Evaluation of plant biodiversity in relation to adaphic and physiographic conditions in natural habitats of the middle Zagros (Case study: North Ilam Forests)

Background and Objectives:The Zagros habitat is one of the important biological resources of the country, of particular importance in terms of size, plant and animal species, genetic resources, grazing under forest cover, etc.The study area is part of the middle Zagros forest ecosystem.Due to its structural and vegetative characteristics, it has a high plant diversity.The aim of this study is to determine the relationship between plant diversity and edaphic factors and to identify the dominant flora of the region. Materials and methods:For this purpose, sampling plots were established randomly on the map.In each sample plot, all tree, shrub, plant and herb species as well as physiographic and soil factors were recorded.The species and the percentage of their cover were used as criteria for measuring vegetation cover.The plants of the area were precisely identified.To determine the desired parameters, 80 square plots with a size of 20 20 square meters were randomly selected.In the main plots, the species and percentage of cover of trees and shrubs were noted, then in the four corners of each sample, 4 plots of 1.51.5 square meters whose area was obtained by the species-area curve.Then, the plant species and the percentage of their cover was recorded.In addition, 8 8 square meter plots were set up in the center of each plot to check the regeneration, and the regeneration was divided into two sections, seed and coppice for each species. Results:The results of a 1700-hectare survey of the region's forests showed that a total of 79 herbaceous species belonging to 66 genera and 32 families, 5 tree species and 6 shrub species were identified in the study area.Among the herbaceous species, Bromus Tectorum (L.) with 69%, Picnomon Cass with 62% and Geranium Lucidum with 58% are represented.Hordeum Bulbosum at 51% and Cretaceous Alfalfa (Medicago Radiata) at 49% have the highest presence in the region and among the oak species, Persian Oak (Qurecus Brantii Lindl.) has the highest presence and cover.The Shannon-Wiener diversity index of plant species was positively correlated with organic matter and nitrogen, so that as these elements increased, Shannon-Wiener diversity also increased.Soil organic matter plays a very important role in the growth and distribution of plants.According to the study, the regeneration of oak and wild cherry seeds showed a positive correlation with nitrogen and potassium. Conclusion:According to studies conducted on various plant species in this section, these species possess nutritional, industrial, and conservation value.Therefore, it is essential to protect these existing areas and make efforts to revitalize and develop them.This is a necessity today.Implementing effective management of the predominant unit can enhance the richness and diversity of vegetation in the area, thereby preventing destructive floods in the region.This area provides the necessary conditions for conducting various ecological research.The destruction of forests, vegetation, and soil can play an effective role.The proposed programs include a comprehensive management plan and revised strategies that should be updated every few years based on the region's conditions.