The effect of different management methods on Richness species and Biological forms of plants

The rangeland ecosystem is an important part of the earth and the largest part of the arid ecosystems. rangeland is of special importance in the supply of products (for example, grazing, medicinal plants, fuel, etc.) and services (such as soil protection, flood control, feeding of aquifers, wildlife shelter, carbon sequestration, protection of plant and animal species biodiversity, etc.) They have human societies. Despite the important role of natural ecosystems such as rangeland and their multiple functions, unfortunately, in many countries, especially in developing countries, these ecosystems are in bad conditions and are undergoing deterioration. The main cause of this situation can be seen in the lack of knowledge of the real position and vital functions of these ecosystems on the one hand, and unmeasured and unprincipled decisions in the process of unsustainable exploitation of them on the other hand. In this context, rangeland need to be monitored regularly for proper management and to prevent its destructive process. Vegetation is the most important component of a natural ecosystem, especially rangeland. Investigating the vegetation cover of rangeland and its richness is necessary to determine the next food chains, i.e. other organisms whose life depends on plants. One of the destructive physical pressures on rangeland is excessive livestock grazing. Animal grazing of any kind affects these ecosystems by changing the abundance of key and essential species that guarantee the sustainability and functioning of ecosystems. Livestock grazing can change the quantitative characteristics of plants, such as density, canopy cover, production of species richness, biodiversity, uniformity and percentage of vegetation cover. Investigating the effect of livestock grazing on the changes in vegetation cover in rangeland ecosystems as plant reserves is essential. Examining the list of plants of a region shows an aspect of the plant diversity of that region, which is called species richness. which shows how the ecosystem works. The stability and health of natural ecosystems depend on species richness and diversity. Species diversity and richness are ecologically very important, and with their increase, rangeland stability and diversity will increase, and the latter will lead to an increase in the value of rangeland fodder. In recent years, the accelerating rate of species extinction has opened a new horizon in the investigations and researches related to species richness and diversity. So, in most ecosystems, one of the basic goals of management is to achieve relative ecological stability by preserving species diversity. Due to the destruction of vegetation in some areas of the rangeland ecosystem in the neighboring areas of Golestan National Park, which in recent years has caused the elimination of some valuable species and the emergence of invasive species due to indiscriminate and out-of-season grazing, it is necessary to investigate the changes resulting from livestock grazing for management decisions. Therefore, the purpose of the present research is to review the list of plants, compare the species richness and biological forms of plants in fully protected areas, semi-protected areas, and free grazing areas.

In this research, three areas with different levels of protection and management include; The area with full protection of Yakhtiklan of Golestan National Park against livestock grazing, the semi-protected area of Gorkhoud with seasonal grazing and the Espakhoo area with free grazing all year round were evaluated. For sampling, an area of 250 hectares was selected as a representative area. The plant species in each of the units were collected and identified by field survey. Identification of plant species and determination of plant characteristics including vegetative form, biological form of existing species were also done using relevant sources. The biological form of the plants was determined based on the Raunkiaer method. In each area was spotted four Replications and in each Replication using the Whittaker plots with dimension 20*50 that are scale sampling 0.1, 1, 10, 100 and 1000 m². Species richness (the total number of observed species) was recorded separately at all sampling spatial scales and analyzed using analysis of variance and regression methods.

In general, 88 plant species were identified in the three areas of Yakhtiklan (33 species), Gorkhoud (30 species), and Espakhoo (25 species), belonging to 21 families (Tables: 1, 2, and 3). The number of biological forms and their abundance percentage in the three management areas are shown in Table 6 and Figures 6, 7 and 8. In order to classify the biological form (biological form) and wintering mode of the plant species of the region based on Raunkiaer method, all the identified plant elements of the region were divided into 5 major groups: Therophyte, Chamaephyte, Hemicryptophyte, geophyte and Phanerophyte, among which These groups, Hemicryptophyte, are considered the largest plant group in the region with an average of 48 to 68 percent. From stand point of biological forms, the following relations were obtained: Hemicryptophytes> Chamaephytes>Phanerophytes> Therophytes >Geophytes.After performing the calculations and drawing the regression Equations, the results Showed that in the studied areas, in the Yakhtiklan area, due to lack of grazing and being in complete exclosure, forage production Compared to Climax reaches its maximum, which acceptsa little more large number of animal units, but The reason for not grazing livestock is the richness and plant development due to moderate grazing and the slope of the regression line is less than Ghorkhoud but more than Espakhoo. This is due to the fact that in: Espakhoo region, overgrazing has taken place, but in Ghorkhoud, due to proper, moderate and controlled grazing, the species richness has increased. It can be said that the greater intensity of the protection level in Golestan National Park compared to Ghorkhoud region has not led to an increase in species richness in different sampling scales. In general, the removal or addition of plant species can cause major changes in the structure and dynamics of the society, therefore, in order to preserve the ecosystem and its species elements, exploitation must be done in line with sustainable development. Also, in order to prevent the process of destruction and regression of rangeland, there is a need to provide appropriate and efficient management solutions in the fields of livestock grazing and rangeland revival and reformation programs.