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Modeling species distribution and predicting the effects of climate change on plant species decline are necessary in restoration programs. This study aimed to predict the occurrence and decline of Astragalus verus under climate change in Central Iran with an area of about 123,167 km2. We recorded 12 and 71 sites for the dead and alive species using the stratified sampling method, respectively. The general circulation model of CCSM4 was applied at two timeframes of present and 2050 under two climate change scenarios of RCP2.6 and RCP8.5. Four environmental variables of annual mean temperature, the maximum temperature of the warmest month, the precipitation of the coldest quarter, and elevation were selected as the inputs of the nine statistical models. Results indicated that Random Forest model had the best performance in predicting climatic niche and decline of A. verus (AUC and TSS of 0.99) compared to the other models. The suitable habitat and decline for this species are 12.4% and 19.87% of the study area, respectively. With the estimated temperature rise of 3 °C under the CCSM4-RCP2.6 scenario, A. verus habitat will shrink by about 3.4% of the study area and will move toward higher elevations with colder temperatures in the future. Most changes in the suitability of the species will occur in the altitude range of 1800 to 2200 meters because the most temperature and precipitation variations will happen in this elevation stratum. The results can be used to prevent its rapid dieback or even restore vegetation cover in regions with similar conditions. [ABSTRACT FROM AUTHOR]

Soil degradation poses serious environmental problems and requires quantitative assessment. This study aimed to investigate the soil properties in rangelands with different management conditions. Based on the assessment of soil erosion, vegetation cover, vegetation composition, and vegetation vigor, 56 sites were selected in rangelands with moderate, poor, and very poor conditions located in 15 grazing-free areas and one wildlife refuge region. Soil samples (0–10 cm layer) were collected from these sites through a systematic-random method to compare their physical and chemical properties. Results showed that soil organic carbon (OC) and total nitrogen content were significantly different between sites with different range conditions. The mean weight diameter of water-stable aggregates and structural stability index in moderate rangelands were 1.56 mm and 3.98%, respectively, and declined towards more degraded rangeland (i.e. 0.84 mm and 0.83%). Grazing-free rangelands exhibited a relatively larger OC deficit; hence specific management measures and control of grazing are required to enhance the quality of soil in these sites. This study highlighted the role of organic matter in preserving soil structural stability. Increasing protection level of rangelands and decreasing grazing pressure may preserve soil quality and combat desertification in these arid regions. [ABSTRACT FROM AUTHOR]

The scale of satellite images affects the recognition of landscape patterns and conditions. Therefore, this research focused on relationships between landscape fragmentation and function using multi-sensor imagery in semi-arid regions of Iran. Landscape function leakiness index (LI) and fragmentation metrics were calculated based on Sentinel-2, Landsat OLI, and MODIS data and compared using regression models and principal component analysis. Upscaled data were obtained based on changing the resolution of native Sentinel-2 from 10 to 30 m and 250 m. Results showed low (4%) and high (91%) fragmentation values in good and poor rangelands, respectively. The Sentinel-2 native LI index was the best indicator of vegetation cover (R2 = 0.99, p < 0.001) and fragmentation (R2 = 0.72, p < 0.05) and its upscaling to 30 m correlated better with fragmentation values than 250 m. The findings indicated that landscape functionality has reduced in the degraded areas because of increasing fragmentation and inter-patch spaces. [ABSTRACT FROM AUTHOR]

The present study explored the habitat suitability for an endangered species, Hedysarum criniferum, in Iran using fuzzy logic. We measured 24 environmental variables including soil, climate, and physiographic variables of eight natural habitats of H. criniferum as the predictive variables and the percent cover of the species as the response variable. The most important environmental factors influencing species distribution and the species response curves were determined by principal component analysis (PCA) and the generalized linear model, respectively. The tolerance range and the optimal growth point of the studied species with respect to the environmental factors were specified, the ranges were divided into 11 classes by fuzzy value, and the fuzzy functions of the environmental factors were calculated. The species habitats were classified by the developed fuzzy model. Three regions with no H. criniferum occurrence were selected to determine their fuzzy suitability. The success in germination and shoot growth length of H. criniferum were used as the metrics of the habitat suitability in these regions. Based on the PCA, H. criniferum occurrence was most strongly affected by soil Mg, K, and Ca content, soil pH, wind speed, annual minimum temperature, slope, and altitude. The results revealed that the seedling length and germination percentage in the site with the fuzzy suitability of 0.6 differed from those in the two other sites with the fuzzy suitability of 0.5 and 0.3 significantly. The method used in this study can be employed in predicting optimal habitats for other endangered species in different ecosystems. [ABSTRACT FROM AUTHOR]

