User:Mrchris/Hugginstown Fen

Hugginstown Fen is an internationally important fen site 4 km south-west of Ballyhale, County Kilkenny in Republic of Ireland. It is also a nationally proposed Natural Heritage Area and also a candidate Special Area of Conservation (cSAC Site Code IE0000404) selected for alkaline fen, a habitat listed on Annex I of the European Union Habitats Directive(92/43/EEC). Located in Atlantic  biogeographical region and the NUTS 2 Southern and Eastern (IE02) region.

It contains a good diversity of other wetland habitats and species. The Common Frog on the Red List of Threatened Species is found at the site. A vegetation survey of Hugginstown Fen was carried out in 2003 to assess the potential impacts of the proposed N9 road on the fen.

Site
The Hugginstown Fen site consists of a relatively large, isolated area of swamp and floating fen developed in a small valley in hilly country. It is underlain by limestone glacial till overlying and surrounded by acid Old Red Sandstone. The catchment is relatively small and iron-rich springs are an important source of water for the wetland. The site encompasses an area of swamp and floating vegetation which is a complex of rich fen (alkaline) and transition quaking mire. Located in a small valley, the limestone glacial till on which it rests, are underlain and surrounded by acid Old Red Sandstone. As the catchment area is small, iron-rich springs are an important component of the hydrology.

The northern third of the fen is dominated by Common Reed swamps with some small areas of open water near springs. The remainder of the site consists of species-rich fen, partly developed on mats of floating vegetation, dominated by a tall herb community in which Meadowsweet, Wild Angelica, Water Horsetail, Bulrush, Water Mint and Lesser Tussock-sedge are common. Other species present include Nodding Bur-marigold, Marsh St. John’s-wort, Black Bog-rush and Tubular Waterdropwort. Other Special Areas of Conservation in County Kilkenny include Hugginstown Fen south-west of Ballyhale, The Loughans near Urlingford, Cullahill Mountain on the Castlecomer Plateau near Johnstown, Spahill and Clomantagh Hill which form part of an escarpment which links the Slieveardagh Hills with the Castlecomer Plateau, Galmoy Fen north of Johnstown, the Lower River Suir south of Thurles, the freshwater stretches of the River Barrow and River Nore and Thomastown Quarry, near Thomastown.

Species-rich Rush/Purple Moor-grass grassland occurs in drained areas at the southern and northern end and around the margins at the peat-mineral interface. Small clumps of Willow occur occasionally on the fen margin. Two uncommon insect species recorded from Hugginstown Fen are Scarce Emerald Damselfly and the Hoverfly Parhelophilus consimilis. The Common Frog, a Red List of Threatened Species species, is found at on the site.

An interesting feature of this area is that the water flows overground initially then disappears abruptly underneath the floating fen vegetation.

Past management of the site has included some drainage channels, peat cutting and grazing. Although this site has been damaged to some extent by drainage, especially in the southern part, it remains one of the most interesting and diverse fen sites in Ireland. The fen vegetation of 1 km2 (63.34 ha) is a complex of rich fen (alkaline) and transition quaking mire. It contains a good diversity of other wetland habitats and species and is an internationally important fen site. The site encompasses an area of swamp and floating fen occurring in a small valley and as the catchment area is small, iron-rich springs are an important component of the hydrology. The fen, and the limestone glacial till on which it rests, are underlain and surrounded by acid Old Red Sandstone.

Survays
The fen was visited in April 2003 and the main habitats were described and mapped. This survey focused on the eastern side of the fen, which is the part most likely to be impacted by the road scheme.

Fen
The main area of fen vegetation is located in the central part of the site. At the northern end it is confined to the margins of the site adjacent to swamp vegetation or transitional to open water.

The main area of alkaline fen vegetation is located in the centre of the site. The vegetation is underlain with a carpet of moss dominated by Calliergon cuspidatum with a good diversity of sedges. Bottle sedge (Carex rostrata) is frequent and other sedges occurring occasionally are carnation sedge (Carex panacea), lesser tussock-sedge (Carex diandra) and more rarely yellow sedge (Carex viridula). In wetter areas common cottongrass (Eriophorum angustifolium) and marsh marigold is locally frequent.

Other species occurring include, cuckoo-flower, willow saplings, marsh pennywort, marsh bedstraw, wild angelica, marsh cinquefoil, jointed/sharp-flowered rush (Juncus articulatis/acutiflorus) and creeping bent grass. Devil’s-bit scabious occurs occasionally. The area was formerly cut for peat.

At the margins of the site other species in the fen include; occasional clumps of tussock sedge, creeping bent, mint (Mentha aquatica), lesser spearwort (Ranunculus flammula), great willowherb (Epilobium hirsuta), meadowsweet (Filipendula ulmaria), common marsh-bedstraw (Galium palustre), water horsetail (Equisetum fluviatile) and horsetail (Equisetum palustre).

Although it is predominantly alkaline type fen, which is classified as Rich fen (PF1) by Fossitt, it contains plant species that are indicative of a slightly more acidic type fen. There is an absence of black bog rush on the eastern side of the fen (the western side was not surveyed in detail), which is typical of the more alkaline fen.

This habitat has links with the Annex I habitat ‘Alkaline fens (7230)’ under the EU Habitats Directive

Water
The extensive area of open water at the southern end of the fen is 20-30cm deep occurring on a peat substrate. There is a very sparse sward of bottle sedge and other species include cottongrass and bogbean. There are some submerged bladderworts and stoneworts and some spike-rush (Eleocharis sp.).

