جستجوی مقالات مرتبط با کلیدواژه « مطلوبیت زیستگاه » در نشریات گروه « کشاورزی »

Considering the special role of freshwater ecosystems and aquatic species on the sustainability of food security and livelihood of local communities, the evaluation and protection of these natural resources is of great importance. In the current study, the distribution of the Roach (Rutilus lacustris) was predicted under two optimistic and pessimistic (RCP 2.6 and RCP 8.5) scenarios of 2050 and 2080 by Maxent model. The set of data collected by the authors and various available scientific sources from a period of 50 years (1970 to 2020 AD) was used. Also, the environmental and climate variables used in the modeling were extracted and prepared from www.worldclim.org. The results showed that the performance of the model in predicting species distribution was excellent (0.910) based on the AUC (Area Under the Curve) criterion. According to the jackknife test, annual temperature range variable had the greatest impact (54.7) on determining the distribution of the studied species among the environmental variables used in modeling. In addition, it is predicted that under climate change the distribution of the species is likely to decrease significantly in years 2050 and 2080, optimistic and pessimistic scenarios. Also, the highest severity is the pessimistic scenario of 2080 (62.05 %). Therefore, control and reduce the effects of climate change in order to prevent the destruction of riverine ecosystems and preserve valuable edible fish is necessary.

Global climate change has led to change in the ecological amplitude of plant growth, expand plant adaptation to hot climates, and decrease plant adaptation to cold climates. Climate change resulting from human activities occurs at such a speed that many species will not be able to adapt to it. These changes have led to a change in the range of plants growth. Such high-speed changes have caused subsequent changes in the structure and entire ecosystems of the earth, therefore predicting the effect of climate change on the distribution of plant species has become a major field of research for its conservation measures and programs. Changes in the range of distribution of plants are mostly predicted by species distribution models. In this sense, every environmental factor affecting the distribution of plant species has a minimum, maximum and optimal value, which, in combination with other factors, separates the territory of the species and forms an ecological niche. These models are used to investigate species distribution and are based on ecological niche theory. This research was conducted with the aim of determining the potential habitats of Pistacia vera L. species and the factors affecting it in the present and future in Razavi Khorasan province.

For this purpose, 28 bioclimatic variables including topographic (4 cases), climatic (19 cases), soil (4 cases), and geological (1 case) factors as prediction variables have been analyzed for the correlation coefficient. The variables with high correlation (more than 80 %) have been removed. Environmental variables in ASCII format along with presence points were added for modeling in R software of the desired species. According to the size of the study area, sampling of data points was done based on the field visit during the period 2021-2022 from the introduced areas. through using the Global Positioning System (GPS) of 129 points from 8 regions (as points of presence) were recorded. Then, in order to prevent spatial autocorrelation and reduce the sampling error, the useful areas were converted into 1000×1000 meters grids in ArcGIS 10.5 software, and one presence point was obtained from each cell. In the modeling process, 70 % of the presence points (Pistacia vera L.) were used to generate models and 30 % of the presence points were used to evaluate the performance of the models. Also, to increase the modeling accuracy, the number of repetitions was considered 10. Then all data and points through R software and using Biomed 2 package models including GLM, GBM, CTA, ANN, SRE, FDA, MARS, RF, and MaxEnt Phillips models, in determining the relationship between vegetation and environmental factors in rangelands of Khorasan Razavi province at current and future distribution of this species in 2080-2100 were predicted under climate scenarios ssp1-2.6 and ssp5-8.5 model. The accuracy of the models was evaluated using the values of KAPPA, TSS and ROC indices, which are prominent and widely used indices for determining and identifying the areas of equal potential.

