ecological sampling methods

Ecological Sampling methods The purpose of the methodological process carried out during the investigation was to identify the path taken to obtain reliable results. Having researched a range of methods, there are few that appear relevant for the study. The table on the right shows the different diversity indexes used to quantitatively measure how many different types of species there are and the evenness of their distribution. An example is the Shannon index which measures the species richness and the proportion of each species within the community via the Shannon-Weiner index (H) A measure of evenness (E) is important when looking at the similarities in the abundances of different species. This is important for studies involving a comparison, so will not be included in this investigation. Researching further has revealed a more efficient method of measurement. The Braun-Blanquet cover/abundance scale having been adapted by D. Mueller-Dombois and H. Ellenberg from “Aims and methods of vegetation ecology” 1974 (8), has been exceptionally useful for the methodology. The aim of this was to determine the best way of measuring percentage cover of plant species. Rather than using the traditional way of counting the number of plant species and using relative abundances to see how much space it takes up, the method details assigning each species to a ‘percentage cover class’(8). As it would be too subjective to assign numbers such as 48% to a plant species on the same plot of land, the cover class system relies on categorically identifying an approximate range for which the percentage cover could be measured. A table showing the Cover class system of measuring percentage cover (8)

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Ecological sampling methods related to biology a level edexcel.

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Ecological Sampling methods

The purpose of the methodological process carried out during the investigation was to identify the path taken to obtain reliable results. Having researched a range of methods, there are few that appear relevant for the study. The table on the right shows the different diversity indexes used to quantitatively measure how many different types of species there are and the evenness of their distribution. An example is the Shannon index which measures the species richness and the proportion of each species within the community via the Shannon-Weiner index (H)

A measure of evenness (E) is important when looking at the similarities in the abundances of different species. This is important for studies involving a comparison, so will not be included in this investigation.

Researching further has revealed a more efficient method of measurement. The Braun-Blanquet cover/abundance scale having been adapted by D. Mueller-Dombois and H. Ellenberg from “Aims and methods of vegetation ecology” 1974 (8), has been exceptionally useful for the methodology. The aim of this was to determine the best way of measuring percentage cover of plant species. Rather than using the traditional way of counting the number of plant species and using relative abundances to see how much space it takes up, the method details assigning each species to a ‘percentage cover class’(8). As it would be too subjective to assign numbers such as 48% to a plant species on the same plot of land, the cover class system relies on categorically identifying an approximate range for which the percentage cover could be measured.

A table showing the Cover class system of measuring percentage cover (8)

The diagram illustrating the percentage cover class being measured

The cover class method provides the most efficient way for measuring white clover on the meadows. This study will adopt the use of such cover classes in measuring white clover, in order to ensure the most accurate results are achieved and to the most suitable standards.