Thursday, 27 June 2013

Parliament, ponds and extreme weather

The Houses of Parliament are so familiar that it is easy to forget just what an extraordinary confection of ornamentation they are. There is not a square inch lacking in Victorian flourishes of heraldic arms, gothic crenulations and worthy relief sculpting. Standing outside the Palace the whole structure radiates a slightly alien feel, as if inside its own protective force-field amongst the throng of tourists. I was there for the launch of The British Ecological Society’s latest publication, a review of the impacts of extreme weather on freshwaters in the UK. A tricky document to pull together because studying extreme events is an ad hoc science, replying on unforeseen opportunities as drought or flood strike the UK and often lacking reliable data from before the crisis against which any impacts can be judged. Nonetheless the review pulls together evidence from lakes, rivers and ponds and paints a fascinating picture of the changeability and resilience of our freshwaters. The broad message is that our freshwaters are vulnerable and can show rapid degradation, but nature bounces back so long as there are refuges elsewhere in  catchment or wider landscape from which the wildlife can recover (the whole document can be downloaded at
Northumberland, and Druridge Bay, feature large in the review, because I helped write the report and they are what I know best. In particular the Hauxley experimental ponds are an unusual example of a long term study, around long enough to have been hit by extreme rainfall and prolonged droughts. The impacts of the June 1997  deluge in Northumberland, an event so unusual that it may be a 1 in 300 year event, are shown in the report in photos of the River Wansbeck strewn with ripped up bulrushes and the Hauxley ponds are pictured because of the thick mats of algal that developed when the ponds did not dry out, with the result that other wildlife was partly smothered out. Odd but also charming to be thinking of Druridge Bay and Hauxley in the wood panelled grandeur of the palace of Westminster, crackling with power and the hushed sound of crustless finger sandwiches being hoovered up.

Friday, 21 June 2013

Ponds and the creativity of extreme weather

2012 has become infamous as the wettest year on record in England. Infamous, at least, in England. This has been followed by a peculiarly long winter, the coldest for fifty years. Britain has had a run of wet summers. One outcome was a recent meeting by climate scientists hosted by Exeter University to try and make sense of the signals from the noise and ,perhaps, the causes. The immediate driver appears to be the jet stream, which has not been shifting as far north has it once did and, instead, acts as a conveyor hauling Atlantic depressions across the UK, one after the other. However what causes the jet stream to linger so far south remains unclear ( . Ponds make immediate and powerful indicators of the impacts of these variations in our climate. The photos above show one of the subsidence ponds at Blakemoor Farm in the summer of 2012, when it was festooned with deep banks of Celery Leaved Buttercup, to summer 2013, when it has dried out, leaving a few forlorn tufts. What is the most worrying; being awash or being dried out? Neither. The pond comes and goes and with it the vegetation. The animals are less obvious but they too wax and wane between years. The extreme year of 2012 created an opportunity for plants and animals that seldom colonised or, even if they did, dominated the ponds. The ability of a landscape to vary  has always struck me as important, although a tricky thing to measure, given how short term so much of our research is. We find it hard enough to describe what we can capture and count, letalone something as abstract as the potenital to change. The variation between years has added to the overall biodiversity, allowing wet and dry year communities to flourish. The risk is that we have not recorded enough data for sufficient years to spot any major step changes, those thresholds beyond which the stage is re-set and some of the cast of ecological characters  never re-appear.

Saturday, 15 June 2013

The fairy fern hints at summer

There are signs of summer in a bucket in my back yard in Newcastle: the fairy fern has sprouted green shoots. Green, feathery branches have grown out from a reddish base, visible in the photo amongst the smooth round duckweed plants. Fairy Fern, Azolla filicoides, is a native of the west coast of the USA, not that these tiny individuals came over the Atlantic. They came from Ellington at the south end of Druridge Bay. The large pond in the village has harboured these New World arrivals for many years. The ones in the bucket in my back yard were a test to see how they would fare through the winter, being plants of warmer climes. Would they cope with being iced up? They were frozen into a solid block of ice, the ferns turning a blotchy red, which seems to be a cold weather response, but they survived and now are sprouting delicate, doily-like new growth.

In a warm year they form a dense mat over the surface of Ellington pond, deceptively like a lawn but, on closer inspection, a serrated fuzz of fronds oddly resembling the jagged canopy of a conifer plantation in miniature. For me the dense mats seem to coincide with drousy, heavy weather, thunder threatening through the heat in late August. In a bad year, when the cold and wet do not suit their west coast roots, they hunker down in circular rafts, nestled amongst the other plants around the edge of the pond. The managers of Ellington Pond have tried to be rid of it, but even one tiny frond is enough to retain a bridgehead and begin the recolonisation. Quite how Azolla got to Ellington remains a mystery and the fronds have not turned up further north in England, although a scatter occur throughout the Central Belt in Scotland. There is a touch of exotic mystery to its presence, almost a glamour, entirely consistent with the Bay’s sense of being between worlds.

Saturday, 8 June 2013

The fret of June

June opens with a week of proper summer warmth, an immediate slap of sunshine you can feel faintly crisping you skin. Sunny days along the Northumberland coast can have a mysterious quality. Out over the sea there are low banks of grey and brown clouds that drape from horizon to horizon a bit like those curtains around beds in hospitals. The North Sea is lost behind them. These are banks of sea fret, condensing out over the cold water. Up at the Bay the fret has been advancing and retreating in probing attacks. Tongues of sea mist drift in for an hour or two, swathing a field or dune, the sun still visible if you look up through the shallow pall of mist, then pulling back to the sea. The fret brings a tingling, hair-on-the-back-of-your-neck drop in temperature as the moisture drifts past. The droplets shred and catch on hawthorn and bramble, traces of mist visibly rolling and tumbling inland then retreating back to recharge out at sea. This has been a dry spring and the subsidence ponds in amongst the field drops are shrinking, some barely wet. The deluges of 2012 resulted in verdant borders of Celery Leaved Buttercup, Toad Rush and Pineapple Mayweed turning many of these pools into vivid summer circles, but 2013 threatens the opposite. This begs a question of those of us who regularly survey pond sites: is one year’s data, a snapshot, sufficient to characterise a pond? Probably not, or, at least a snap shot cannot capture the extent of change across the pondscape. Some ponds do not seem to vary much from year to year. For others the very variability is their most striking feature. One boon to the work at Druridge Bay is that we have got to know the sites well and have sense of time as a factor in the ponds’ ecology. This year I’ll be re-surveying the vegetation of the ponds at Blakemoor to compare to the summer 2012 plants. For now though I’m enchanted by the fret seeming to briefly stop summer and hide the ponds from our gaze.