Ecological survey of the vegetation in the forest area of ??Vezag (southeast of Yasuj)

Master's thesis in the field of forestry

Ecological investigation of the vegetation cover of the Vezag forest area (southeast of Yasuj)

Abstract

In applied studies to solve ecological problems related to the management and protection of ecosystems Naturally, knowing and investigating vegetation is very important. Ecological investigation of the vegetation of Zagros forests, which are considered the largest vegetation area in the country, the issue of protection and protection is of particular importance. The purpose of this research was to investigate the ecological vegetation of the Vezag forest located in the southeast of Yasouj. In order to collect data related to tree and shrub cover, 61 sample plots of 450 square meters were randomly selected. In each sample plot, the estimation of tree and shrub species coverage was expressed objectively and as a percentage. In order to harvest the grass cover, five micro-plots with dimensions of one square meter were taken in the four corners and center of the main plot, and the type of species and the percentage of its cover were estimated by the Brown-Blanquet method. Also, in order to measure the reproduction of wood species, in each main sample plot, square sample plots with dimensions of 8 x 8 meters were planted and all the branched and seed-bearing seedlings for each species were recorded. In order to determine the ecological groups and index species in the study area, two-way analysis of index species (TWINSPAN) was used. In order to determine and estimate the biodiversity of plants, the numerical indices of species richness of Margalf and Menhinik, Pylo's uniformity, and species diversity of Shannon-Wiener and Simpson were used. Two ranking methods, arcuate adaptive analysis (DCA) and conventional adaptive analysis (CCA) were used to analyze the relationship between vegetation cover and reproduction with environmental variables. The collected samples were identified using different flora. The results showed that there are four ecological groups in the studied area, which are: the first group Quercus brantii-Anthenus italica, the second group Heteranthelium piliferum-Avena clauda, ??the third group Teucrium polium and the fourth group Salvia reautreana. Also, the relationship between ecological groups with environmental variables and biodiversity indicators was significant. The most effective environmental variables in relation to ecological groups were the percentage of litter, height above sea level, percentage of grass cover and percentage of slope. The results showed that the physiographic factors had a significant effect on the indices of plant biodiversity, such that the height above sea level had a significant effect on the Simpson diversity index and uniformity, the geographical direction on the Margalf and Manhinik richness indices, and the slope percentage had a significant effect on the Simpson and Shannon-Wiener diversity indices and the uniformity index. According to the obtained results, the reproduction of tree and shrub species showed a significant relationship with variables such as height above sea level, percentage of stone cover, percentage of litter and soil lime and potassium. In the floristic examination of the plants of the study area, 122 plant species were identified, which belonged to 32 genera and 102 genera, and the most vegetative forms belonged to trophites, and the highest percentage of the elements identified in the study area belonged to the elements of the Turani region of Iran.

Words Key words: Zagros, vegetation, ecological groups, biodiversity, reproduction, flora, environmental factors, Yasuj, toads rtl;">1-1-Introduction

Vegetation includes all plant species and their spatial and temporal distribution in an area and consists of different species (Talis[1], 1991). Plants live socially and in an ecosystem, there is a close relationship between plants and other components (Bebe[2], 1993, Stilling[3], 2002). Since plants are influenced by environmental factors such as climate, soil, and physiography, they have been used in habitat classification for many years to show the habitat conditions and potential production of the forest (Mirzaei et al., 2016). On the other hand, the gathering of trees and shrubs and other small and large plants and animals in a certain habitat is not random at all (Ahmadi and Sheikh Al-Salami, 2013).Vegetation has many conditions and merits to be studied on earth because firstly, the distribution and definition of different types of plant cover and communities is introduced as the science of phytosociology, in which the types and communities are drawn in vegetation maps, and secondly, the study of the relationship between plant species and their environment as a habitat for animals, birds and insects plays the most important role in the fate of the creatures of the planet. The effects of environmental heterogeneity on vegetation are well known, and although such reactions of vegetation are manifested in their distribution patterns, they mainly change the composition of vegetation and appear on a macro scale (Moghadam, 2010). Having information on vegetation cover may help us to solve ecological problems such as management objectives on cover and biological protection. In fact, by studying vegetation and various environmental factors such as physiography, soil and climate, it is possible to understand the stability of plant communities and the correlation of these factors with vegetation, which is very important and practical for the development and restoration of forest communities (Basiri, 2012). Vegetation description has always been an important part of ecology studies and the relationship between habitat conditions and vegetation has been investigated by various researchers (Whitney [4], 1991, Hicks and Piercy [5], 1997 and Kashin [6] et al., 2003). Geographically, Iran is located in an area of ??the Northern Hemisphere that is usually poor in forests. Nevertheless, due to the country's climatic diversity, its vastness and the Alborz and Zagros mountain ranges, various forests have spread in it. The Zagros vegetation area is considered as the largest vegetation area in the country (Arianvand and Pirokili, 1374), which with an average length of 1500 km and a width of 75 km extends between two orbits of 29 to 38 degrees north latitude and 45 to 52 degrees east longitude, from an altitude of 650 to 2700 meters above sea level (Yousfi et al., 1381), which extends from Sardasht located in West Azarbaijan province to Fasa. Located in Fars province, it has expanded and includes the provinces of West Azerbaijan, Kurdistan, Lorestan, Kermanshah, Ilam, Khuzestan, Isfahan, Chaharmahal and Bakhtiari, Kohgiluyeh and Boyer Ahmad and Fars. These forests play a very important role in preventing soil erosion, softening the climate and protecting the environment of the region and the country. Also, the presence of diverse plant and animal species has made this region different from other regions and has drawn the attention of most biological science researchers. Today, these forests are exposed to destruction (Fattahi, 2013). Therefore, these forests are in urgent need of support and protection, which requires a better understanding of the relationships between plants and habitat conditions in the ecosystem and its biodiversity, which are one of the important goals of managing environmental units and achieving the principle of continuous and sustainable development. The forests of Kohgiluyeh and Boyar Ahmad provinces are located in the growing area of ??South Zagros and include one million hectares of Zagros forests. The dominant species of these forests is Iranian oak, and other species such as acorn, wild almond, hawthorn, sparrow's tongue, wild pear, maple, etc. are present along with it. The researched area is a part of the forests of Kohgiluyeh and Boyer Ahmad province, 15 km southeast of Yasuj in the Vezag region, which has great diversity in terms of topography, geographical directions, species richness, and specific habitat conditions, and has created a special vegetation landscape in the region. Due to the fact that there is no report on the ecological study of vegetation in this area, for this purpose, this research is carried out in order to conduct studies of vegetation and separate the existing communities and investigate the biodiversity of the area for better management. In addition, in this research, the natural reproduction of tree and shrub species in the region is also investigated, so that by obtaining this information, an important and effective step can be taken in the direction of preserving and reviving tree and shrub species in the region, and by examining the effect of various environmental factors on the natural reproduction of species, practical and appropriate solutions can be provided in the matter of afforestation of native species.