Friday, 15 July 2016

Storm Desmond resets the ecological stage at Hauxley six months on

Storm Desmond hit Hauxley Nature Reserve hard. The immediate problem in mid-December 2015 was the flowing across the main road in into the field with the little experimental ponds we dug out in 1994. The deluge cut off the reserve, right in the middle of the new build. The car park was just about accessible in a 4x4 though a hovercraft was probably the best bet. Here is a photo, from the Wildlife Trust,  looking back along the road with the flood waters spilling over into the field on the right,home to the little ponds.

At the time we thought the waters would recede. The field by the entrance has flooded before, even at unlikely times such as the early summer of 1997 when an intense rain storm hit just when the little experimental ponds would normally dry up. They didn’t dry for another two years and changed markedly. The plants and animals that like a bit of drying out were much scarcer and instead thick blankets of green algae took over. A couple of years later, once the ponds had dried out again in the summer of 1999o the algae disappeared. Animals and plants benefit from the disturbance caused by drying, creatures like pea shrimps (Ostracoda) or rarer algae such as the stoneworts (Chara) re-appeared, maybe from drought resistant eggs or, in the case of Stoneworts, oospores in the mud, activated by desiccation.
Storm Desmond seems to have changed the field. Six months on and it is still almost completely flooded over. Here are two views from the middle of the field back to the road, across the ponds. Firstly July 2012, a very wet year, but no total flooding. On the right, the same view July 2016.

The water is not falling which begs the question is it being topped up somehow? More pressing for the wildlife are the impacts. Gone is the lush, flower strewn high summer wet meadow. Instead spike rush (Eleocharis palustris) is one of the few obvious survivors and the reeds from the pond to the side of the field have pushed out two bridge heads, their advance guard visibly snaking out into the flood.
One extreme event has reset the ecology of the whole pond system.

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