The variables of climatic factors were removed from the modeling due to the high correlation of 80 %, and the analysis was done using four topographic factors, eight climatic factors, four soil factors and one geological factor. The results of this research showed that according to the accuracy evaluation index, the best modeling for the present time is done by the random forest (RF) model with the ROC, KAPPA, and TSS equal to 100. In the future, the 2.6 and 8.5 scenarios of the random forest model for the ROC, KAPPA, and TSS indicators, with the accuracy of 0.999, 0..982, and 0.989 respectively, have the highest level of accuracy; Also, in the random forest model, the factors that had the greatest impact included: Bio12 (annual precipitation) and Bio15 (seasonal precipitation changes) and land unit at the present time, in the future time under the scenario 2.6 Bio12 (annual precipitation) and Bio15 (seasonal precipitation changes) and DEM and in the scenario 8.5 Bio15 (seasonal precipitation changes) and Bio12 (annual precipitation) and aspect. The results of the relative importance show the great influence of climatic factors on the distribution of this species. It is most present in the habitat with an annual rainfall of 200-285 mm, and more than this amount of rainfall was associated with a decrease in suitability for the establishment of the species. Besides, the height of 800-1300 meters above sea level and rainfall changes up to 7.8 mm in seasonal rainfall also had a positive effect on the suitability of the habitat for the presence of wild pistachio. Also, the most desirable habitat is in low to relatively high hills with a rounded and sometimes flat top consisting of limestone, metamorphic, conglomerate, and shale sandstones and a slope of 40 to 50 % and with shallow to relatively deep gravelly soils. The highest distribution of Pistacia vera L. species is in the northeastern region to the east of Khorasan province. In general, by examining the outputs of the random forest model and comparing the areas prone to the growth of Pistacia vera L. species in the present and future climate scenarios, it can be stated that the trend of stable habitat in the province can be expected.

The results of this research can be used to identify areas prone to growth, improvement, development, protection, economic exploitation, and expansion of the habitat of Pistacia vera L. species. From the ecological point of view, the wild pistachio species is considered as one of the most important factors preventing and destroying land in the high mountains of arid and semi-arid regions in many geographical and ecological regions. On the other hand, the economic importance and the income-generating aspect of wild pistachios are also important for local operators. In general, it can be stated that vector machine models provide very good performance for identifying such prone areas. In this research, an attempt was made to evaluate different species distribution vector machine models, and then the most suitable model, which was random forest, was selected.

Environmental flow of the Beshar River was evaluated using Tennant's hydrological method, the comparison of the depth and speed of the water in the transverse sections of the river, and the needs of indicator fish species in different stages of the life cycle. Field samplings were conducted in October and January 2021 to monitor the status of fishes in the Beshar River and to collect cross-sections of the river. Indicator species were selected based on the expert judgement survey method. Among 23 fish species of the Beshar River, five species from the Cyprinidae family recieved the highest scores. The biological requirements of these species were extracted and used as the basis of comparison with the data of cross sections of the river. The obtained results showed that in the upper reaches of the river (between the two hydrometric stations of Qalat and Shah Mokhtar) the good class of the Tennant method, that includes 40% of the average annual discharge for the period of high flow (April to May) and 20% of the average annual discharge for the period of low flow (June to November), is suitable to provide the biological requirements of adult and larva of cyprinid species of the Beshar River, respectively.

Understanding the optimal habitat of species, especially closely related species, can help in their better management and protection. For this purpose, in the present study, the response of two sympatric species, Garra rufa and Garra gymnothorax, to some environmental variables and the differences between them were analyzed. In this regard, the effect of six habitat variables including the width (m) and depth (cm) of the river, water current velocity (ms-1), altitude (m), temperature (°C) and substrate index evaluated on the Habitat Suitability Criteria (HSC) pattern in 27 study reach, almost in the entire distribution range of these two species. The results showed that G. rufa lives in rivers with width <40 m, depth <45 cm, temperature >22 °C, substrate index 3.5 - 6.5, and depending on the conditions, water current velocity less than 0.45 or more than 1.2 ms-1, which are located at an altitude between 600 and 1000 m, while G. gymnothorax prefere habitats with width <10 m, depth <150 cm, temperature >24 °C, substrate index >4.5, water current velocity <1.05 ms-1 located at an altitude >400 m. The analysis shows that the G. gymnothorax has a smaller range of favorability than G. rufa for all six habitat variables studied, which it somehow indicates its narrower ecological niche and the greater vulnerability of this species to changing environmental conditions. The wider distribution of G. rufa may contribute to the ability to maintain larger populations of this species. This wider presence of the species not only helps to facilitate autecology processes but also increases the probability of survival in case of local environmental disturbances. The results of this study can help in determining the protection priorities for both species.

