Thursday, 26 June 2014
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.