Comparison of the composition and species diversity of inside and outside of the Arshagh research exclosure in Ardabil province

Biodiversity is the diversity of livelihoods, ecological processes and genetic variation of all species in different periods and the ecosystem structure in order to preserve the life of living organisms. Biodiversity encompasses the number, richness, and composition of beings. In the simplest form, diversity is variation. This study was conducted to compare the composition and diversity of the species in rangelands of inside and outside of the Arshagh research exclosure in Ardabil province. In order to compare the composition and diversity of the species in rangelands of inside and outside of the study area, it was attempted to identify sampling areas with a variety of grazing intensities. Three sites were located in inside and 3 sites in outside of exclosure and sampling was conducted at flowering stage of dominant species. In each of the studied site, vegetation sampling was performed using a randomized-systematic method. In each site, 3 transects of 100 meters were spaced with 20 meters from each other, along the slope and parallel to each transect, and 10 plots of 1 × 1 square meter were deployed at intervals of 10 meters. After sampling and identification of existing species and determining the percentage of canopy and the number of individuals of each species, composition and diversity of species in the site leve was calculated. In each sampling site, soil samples were taken from the root activity depth, and then in the laboratory, some soil characteristics such as silt, clay, sand, acidity, organic carbon, phosphorus and potassium were measured. The study of flora was based on conventional taxonomic methods and the collected samples were identified using relaiable literatre such as Flora Iranica, Turkish Flora and Persian Flora. In order to evaluate species diversity, Simpson, Shannon-Weiner, Brillian and Shannon indexes and Margalof enrichment index were used by PAST software. Comparison of vegetation cover parameters inside and outside of exclosure was performed using SPSS19 software and t-pair test. Results showed that there was a significant difference between the studied parameters, the percentage of bare soil, litter, caopy cover, and content of clay, phosphorous, and electrical conductivity, soil acidity and richness and diversity indices in two conditions. There was no significant difference in percentage of rock and pebble, plant density, percentage of silt and sand, nitrogen percentage, organic carbon of soil and evenness index. Generally, the type of management in rangeland ecosystems in the form of grazed and exclusure in the studied area showed that exclusure can have a positive effect on soil and vegetation characteristics. In other words, with relative improvement of soil conditions and vegetation, the diversity of species in the rangeland was significantly increased.