Sunday, 24 February 2013

"it's a lake"....

Pete is looking out over Druridge Pools, a glittering wash land of late winter submerging the verdant meadow. The Pools lie about half way along the Bay, on the north side of the site a deep lake that was once opencast, to the south the old mine infilled and landscaped and now a mirror to the sky. There are supposed to be five distinct ponds here, often hard to pick out low amongst the burst of rushes and wetland grasses. There are also lost ditches and sudden soak-aways: I know from gingerly feeling my way across the field a couple of years back, recording the plants whilst swallows scalpled the air, winnowing the mass of midges, and damselflies flickered around my feet. I tried to keep count but I was more concerned to keep balanced. Dave Cherry, a final year undergrad at Northumbria, has taken some sediment cores across the ponds in the summer of 2012. As with the other permanent, vegetated sites the organic carbon levels in the upper sediments proved markedly higher than in the soil adjacent to the ponds. Pete and I were checking the site to include in our first season of major sampling effort, but as Pete says “it’s a lake”. Which begs the questions when is a lake a pond? One of those questions I always get asked whenever I do a talk. I suspect everyone knows ponds when they see them, which can be confusing when they look like a lake

Wednesday, 6 February 2013

Back to square one

January ice and flood has kept us away from the experimental ponds at Hauxley Nature Reserve, but Scott, Pete and Dave were out at the end of January to begin regular recording of water chemistry, comparing three of the original ponds which were dug out in 1994 to their newly excavated neighbours. The new ponds are clouded with muddy water, the clay seeming to be whipped up by storm and wind. This is how the ponds first looked eighteen years ago too, but soon settled down, the water clearing to leave a faint blur of green algae. Pete is using a portable probe to measure the conductivity and pH, and waters samples will be taken back to the lab to determine nutrient levels, particular phosphate and nitrates. These can be surprisingly variable but that has more to do with the herons who loaf and preen and poo amongst the ponds. The new ponds also beg an ecological question: will their wildlife develop along the same broad pathways as their original inhabitants did eighteen years past? The first two or three years after 1994 were dominated by species thriving on the bare mud, amongst the strands of algae or a twine of Stoneworts. However the ponds are now surrounded by a changed landscape, with a rich cast of wildlife in the adjacent ponds. Perhaps a new sequence of species will colonise, or the old familiar species but faster. I am curious to find out, having recorded the animal life in the ponds ever January and early summer for ten years. It is partly a test of serendipity and history. Will the animals and plants reflect the stark clay walls and bed of the new ponds or will the wildlife be more the result of the variety of species around about, their availability overcoming the limitations of the raw habitat?