تعيين الگوي پراكنش محيطي و فراواني گونه هاي سرخس در سري يك طرح جنگلداري شصت كلاته

Determining the spatial distribution pattern and abundance of fern species in the series number one of the Shastkalateh experimental forest

Forest ground vegetation is considered to be an important part of forest ecosystems. The aim of this study was mainly to quantify the relationships between the distribution and abundance of fern species with the abundance of dominant trees and also with some abiotic factors of habitats (including physiography, light, and soil) in the series number one of the Shastkalateh experimental forest. As a sample size, a number of 172 plots with dimension of 20*20 m2 across six elevation classes (including 350-450, 450-550, 550-650, 650-750, 750-850, and 850-950 meters above the see level) were used. For each plot, altitude, slope, light intensity, thickness of litter layer, biomass of fern species, and tree canopy cover were measured. At the center of each plot, a soil sample with the depth of 20 cm of topsoil was taken. Soil samples were then analysed to determine moisture content, texture, pH, and, organic C. The biomass of fern species was compared among forest types, elevation classes, and soil moisture using ANOVA and Duncansʹs multiple range tests at 0.05 level. The relationships between fern species abundances and some abiotic factors of the stand were established using Pearson correlation coefficient. Ecological similarity between the fern species were investigated using cluster analysis. Results of this study show that ecological impact of Dryopteris filix-mass (L.) Schott and Pteris cretica L. are more significant in comparison to other species of ferns. The dominant tree species significantly influence on the abundance of fern species. With the exception of Asplenium adiantum-nigrum L., the abundance of fern species is not the same at the different types of forest stands. In this study, fern species are classified into three groups based on their specific ecological requirements. Elevation, soil moisture content and dominant tree species (Oriental beech, Hornbeam, and Ironwood) are among the most important factors influencing on abundance and spatial distribution of fern species in the Shastkalateh experimental forest.