Journal of Rangeland Science
Volume:13 Issue: 3, Summer 2023

This study was aimed to investigate the changes in surface and vegetation cover of the Sirjan Salt Playa (SSP) located in Kerman, Iran using Remote Sensing (RS) data. The ASTER data from 2002, 2008, and 2013 were used as the main tool. Also, using the Normalized Difference Vegetation Index (NDVI) on satellite data, the vegetation area and species diversity were determined. The research technique was correlation and comparison methods, and data analyses were made using SPSS and Edrisi software. Result showed that RS systems, in some ways, have a very good ability to study developments in desert areas. Based on the results of 15 years evaluation, the area of SSP was changed in different years and the vegetation area was changed in each period compared to the previous period, but vegetation diversity was not changed in this area. After extracting the vegetation map using NDVI index, considering the mean and standard deviation in satellite images of each period, the vegetation of the study area was divided into four classes of good, average, very poor and no vegetation. Also, the results showed that the area of good vegetation cover was 19278 ha in 2002, which increased to 22971 ha in 2008 and decreased by 20499 ha in 2013 compared to 2008. The medium vegetation class comprised 104985 ha of the land in 2002, which increased to 136128 and 108340 ha in 2008 and 2013, respectively. The kappa coefficient obtained from the comparison of the vegetation map using NDVI index and land cover map for 2002, 2008, and 2013 were 0.81, 0.83, and 0.84, respectively, which gave higher values than the SAVI vegetation index. Generally, the study suggested using other indices as NDVI and Soil-Adjusted Vegetation Index (SAVI) indices in arid lands and playa margins, with very poor vegetation cover.

Identification of habitats and suitable environmental conditions for the presence of various animal and plant species is one of the key issues in ecology and environment modeling. In Iran, Gymnocarpus decander species is the main and most abundant plant of the Baluchi flora, especially in the rangeland areas. Due to its high resistance to harsh environmental conditions and salinity, this species can be useful for rangeland reclamation and restoration. In order to assess potential habitats of G. decander in Sistan and Baluchestan province, Iran, this research was conducted in May 2020 using multivariate statistical methods including factor analysis, clustering and logistic regression. To do so, the map of real habitats of G. decander, was modeled using altitude and 62 climatic variables which were prepared using 24 meteorological stations across the province and neighboring. Climatic variables were reduced to 5 factors using PCA, including temperature, precipitation, radiation, dust and maximum temperature, which accounted for 88.3% of the climate change in the studied region. According to the regression models, the precipitation, temperature and altitude variables were the most significant independent variables (p <0.05) which influence the potential habitats of G. decander in the study area. Also, the study area was divided into 5 groups (G1:G5). The results suggest that models are more accurate in homogeneous groups than in the whole region. The Kappa coefficient and perdition accuracy had the highest and lowest values for G1 (68% and 88%) and G5 (19% and 59%), respectively. The results also showed that currently, 48.2% of the studied region has actual habitats. While the modeling results based on the model of the whole region showed that the potential habitat area of this species was 52.3% and based on the grouping models, it was 53.7%. Therefore, based on differences between actual data and modeling result, 4.8% of potential habitats have no G. decander. Also, results indicate that the G4 region with altitude range between 800-1250 m, growth season mean temperature was about 16 °C and annual precipitation about 170 mm was the main habitat for G. decander in Sistan and Baluchestan. According to the results of this study, G. decander is an endangered species and it is necessary to plan long-term management to preserve and restore its habitats in the arid regions of southeastern Iran.

Economic, social, and ecological factors in rangelands affect range management. By integrating and studying these factors, a more appropriate method can be applied to assess the sustainability of rangelands. In the present study, Analytical Hierarchy Process (AHP) as well as the experiences and views of rangeland exploiters and nomadic and natural resources experts in Kerman province were used to compare and prioritize the economic, social, and ecological factors affecting sustainable range management in semi-arid rangelands of Kerman province in 2017. Then, the means comparisons were made between priorities of rangeland exploiters and experts. Using AHP weight data, our results showed that ecological capital had the most impact of 0.71 and 0.61 from the viewpoints of rangeland exploiters and experts, on sustainable range management in the study area, and the two other factors including economic ones with 0.17 and 0.19 and social ones with 0.09 and 0.19 capital were ranked, respectively. Furthermore, according to the results of comparing the views of rangeland exploiters and experts, significant differences were found between the views of the two mentioned groups for 14 indicators including plant species diversity, soil erosion, groundwater, unity and solidarity at the range allotment level, trusting the experts and promoters, the presence of people in decision making and planning, the presence and role of women in livestock and non-livestock products, living cost, and livestock number. Overall, the results indicate the inconsistency between the views of these two groups. Therefore, prior to policy making for sustainable range management, more consistency is required between the views of rangeland exploiters and experts in each of the related organizations for greater participation of range managers.

