An investigation to determine variation in marsh orchid (Dactylorhiza) populations at Moses Gate Country Park, Bolton

Abstract

In June 2006, two populations of Dactylorhiza were examined at Moses Gate Country Park, in Greater Manchester, to determine whether variation exists between the two populations. Careful measurements of orchid characteristics were taken at both sites, in addition to soil pH recordings, and the results compared and tested for significance using one-way ANOVA and Chi-square significance tests. Descriptive statistics and box-plots showed that there were indeed differences in orchid height, leaf width and leaf number between the two populations, with one-way ANOVA confirming their significance as P, 0.001 for all the variables. Further analyses using frequency data and Chi-square tests also showed that there were significant variations in spur size, leaf type, labellum shape and petal colour between the two sites with P, 0.001 for all these characteristics. Soil pH data were also analysed and tested using one-way ANOVA which showed that there were significant variations in soil pH levels at both sites with P, 0.001 for this data. It was concluded that there were indeed significant differences between the two populations of Dactylorhiza at Moses Gate Country Park, therefore the null hypothesis was rejected. It was suggested that further investigations could be undertaken at this site, using similar methods, over a number of years, to support this study and to provide further constructive information on the status of the two populations of orchids, which may increase the conservation value of the site.