Calcareous springs
Hugginstown fen is fed by a number of calcareous springs. A notable spring/seepage area occurs at the end of the site. This flows out of the fen in a north-easterly direction. The presence of watercress officinale) and fool’s water-cress (Apium nodiflorum) frequently along the stream channel suggest nutrient rich water. Although no other springs were observed during the survey, there is flow of water out of the fen in a southerly direction. This watercourse is a tributary of the Derrylackey which flows into the Blackwater River.

Reed and large sedge swamp
There are extensive areas of swamp on Hugginstown fen growing in standing water of more than 25cms deep. The swamp habitat within can be divided into three distinct categories on the basis of the dominant plant species. The swamp vegetation is dominated either by common reed (Phragmites australis), bulrush (Typha latifolia) or water horsetail (Equisetum fluviatile) and these categories are described separately below. 'Phragmites-dominated swamp. This is the most widespread of the swamp vegetation types and covers a large area of the site to the North of the fen. It is characterised by dense stands of common reed. This grades into fen vegetation (PF) in the centre and at the margins of the site.

Bulrush/Sparganium-dominated swamp The vegetation of this swamp category is dominated by bulrush and bur-reed (Sparganium sp.) with other species such as greater bird’s-foot-trefoil (Lotus uliginosus) also occurring. There is one main extensive area of this habitat that encompasses an area of standing water with a floating mat of creeping bent (Agrostis stolonifera) and bogbean (Menyanthes trifoliata). Other species occurring occasionally in the bulrush and bur-reed swamp areas include bottle sedge (Carex rostrata), water horsetail and marsh marigold (Caltha palustris). Hawthorn (Crataegus monogyna) saplings are encroaching into one of the regions.

Horsetail-dominated swamp Swamp dominated by water horsetail is the least extensive of the swamp habitats present and occurs at two locations at the central-northern end of the fen. It contains areas of open water with dense stands of water horsetail and a localised patch of bogbean is also present.

Transition mire and quaking bog
The transition mire is an extremely wet peat-forming system. It is located in a few small areas of the site at the margins of open water. It consists of a mosaic of quaking hummocks of alkaline fen vegetation, interspersed with areas of open water (20-30cm in depth). The hummocks range from small clumps with an area of 50cm2 to large floating mats raised 20-40 cm above the water level. These mats are carpeted with mosses dominated by Calliergon cuspidatum with Plagiomnium undulatum and also present are the mosses Drepanocladus sp., occurring at the base of hummocks, and Aulacomium sp. Other species include lesser-tussock sedge, marsh cinquefoil, marsh bedstraw, marsh pennywort, cuckoo-flower, devil’sbit scabious, water mint, lesser spearwort, marsh marigold and marsh lousewort (Pedicularis palustris).

The areas of open water support bladderworts (Utricularia spp.) and stoneworts (Chara spp.). Common cottongrass and bottle sedge also occur.

This habitat has links with the Annex I habitat ‘Transition mires and quaking bogs (7140)’ under the EU Habitats Directive.

Grassland
Several areas of 'wet grassland occur within the site at the margins of the fen. These areas are typically grazed of previously grazed and are dominated by soft rush and Yorkshire fog. Other species include meadow buttercup, ribwort plantain and jointed/sharp-flowered rush.

At the southern end of the site there is also a large area of wet grassland-fen transition (GS4/PF), which occurs on peat and is more species-rich than the other areas of wet grassland. The vegetation includes abundant soft rush and hard rush. Other species present include jointed/sharp-flowered rush, carnation sedge (Carex panicea), glaucous sedge, creeping bent, cuckoo-flower, meadowsweet, creeping buttercup, white clover, marsh thistle, mint, marsh pennywort and lesser spearwort. At the northern end of the site purple moor-grass (Molinia caerulea) is common in the grassland.

Dry calcareous and neutral grassland' In the southern region of the site, there is a slightly elevated knoll of mineral soil with species rich grassland. It contains a number of grass species including fescues (Festuca spp.) and bents (Agrostis spp.) and a number of other species including glaucous sedge, field wood-rush (Luzula campestris), dandelion (Taraxacum agg.) common bird’s-foot trefoil (Lotus corniculatus), yarrow (Achillea millefolium) and moss (Rhytidiadelphus sp.).

Areas of improved agricultural grassland occur around the perimeter of the fen. These are heavily modified habitats with low species diversity and low ecological value. The majority of fields are dominated by perennial rye-grass (Lolium perenne) and contain only a few broadleaved herbaceous species such as clovers (Trifolium spp.), daisy (Bellis perennis), buttercups (Ranunculus spp.) and chickweed (Stellaria media). There are some rush species (Juncus spp.) in the wetter fields. Mixed broadleaved / conifer woodland (WD2)

This habitat is found at the eastern edge of the fen and rises up to the road at a slight gradient. The woodland is largely comprised of Scot’s-pine (Pinus sylvestris) with larch (Larix sp.) and occasional sitka spruce (Picea sitchensis). Adjacent to the fen, where the ground is flatter and wetter, willows (Salix spp.) are the dominant species.

Woodland
Wet willow-alder-ash woodland There are a number of patches of willow scrub/woodland at the margin of the fen. Willow is the main species becoming quite dense and up to 8m high. There are occasional alder trees along the landward side of the fen.

A mixed conifer plantation dominated by sitka spruce and Scot’s pine occurs at the eastern edge of the fen. Other species include larch, and rarely beech and ash with some hawthorn in the understorey. The ground is poached and the ground flora is dominated by ivy and bramble with some violet (Viola sp.) and vetch (Vicia sp.)

The scrub habitat at the site is dominated mainly by willow and gorse. The large island of dense scrub on the north-western edge of the fen is dominated by these species but also contains hawthorn, blackthorn, holly and some ash. Where scrub is encroaching into grassland habitats it is dominated by gorse with heather and hawthorn.