Aboveground Net Primary Production (ANPP) is one of the most important characteristics of rangeland ecosystems that is involved in important issues such as carbon balance. The aim of this study was to model the ANPP of Plant Functional Types (PFTs) and total ANPP with topographic factors in Siahpoush and Ganjgah rangelands of Ardabil province, Iran. Sampling was performed in one square meter plots in three elevation classes, three sloping classes and six geographical directions by clipping and weighing method. ANOVA was used to investigate the relationship between ANPP and topographic factor and ANPP maps were modeled in ArcGIS software using the extracted regression relationships. Results showed that the shrubs ANPP has a significant relationship with elevation. The highest ANPP of grasses and total ANPP which were 1008.27 and 1650.00 kg/ha, respectively were observed in the middle elevation (2107-1877 m). The shrubs ANPP was directly related to the slope and 209.86 kg/ha was estimated at slopes higher than 30%, but the ANPP of grasses and forbs decreased with increasing slope. The highest ANPP of Shrubs (266.25 kg/ha) in the northwest, forbs (458.51 kg/ha) in the eastern direction, grasses (853.44 kg/ha) and total ANPP (1447.00 kg/ha) were observed in the southwest direction. Topographic indices including Topographic Wetness Index (TWI), Stream Power Index (SPI) and Plan Curvature Index (PCI) had no significant effect on variation of ANPP. Assessing the accuracy of the modeled maps was acceptable. These results can provide basic information for estimating ANPP to support rangeland management and balance supply and demand with rangeland products.

About 9% (349000 ha) of Khuzestan plain is the source of dust and it has seven dust hot spots. In this research, we investigated vegetation types, the floristic composition, life-form spectrum, and the phytogeography of the area during 2016–2020 by collecting vascular plants to provide an annotated checklist of the plants in Khuzestan province, Iran. In a period of five years, we focused on the vegetation of the septet areas as the source of dust and dune. A primary vegetation map was extracted from Google Earth images based on the texture, tone, and pattern, last vegetation map, and map of dust hot spots. To prepare vegetation types, they were checked in the field. The floristic composition, life-form spectrum, and the phytogeography of the area during five years were obtained by collecting vascular plants to provide a checklist of the sources of dust and dune. The 80 sample vegetation data from selected sites were analyzed using multivariate analysis methods. So, for assessing the relationship between plant species variation and environmental variation, the Canonical Correspondence Analysis (CCA) was used. The data of (80 samples of 8 species) and their soil factors (11 factors) were analysed using Rstudio software. The result showed that dust sources No. 1 and 2 had been covered by 24 vegetation types, and the species Seidlitzia rosmarinus, Halocnemum strobilaceum and Tamarix passerinoides were regarded as dominant. The dust source No. 3 was covered by 22 vegetation types and the species Halocnemum strobilaceum, Aeluropus lagopoides, Seidlitzia rosmarinus and Cornulaca monacantha  regarded as dominant have been located in the east of Ahvaz. The dust source No. 4 had covered 39 vegetation types and dominant species were Aeluropus lagopoides, Halocnemum strobilaceum, Atriplex leucoclada, Salsola spp. Seidlitzia rosmarinus and Tamarix spp. in small rain reservoir. The dust sources No. 5, 6, 7 (with 249000 ha) were the major part of dust storm sources in Khuzestan, covered by 28 vegetation types. The CCA species-environment biplot showed that CaCO3, EC, Na, SAR, ESP, OC, and CaMg from 11 soil factors were the key factors affecting vegetation in dust sources at our study site.

