JOURNAL OF RANGELAND SCIENCE
Year:2017 | Volume:7 | Issue:4|Papers Count:11

This edited volume is devoted to the examination of the implications of the inevitable changes wrought by global change on the welfare and livelihoods of tens of millions of people who live in dryland regions. Global change is more than just climate change and the ramifications of changing trade patterns (geopolitical and economic aspects), the shift to the market economy, demographic factors (population growth, urbanization and re-settlement), receive attention here. Land use change specialists, policy makers and natural resource management agencies will find the book very useful.....

This study was conducted in Alzzazah area which lies approximately 25 km East of El-Dmazein city, the capital of the Blue Nile State, Sudan. This study was carried out at the end of the autumn 2015. The aim of the study was to evaluate the impacts of continuous grazing on the rangeland of the study area. To determine this effect, two range sites were selected to represent the rangeland in the study area; a grazed one and a protected one by enclosure. At each site, eight line transects were systematicly distributed.Parker loop method was used to determine botanical composition and ground cover.Quadrate method was applied to determine plant density, frequency, biomass production and carrying capacity. The obtained data were organized and analyzed using standard range management equations and SAS statistical package. The result showed that the continuous grazing increased the bare soil percentage and decreased the vegetation cover.Also, it had negative impacts on botanical composition, biomass productivity and range carrying capacity. It was concluded that continuous grazing has a negative impact; it led to change the botanical composition of range plants of undesirable species with low nutritive value. So it can be considered as one of the main factors responsible of rangeland degradation in the study area.

Species diversity, richness and biomasses (aboveground biomass) and their relationships are the key variables of ecosystems. This study was conducted to determine the relationship of Species Diversity (SD) and Species Richness (SR) with Above-Ground Biomass (AGB) at a local scale at 5 different habitats (shrubland, forbland, grassland, shrub-forbland and forb-shrubland) in Zagros mountains in west of Iran (2015). For each habitat, 50 plots (2m2) were determined. SD was estimated by Shannon–Wiener’s index, SR was defined as the number of species per plot and AGB was detected per unit of area (gm-2). Results indicated that all of relationship patterns existed in these habitats. The unimodal relationship was found in shrub-forbland and forb-shrubland whereas the relationship of SD/SR vs.AGB in shrubland was linear and negative, and in forbland and grassland, it was positive. There were many complex and variable mechanisms dealing with the SD/SR vs. AGB relationship. The unimodal relationship indicates that SR and SD peaked at intermediate levels of AGB, and it is an inherent attribute of the spatially heterogeneous habitats affected by life forms, micro-sites, facilitation and competition. The positive linear was related to positive response of SD, SR and AGB to environmental factors or because of any reason (grazing, disturbance level…), the AGB may not reach to the highest possible level; thus, it may only show a positive relationship. When SD and AGB are affected in the opposite directions by environmental factors such as soil fertility, negative patterns may be caused. The negative pattern represents short gradients indicating a similar species composition among plots. Greater R2 in SD vs. AGB than SR vs. AGB at all habitats showed that evenness and richness (components of SD) are more important than just SR; thus, SD vs. AGB relationship is better and more reliable to predict the variations (SD and AGB).

This study was carried out to evaluate drought stress tolerance inThymus kotschyanusaccessions using a factorial experiment based on a Completely Randomized Design (CRD) with 5 replications during 2013-2014 in Qom, Iran. The first factor was the accession with 17 levels and the second factor was drought stress with three levels of irrigation including 80% (control), 60% and 40% Field Capacity (FC). Data were collected for shoot length, root length, root to shoot length ratio (R/S), shoot fresh yield, oil percent, oil production and Relative Water Content (RWC). Result of analysis of variance showed significant differences between accessions, irrigation and accessions by irrigation interaction for all of traits (p<0.01). Results of means comparison showed that by increasing drought stress, the shoot length, shoot weight and RWC were decreased. For root length, R/S, oil content and oil yield, higher mean values were obtained in drought stress. Higher shoot weight, oil yield and oil content were obtained in moderate stress (60% FC). Results showed that accessions 29 and 50 (Abhar) for shoot length, accessions 29 and 10 (Uremia) for root length, accessions 29 and 47 (Lorestan) for shoot weight, accessions 29 and 5 (Alamoot) for oil yield and accessions 29 and 10 (Uremia) for oil content had significantly higher values in moderate irrigation (60%FC) than others and ranked in class a. For root length, and shoot weight, the accession 23 (Divandare) and for R/S, the accessions 22 (Abyek) and 10 had higher mean values in severe irrigation (40% FC) than others.Thymus kotschyanus accessions showed a high variation for drought tolerance in greenhouse conditions and this species is semi-tolerant to drought stress.Accessions Qazvin 2, Abyek, Uremia and unknown had higher oil productions than others.Therefore, these accessions can be used for cultivation in irrigation deficit and Lowyielding pastures.

