Gwent Wildlife Trust
Ymddiriedolaeth Natur Gwent

Gwent Levels – a summary of ecological information

The Gwent Levels is one of the largest surviving areas of ancient grazing marshes and reen (drainage ditch) systems in Britain. It is the largest area of its kind in Wales, of acknowledged UK-wide significance for its wildlife and archaeology. The proximity of the site to the internationally important Severn Estuary and River Usk add further value to this wetland complex.
 

A total of 5148 hectares of the Levels are covered by a SSSI designation covers. It has been estimated that around 4000 ha have already been lost through industrial, housing and infrastructure development. There is some additional wetland interest outside the SSSI boundary, including relict wetland fragments and post-industrial wetlands on the Corus Llanwern Steelworks site, and in areas of farmland divided by reens adjacent to the SSSI boundary. The SSSI notifications on the Levels are as follows: Magor Marsh – 21.9 hectares Gwent Levels – Redwick and Llandevenny SSSI – 940 hectares Gwent Levels – Whitson SSSI – 937.4 hectares Gwent Levels – Nash and Goldcliff SSSI – 954 hectares Gwent Levels – St Brides SSSI – 1322 hectares Gwent Levels – Rumney & Peterstone SSSI – 972.5 hectares

The designation of these SSSIs is primarily as representatives of grazing marsh / reen habitat  with Magor Marsh Reserve having additional significance for its fen vegetation. In addition, the Levels also qualify as SSSI on the basis of their invertebrate assemblages, with significant plant species, otters, water voles and breeding birds also being additional qualifying features.

Vertebrate Interest
Otters (Schedule 5, Wildlife & Countryside Act; EC Habitats Directive) – frequent on Levels, but with the population expansion that has taken place, road mortalities are now relatively frequent.

Water voles (Schedule 5, Wildlife & Countryside Act) – now scarce and localised, but still a key area for this seriously declining species.

Breeding waders – lapwing, snipe, redshank and curlew all breed locally across the Levels, with further species on the Newport Wetlands reserve.

Invertebrate Interest
144 Nationally Notable or Red Data Book invertebrate species have been recorded from the Gwent Levels. The assemblages of water beetles and Odonata (dragonflies & damselflies) are both qualifying features of the SSSI designations. The Levels are also well-known for their particular importance for soldier-flies (Stratiomyidae), with further known interest from other fly and beetle groups, moths and snails. Furthermore, our sparse knowledge of invertebrates makes it certain that further interest remains to be discovered – indeed a horse fly apparently new to science and as yet un-named (and thus additional to the total of 144 species referred to above) has been found once at Magor Marsh.

Higher Plant Interest
The Levels support the Nationally Scarce rootless duckweed (Wolffia arrihiza). This is considered to be the world’s smallest flowering plant! It occurs nowhere else in Wales.

Other significant plant species include:-

Lower Plant Interest
The area is important for a range of aquatic liverworts.
The reens are rich in plant life and hold 25 rare species of water loving plants. These special conditions also support 144 species of rare dragonflies, beetles and other tiny creatures.
 

The combination of drainage ditches, grazing marshes and ancient hedges also provide ideal conditions for otters, water voles, bats and great crested newts, all protected species, and 4 different breeding waders. (Redshank, lapwing, curlew and snipe.) In recent years otters have been recovering from an all time low but now the biggest threat is from road kills – a new motorway will cause even more deaths.

Julian Branscombe.