Description of Vegetation Using Visual Ranking of Species

A vegetation sampling technique is described where the prime measurement is only the listing of the relative order of abundance (rank) of species at a series of sample points and is estimated visually. Such data are appropriate for ordinal methods of statistical analysis. Repeated measurements show that the observer is only a small component of variation in rank values. The analysis of rank data for individual species is shown for deriving summary parameters, deriving association between species, and determining significance of changes in ranking with respect to qualitative or quantitative treatment variables. Vegetation types can be defined by the rank order of constituent species, and a hierarchial procedure is described for subdivision of sample data. Repeated measurements at regular intervals allow the application of the transition matrix approach to the study of vegetation trends.