I will be investigating the effect of temperature on the abundance of rabbits in a given area. The organism I will be investigating will be the rabbit and I must ensure it is the same species of rabbit to ensure valid results as different species of rabbit may prefer different temperatures. My independent variable is temperature and to carry this out I will measure the population of the rabbits in a given area at different times of the year and therefore at different temperatures. I will take readings on days where the temperature is roughly 0°C, 5°C, 10°C, 15°C, 20°C, 25°C and 30°C and will use various thermometers in the area to obtain an average value for the temperature. I will repeat my readings at least three times at each temperature to improve my reliability. The dependent variable will be the population size of the rabbits in the given area. To measure this I will use the mark, release and recapture method whereby the rabbits are safely caught using a rabbit trap are marked with a band and then recaptured. These rabbit traps will be randomly distributed within the marked out area using a random number generator and the traps are placed on a coordinate grid. Those of which are marked and unmarked are noted and counted again. The time period over between release and recapture will be 120 minutes and this will be one of my control variables. Using the Lincoln index I will put together these values to obtain an estimate of the population in that area. My control variables will be the availability of food meaning there should be no lack of food in the area otherwise this may put off rabbits and affect the results. This may mean that when there is significantly less vegetation, putting in place food substitutes to maintain a constant food supply. As well as this, I will control predation in the area, preventing animals such as foxes from affecting the rabbit abundance.
There are issues associated with this experiment as it assumes there are no deaths, births of migrations. Therefore to take these into account I will make a note of the time of year the readings were taken to work out if they were taken before, during or after breeding season so I know of any external influences on the results. As well as this, when carrying out the mark, release and recapture sampling method, I will ensure that the way in which the rabbit is marked is safe, ethical and will not affect their chance of survival by reducing their movement which would therefore affect the results. Another issue with this would be that assumptions are made with how effectively the rabbits will be distributed after being released. I will take into account that they will not be evenly distributed which means they are likely to be more abundant in certain areas. To overcome this problem, I will leave them for 120 minutes (2 hours) to allow more time for them to spread out.
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Ciara Branagan
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October 2016
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