Here is one of the two methods being used to collect the samples at each site. Verity & Alex are currently using this technique, which involves drawing three figures of eight in the lower, mid and upper regions of the pond. The net used is a fine mesh, rectangular aquarium net.
One type of freshwater invertebrate that we have identified from our ponds belongs to the family Culicidae, and is commonly known as mosquito larvae. We have found this species to be quite abundant in certain ponds. These larvae have a well-developed head with mouth brushes used for feeding. They also have a large thorax with no legs and a segmented abdomen.
They tend to be found on the surface of the water, and will only dive below the surface when disturbed. The larvae must come to the surface regularly, as located on their eighth abdominal segment are spiricles which they use to breathe through.
The larvae move in a figure of eight motion, and are often referred to as ‘wrigglers’. They move through propulsion with their mouth brushes.
Photo by Neil Phillips
The mosquito larvae mainly feed on algae, bacteria and other micro-organisms found towards the surface of a pond.
In order to grow, during their larvae stage, they shed their skin around four times, getting bigger each time. How long the larvae stay in the water depends on the temperature of the water, but generally takes between 7-14 days.
Water mites (Family: Hydracarina) are mainly found in fresh water habitats. They are usually brightly coloured and are normally between 0.5mm and 2mm in size. A water-mite cannot chew his food. When he attacks an insect larva or some other animal, the mite sucks the juices out of its body, much as a spider sucks the body fluids out of a fly.
Water mites look very similar to spiders in that they have four pairs of legs and they also have a pair of palps. What makes them different is that their bodies are fussed into one, however in spiders their bodies are divided into two segments (cephalothorax and abdomen).
One type of insect that has been observed in the ponds is the swimming mayfly nymph, Baetidae. There are 4 main types of mayfly nymphs: swimmers, burrowers, crawlers and clingers. This website shows the differences between them, and how to find out their genus: http://www.delawareriverguide.net/insects/nymphid.html. Swimming mayfly nymphs are mainly found in ponds and other still bodies of water. These pond invertebrates can be distinguished by their long, flat, torpedo shaped body which ranges from around 3-20mm in length. They have 3 thin long tails at the end of their abdomen, and 6 legs with claws on the end joined onto the side of their thorax. Mayfly nymphs have gills on the sides of their abdomen, which can be feathery or plate-like in structure, which take in this oxygen from the water. They are used in water quality assessments, as they tend to live in areas of high oxygen levels and so are a good indicator of how clean the water is. (Species shown below is an olive swimming mayfly nymph caught in the river Teifi in Wales)
These species are herbivores as they eat plants and algae in the water, and are preyed upon by many different types of species, such as water spiders. They live nearly all their life as a nymph, which can be from a few months to a year, until they shed their skin and emerge as an adult to live out of the water. This process normally occurs in May, hence the name of mayfly. They only live in their adult form for a day or so, of which they use to find a mate and reproduce before they die.
This video, from Ralph and Lisa Cutters “Bugs of the Underworld”, shows more detail on the life cycle of mayflies in general:
In the ponds we tend to be finding a lot of red worm like larvae. We have identified these to be non-biting midge larvae that belong to the family Chironomidae. These are a very biodiverse family and are very hard to identify to species level as their morphological characteristics are very similar throughout the different species. The species in our ponds are thought to be Chironomus sp, also known as “bloodworms”, they are the most common type of non-biting midge larvae in the UK, found in many freshwater habitats such as ponds, lakes, marshes and any other aquatic or semi-aquatic environments. They can tolerate low levels of oxygen and can be found in the bottom of bodies of stagnant water within the mud and detritus at the bottom.
They move by wriggling their bodies in a figure of eight movement and feed off dead plant and animal matter (detritus). They also consume bacteria that live in the mud. The larvae are red as it contains a substance similar to haemoglobin which is good at holding and absorbing oxygen from the gills. Non-biting midge larvae are seen as indicator species as their presence, absence or quantity can indicate the quality of water and if it is polluted or not.
Some say our pond mesocosms look like Beach cocktails, others have said it looks like something from Mary Poppins. But what ever their appearance these little ponds are going to help model colonization rate.
Finally, after much backbreaking work all 32 ponds for the experimental field trials have been dug. Next a quick fill with tap water – not generally seen as best practice for creating wildlife ponds but its part of our study. Then, checked for leaks and left to stand to allow for any chlorine present to evaporate off. After this its up to mother nature to do her bit!
Recent publication raises awareness and educational value of the Reading Urban Pond Project. The case study has been published in the Summer edition of The Journal of The National Association for Environmental Education (NAEE). Its is hoped that creating ponds in people’s gardens will open up a diverse habitat they can explore and learn from.
One who is never shy of exploring the wonders of nature is the former NAEE President David Bellamy. In this NAEE journal edition his successor is introduced. Here is a clip of the great TV botanist doing what he does best.