Changes in river ecosystem conditions, including dam construction, provide new ecological conditions for the inhabitants of these ecosystems that must adapt to survive. This study was conducted to investigate the effect of Taleghan Dam on the suitability indices of Barbus cyri based on the Kernel smoothing method during 2018-2019. The environmental factors, including water depth, velocity, river width, pH, temperature, electrical conductivity (EC), total dissolved solids (TDS), slope, elevation, bedrock diameter, and the number of rocks larger than 15 cm are measured and recorded. The Root-mean-square deviation related to bandwidth from 1 to 1000 was examined for each environmental factor. The results showed that increasing elevation, river width, velocity, EC, and TDS decrease the suitability of the studied species, and the suitability increased by increasing depth, slope, temperature, and pH. Some factors, including depth, river width and water temperature had many changes. In conclusion, the downstream conditions of the dam were better in the habitat suitability of Barbus cyri than the upstream region.

Being at the top of the food pyramid, as a pioneer species, has led the Persian leopard (Panthera pardus saxicolor) to expose habitat degradation and prey reduction, in the recent years, in particular, necessitating the development of habitat conservation plans. In this study, habitat suitability modeling of the Persian Leopard was conducted using QGIS with only presence data as well as general linear model (GLM) with presence/absence data based on the binomial distribution, run in the R software. In QGIS, using topography, DEM, slope, and aspect maps as well as villages maps, the continuous population distribution map was delineated. The presence points, derived from field-working, were then inserted, and other mandatory layers were also collected and geo-rectified, where applicable. Afterward, each one of the layers was categorized and rasterized. Following the validation, the final suitability map of the Persian leopard was performed. In the GLM, simulations were generated using a full model with all variables and a leave-one-out procedure, gradually dropping the least contributing variable to form a minimal model. The results showed throughout the area, the most suitable habitats are scattered. Considering the substantial reduction in the preys population in Gisakan alongside the abundance of livestock, goats specifically, habitat suitability is largely increased near the rangelands and water resources. Furthermore, the habitats placed in northern aspects with > 1000 m height, slopes of 30-65%, 0 to 1000 meters distance to the roads, and 1000 to 2500 meters distance to the villages, showed higher suitability.

Flow resistance is a key factor in open channels hydraulic analysis. Resistance to bed particles causes energy loss. As the particle size increases, the resistance increases. Experimental evidence shows that large particles in the river bed exert flow resistance. In this study, the factors that cause flow resistance in rivers have been investigated and the effective parameters (depth and width of flow, equivalent roughness height) on the habitat have been discussed. To investigate the effect of flow resistance parameters on aquatic habitat, Jajrood River and rainbow trout species have been selected. During the field visit, the coordinates of the map were matched with the location and samples of surface and subsurface materials were taken. By performing gradation in the laboratory and using Manning’s equation and stage discharge curves, the hydraulic roughness coefficient was calculated. Then grain size roughness was obtained using experimental relationships. Shape roughness coefficient was calculated by subtracting the two roughness coefficients and was used in the hydraulic simulation. Water levels obtained from the hydraulic model were used to simulate the habitat. The effect of flow depth and width and equivalent roughness height parameters on the habitat at the three life stages of the target species, namely fry, juvenile and adult, was analyzed using simulation results. In general, with increasing the width and depth of the stream and the equivalent roughness height, the habitat suitability for the target species increased. The factor that causes the most change in habitat suitability is the width of the stream,

Since the selected habitat indexes provide a description of the habitat characteristics of a species, this study was conducted to investigate the habitat preference of Garra rufa in Dinorab River (Kermanshah Province), a tributary of the Karkheh River basin. For this purpose, the habitat characteristics, including water depth, water velocity, river width, potamal area width, predominant type of bedrock cover, pH, temperature, electrical conductivity (EC), total dissolved solids (TDS) were measured and recorded in 18 sub-stations belonging to six main stations from downstream to upstream. The used and selected habitat ranges were obtained according to the availability of each habitat unit for each variable. The results showed that the most preferred water depth is 26-30 m with a suitability index (SI) of 0.779, river width of 6-7.2 m with SI of 0.7, the water velocity 0.24-0.31 m/s with SI of 0.38, bed structure with medium diameter of 5-5.5 cm with SI of 1, water temperature 18-19 °C with SI of 0.618, pH 7.32-7.44 with SI of 0.545, EC 290-310 with SI of 0.767, TDS in the range of 580-610 ppm with SI of 0.712 and potamal width 4.8-6 with SI of 0.634. The results showed that the Dinorab River is a moderately suitable habitat for Garra rufa.

