The aim of this study was to identify the ecological species groups and investigate the diversity among them. The research area comprises in a coastal system of Boujagh National Park, in Northern of Guilan Province, Iran. Vegetation sampling was carried out along 6 shore perpendicular transects, ween minimum 153 m and maximum 5562 m long. A total of 52 plot of 25 square meters were taken in transects. In each sampled plot, the cover percentage value of each species was estimated using Bran-Blanquet scales. Vegetation classified using Two-Way Indicator Species Analysis (TWINSPAN). Classification of plots showed four vegetation groups: Convolvulus persicus - Crepis foetida, Argusia sibirica, Eryngium caucasicum - Juncus acutus, Rubus sanctus. Plant diversity in these vegetation groups have been evaluated. The comparison of diversity indices among groups were performed with ANOVA test. Results of analysis of variance in species diversity indices showed significant differences among the groups in terms of biodiversity indices. The survey of variation in the groups showed that group 3 had the highest and group 2 had the lowest Shannon-Wiener’s, Simpson’s and Fisher’s diversity indices respectively. In Menhinink’s and Margalef’s richness indices group 2 and 3 had the highest and group 1 had the lowest measure. In Sheldon’s evenness index group 2 had the highest and group 3 had the lowest measure. Finally, the overall survey of indices showed that groups 1 and 2 had less diversity but had more evenness than groups 3 and 4.This shows that despite suitable living conditions for the growth and development of vegetation in the groups 3 and 4, the abundance of species has declined Because of the destruction done in this section.
