"The small gilded fly doth lecher in my sight" (King Lear, nature lover)

Nature is famously good for us, with talk of “green gyms” (marketing speke for a walk in the countryside) and mental health.  The verdant green of a spring time woodland or flower strewn verge are a delight. I am less sure about the darkened woods of late summer as the leaves strip out all light or the wilder moors: Wuthering Heights, The Hound of the Baskervilles and Lorna Doon are not set high on the moors by accident. Nonetheless Druridge Bay has that overwhelming calm of sea and sky that King Lear could have done with instead of contemplating flies out in the storm. I have always assumed the “small gilded fly” he observed were Long-legged Flies, Dolichopodidae, perky, iridescent inhabitants of damp vegetation and exposed mud. They do a lot of letchering in sight (green bottles do not, so I’m ruling them out). The sun has brought out the more conspicuous Dolichopodiae in skipping, fizzing mobs. Most are very tricky to identify but one is not, Poecilobothrus nobilitatus, on account of the white wing tips of the males. These frantic suitors whirr and fan their wings to females, then hop and skip back and forth over the object of their amorous attention. However since they all tend to crowd together in the drying puddles and rims of the ponds the mob is a constant agitation of distracted flirting and collisions. As each fly shifts and twitches new neighbours jump into view so within seconds they seem to have lost sight of their intended.  They are also easily distracted trying to yank midge larvae out of the mud which they chew up with macerating mouth parts.  If you approach to abruptly the whole mess of flies scatters but lie down to watch and they will soon return to their choice patch of mud for another round of dancing.  They are flies of high summer’s hot days as the ponds dry down to squirming mud and a delight to watch.

The burnet moths cyber noir day out

The July warmth has unleashed a very special day along the dunes around the Druridge Bay Country Park; the burnet moths have hatched. They are not rare nor unfamiliar, but well worth the time to creep up and admire. The newly emerged are shimmering black winged, whilst their bodies are the deepest sable fur. Vivid red spots blotch their wings, five or six spots per forewing depending on the species. Antennae stand proud, a filigree segmented hook of which the finest blacksmith would be proud. They seem slightly out of place on the dunes, dressed for Frank Millar's Sin City. Seen against the yellow of Birds Foot Trefoil or gaudy purple-pink of the Bloody Cranesbill, the burnet moths add to a remarkably colourful dune-scape. Maybe the Burnets are more fin de siècle Gustav Klimt that contemporary cyber noir. The males whirr, slightly clumsily, low through the marram stems or cluster on thistles. They can detect a female in her cocoon even before she emerges and the males wait around to mate even as she hauls herself out. Here are a pair with the females white cocoon as their foot hold. They shimmer in the sun. The high summer butterflies are also out in force. Common Blues fizz  past, the more tentative Small Heaths flitter away from out under your feet and Ringlets bob low amongst the stems as if on the end of invisible strings. Walk the dune path south of Druridge Bay Country Park and you will find these beautiful insects in abundance. The burnets do not last long, their extraordinary looks maybe burn out too soon, befitting their vanity, which deserves your attention.

The Hauxley time machine pond comparison website

The experimental ponds at Hauxley were dug in the autumn of 1994, to monitor the development of the animal communities from the very origins of the habitats. I had imagined this might go on for a few years but not twenty, but the value of the ponds as a study site increases with every passing year. The photo shows one of the original ponds at the front and, just behind, one of the new pools dug out by postgraduate Scott to explore the links between productivity, water chemistry and carbon accumulation in the sediments. In 1994 the old pond looked just as bare and abrupt as its new neighbour, the exposed clay base glistening in the June sunshine, stamped with heron footprints and jackdaw beak stabs. The old pond is now substantially infilled with debris and this is overlain with a sward of moss. Sticking up through are the stems of curl dock, Rumex crispus, their leaf edges conspicuously waved as if the growing leaves had expanded to some precise oscillation. These docks are common place but do not establish in properly submerged habitats. Here they are evidence of the increasing terrestrialisation of the old ponds. The new ponds have rapidly acquired the same pioneer animals that have now largely vanished from the old sites. In particular swarms of waterfleas, Daphnia obtusa, have appeared. The raw, new ponds seem to hold as many species as their twenty year old neighbours. It looks like the new ponds will follow the same trajectory of colonisations and extinctions as the older ponds.

The pond field is looking very beautiful. This year the greens are especially verdant, and the flowers radiate red, yellow and pink against this perfect backcloth. The clouds of pink are ragged robin, Lychnis flos-cuculi, their flowers seeming to hang in the air as if the slightest breeze can keep their confetti shape aloft.

The giant fly attack time of year

Summer now has the wetlands and dunes in its thrall. The warm, wet spring seems to have nurtured the richest greens and every flower is all the more intense against a backcloth of verdant meadow or hedge. At Hauxley yellow buttercups, Barbie doll pink ragged robin and purple spikes of orchids rocketing out of the fields compete to be the most garish. By mid June in some years the land already looks parched, the greens half hearted, but not this year. It is also an in-between time, with many birds having got their nestlings away and the occasional flourish of song suggesting a second brood might be on their minds. At Cresswell Lagoon young little gulls and sandwich terns are already hanging around waiting for something exciting to happen, or, at very least a fish to be brought back by parents who now look smaller than their indolent brood. For me high summer only begins when the meadow brown butterflies appear. Other insects are skipping, hopping, pinging and whirring from every footstep. Get down into the grasses and herbs and the sheer effervescence of life is shocking. as are flies as big as the one above, homing in on me. Nervous readers rest assured, it is not huge, high in the sky coming in from behind the tree, but somewhat smaller and probably disturbed as I crept up on a damselfly, whose turquoise body you can see out of focus bottom right. The marauder turned out to be an Empid (or Dance) fly, which often come with a conspicuous, rigid proboscis on which to skewer smaller brethren and suck them dry. They have perky, upright stance and are often furry too; if it was not for the vicious looking mouthparts they might pass as cute. During this same foray I saw an empid knock down a much larger cranefly and try to find purchase to spear its quarry, although its would be victim managed to buzz free and clamber up a stalk to re-launch itself. Judging by those raised legs and direct approach I got off lightly.