With the intensification of biodiversity decline and habitat loss due to destruction and fragmentation, scientists are looking for criteria for prioritizing wildlife habitats and expanding protected areas based on the high distribution and abundance of the species, especially indicator species. One of the Iranian middle-sized carnivores is Honey Badger with Afrotropical distribution the utmost spread of its northern dispersion reaches Iran. Its distribution and ecological information are scarce in Iran and in all its distribution range in the world. In this study, through gathering presence point data in Kerman province, potential habitats and effective biogeoclimatic parameters affecting the species distribution during the year were identified. The Maximum Entropy modeling approach was applied. According to the results, more than one-fifth of the province is suitable for the species. Most parts of the preferable habitats are in the western half of the province at an altitude of above 2000 meters above sea level. Habitats with the lower annual mean temperature and higher annual precipitation are more suitable for the species increasing annual mean temperature and dryness, the suitability of habitat decreases. Field surveys showed that damage to the poultries and beehives resulted in a high conflict between Honey Badger and local people.

This study was conducted in 2017 by sampling from 7 stations in the headwaters of the Taleghan River to study the habitat suitability of Brown trout, Salmo trutta. Sampling was carried out using an electrofishing device with three replications in each station. Eight environmental factors, including water temperature (°C), water depth (cm), river width (m), slope (degree), water velocity (m/s), average diameter of the dominant bedrock (cm), potamal width and elevations were measured. The values of suitability index of the studied factors in each station were determined and the arithmetic mean of the indices in all sampling stations was considered as the suitability index of that factor. The results showed that the most preferred temperature is in the range of 10-5-12°C, depth in 20-30cm, river width in of 2.5-3m, slope in 1.6-1.9, water velocity in 0.41-0.62m/s, elevation in 2250-300 m and average diameter of the dominant bedrock in 11-20cm, and the potamal width 1.8-3.6m were calculated. As a general conclusion, the Taleghan River had a moderate suitability for S. trutta.

Investigation of ecological, hydrological status and habitat Suitability of river is one of the key elements in river ecosystem management. In this regard, in the present study, in order to evaluate the ecological sustainable conditions in Zarrin-Gol River of Golestan Province, during stepwise calculations, echo-hydraulic and hydromorphocological analysis of the habitat of Capoeta gracilis (Keyserling, 1861) and ecological flow were studied estimation using hydrological and flow methods (Tennant and Aquatic base Flow) during the 10-year statistical period (2009-2019), hydraulic method (wetted perimeter) and habitat simulation model in different seasons of 2017 and 2018. For this purpose, physical simulation of habitat based on habitat suitability criteria curves was performed by field studies and sampling of hydraulic (depth, velocity and bed index) and ecological (aquatic communities) parameters. First, the geometry of the river model and cross sections were created using the topographic map of Zarrin-Gol River and ARC-GIS software. Then hydraulic simulation of river was performed with HEC-RAS software. In the next step, hydraulic and habitat simulations were performed in PHABSIM model. In this ecological-hydraulic model, the relationship between hydraulic flow and habitat needs of the target species was established using the Weighted Usable Area and the flow- suitability curve of the target species was extracted in different discharges in both adult and juvenile tow age group and new method of classifying the ecological flow regime was considered according to the indices of habitat suitability (water depth, flow velocity and bed). By elicitation of flow-habitat suitability curve, suitability river in terms of quantity and location was investigated. Based on the results, the optimal ecological flow regime to provide the ecological potential of habitat of index species is different by combining different methods for the studied periods during the year and accordingly, to maintain optimal conditions and protect the ecosystem and habitat components of biological communities, The required flow between 1.43 (in July-February) to 3.76 m3/s (in April), with an mean annual bio-flow of 1.74 m3/s (equivalent to 74.3% of  natural stream of the river) should be inside of Zarrin-Gol River. Also, the susceptibility of the Capoeta gracilis species to changes in velocity and bed materials is high and the weighted usable area increases with the depth remaining in optimal conditions. According to the results of this study, the distribution of habitat suitability along the Zarrin-Gol River, under the influence of geometric, hydraulic parameters and flow rate, indicates the favorable habitat conditions of the Capoeta gracilis species in the downstream area and poor conditions in the upstream area.