Fodder trees and shrubs are crucial sources of animal feed in Sudan, particularly in arid and semi-arid areas. This is because they can fill up the feed gaps in the summer period when grassland growth is limited due to unfavorable weather conditions.The study was conducted in Elnour forest-southeastern Sudan in 2015, which is dominated byAcacia seyal. The objectives of this study were to estimate the browse productivity, and to establish relationships with the crown area forAcacia seyal. The twig-count method described in this study converts a count of twigs to weight of browse by use of an average weight per twig for individual trees. Regression analysis was used to establish relationships between browse biomass and crown area. The average available browse (8.1 kg/ha) and tree density (162 tree/ha) forAcacia seyal was low in the study area that makes the density as the main factor that determine the amount of available browse/ha. Strong positive correlations were found between browse biomass productivity (available and total browse) and crown area with average values of 0.86 and 0.90, respectively. The study concluded that crown area as the main parameters used for predicting the browse biomass productivity. It is recommended that more effort be made to expand the use of more species to investigate the relationships between browse biomass productivity and growth parameters.

More than one-third of the earth is characterized by arid and semi-arid climate and desertification phenomenon in these areas has been intensified in recent decades. This study aims to investigate the trend of desertification using vegetation indices and Iranian Model of Desertification Potential Assessment (IMDPA) in AbarkoohPlain, Yazd province, Iran. The satellite images (Landsat images inMay 1987, 2000 and 2013) were used to map the land uses in the region. After the image preprocessing with a supervised classification method (support vector machine) that had the highest accuracy in all years, the map of land use changes was prepared in five kinds of land uses such as residential and industrial lands, agriculture and horticulture lands, arid and desert lands, playa and saline soils, and mountains. Then, the desertification map of Abarkooh Plain was prepared by calculating the Normalized Difference Vegetation Index (NDVI(and Modified Soil Adjusted Vegetation Index) MSAVI (according to IMDPA model. Three criteria, urban and residual lands to agricultural land ratio (Ur/Ag), plant canopy density and vegetation renewal indicators were used in IMDPA model. On the basis of the Ur/Ag ratio, 5.74%, 6.74% and 87.52% of the region were characterized by severe, moderate and low desertification, respectively due to land-use change factors. In the viewpoint of aboveground canopy density indicator, desertification in the area was classified into four classes including very severe, severe, moderate, and low desertification. In this regard, 99.06%, 0.76%, 0.13% and 0.05% of the areas are put in very severe, severe, moderate and low desertification classes, respectively. According to vegetation renewal indicator, 92.51%, 3.21% and 4.28% of the area were characterized as unchanged, low and very severe desertification, respectively.

There is less published research on ecosystems of forested rangeland in Iran.This research was conducted to investigate the forested rangeland area based on legal definition via comparison of indices species richness, diversity, and morphology of the trees and shrubs in Sabzkouh watershed, Chaharmahal Bakhtiari province, Iran.Quantitative characteristics of trees and shrubs were measured by 56 transects using the ' sample line with the fixed tree' method in 2016. In each transect five plots were thrown to measure understory factors. The data was divided into two categories, less and more than 1% and 5%, according to legal definitions of tree canopy cover percentage. In addition, timber volume was divided into two categories, less and more than 20 (m3/ha). Two independent sample analyses (U test and T test) were used to compare between communities and Kappa index method were used check the maps accuracy. In this study, no significant differences were observed in structural changes in two community of 5% crown canopy. The results showed that in habitats, crown canopy more than 1%, and the timber volume less than 20 (m3/ha) based on legal definition were estimated as a common area of forested rangeland. In this range the best crown canopy 0.5 to 4 percent, shrub height up to 2.7 m, the tree density 21 to 156 per ha, the (DBH) 10 cm, timber volume up to 20 m3/ha has been extracted. This area was introduced with an increase in understory species richness. The main associated species of forested rangeland in this area were dominants shrubs. The comparisons of the maps the Kappa index confirmed the introduced area as a wooded rangeland in a good agreement. Hence, to decline a little interfered and to achieve more accurate results, it is suggested to research on native people and expert definition.

