Ptyxis Ecology - Our Botany Blog

Tuesday, 14 August 2007

Hetton Bog horror

I had a horrific shock recently botanising for the Durham Biodiversity Partnership's fen inventory project. We are locating and surveying as many fen and mire sites in the Durham magnesium limestone natural area as we can by the end of September, focussing on 2nd tier sites rather than SSSIs. Our survey team visited Hetton Bog SSSI to practice the fen condition assessment and site survey methodology. This site is designated for its valley mire herb-rich fen communities. Or so we thought...the site now bears very little resemblance to the SSSI description. Much of it is now MG1 false oat-grass Arrhenatherum elatius grassland. There was no sign of any of the choice species like brown sedge Carex disticha and marsh valerian Valeriana dioica. Sadly, I suspect these are long gone. The small patch of surviving fen meadow is a species-poor M27 Filipendula ulmaria - Angelica sylvestris mire. Hetton Bog was "one of only two sites known to contain such wetland communities in the Tyne-Tees area" so we are down to one site (hopefully).

The official condition assessment is that Hetton Bog is in unfavourable condition but recovering. It looked like it was drying out even further to me. Grazing, or at least multiple cuts, would be needed to reduce the cover of the false oat-grass, but obviously the hydrology must also be knackered and I don't really know what you can do about that.

I expect a non-botanist would think this is a lovely site; it is still very valuable for conservation, particularly for invertebrates. But someone who knows their vegetation would be able to tell instantly that it is not what it once was. This is a bit of a sad post; and I am sure there are lots of issues which would explain the situation at Hetton Bog. But that doesn't stop me feeling very upset when I see a site that has deteriorated so much, especially as botancially-rich wetland sites are so threatened nationally.



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