In this study, environmental and climatic variables were used as independent variables to determine the habitat suitability of Cyprinion tenuiradius in Fars Province and to investigate the impact of climate change on its distribution. Modelling was conducted in an R software environment using the MaxEnt algorithm. Based on the results, the performance and accuracy of modelling were good (AUC = 0. 790). Also, the mean annual temperature and annual precipitation were the most important variables in determining the habitat suitability and distribution of this species, respectively. According to the species prediction under optimistic and pessimistic scenarios of climate change in 2050 and 2080, it is expected that the distribution range of this species will decrease slightly under the optimistic scenario of 2050 and 2080. However, the distribution range under the pessimistic scenario of 2050 will be increased slightly while in the pessimistic scenario of 2080, its suitable habitats will be significantly increased. It is recommended to use the obtained results for management and conservation purposes.

This study aims at comparing the performance of MaxEnt and logistic regression in preparing the predictive habitat distribution map of Thymus kotschyanus and determining the factors affecting in the northern of Ardabil Province rangelands. 28 sites were selected and at each site, three transects with a length of 100 m and on each transect ten 1m2 plots were established. Soil samples were taken digging of nine soil profiles and samples taked from 0-15 and 15-30 cm depths. Geostatistical techniques were used to provide the soil maps. Digital elevation model was used to prepare the topography maps as a data layer. The Landscape metrics using Fragstats was calculated. Model accuracy in MaxEnt method was evaluated by using the AUC. By jackknife method and response curve, the most important environmental predictor variables were found. Model accuracy in logistic regression method is evaluated by using Hosmer and Lemshow Statistic and ROC. Then predictive distribution maps were produced. The Kappa coefficient index was used to evaluate the accuracy of the distribution maps. Based on logistic regression model, potassium of the 2th depth, aggregation index (positive correlation), slope and bare soil were the negative correlations and based on MaxEnt model, clay of the first depth, patch area (coefficient of variation), slope are the most influential factors affecting the presence of this species in this habitat. T.kotschyanus is widespread on light-textured soils (clay<15%), potassium (<18 meq/L), Silt (<20%) and high elevation (300-2700 meters above sea level), and slope (35-55%). Based on kappa coefficient, logistic regression model was able to predict the habitat distribution of studied species at the good level (kappa= 0.64) and MaxEnt had in intermediate level (kappa 0.42). These results indicate that the logistic regression model is more accurate.

Hydrological variability is of great importance for water resources management. Analyzing the instream environmental flow demand by coupling the hydrological cycle and the hydrodynamic process with aquatic ecological processes at a watershed scale remains one of the most important yet most difficult issues. Ecological water demand (environmental flow) refers to the typical—intra-annual and inter-annual natural flow regime variability—which describes the quality, quantity, and timing of flow discharge required to preserve the ecosystem and sustain essential services upon which human livelihoods and well-being depend. Therefore, ecological water demand (EWD) should be considered as a constraint in water resource planning and management.

Numerous methods and frameworks have been developed for establishing ecological water demand at regulated rivers. Hydrologically-based ecological water demand methods, because of their simplicity, data availability, and other economic and social aspects, remain the most applied ones. A suitable range of discharges environmental flow Dinavar River was estimated using advocate statistical analysis of hydrological methods Tennant, Annual Distribution Method, and Texas, coupled with habitat suitability model using the program River2D to natural flow variability need. River2D is a two-dimensional, depth-averaged hydrodynamic and fish habitat model widely used in environmental flow assessment studies. A detailed digital model of the river channel and its surrounding area was developed, including all the morphological characteristics of the river channel and its various sandy islets. Data collection was performed through GIS/GPS mapping surveys, hydro-morphological measurements (water depth, flow, substratum type, etc.), and electrofishing samplings at a microhabitat scale under different discharge conditions. Several different steady-state hydraulic simulations were conducted under typical low flow conditions, producing water depth and water velocity (direction and magnitude) maps for each discharge scenario, while results were verified with the use of field measurements. In the next step, River2D was used for the fish habitat modeling of the study area, with the application of fish preference curves developed specifically for the study area. Finally, the fish habitat modeling was conducted for the Capoeta trutta (Heckel, 1843) species, divided into two life groups, forced under the flow conditions. Also, the suitable level of ecological water demand and crucial values with different flow frequencies were analyzed, including water level, water surface width, and Weighted Usable Area.

