Blog by Sally. Photos by Julio and Sally
On a fine May morning, 16 members of Abingdon Green Gym assembled at Boundary House Fen on Frilford Heath Golf Course SSSI to continue with its restoration. The fen is calcareous, which is an extremely rare habitat. The spring water that feeds the fen percolates over a large catchment area and through a layer of chalk, where it picks up calcium. Under the chalk is a layer of impervious clay and the spring water then has to find a way through sand and gravel to the surface where it can form tufa (which is a bit like the limescale in our kettles). Sadly, this fen is under the very real threat of the possibility of a quarry, as two fields near the Golf Course in the fen catchment area have been let to a firm of gravel extractors. If this sand extraction goes ahead, it will impact the hydrology of the fen disastrously. However, we didn't want to think about this today, but focus on the job in hand.
Roger was our leader for the session and we worked under the direction of consultant ecologist, Rod d'Ayala. We set up our base in our usual spot and Rod explained the various tasks we would be doing.
Rod briefs the group
The main tasks were to finish off the raking from our last visit to this site in April, scythe the nettle patch, dig up any hemlock and creeping thistle, scythe around the runnel and scythe more of the fen area where sedge and reed dominate, making it difficult for other more delicate fen specialists to thrive. And, of course, after the scything, we must rake the cut vegetation and remove it from the fen to avoid nutrients from building up, as the specialist fen plants prefer less fertile conditions.
Before work began - the nettle patch is just out of sight in the top left hand corner of the photo
Adrian and David scythed the nettle area and Michele and Julio raked up after them. The nettles dominate this area and it is hoped to encourage other plants to improve biodiversity around the marginal fen area.
David and Adrian scythe, as Michele rakes the cut nettles
The start of the nettle patch, with foxgloves in the foreground
Carolyn and Dieuwke with a drag sheet full of cut vegetation from the main fen area
Jim continues scything the main area of fen (on the right), as raking and clearing the fen of cut vegetation continues by Dieuwke, Rhian, Simon, Rosie, Carolyn, Kevin, Eleanor, Roger and Rod
Another main task was to dig up any hemlock and creeping thistle and pull any emerging Himalayan balsam. Hemlock is on the increase, being a nitrophile, and is now often found in hedgerows. It is toxic and should not be touched without wearing protective gloves. It can be distinguished from its close relative, cow parsley, mainly by the purple splotches on it stem.
Lesley and Rod hunt for hemlock
With all the hemlock removed (for now!), Lesley focuses on digging up creeping thistle in a bid to prevent it from encroaching onto the fen area
Barbara cuts a lonely dash, starting the cut of sedge and reed in another area of the fen.
The runnel also needed to be scythed. Jim started on one side, whilst Sally started at the other end. It was tricky trying to avoid cutting down emerging marsh thistles, figwort and the delicate parsley water dropwort, but we tried our best. It was lovely to see the first emerging dragonflies enjoying the spring sunshine.
The runnel just below our base curving around, which needed to be scythed.
It did not seem long until break time at 11.00 was called and very grateful we were for it, too! It is always good to gather over refreshments for a catch up and to review progress and switch tasks if we want to.
A welcome break!
Suitably refreshed, we returned back to work and made a concerted effort to finish clearing around the runnel so that Rod could assess it and check for any leaks. The purpose of the runnel is to assist in re-wetting the fen, which had dried out a lot mainly due to the trees that were growing on it and also that the Blackwater stream, which runs through the fen, had at some time in the past been dug out to form a ditch. The fen is become more wet and the fen plants are responding well. The reintroduction of marsh lousewort has suppressed reed and sedge growth and allowed other fen plants to emerge and thrive.
The cleared nettle patch. Raking also disturbs the surface the soil and seed bank, so it will be interesting to see what other plants emerge.
The heap of cut nettles
Michele and Dieuwke having heaps of fun
Meanwhile, a cock pheasant keeps a watchful eye.
Foxgloves emerging in the sunshine
Comfrey looking resplendent
It was soon time for us to pack up the tools and leave the site. Looking back, we could see how much we had achieved in a relatively short period of time. That's teamwork!
The runnel after scything
Boundary House Fen after our efforts.
We look forward to returning next month to continue the good work!
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