Zagros Mountains in west of Iran are covered by unique forests and rangelands.Increasing population, low level of development and high dependence of local people on natural resources for primary livelihood needs resulted in degradation of Zagros forests and rangelands. Along with these factors, since the last decade, climate change including severe drought is an important issue in the world, particularly in semi-arid natural areas of Iran including Zagros. This research was conducted to develop an integrated method for mapping vulnerability of natural resources to droughts in Kashkan basin Lorestan province, Iran in 2015. Hence, a combined method including AHP as a Multi-Criteria Decision Making method and GIS was used. Based on literature review, study area conditions and experts’ opinions, six criteria and nineteen sub criteria were determined.The weights of this initial set of criteria and sub criteria were determined by experts using pairwise comparisons and weights of them were calculated. Then, maps of different sub criteria were analyzed in the GIS environment using calculated weights. Results showed that the most important criteria in drought sensitivity were hydro climate, physiography, and vegetation cover. Annual mean precipitation and temperature, vegetation cover were the most important sub criteria. Findings of research also indicated that 17.11%, 26.28% and 7.67%, of the studied area were classified as low, moderate and high vulnerable areas, respectively. In addition, 8.50% of the studied area is classified as extremely high vulnerable to droughts. This study introduces a combined method to mapping vulnerability of natural resource to droughts. Findings of this study could be considered by managers to develop proper plans for vulnerable areas.

Astragalus fridaeRech. F. is a native and endemic species in Iran. Considering the circumstances of this species in the country and the world and the importance of conservation of genetic resources, the awareness ofA. fridae forage quality seems necessary. For this purpose, forage samples ofA. fridae were taken at four phenological stages including vegetative growth, flowering, seed setting and maturity over three years (2012- 2014) in Semnan province, Iran. Forage quality factors such as DMD, CP, WSC, ADF, Ash, CF, NDF and ME were measured by NIR. Their overall means over phenological stages were 67.38%, 7.58%, 17.43%, 27.79%, 5.89%, 39.87%, 47.47% and 9.46mj/kg, respectively. Result of analysis of variance showed significant differences (P<5%) between phenological stages for all of traits. The lowest values of DMD, CP, WSC, Ash and ME were obtained at the vegetative stage, but there were no significant differences between three other phenological stages. The highest values of latter traits were obtained in seed setting stage and could be attributed to higher nutritional values of seeds.The means of ADF, NDF and CF were increased by the development of plant growth. But their increases did not have significant effects on reducing forage quality. DMD, CP, WSC, Ash and ME had a positive and significant correlation with each other and all of them were negatively correlated with ADF, NDF and CF.

The possible effects of seed priming on mitigating the effects of drought stress on germination and early seedling growth of two rangeland plants were evaluated in a laboratory research during 2015-16 growing season. The research was conducted as a 2 3×3 factorial experiment based on completely randomized design with three replications.The first factor was plant type (Festuca ovina and Bromus tomentellus), the second factor was drought stress (including 0.0, -0.3, -0.6, -0.9 and -1.2 MPa simulated with PEG6000) and the third factor was seed priming technique (including no-priming or control, hydro priming and salt priming with KNO3). Results indicated that drought stress reduced germination performances of two rangeland plants, where germination percentage, seedling dry weight, root length and stem length decreased under water deficit condition.However, B. tomentellus tolerated low-to-moderate levels of drought stress (osmotic potential of -0.3 and -0.6 MPa) butF. ovina showed a high sensitivity to drought stress where this plant did not tolerate even low levels of drought stress (-0.3 MPa). Seed priming improved germination performance of B. tomentellus under drought stress conditions but primed seeds ofF. ovina had no improved germination under low availability of water.Therefore, F. ovina should experience no-stress during seed germination and seedling establishment. There was no significant (P≤0.01) difference between hydro and osmo priming for improvingB. tomentellus under drought stress. However, because of low cost and easy use of hydro priming, this priming technique can be suggested for improving germination performance ofB. tomentellus under low and moderate drought stress.