Lowland fens produce very colourful displays of wildflowers such as meadowsweet, valerians, globeflowers, bogbean, water avens and scabious between June and August. These fens typically occur in flat (valley-bottom) situations and are fed by naturally nutrient-rich ground-waters.
The UK is thought to host a large proportion of the fen surviving in the EU with the base-poor fen at Insh Marshes in Scotland, the calcareous-rich fen and swamp of Broadland, the extensive areas of the Lough Erne system in Fermanagh being three important examples.
In the Dales, lowland fens are an important and very scarce habitat. The fragments of rich fen that remain, most notably on the Malham Tarn NNR and at places like Helwith Moss in Ribblesdale support an extremely diverse flora and fauna including an impressive array of rare and scarce species like the narrow small-reed, montane eyebright, lesser tussock-sedge, fibrous tussock-sedge, dark-leaved willow and invertebrates including a rare leaf beetle and scarce craneflies, hoverflies and a soldier fly. The lowland fen habitats support a real diversity of specialist species as well as being vital feeding or breeding areas for a number of birds and other animals that also use other habitats.
In the Dales, lowland fens are arguably the habitat that has been most reduced by human activity over the centuries. Even with the widest definition of lowland fen, they now cover less than 1.5% of the Dales! This can be compared with the more intensive agricultural grassland that covers nearly 30% of the Dales and which has been largely been converted from the fen, wet grassland and wet woodland/scrub that would originally have covered the valley bottoms and lower valley sides. Lowland fen has suffered these drastic losses because it is relatively easily drained and can be converted to productive grassland with the use of fertilisers. The fragmentation of lowland fen is already a serious concern with populations becoming small and isolated and highly susceptible to local fluctuations and extinctions. It is important that we not only conserve the remaining areas but work with farmers and landowners to restore more of a patchwork of fen across the Dales.
Globeflower
Narrow Small-reed
Calamagrostis stricta
Family: Poaceae
This species is one for the experts. A challenge to identify at the best of times this species is also thought to hybridise with its close relatives, which makes identification even more tricky. The Botanical Society for the British Isles (BSBI) has some of their best brains carrying out research on it.
It is a tufted rhizomatous perennial with a scattered distribution in Northern Britain, South to West Suffolk, Cheshire and County Antrim in Northern Ireland. It is native of near neutral marshes, fens and lakesides at an altitude of 0-340m. In the Yorkshire Dales National Park it has been recorded recently on Malham Tarn National Nature Reserve.
The on-going morphometrics research includes comparing Calamagrostis stricta with its close relative C. scotica. We are looking forward to the findings and hope they will shed new light on this national priority species.
Northern Marsh Orchid
Bog Bean
Menyanthes trifoliata
Family: Menyanthaceae
Its name might be a little plain but the bogbean is anything but. Its attractive flowers each has five petals; flushed with pink on the lower surface with a feathered appearance on the upper surface.
The bogbean has a number of traditional uses. Its leaves have been used as a substitute for hops in beer, the rhizome, when powered has been used in bread making and parts of the plant have been used as a treatment for arthritis. The plant also contains a chemical compound which attracts cats.
Bogbean can be found in unpolluted shallow ponds, marsh and fen habitats throughout the UK. In the Yorkshire Dales National Park these habitats are often small and scattered but the boardwalk through the alkaline fen on the Malham Tarn National Nature Reserve is an excellent place to see bogbean in flower between May and July.
Water Avens
Geum rivale
Family: Rosaceae
Water avens is a common perennial herb with orange-pink drooping flowers that are protected by purple sepals. It has several other local names including ‘Billy Buttons’ and ‘Soldiers’ Buttons’. This plant has a clever way of dispersing its seeds – the seeds feature tiny hooks that catch onto passing animals, allowing them to be spread. The roots of Water avens smell like cloves and have historically been used to cure a variety of ailments. They have also provided flavouring for drinks such as beer.
Water avens can be found throughout the British Isles, although the herb can be very localised in the South of England. In the Yorkshire Dales National Park, Water avens is common and flowers between May and August. Here its preferred habitat is damp grasslands, fen, ditches, open areas within woodland and on roadside verges. In woodland habitats, Water avens readily hybridise with the woodland species wood avens. The hybrid form can also be found in the National Park, in or close to woodlands where both of the parent species are present.
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Credit: Whitfield Benson