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SEPG 2165 Date Awarded 2003
Long-term vegetation change in UK chalk grasslands: 1953-2003
Dr Jonathon Bennie
Abstract
Chalk grassland vegetation plots from Dorset, Kent, Yorkshire and East Anglia that were first surveyed in the early 1950s were revisited and surveyed in 2003 to assess trends in vegetation change in this habitat over the past 50 years. 92 sites (35% of the original sample) were suitable for resurvey. Multivariate analysis of this data shows a distinct gradient in vegetation from species-rich grassland of high conservation value at one extreme to mesotrophic swards dominated by more competitive grasses at the other. Over the past 50 years the surveyed plots have tended to shift significantly in composition towards the mesotrophic end of this gradient. The magnitude of this change was found to be negatively correlated to both angle of slope and a topographic radiation index derived from slope and aspect. This result suggests that the slope and aspect of a plot indirectly influences its resistance to vegetation change through effects on soil factors and microclimate.
Published papers:
Bennie, J. , Hill, Mark O., Baxter, R. and huntley, B. Journal of Ecology 2006, 94 355-368,
www.blackwell-synergy.com/pdf/10.1111/j.1365-2745.2006.01104.x
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