Vegetation boundary detection: a comparison of two approaches applied to field data
2002
Choesin, D. | Boerner, R.E.J.
We examined and compared two approaches to vegetation boundary determination by applying them to field data collected from Betsch Fen, an alkaline wetland in Ohio, USA. Two boundary detection methods were used to test hypothesized boundary locations determined through field observations: gradient analysis by detrended correspondence analysis (DCA) and the moving split-window (MSW) technique. These two methods represent approaches suggested by vegetation analysis and landscape ecological literature, respectively. DCA was more successful in detecting vegetation changes at the community level, but it was often difficult to extrapolate this information to a landscape context. In contrast, MSW detected changes at a landscape level which overestimated minor shifts in species composition at the community level. Although results from MSW were more easily interpretable, neither method completely confirmed hypothesized boundary locations derived from field reconnaissance and aerial photo analysis. While DCA and MSW can be used in conjunction to provide maximum information on boundary location and ecological significance, this would be unrealistic in practical applications because of the time and effort required to do both simultaneously. We suggest an approach using primarily MSW principles, which take into consideration community-level information and optimum sampling plot placement and spacing.
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