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 http://www.britishecologicalsociety.org/public-policy/our-position/ecological-issues/)

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.

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 (http://metofficenews.wordpress.com/2013/06/18/meeting-on-uks-run-of-unusual-seasons/) . 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.

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.

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.

Students of pond difference

I’ve spent the last week in the Lake District with our first year undergraduates on their annual field trip, a mix of core ecological skills for conservation and landscape in the UK (Phase 1 mapping, National Vegetation Classification), ping pong and stone circles human sacrifice re-enactments. They worked hard, twelve hour days, apart from the final night when they stayed up even longer to craft the data they had been collecting into presentations. Creating a pressed flower collection may not seem  the most compelling activity when you are 19, but I am confident those slightly mangled specimens of pignut and pink campion will one day be treasured possessions. Each student had a particular flower to find, hampered a bit by the late spring but also resulting in a bout of botanical blind man’s buff, watching them walk past their quarry. They have to do a group project too. One five-some, Ryan, Chloe, Dylan, Andrew and Jack took up the challenge of comparing the richness of invertebrate in two ponds compared to two streams. We’ve not tried this before but after several days of counting grasses in quadrats you can see the attraction. They took kick samples from two streams coming off the southern slopes of the Blencathra ridge up by Skiddaw, then samples from two nearby ponds. The streams yielded Heptagenidiae and Baetidae Mayflies, Leuctridae and Chloroperlidae stoneflies and a supporting caste of oligochaete worms and cranefly larvae. The two ponds were more of a surprise, both teeming with tadpoles but otherwise rather different, one pinging Copepoda zooplankton and creeping Nemouridae stoneflies, the other with Polycelis flatworms, Pseudocrangonyx gracilis shrimps and the giant Ramshorn snail Planorbis corneus. They used Jaccard’s Index of Similarity to summarise these patterns, essentailly a measure of how many taxa two sampels have in common ranging from none, 0%, to an identical inventory, 100%. The two streams were 50% similar to one another, the two ponds only 17% similar to each other, a neat demonstration of the heterogeneity of ponds in the landscape, and a neat demonstration that students can do good work given the opportunity plus  staff suffering from an overdose of Protestant work ethic and slightly sleepless nights.

Spray time at Blakemoor

The subsidence ponds at Blakemoor Farm at the south end of the bay are so familiar to us that we forget how startling they can seem to visitors. The pond in the photo above swells across a hollow in the middle of a large arable field that is given over to oil seed rape of winter wheat. The extent of the water varies markedly with seasons and years. A dry summer can see the whole shallow basin exposed into a reticulated pavement of cracked mud, dotted with pineapple mayweed and knotweeds. A sudden rain storm can refill the whole hollow. This is one of the ponds over the ten abandoned seams of nearby Ellington pit. The coal measures extended far out under the sea, but were so near the sea bed that the miners could hear ships passing overhead. Many of these field ponds lie in suspicious rows across the fields, perhaps echoing the subterranean tunnels. The wet year of 2012 and dry winter of 2013 has left the crops stunted and patchy, much of the ground dried out to a tough crust. The crop sprayers have been out to catch the first sustained spring warmth. We are curious to find out if any of the farm management affects the productivity of the ponds. These arable field ponds black foetid mud of the deeper swamps which seems a better trap for organic carbon. However these field ponds can be carpeted by vivid turquoise and green crusts of algae, visibly fizzing trails of oxygen bubbles on sunny days, so may be briefly but intensely productive whilst the sumemr sunshien lasts. The sprayers do not drive through the cloying mud, perhaps nervous of just what lies beneath (or, more ominously, does not because it has all been dug out) from the days when mining dominated south east Northumberland.

The cook, the core, its bung and his oven

After several decades working in the sciences I am still troubled by the awkward conventions of neutrality that were drummed into us as students, for example how we must not to write reports or academic articles in the first person. No “I” or “we”. “Data were collected” or “this report demonstrates”, as if data collects itself or reports self-publish. I let “I” sneak into work these days, partly as a reminder that research is carried out by people. For example Pete who, in the photo above, has our new corer wedged into the oven of his flat. The new corer is a marvel of practicality. The bottom end of the tube is sharpened and has cut through sediments that are reinforced with a lattice of bulrush rhizomes as easily as it does through softer muds. The top of the tube has extra flanges so you can push down with your foot too. A wooden plug allows the sediment to be pushed out, the plug attached to a calibrated rod so we can measure precise slices. It is this plunger which has caused trouble. It is beautifully cut to be flush with the inside circumference of the core tube, but the wood has swollen in the water and got stuck. Dave says this would not happen if it were made of mahogany wood. So, in addition to the elegant steel engineering we can perhaps add a touch of high class woodworking. Meantime Pete has stuck the core in the oven to dry out the bung. This is a fine example of the “we” in science. Dave designed the core; that is a real skill. Pete has been trying it out in ponds containing glutinous goo through to others solid with roots and rhizomes; that is a real skill too. Getting a corer that works slickly and effectively across all these pond types is important so that we can take equivalent cores and slice the columns of mud into similar sized discs to compare the amounts of organic material trapped through the varying depths of mud. Because the corer allows Pete to extract precise, replicate samples he has been able to work out the density of carbon buried in the sediments. Meantime I am glad he will have to explain why his remarkably well equipped kitchen has a mud corer stuck in the oven and not me. That is quite another skill.