The chamber of earthly delights and a question of scale

 

 

Pete, Dave and Philip are unveiling the latest piece of field work kit. A fine example of the different scales at which people work: Pete seems to be taking a remote sensing view point, Dave bit more hands on, Philip going for the fine detail. The item they are revealing should allow us to work at the scale of whole ponds at Hauxley, the new arrival being a perspex chamber manufactured to fit over individual experimental ponds. This will allow Pete to monitor the gas exchanges from a whole pond, in addition to the more fine grained analyses with smaller floating chambers that we can position over small sections of distinct vegetation types. Initial data show that the individual ponds vary markedly, some ponds exhaling CO₂ and methane, others acting as sinks for those same gases at the very same time. The chamber looked surprisingly large when it arrived, (it looked surprisingly large when Pete tried to get it in his car at the factory). It is designed to extend either side of the ponds and wedge down into the surrounding vegetation to create a strong seal. Eventually the lure of bubble wrap got the better of us.

 

Dave, who is no mean craftsman himself is inspecting the workmanship. The chamber is a hefty and stout piece. The next step is to try this out in the field. We will put the chamber over a pond, and connect it up to the portable gas analyser which samples the air inside the chamber and gives real time measures of the changing concentrations. One unexpected outcome of this approach is the very concrete feel for the ecosystem's processes that you get from watching the numbers tick up on a display screen. Suddenly those invisible gases seem very real, the squidgy ground beneath our feet very lively, as if we are standing on some giant creature, submerged in the swamp.

 

What exactly do you do in that field? Sampling Hauxley's ponds

The experimental ponds at Hauxley have proved a revealing time machine. Since they were dug out in the autumn of 1994 their animals and plants have been monitored, allowing the changing communities to be tracked in detail. For the first ten years all thirty ponds were sampled in January and early summer (late April to early June, depending on how fast they were drying out). Since 2004 the animal life has only been checked in five of the ponds, simply because of the logistics, although it is a race between the science and my knees giving out. The sampling is used to record the presence and absence of taxa, first of all using a small, fine meshed aquarium net to sweep the open water, then a stout pond net to rake round the edges and through the plants. Each pond is sampled for between 2-3 minutes. I keep on doing this until no new taxa turn up in the white trays. Here I am crouched over the trays checking all the creatures wriggling and crawling.
As I do each tray I pour the contents into the blue box to hold the animals until I can put them back alive into their home pond.  Presence/absence is very basic but I like the idea of putting back the animals rather than killing them all in samples, though I suspect they are not keen on being dredged out in the first place. Many of the animals are small, but a hand-lens works well for identification although I do keep some beetles, Chironomid midges and Ostracods (pea shrimps)to check. All of the ponds are now choked with mosses and grass. The animals of the bare, raw ponds of 1995 and 1996 are largely gone and overall species richness has declined, probably a mix of predictable changes as ponds age but also degradation from increasing drying out after two very wet years early on in 1997 and 1998. Hunched over the trays has some benefits. Inquisitive stoats have crept up, perhaps wondering if I'd make a suitable meal. A local fox took to lying up next to the hedge to watch me with, I'd swear, an amused smirk on its face. In winter geese wheel away horrified to find a human crouched under their flyway. I probably miss even more wildlife baffled by this strange performance but those trays of animals do not sort themselves.

Monsoons... the pessimism of pollen trapping

Time underpins much of out work at Drurdige Bay: how does the number of ponds vary between seasons, what happens to the animal communities as rainfall patterns change with the years, how much organic carbon accumulates in the sediments since the ponds were dug? We have now added one of the classic methods for tracking the ecology back through time; pollen analysis. Pollen is tough stuff. The pollen spores of different species of plants linger in the sediments, undecayed. Each species, or, at least Family and Genus, has its own distinct spores, characterised by pits and spines, shape and size which can be identified with practice and patience under the microscope. Pollen analyses are the familiar science for characterising thousands of years or more, but we are exploring how fine a scale we can detect changes in the sediments of the experimental ponds at Hauxley in particular inter-annual changes which may be linked to wetter or drier times. Pippa is leading this work, which, like much of what we do, seems to involve digging. Here Pippa is not digging out a core for analysis. Instead she is putting in pollen traps to sample the rain of grains from the contemporary vegetation. Two sorts of traps are involved. The first looks like a minuature R2-D2 from Star Wars that has been sunk into the ground leaviung only its silver dome surmounted by an ornage or pink mesh cap. You can see one just below Pippa's hand. The second type of trap is a thinner tube held aloft from the ground on a stick. Apparently this is the sort of trap you need for monsoon conditions. I'm not expecting a monsoon, although after the deluge of the summer of 2012 it may be best to be prepared. Generally the coastal strip of Northumberland is dominated by rain shadow from the hills to the west, almost semi-arid by some measures. A monsoon would be new.....