Evaluating the different indicator species analysis in the classification of plant communities

The goal of this study is to evaluate the quality of numerical methods (Phi fidelity and indicator value indices) and non-statistical (constancy ratio and total cover ratio indices) in determining the indicator species of Beech plant communities in the eastern Hyrcanian forests. For this purpose, six ecological groups were first classified using two-way indicator analysis or TWINSPAN. Then, by using sum of the indicator value/association indices or TFVI, as a similarity index for assignment of the plot to the plant communities, with emphasizing the result of species and plant communities association (based on 10 algorithms), the groups were reclassified. Evaluating the compatibility of the results of each classification algorithms with the initial plant communities which have been classified by Braun-Blanquet synoptic table showed that reclassification of sample sites by using TFVI when is derived by group-equalized and incidence-based phi index (84%) and constancy ratio method (82%) showed the highest adaptability with the initial plant communities respectively. Totally, the results of this research revealed that group-equalized and incidence-based phi fidelity and constancy ratio indices have the most priority in assessing the association between species and groups of sites or in determining the diagnostic species of plant communities than the other association indices.