Fen frolics: survey and condition assessment of fen habitat in Durham

(top) Fringed water-lily at Loch Kenny Pond, Co Durham

(left) Greater tussock-sedge at Hardwick Hall, Co Durham

(below) painted lady on creeping thistle, in lesser pond-sedge swamp

The gap since our last post reflects the lack of in-door desk time we had in September - both John and I were surveying flat out to complete an assessment of fen and reed-bed habitat in the Durham Magnesium Limestone Natural Area. This equates to a fair chunk of county Durham, including the coastal denes, but excluding SSSIs, focusing on tier 2 sites like County Wildlife Sites and other undesignated areas.

We were doing a condition assessment of each site using Natural England's common standards monitoring methodology. Not many people have tried this out in the field in the North-East and we found that you really do need to be an experienced NVC surveyor who can accurately name communities more or less instantly, otherwise you'll be there all day (which kind of defeats the point of the CSM method - supposedly aimed at non-experienced people); plus you really need to know at least a key selection of bryos to do it properly. The next stage is to analyse our data and come up with a classification for Durham fens in the broad sense - which includes both mire (e.g. M10), swamp (S4 onwards - lots of these; boring buggers!), tall herb fen (e.g. S27) and wet grassland (e.g. MG4, MG 10) NVC communities.

We managed to cover a whopping 107 sites in total, in 4 weeks, out of 135 possibles, which is quite good going, especially with Foot & Mouth lurking in the background - a few farmers did refuse access, although most, even those with cattle, were pretty unconcerned.

The shock headline news appears to be that many sites have declined since their last visit (1991 for most) and almost all are in unfavourable condition, often turning into a species-poor M27 or much worse, OV26, featuring greater willowherb Epilobium hirsutum. I am now sick of Epi hirs!

Species-poor M27 - mostly dead! Part of the challenge for this survey, in September, was the dead and vegetative plant identification!

Even the few SSSIs we looked at (as they were next door to a CWS) are pretty knackered (see post below about Hetton Bogs). Bit of a doom and gloom situation. The sites that are hanging on in there are invariably on private farm land where the farmer is interested and is doing the right level of management.

The worst sites, by far, were ...

in local authority ownership. Probably no surprises there, unfortunately. We need to do a massive education effort to get the right people in local authorities doing the right thing; it's tragic that on sites where we do have the power to do some management, nothing, or not enough, is being done!!

The other shock was the apparent decline of a few widespread plant species characteristic of fen, like marsh cinquefoil Potentilla palustris. This is quite a common plant ... or was. It's not regarded as threatened nationally and plenty of SSSIs have good populations, but it does seem to be disappearing from lowland Durham sites. Like ragged-Robin Lychnis flos-cuculi (love that name!), it's one of those iconic fen species.

Ragged-Robin, on a lovely bit of cattle pasture (M23) marsh, Beacon Hill, nr South Wingate, Co. Durham

Ragged-Robin is much more iconic than the rarities like milk parsley Peucedanum palustre. I think conservationists need to focus on plants that people at least have a fair chance of seeing locally! I remember finding ragged-Robin in lots of roadside ditches as a child in Cambridgeshire. Twenty-five years on, eutrophication has wiped out most of those populations around where I used to live. Plantlife's new fens officer, Tim Pankhurst, is the person to champion these species. Tim is a top fen specialist and it's great that he is able to focus effort on fen habitat nationwide - it's not all in East Anglia guys!! You can read about Plantlife's work at http://www.plantlife.org.uk/

Clare