Results show that high environmental flow releases did not necessarily provide the highest habitat availability and suitability at all seasons and fish life-stages. The adult life stage resulted in being more vulnerable to water diversion, particularly during the spring season. Shallow-water hydromorphological units suffered the highest habitat loss. Some of the environmental flow methods demonstrated inconsistent results over seasons and fish life-stages by either allowing for higher environmental flow releases. Also, the Weighted Usable Area -Discharge curve was calculated with the suitability index in medium flow conditions. From the result, the Weighted Usable Area is changed according to flowrate. In the flowrate- Weighted Usable Area/A graph, ecological flow can be determined at 1.38 m3/s for Capoeta trutta (Heckel, 1843) species. Ecological flows were calculated in the range 0.17–3.71 m3/s as the required discharge, which assures the welfare and sustainability of protected fish species populations. It was also noticed that low flow months (June to November) required more proportions of mean monthly flow than high flow months (December to May). When compared with flow-duration analysis, it is demonstrative that simulation results fitted EWD considering the quantity of available habitat for fish species. Also, the results of the study indicated that monthly EWD had an increasing trend during the flood season and a decreasing trend during the non-flood season in three sections at different suitable levels. With the increase of suitable levels, the range of EWD in the three sections also increased. The EWD and crucial values were the lowest in April with the smallest range and were the highest from June to October.

The major finding of this research is that the estimated Suitable Range of Discharges could better address environmental water requirements, rather than simply allocating single value minimum ecological flows. Results reveal that the ecohydraulic modeling of river basins should be considered as an indispensable component in sustainable water resources.

effective management and protection of wildlife populations depends on human understanding of the relationship between wildlife populations and habitats. The destruction and fragmentation of habitats reduces the living area of local communities, limits them to small habitats, and isolates wildlife populations, leading to increased intra-reproductions, reduced genetic diversity, and eventually the increased risk of extinction in the long run.  Therefore, habitat optimization modeling techniques have been developed based on the analysis of the relationship between species and habitat to determine the range of species’ distribution and habitat suitability which is required for the preservation and management of populations, especially the endangered species. The Gazella subgutturosa is currently protected by the Iranian organization for environmental protection and placed as the vulnerable class in the Red List of IUCN. Characterized by special natural features, Monteh Wildlife Refuge is regarded as one of the best protected habitats for Gazella Subgutturosa. In fact, it is considered as one of the richest habitats in the Middle East in terms of wildlife diversity and the high number of animal species living there, making this biologic field seem much more important. This study sought to evaluate the Gazella subguruttosa’s habitat in Moteh Wildlife and present a desirability model in this regard, trying to identify optimal habitats for Gazella subgutturosa in the region, determine the factors involved in the desirability of such habitats, and discover its limiting and threatening factors. The Gazella subgutturosa habitat threatened the area. Thus, to reduce the interference of human activities with the wildlife activities, it is necessary to identify and preserve areas that are more important in terms of preservation by preparing a map of habitat desirability. This helps identify the most destructive and threatening factors to the habitat and target species, and prevent the reduction of the target population by controlling and eliminating such factors.   

with an area of 205,000 hectares, the Moteh Wildlife Refuge is located in the northwest of Isfahan province, having a cold or semi-arid cold climate. Having surveyed the region in spring, summer and autumn of 2018, this study recorded the presence points of Gazella subgutturosa species in Moteh Wildlife Refuge via direct and indirect observation (the dung and footprints), using the Global Positioning System. Following the review of the related literature and interviews with experts and Moteh Wildlife Refuge’s park rangers, 12 variables were identified, all of which were analyzed in terms of correlation with each other before starting modeling. As for analyzing the data correlation, six environmental variables including maps of distance from rangelands, slop, distance from waterways, distance from agricultural lands, distance from main roads, and distance from mines were selected. The map the desirability of Gazella subgutturosa habitat was, then, developed based on the presence points of the Gazella and environmental variables, presented in two classes of desirable and undesirable. Moreover, the MaxEnt model was validated via the area below the curve which shows the probability of discernment between the points of presence and absence of a model.  

