Marzban Faramarzi

Rangeland condition in relation to environmental variables, grazing intensity and livestock owners' perceptions in semi-arid rangeland in western Iran

Rangeland condition has often been assessed in relation to either botanical, edaphic, environmental or management factors. In this investigation, we analysed the interaction of soil and topographic variables, management and range condition against the background of a sociological survey of livestock owners in western Iran to better understand the main influencing factors of rangeland quality in the area. In four grazing areas in Kermanshah differing in grazing pressure, environmental variables and livestock owners’ perceptions on range condition, investigations of botanical composition, soil and topographic variables were carried out on 43 main plots. To evaluate range condition, four factors were considered, namely litter frequency, herbage palatability, amount of biomass, and percentage of bare soil. A questionnaire was used to obtain information about management practices, the perception of livestock owners on range condition and suggested solutions to problems in the different grazing areas. The range condition scores showed that the condition of the sites was either fair or poor. Of the soil and topographic factors, only north-facing aspect explained part of the variation in range condition scores. High grazing intensity was associated with poor range condition. To improve the rangeland condition, measures influencing water availability and a reduction of grazing pressure seem to be more relevant in the study area than fertilisation or seeding.

Variation of plant diversity components in different scales in relation to grazing and climatic conditions

Background: Understanding the role of livestock grazing on plant diversity can be improved by an accurate measurement of diversity at all hierarchical scales due to the changeability of diversity components in space. Aims: We evaluated the effects of grazing on plant species diversity at different scales of all common and rare species in two regions that have different climatic conditions (arid vs. semi-arid). Methods: In each region, we collected abundant data of plant species from a nested sampling design that consisted of local (80 plots) and regional (16 sites) scales. We partitioned total species diversity (γ) into within plots (αl), among plots (βl) and among sites (β2) using the additive partitioning. Results: Diversity among sites contributed the most to total diversity for all and rare plant species in both regions. In addition, α1 and β1 diversities in ungrazed areas were greater than those in grazed areas for all and common species in both climates. Conclusion: Abandonment of grazing after 10 years resulted in significant regeneration of common species at the local scale, with no change in rare species. We conclude that low grazing intensity is likely to be an important tool for conservation of plant diversity in which all scales should be considered.

Landslide susceptibility mapping by using fuzzy logic: a case study of Cham-gardalan catchment, Ilam, Iran

Landslides are introduced as regional movements, which influence different engineering structures such as roads, railways, and dams and cause the person’s death. Identification of landslide zones may decrease the financial losses and human injuries or deaths. This study tries to achieve a landslide susceptibility mapping in Cham-gardalan catchment by weighting the main criteria and the membership functions of fuzzy logic. For this, we applied the best relationship function between the presence and absence of landslides as well as a collection of the elements. At first, the landslide points were identified by the means of some components those of satellite images, topographical (1:50,000) and geographical (1:100,000) maps, field visits, and Google Earth software followed by the preparation of landslide distribution maps. Then, all effective landslide factors such as percentage of slope, slope aspect, height, geology, land uses, distance from roads, distance from drainages, distance from breakage, and precipitation map have been utilized in order to conduct the fuzzy analyses. Landslide susceptibility map was performed by fuzzy operators (Gamma, Product, Sum, Or, And) in the study area. After fuzzificating and weighting, the effective criteria of landslides were determined through fuzzy Gamma operators with the landaus of 0.2, 0.5, 0.8, and 0.9 and by comparing final maps for making an appropriate model of landslide susceptibility mapping. The regional susceptibility map represents the landslide-prone areas in five categories those of very low, low, moderate, high, and very high. Our results indicated that among the applied operators, Gamma with landau of 0.9 can be used as an appropriate method for mapping the landslide susceptibility due to the suitable fuzzification of given criteria based on landslide distribution maps. In addition, the elements of road, percentage of slope, distance from drainage, and geology were recognized as the most important factors for occurring the landslides.