Matt and I needed to thrash this churned up pond during my work experience with him, and we found a wealth of interesting life hiding in the rising silt of the pond. Grazing animals such as cows and sheep often come into ponds like this to bath and drink, and as a result a lot of grit and animal faeces are stirred up and reveal some interesting life near the pond floor. We located two major habitats within the pond that we needed to thrash, one of which was the clear bank nearest to us, where we could see pond skaters and whirligigs Whirligig beetles are small predatory beetles that skim on the surface of water, and use a collection of air bubbles they carry around with them, in order to dive and catch small invertebrates. They get their peculiar name from the unmistakable circling pattern they make when moving on the surface of the water, which is reminiscent of the spinning tops that they are named after.

On the left and right sides of the pond, where there was more aquatic vegetation, we found smaller water beetles. The water was murky from the silt, making it hard to see anything below the surface, and Matt had to wade in quite deep to find any of the dragonfly or mayfly larvae, or to pick leeches off the surface of the sedge and pondweed. Thrashing this area was harder than the first, since we could not properly see where the weeds were below the surface, and they dragged into our nets. Despite this, we found a number of beetles we had not seen in any pond that day, and collected them to be dissected to identify their exact species.

 After thoroughly thrashing the pond for about an hour, Matt and I found water boatmen, water skaters, whirligigs, a nasal leech, emperor dragonfly larvae, mayfly larvae, caddisfly larvae cases, many small water beetles and bloodworms. The pond can be considered fairly productive, with a healthy foodweb, although it is likely that grazing animals wallowing in it has had a large effect on the ponds diversity.

While pond thrashing on my work experience with Matt, we went to a pond that was filled with numerous amphibians, such as frogs and newts. It had been listed as a fishing pond on the map, and the water was filled with healthy British plants, all of which point towards a diverse and productive pond. Upon reaching the pond, we could hear the croaking of marsh frogs, which are a non-native species, and shouldn’t have been in the pond. The most likely reason for their presence in this pond is that someone had them as pets, and chose to get rid of them by dumping them in a nearby pond. They are part of the genus Pelophylax, which contains the ‘green frogs’ of the Old World. We searched the pond’s banks for the different areas that we’d need to thrash for invertebrates, and found a few separate habitats. On the close bank, it was all open water, with few pondweeds and many larger snails floating in it, such as greater pond snails, and ramshorn snails. Water beetles and other smaller invertebrates lived in this area, with most of the larger, carnivorous invertebrates living deeper in the weeds.

On the left bank, there is a thicket of dense water mint, and lots of pondweeds in the water next to it. This is ideal habitat for newts, as they have covered areas to hunt and hide, as well as the large thicket of water mint, which is ideal for newts to lay their eggs on. We found two kinds of newt in the pond, including the rare and protected Great Crested Newt, which prevented us from disturbing that area of the pond further, to avoid agitating the newts. We also found a full grown Palmate Newt and a Common Frog and it’s tadpole hidden in the weeds and on the bank. On the far bank, there is an area of deep water, which can be seen by the lilies, which will only grow in places where the water is deep. The marsh frogs that Matt and I heard earlier jumped off of the bank and into the pond as we came past, although none of them sat on a lily pad. Thrashing in this section was fairly easy, and we found a good number of frog tadpoles and larvae.

Matt and I thrashed the pond for nearly an hour before we stopped. We had found a large number of amphibians and invertebrates, including water boatmen, caddisfly larvae in their cases, mayfly larvae, dragonfly larvae, damselfly larvae, various small water beetles, water skaters, greater and lesser pond snails, ramshorn snails, palmate newts, great crested newt tadpoles, common frogs and marshfrogs. This was an extremely healthy and diverse pond, with numerous predatory vertebrates, many specimens of smaller invertebrates, and abundant local flora, such as the water mint.

While going pond thrashing for my work experience with Matt, the third pond Matt and I needed to thrash was a large, open pond complex in the middle of what used to be an airfield. The area had been allowed to become overgrown and turned into a nature reserve, and the pond we were thrashing had used to be a gravel pit where a large tanker had once sat. We inspected the pond for potential habitats, which we would thrash to find the invertebrates in the pond. We found that the pond was filled with a pond weed called Crassula Helmsii, or New Zealand Pygmyweed, which is a highly invasive species that has taken over many ponds in Britain and killed of other pond flora. The far bank there is a large area of open water, free from pond weeds, and home to many of the smaller water beetles within the pond. It was easy to thrash this area of the pond, since it wasn’t strangled by Pygmyweed, and by stirring up the mud and slit beneath the surface of the water, we easily brought up a number of beetles.

On the far left there was an area that became shallow and clogged with mud, that made it difficult to thrash, and contained various tiny larvae, such as fly and mosquito young and bloodworms. Due to the difficulties we faced with the shallow mud in this pond, we used a different method to survey this habitat. This involved creating holes in the mud with our feet, so that water would flow into them, and we could use a fine sieve to pick out and organisms hiding amongst the dirt. Beyond the muddy section, just out of shot of the camera, was an area filled with Crassula, creating a swampy habitat, that many invertebrates such as boatmen larvae and backswimmers could live in, hiding under the cover of the weeds. This meant that we needed to search this area thoroughly until we could find no new species. Following thrashing the pond for nearly and hour, Matt and I had found water boatmen and their larvae, emperor dragonfly larvae, mayfly larvae, damselfly larvae, the shells of caddisly larvae, mosquito larvae, bloodworms, various water beetles, pond skaters and small pond snails. Interestingly, on the bank of the pond, we found evidence of solitary bee nests in the soft, red earth, although it was to windy for them to come out. Overall, this pond could be considered productive and diverse, with a great number of small water beetles and different larvae, although the presence of New Zealand Pygmyweed likely removed some of the diversity in the flora of this pond.

While doing pond surveys on my work experience, Matt and I arrived at a pond only to find that it was no longer there, leaving only a scattering of leaf litter and various aquatic mosses, surrounded by sedge and other plants. After the hot spring, the shallow woodland pond had dried out, and all of the invertebrates and other organisms had moved to other ponds or died out. Many ponds are temporary and will appear and disappear with the changes in the seasons, and the invertebrates in them, such as Mayflies and Caddisflies will move out to different ponds that are still around at the time, before returning when the pond refills, if it ever does. Such temporary ponds are essential to allow invertebrates and amphibians to thrive, since fish are unable to live there. This means that many species are preserved in such ponds, and the protection of these areas is essential too preserve the diverse ecology in British ponds. Unfortunately, it was not possible to survey this pond while dry, so we took a few photos of the area, and marked it down as dry when visited.