The study was conducted in Shinile district of eastern Ethiopia to evaluate soil carbon stock potentials under three indigenous rangeland management practices (communal grazing land, prescribed fire and grazing enclosure) and to address the current pastoralists knowledge on constraints and opportunities for increasing soil organic carbon in the rangelands. Soil samples at different soil depths (0-20 cm, 20-40 cm and 40-60 cm) from the study district were collected to estimate the below ground soil organic carbon. The soil attributes were analyzed of variance. Priority index was employed to study constraints and opportunities to use rangelands for carbon sequestration. In the study district, enclosure grazing land management had the highest (p<0.05) carbon sequestration potential as compared to the other practices. In addition, the soil organic carbon content decreased with increasing soil depth. The major opportunities to use the rangelands for carbon sequestration were availability of vast rangelands, and rotational grazing. However, there are also constraints, which includes knowledge and experience gap on rangeland resource use for carbon economy and climate variability. Therefore, appropriate land management systems are very important in improving soil organic carbon on rangelands to minimize effects of climate variability on food security in semi-arid areas.

Fire causes extensive damage to rangelands’ ecosystems in arid and semi-arid regions. The purpose of this study was to investigate the effects of rangeland fire on vegetation and forage production in mountainous rangelands of the Solan area in Hamadan province, Iran. A burnt area and a homogeneous area without fire (control) were selected for this study. In the burnt area, the fire has occurred in July 2018. In each site, data were collected in the months July to October using four linear transects with a length of 200 m using a systematic random sampling method. In each transect at a distance of 20 m, 10 plots of 1m2 were considered. Vegetation sampling was done during (July to October) three years of 2018, 2019, and 2020. Some factors such as forage production, percentage of bare soil, stones and gravels, litter, survival rate, canopy cover, and percentage of shrubs, perennial and annual forbs, perennial and annual grasses were measured. The results showed that there were significant differences between the two areas for all variables except perennial forbs cover, shrubs cover, and stone and gravels percent in the first year. Fire reduced the litter percent, forage production, canopy cover, survival, and increased bare soil, soil erosion, and sediment. The geophytes life forms of the species in the study areas had the highest coverage percentage (38.66%) in both areas. Some species such as: Astragalus verus, Astragalus gossypinus, Acantholimon bromifolium, Acantholimon olivieri, and Acanthophyllum crassifolium were sensitive to fire. On the other hand, species such as Rosa persica due to having rhizomes and extensive underground roots were resistant to fire.

Rangelands represent a potential resource with a high socio-economic value. This value remains unmonetarized and therefore, not taken into account in public policies, which does not reflect the real value of this Ecosystem Services (ES) and negatively affects the sustainable management of rangelands. This study was carried out in 2019; it aims to estimate the economic value of the supply service of the rangelands and to demonstrate its place in the local economy. The result reflects the socio-economic importance of this service, offering an average of 22.65 million forage units (FU/year= 1 kg barely grain), with the gross economic value of 6.79 million  USD/year. The study also illustrates the degree of pressure on these pastoral ecosystems, represented by high overgrazing rates and negative net economic value. The comparison between the supply and demand of forage units shows an average cost of degradation of 760 USD /ha in forests and 209 USD/ha out of forests, which negatively affects the sustainable management of these resources. To this end, the strategies adopted must respond to all environmental and socio-economic challenges, based on the preservation of the fragile environment to benefit the socio-economic development of local populations. These strategies must give users a sense of responsibility in the process of setting up, monitoring, and eventually adapting the management systems practiced.

Rangeland biodiversity is a multidimensional spectacle that includes the diversity of organisms, genetic differences among them and the communities, ecosystems, and landscape patterns. The variety of biodiversity life and processes is essential for moral, aesthetic and economic reasons. This review aimed to combine the earlier works on rangeland biodiversity: status, challenges and opportunities. Despite being less suited for crop cultivation, rangelands with low and variable precipitation, rocky topography, poor drainage, or harsh temperatures offer feed and water for free-ranging wild and domestic animals, as well as timber and mineral resources. Rangelands often have shallow soils, little rainfall, and slowly cycling nutrients. Habitat destruction and fragmentation, alien invasive species invasion, climate change, the incidence of accidental fire, prolonged drought, overgrazing, poor coordination among various disciplines and implementation schemes are the current critical challenges of rangeland biodiversity. Community-based management systems and participatory approaches, managing invasive species and rangeland rehabilitation, sustainable and integrated rangeland management practices, building resilience for rangeland resource dynamics, the presence of indigenous knowledge and donor support are the main opportunities for the improvement of rangeland biodiversity. Therefore, it was concluded that the current rangeland biodiversity was drastically shrinking and degrading. This suggests an urgent need for rangeland management strategies that promote biodiversity conservation.