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.


Monday, 13 August 2007

Tetraplodon mnioides

I was just about to finish botanising at Bellcrag Flow yesterday when I came accross Tetraplodon mnioides growing among mosses in the drain at the side of a forestry track. Even to people who never notice mosses this is a very striking species. Unfortunately none of my photos of it were in focus.

Nationally it is quite uncommon, although more frequent in bogs and heaths in the north and west. It has a very interesting life cycle. It grows on the bones of dead animals or sometimes on dung. The spores are dispersed by flies. The spore capsules give off a scent of rotting animal which is attractive to flies. They pick up the spores and deposit them on the next rotting animal they visit.


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Monday, 6 August 2007

NEW county record for Durham v.c. 66

I can remember desperately wanting to get my first new VC record when I got into field botany. It was pretty hard to achieve this as at the time I was living in Surrey, one of the most thoroughly botanised counties in England. The chances of a new VCR were limited and only ever likely to be a non-native species. Eventually after obsessively recording in every tetrad in the BSBI's Local Change project in Surrey, I found that holy grail, a new VCR in Verbascum speciosum, Hungarian mullien. John and I have found a few new county records for Durham and Northumberland since moving up here in March 2006, and this year spotted an odd looking spurge while doing a recce for a training day at Hamsterley Forest. Eric Clement, one of Britain's top experts on non-native plants, kindly confirmed it as Euphorbia dulcis, sweet spurge, which I think is new to Durham v.c. 66.

My best botany moments have been when routine recording has turned up some really unusual species; going to a site specifically to re-find something (no matter how rare or endangered) is a very poor second best. I try to encourage people who do the latter to have a go at recording because I think that it is really so much more exciting to find new, unexpected things for yourself!

What do you think? What's your best botany moment??



Saturday, 4 August 2007

Species-rich banks in meadows

The meadow survey season is now well and truly over for this year and we have started our green hay harvesting at last. The weather has been dreadful and has held us up much longer than we hoped. Since I started the hay meadow job last year I have surveyed nearly 400 meadows in the North Pennines AONB, so I am starting to build up a reasonable picture of what's out there. Overall there are very very few really herb-rich upland hay meadows left - considerably less than official estimates. Many of the really good sites identified in the NCC surveys of the mid 1980s have been agriculturally improved. I've been a bit shocked by this. The losses of species-rich grassland between the 1950s and 1980s are well documented, but it seems like the small number of sites surviving in the 1980s have suffered major losses in the last 20 years despite conservation initiatives like SSSIs and the ESA scheme.

Where meadows include awkward or steep banks that are too difficult to access with large modern machinery, these often have interesting vegetation. A few (bad) pictures below show a small sample of the variation you can get. The main upland hay meadow community on dry soils is MG3 and there are some very good examples of herb-rich MG3 on some of these banks. But the really interesting thing about them is that you can sometimes get several different types of vegetation on the same bank. Many of these banks would have been mown for hay using hand tools in the distant past, but nowadays the only management they get is grazing in spring and autumn. They may never have had any fertiliser (including farm yard manure) or lime applied.
My favourite type of bank vegetation has to be U4c. This is strange vegetation that I don't understand yet. It usually includes several calcifuge species but yet is often very species-rich. Species-rich acid grassland is not something I have come accross before. There is usually a good bit of tormentil and heath bedstraw along with sweet vernal-grass, red fescue and common bent. Sometimes you get mat-grass, heath rush and other species that I think of as strong calcifuges. Sometimes its not much richer than this so it conforms quite closely to normal species-poor U4. But there is a group of species that indicate vegetation that is often much richer. These are betony, zig-zag clover, devil's-bit scabious, heath grass and bitter vetch. These areas are usually very herb-rich and are good places to look for uncommon hay meadow plants like greater butterfly-orchid, alpine bistort, fragrant orchid (usually subsp. borealis) shade horsetail or small white orchid.

A moderately interesting U4c bank near Wolsingham

Some MG3 vegetation on a bank in the Harwood Valley

An unmown herby bank just outside Middleton-in-Teesdale

A forest of wood horsetail

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