Sixth Form Scientists put theory into practice at Ecology Field Day

Our Year 13 Biologists recall some of their most memorable moments of the wonderful, sunny day in October which they spent carrying out Ecology Field Work. They were shown how to utilise different techniques to estimate populations of a range of organisms living in various habitats and also spent time collecting data for a required practical they had already planned, investigating the effect of an environmental factor on the distribution of an intertidal species at Kimmeridge.

Upon arrival at Leeson House we were shown some Longworth Mammal traps which had been set out the night before, only one of which was successful. We emptied the trap into a plastic bag with shredded paper, to maintain heat, to find a Bank vole in there. The Bank vole was released in the same area that it was originally trapped, in the woodland area next to the stone wall. One of the other traps had been successful, up until the point the mammal inside had managed to eat its way through the metal casing.

The moth trap we were shown was essentially a large bucket with a plastic lid with a hole in it. On the previous night a light had been placed inside the trap and moths flew in attracted to the light and were unable to fly out. There were egg cartons and newspaper shavings in the trap for the moths to rest in once they were inside. One by one we took out the egg cartons covered in moths. Mike was able to identify the different moths, my favourite being the snout moth. The moths were cold and had to vibrate their abdomens before they could be warm enough to fly away. When they did it was beautiful and they often flew straight into hedges.

At Leeson House we used the mark-release-recapture technique to compare two populations of woodlice, by taking samples from underneath wooden logs or in a stone wall. The woodlice had been caught and marked with pink paint the day before our count and we had to recapture as many of the population as we could in a 10 minute period. After collecting our samples we counted how many of the woodlice we found had been marked with pink paint and the number of woodlice without pink paint. We then used the Lincoln index to calculate the approximate populations of woodlice in each area.

Lichens are a type of pioneer species formed of two different species coexisting, algae and fungi. The algae are protected by the fungi and carry out photosynthesis to make organic compounds from carbon dioxide and water. We were shown the distribution of lichens on a wall, and how the abundance of different types was affected by the varying conditions of light on the North and South sides of the wall.

Sweeping nets were used as a method of collecting animals from vegetation by sweeping the nets through long grass and bushes; this led to different types of species falling into the net and enabled us to examine them up close. Another method we conducted was tree beating. One person stood under a tree with a large catching net while the other shook the tree, resulting in different species falling into the net due to them becoming dislodged and falling off the leaves and stems into the catching net where we collected them for examination. Using these methods we collected and named many organisms including different spiders, red spider mites, ladybirds, leaf hoppers and snails.

While we were at Leeson House Mike set up a mist net and showed us two birds (a Nuthatch and a Bluetit) that had been caught and then placed in bags. A mist net is a fine meshed net strung up vertically, catching the birds as they cannot see it and fly into it. Once caught, the birds were handled carefully and had a numbered metal ring put around their leg which has the contact details for the Natural History Museum. After the rings were fitted various measurements were taken like wing length, approximate age and gender before we were allowed to release the birds again.

Another activity we carried out at Leeson House was pond dipping. We went to a small pontoon with a net and caught animals by moving the net in a slow figure of eight motion. We then put the animals in a small tray to examine them closer. Creatures we collected included leeches, red blood worms, newts and pond skaters.

Then we went to Kimmeridge Bay where we had lunch and then carried out our required practical 12. This was an investigation into the effect of distance from the low water mark on the distribution of either a species of mollusc, limpets (Patella vulgata) or rough periwinkles (Littorina saxatilis), or of barnacles, which are crustaceans,. Each group agreed that Kimmeridge Bay’s rocky shoreline showed great examples of zonation, of seaweeds and various species of invertebrates, and I definitely feel that I learnt a lot when we were down by the water. Our guide from Leeson House, Mike, was very knowledgeable about marine life, sampling techniques as well as fossils and it was great being able to ask him questions about the ecology of our local beaches. We worked in groups using transects and quadrats to acquire data that we have since used to learn about statistics. We also measured temperature and height changes from the water line, and it was definitely nice to be able to practice these techniques ourselves rather than just learning them from a textbook.

After we had collected data for our required practical, we spent extra time down on the beach at Kimmeridge looking in rock pools. Within a matter of minutes we were showing each other the biggest cushion starfish we could find and multicoloured crabs of several different species, some the size of our hands but some smaller individuals which were very aggressive. Snakelocks and beadlet anemones were dotted around, which grasped onto our hands as we brushed past them, and the small shrimps and fishes were a great entertainment to see dancing between the colourful seaweeds. If there hadn’t been the temptation to go looking for more animals in the River Piddle we may never have left.

At the River Piddle we used the kick sampling technique to catch and then identifybenthic invertebrates living on the river bed. Having put on particularly attractive thigh length waders we held large nets downstream and kicked and stomped in front of the net for 10 seconds to disturb the substrate and catch any organisms. Some invertebrates we found were snails, caddis fly larvae in their cases, water boatman, bloodworms and some fish.

Abiotic (non-living) information was obtained from data we collected testing pH, concentrations of phosphates, nitrates and oxygen and the flow rate of the water where we were taking our Biotic (living) samples from the River Piddle.

Back at school it was interesting to see the results of using the technique of thin layer chromatography (TLC) on the samples of seaweeds of various colours collected from different zones on the beach at Kimmeridge. Thanks to Mrs. Newland, Dr. Jancis and Cora, the Biology technician, for organising such an enjoyable and educational day out and for helping us to carry out our practical work and introducing us to some of their favourite ‘animals without backbones’ and helping us to identify some of these invertebrates.