, producing a wide range of soil types
and fertility.
The site includes the Moss Brook from near Ford village in the west, to Eckington
in the east. It contains wet habitats of the valley bottom associated with the brook
and its flood plain, and the bogs and open water of several derelict mill ponds.
There are areas of open marshy grassland, shady wet woodland, old hedgerows,
ditches, and scrub. The meanders of the brook produce high, shaley banks and
pools. The woodland and field boundaries contain old and rotting trees and much
fallen dead wood. This diverse mosaic of topographic features and vegetation types
supports rich assemblages of invertebrates, including nationally rare species. The
site provides essential habitats for the life cycles of these invertebrates, many of
which are at the edge of their range here.
The wet woodlands are dominated by alder Alnus glutinosa, with crack willow
Salix fragilis, ash Fraxinus excelsior and sycamore Acer pseudoplatanus. The
understorey contains hawthorn Crataegus monogyna, hazel Corylus avellana and
willows Salix spp. The ground flora is dominated by bramble Rubus fruticosus,
wood club-rush Scirpus sylvaticus and great willowherb Epilobium hirsutum, with
reed canary-grass Phalaris arundinacea, wild angelica Angelica sylvestris and
common marsh-bedstraw Galium palustre. There are two types of drier woodland.
Some areas are predominantly sessile oak Quercus petraea and silver birch Betula
pendula with a ground flora of wavy hair-grass Deschampsia flexuosa and creeping
soft-grass Holcus mollis. Elsewhere wych elm Ulmus glabra and sycamore are
dominant, with birch, ash and alder locally abundant. The understorey contains oak
and hazel and the ground flora includes wood melick Melica uniflora, dog’s
mercury Mercurialis perennis, ivy Hedera helix and yellow archangel Galeobdolon
luteum. The range of woodland types and their component of dead or dying timber
makes them or special importance for invertebrate communities.
The neutral grasslands are dominated by creeping bent Agrostis stolonifera and
Yorkshire-fog Holcus lanatus with devil’s-bit scabious Succisa pratensis and
betony Stachys officinalis. Areas of marshy grassland are dominated by tufted hairgrass
Deschampsia cespitosa and rushes Juncus spp. with bulrush Typha latifolia in
the wettest areas. There is a diversity of wet grassland plants here including
common bistort Polygonum bistorta, common spike-rush Eleocharis palustris,
greater bird’s-foot-trefoil Lotus uliginosus and marsh ragwort Senecio aquaticus.
The site is of special interest for its range of invertebrate species. The beetle and
hoverfly fauna associated with dead and dying timber is of particular importance.
Beetles include the net-winged beetle Pyropterus nigroruber, the larvae of which
live in dead wood, and Hylecoetus dermestoides which requires dying wood.
Hoverflies include Melangyna guttata, the larvae of which feed on aphids in ancient
woodland sites, and Xylota florum which requires dead wood in wet woodland.
At least two other nationally scarce species and seven species of regional
significance associated with overmature timber are found here. About 30 species
which are recognised as indicating a continuity of cover by mature woodland have
so far been recorded.
Other uncommon species present include those associated with acidic wet grassland
such as the cranefly Prionocera pubescens and others such as the digger wasp
Lindenius albilabris which requires open sandy soil in which to nest. A total of 14
nationally scarce species has been recorded from the site.
The area is important for grass snakes Natrix natrix which inhabit the wet grassland
areas of the Moss Brook. Great crested newts Triturus cristatus are recorded from
the site and the native British freshwater crayfish Austropotamobius pallipes is
found in the waters of the Moss Brook.
The valley is also important for breeding birds. Species recorded from the site
include green woodpecker Picus viridus, great spotted woodpecker Dendrocopos
major, tawny owl Strix aluco, kingfisher Alcedo atthis and grey wagtail Motacilla
cinerea.