As of today, I am beginning a new series of my blog posts. These will be released every Wednesday and will focus on the wildlife around my home in Norfolk.
In the first of these I will be taking a look at the life in our garden pond: since I used my GoPro to film underwater a couple of months ago I have been really excited to take a closer look at the organisms residing there.
Armed with my cameras, a net, waterproof notebook and a couple of plastic tubs, I set about extracting organisms from different areas of the pond. It is amazing just how much life there is below the surface – the amount of times I have walked past the pond and not even given it a second thought is ridiculous!
The pond does seem to dry out each summer, which lead me to wonder how so much life exists there if it cannot be supported all year round. Having done some research, I have learnt that any creatures that can fly will often leave and then return when the water levels are up again. Some types of larvae can burrow into damp mud in order to survive, but the other organisms are likely to die. They are reintroduced to the pond by accidentally being carried over by visiting birds or mammals.
Unfortunately I do not have identification books for pond life (I really ought to invest in some keys to help me), so I apologise in advance if I have made any mistakes in this post.
The most common creature that I came across was mosquito larvae. I was able to identify this easily due to the way that these organisms hang vertically in the water, and their particular swimming pattern.
The picture below shows two mosquito larvae at different stages in their development. The one on the right hand side is younger and more curled up than the older one on the left hand side.
I believe that the next creature is a caddisfly larva – initially I was unsure, but then I saw some of them inside ‘cases’. Normally these are constructed using tiny pieces of plant and grains of sand, however I saw cases made out of flat leaves: this is a distinctive feature of the mottled sedge caddisfly larvae.
On the surface of the pond I observed pond skaters and whirligig beetles. Before I began to read about pond skaters I was unaware of the fact that they are actually predators that target other animals that have fallen onto the surface of the pond. They also scavenge on dead animals.
Whirligig beetles usually stay near the surface, however if they happen to be disturbed they will swim underwater. In the video at the bottom of this post you can see that the whirligig beetle I discovered must have felt threatened by my presence, as it swam to the bottom of the container I placed it in. (In the interest of the welfare of all of these creatures, I tried to limit the time they spent away from the pond to just a few minutes).
This picture of the whirligig beetle isn’t of particularly good quality – they move so fast that it is difficult to capture them at all…
Just below the surface I came across the common water flea. These transparent filter feeders are abundant in the pond and provide an important food source for beetle larvae.
I initially thought that the next organism was a leech, but was relieved to discover that I was wrong! It is a flatworm, and whilst it is a predator, it wouldn’t have been interested in me as it prefers to feed on larvae and larger dead organisms.
The picture below shows the common water slater: these are mistakenly believed to be an indicator of polluted water, however this is not true (they are just particularly tolerant of low oxygen levels).
In the shallows amongst the plants there were numerous pond snails (I am not entirely sure of the exact species). Many people think that these reduce pollution in the pond but this is not strictly true; whilst the snails do ingest a lot of material, they simply recycle it into other forms – so the pollutants are not actually being removed from the ecosystem.
Much of the life in water is too small to be seen with the naked eye: I feel that I have probably only seen the tip of the iceberg with the amount of life that exists in our pond.
Despite seeming like an entire ecosystem by itself, the pond is not isolated from the world around it. The diversity of life under the surface supports many other groups of animal – for example garden birds, frogs, toads, bats and grass snakes.
The video below shows some of the video clips I gathered whilst pond-dipping. Some were taken using the GoPro in the pond, whereas others were filmed whilst the animals were away from the pond.
I hope that you enjoyed the first post in my new ‘Wildlife Wednesday’ series – stay tuned for more exciting discoveries next week!
(The following website was used in the writing of this blog post: freshwaterhabitats.org.uk )