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Hi, My task is to plan an investigation to find out the distribution and abundance of two named species of plant in a specific habitat and to determine if this is affected by the water content of the soil. I've chosen 2 species of buttercup in a water meadow. Please could you read over it and suggest any areas for improvement. There is a word limit of ~1000 words, but mine is currently 1900! So if there are any areas you feel that I don't need please point them out! Many thanks, AN INVESTIGATION INTO HOW THE DISTRIBUTION AND ABUNDANCE OF RANUNCULUS REPENS AND RANUNCULUS BULBOSUS IN A CAMBRIDGE WATER MEADOW ARE AFFECTED BY SOIL WATER CONTENT Numerous factors exist that influence the distribution and abundance of plant populations in an ecosystem. Factors may be either abiotic, (physical characteristics of a habitat), or biotic, (caused by living organisms). This investigation will explore the effects of one abiotic factor, soil water content, on the distribution of two buttercup species, (R.repens and R.bulbosus), in a Cambridge water meadow. Differences in the environment allow species to survive over others in a habitat. The species best adapted are more likely to survive by out-competing others for vital resources. Interspecific competition is competition between different species for a particular resource in short supply and occurs when the niches of two species overlap1. (The niche of an organism is its role in the ecosystem2).
by the river), place the 0.25m2 grid quadrat next to the tape measure. Count the number of small squares of the quadrat which contain creeping buttercup, (R.repens), and the number which contain bulbous buttercup, (R.bulbosus), using the plant identification guide if necessary. The grid quadrat is divided into 100 smaller squares and thus the number containing each plant species represents the percentage cover of the species in that area. 3. Using the trowel, dig up approximately 10g. of soil from the centre of the quadrat and store it in a sealed and labelled soil sample bag for later analysis. 4. Repeat steps 3 and 4 at 5m. intervals along the transect,up to 50m. This will allow the change in the distribution of creeping and bulbous buttercups across the water meadow to be determined, as well as changes in soil water content. 5. Repeat steps 1 - 5 twice more from different starting points, so that a total of 3 transects will have been taken across the habitat, (as shown below). Repeating the procedure will increase the validity of the results by ensuring anomalous results are noticeable and also provide more extensive evidence to which trends can be confirmed. 6. On return to the laboratory, the water content of the collected soil samples must be determined by weighing out approximately 10g.
One would logically expect the water content of the soil to decrease along the transect, i.e. away from the river. Subsequently, if the prediction that R.repens prefers growing in wet soil, whilst R.bulbosus prefers growing in dry soil is correct, then one would expect to see the abundance of R.repens decrease along the transect, with the abundance of R.bulbosus increasing as one moves further away from the river. If this investigation is successful, further investigations could be conducted into the effects of other abiotic factors on the distribution of these species across such an ecosystem. For example, how changes in the pH, organic matter or mineral content of soil may affect their distribution and abundance. ~1900 Words RESOURCES - Biology 2, Mary Jones & Jennifer Gregory, OCR Cambridge University Press 2001. - Biology 1, Mary Jones, Richard Fosbery & Dennis Taylor, OCR Cambridge University Press 2000. - Environmental Biology, Michael Reiss & Jenny Chapman, OCR Cambridge University Press 2000. - Biological Science 1&2, Green, Stout & Taylor, Cambridge University Press 1997. - Environmental Science, Kevin Byrne, Nelson Thornes Press 2001. - Drawings of British Plants, Stella Ross-Craig, Bell Publishers 1948. 1 Biology 2, Mary Jones & Jennifer Gregory, OCR Cambridge University Press 2001, p32 2 Biology 1, Mary Jones, Richard Fosbery & Dennis Taylor, OCR Cambridge University Press 2000, p93 3 Environmental Biology, Michael Reiss & Jenny Chapman, OCR Cambridge University Press 2000, p85 ?? ?? ?? ?? 29 July 2009 1
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