Spatiotemporal complexities increase the uncertainty of the results of various desertification assessment models. We integrated the Mediterranean desertification and land‐use (MEDALUS) model with Bayesian networks (BNs) to develop a novel method for desertification assessment in central Iran. We first derived the current desertification status of the study area from empirical observations of actual, current desertification conditions and mapped the obtained status based on the criteria of the MEDALUS model. We then utilized BNs to produce three separate causal models for the soil, groundwater, and wind erosion indicators of the MEDALUS model. We then integrated all the related indicators and indices into a desertification assessment BNs model. After the reevaluation and sensitivity analysis of the model, we compared its results with those of the MEDALUS model. The obtained results highlighted soil condition and wind erosion as the main determinants of desertification in the study area. Considering the ability of BNs to accommodate uncertainty in the assessment process, these models can assist relevant authorities in making informed decisions. They can also be applied as decision support tools for adaptive management in fragile ecosystems of arid areas. [ABSTRACT FROM AUTHOR]

Monitoring is essential for appropriate rangeland management. The present study aimed to examine the potential of moderate resolution imaging spectroradiometer (MODIS) satellite imagery in rangeland condition assessment and monitoring within and across vegetation types in the arid and semi-arid rangelands of central Iran. The normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were calculated from MODIS Aqua/Terra Level 1B data (related to 2003–2013). The obtained values were compared with vegetation cover measurements and rangeland condition classes at 110 sampling sites using linear regression, one-way analysis of variance (ANOVA), independent-samples t-tests, and Tukey’s pairwise comparisons. The results showed that two indices made stronger predictions of vegetation cover within a vegetation type (R2 > 0.87,P < 0.001) than across vegetation types (R2 > 0.51,P < 0.001). Both NDVI and EVI worked well across vegetation types (P ≤ 0.001) in predicting rangeland condition classes (poor, fair, and good), but their performance varied between vegetation types. The NDVI classified about 73, 19, and 7.5% of the rangelands in poor, fair, and good condition classes, respectively. The good performance of MODIS NDVI index at different landscapes indicates that this index has high potential in detecting vegetation cover and discriminating different condition classes, therefore, it can be used to aid field- based techniques in rangeland condition assessment and monitoring. [ABSTRACT FROM AUTHOR]

Antagonists and mutualists both play important roles in a plant's reproductive fitness. In the present study, seed predator and pollinator effects were studied simultaneously in a patchily distributed legume, H edysarum criniferum, in its natural habitat in the Irano-Turanian region. This experiment examined whether a relationship existed between seed predator and pollinator effects on H . criniferum seed production, and the degree to which each of them impacts the plant's seed survival. To achieve this goal, the effects of seed predators and pollinators in an exclosure were separately and simultaneously evaluated, using a 2 × 2 factorial design, with 16-20 plants per treatment ( n = 70) in four replications. The results show that the pollinators caused a 40-fold increment in loments, a 59.3-fold greater production in seeds and a 14-fold increment in gross fecundity compared with their absence. Moreover, the seed predators infected on average 23% of the seeds. It was also observed that seed abortion, as well as the interaction of seed predator × pollinator effects on seed production, was insignificant. Despite the loss of some seeds caused by seed predators, the healthy seeds were sufficient to guarantee plant survival. Consequently, seed predators seem not to be the main factor in the patchy distribution of H . criniferum and, therefore, to develop plant habitats by seeds, it is more important to protect the pollinators than to devise any intervention to remove the predators. B ruchidius koenigi Schilsky and a description of its host plant are reported here for the first time from Iran. [ABSTRACT FROM AUTHOR]

Floristic studies have great importance as it represent the existence and the status of all plant species in an area. This study aimed to investigate the flora of Meymand Protected Area, located in central Zagros and in Kohkilouyeh va Boyer Ahmad provice with an elevation range of 1806 to 2730 meters from sea level. Plant families, genera and species were identified using taxonomic methods and available resources. According to the results, the flora of this area included 279 plant species belonging to 198 genera from 48 families. The richest families were Asteraceae with 50 species (17.9%), Poaceae, Lamiaceae with each 23 species (8.2%) and Fabaceae with 22 species (7.8%). The dominance of hemicryptophytes and therophytes (totally, 82%) life forms in the flora, were the characteristics of mountainous regions in central part of Iran. The high proportion of hemicryptophytes plants in the flora also indicated the dominance of a cold and montinious climates in the study area. The chorotypes of plants species showed that 57 percent (160 species) of the plant species belonged to Irano-Touranian zone but other remaining species (119 speciecs) grew in other geobotanical zones too. There were 5 vulnerable, 24 lower risks and 1 data deficient species in this protected area. [ABSTRACT FROM AUTHOR]