Study of plant species diversity and species abundance models in Hackberry habitats, Case study: Rezvanshahr and Taniyn of Guilan

The aim of this study was to determine diversity of plant species in Hackberry sites in Taniyan and Rezvanshahr areas in Guilan province. For this aim, circular sampling plots of 0.1 ha were implemented selectively based on presence of the Hackberry trees in study area. In sampling plots, DBH of all trees and number of all shrubs were measured. For wood species regeneration, a sampling plot of 100 m2 was implemented in center of large sampling plots and regeneration counted. Also, for record of herbaceous species, Whittaker nested plot method used that 32 m2 obtained. Values of diversity, evenness and richness were calculated using biodiversity indicators in trees, shrub, regeneration and herbaceous layers. The results showed that Menhinic richness index in tree (1.47) and regeneration (0.91) layers in Rezvanshahr site has more than Taniyan site. Maximum of Shannon-wiener index value in both site was in the tree (2.05) layer and lowest was in shrub (0.27) layer in Rezvanshahr site and in regeneration (1.05) layer in Taniyan site. Shannon-wiener diversity index in tree (2.05) and regeneration (1.56) layers in Rezvanshahr site was more than Taniyan site. Amount of this index in shrub (1.36) and herbaceous (1.2) layers in Taniyan site was more than Rezvanshahr site. Also, Smith and Wilson evenness index in each four layers of tree (0.45), shrub (0.58), regeneration (0.63) and herbaceous (0.54) in the Taniyan site more than Rezvanshahr site. Also, in study areas, species abundance followed in tree layer of the broken stick model and in herbaceous layer of log normal model in Rezvanshahr site and followed of broken stick model in Taniyan site.