According to the results of the response curves, Gazella subgutturosa prefers areas far from mines and agricultural lands which are near water resources and rangelands, and areas with low slope. The level below the curve was found to be 0.92, indicating that the model worked well. According to the table obtained from MaxEnt, the most important factor in selecting the Monteh wildlife Refuge as the Gazella subgutturosa habitat is its distance from the rangelands, with 33.3% contribution and 36.3% effect coefficient, with the habitat’s desirability considerably decreasing with an increase in distance from the rangelands, followed by slope, waterways, agricultural lands, roads, and mines as other variables involved in this regard. The Jack Naifchr('39')s chart shows that distance from wetlands alone greatly contributed to modeling. The results of the classification of the habitat’s desirability model show that 40240 hectares, equivalent to 19.7% of Monteh Wildlife Refuge are classifies as desirable in terms of the Gazella subgutturosa habitat’s desirability, and 164102 hectares, equivalent to 80.3%, are placed in the undesirable class.  

In this study, the AUC value was found to be 0.92, indicating a very good performance of the model. Moreover, distance from the rangelands was identified as the most important factor in the desirability of the Gazella subgutturosa habitat, with the habitat’s desirability considerably decreasing with an increase in distance from the rangelands. The findings also suggested that Gazella subguruttosa prefers areas near the rivers. The results of other studies also indicate the high importance of water resources for Gazella subgutturosa species. In general, monitoring and careful management of water resources, preventing the advancement of mines, and controlling the entry of domestic livestock to prevent the destruction of regional vegetation are some important measures that should be carried out in managing the habitat of this species.ش

Predicting the habitat suitability of wildlife in response to climate change is essential for their conservation and management. Wild sheepis a wildlife species native to Iran. Therefore, this study aimed at predicting the effect of climate change on wild sheep (Ovis orientalis) habitat suitability using ensemble modeling in Markazi Province. In this regard, Five modeling approaches suchas Surface Range Envelop (SRE), Multiple Adaptive Regression Splines (MARS), Random Forest (RF), Classification Tree Analysis (CTA), Flexible Discriminant Analysis (FDA) were used to determine relationships between the occurrence of species and environmental factors under the ensemble framework by using Biomod2 and R software. R results showed that AUC values greater than 0.9 and functioning of all models been excellent. The mean temperature annual range and Annual precipitation had the most important role for habitat suitability of this species and 113.1% changes in O. orientalis habitat suitability was justified. R results of the model showed that 1211316.19 ha, (41.55%) of in Markazi province for the O. orientalis have had high habitat suitability. Under RCP2.6 and RCP8.5 climate scenario O. orientalis might lose respectively 50.30% and 73.42% of its climatically suitable habitats due to climate change factors, by 2050, while in a number of areas 4.1% and 12.1%, the current unsuitable habitats may be converted to suitable. More habitat reduction in protected areas related to Varsan, Bazarjan, Mouteh, Jasb and Haftad-Gholeh areas. The lowest habitat reduction in the Razeghan and Chal-khaton areas. The results of this study can be used in planning, conservation and rehabilitation of O. orientalis and protected areas managemen.

A good understanding of the river natural flow regime plays an important role in many hydrological studies. Such studies also quantify the environmental flow, the basis for the conservation of river fish habitats and aquatic ecosystems, and need to be recognized in the policies and decisions of water resource development plans and their inclusion in watershed management plans. In the present study were calculated and evaluated hydrological methods such as Tennant, Aquatic Base Flow, Arkansas and Range of Variability Approach (RVA) to estimate the minimum ecological flow and Habitat Simulation model to preserve the ecological potential of the Jajroud River. In this regard, based on the research framework, after hydrological analysis and field observations, a habitat suitability model was developed for the target species and finally, habitat simulation was performed by combining ecohydraulic and hydrological indices of flow and analysis of flow - habitat physics time series using suitability curves. Based on the results, to maintain optimal conditions and protect the ecosystem components and habitat of biological communities, using the River2D model range of flow regime required to provide habitat ecological potential Squalius namak, it should be located along the Jajroud River between 1.24 to 18.55 m3/s, with mean annual flow 5.91 m3/s (86.7 Percent Mean Annual Flow). It is noteworthy that the Tennant methods should be used with caution in summer because this method offers between 9 and 96 percent of the mean annual flow. Finally, it was concluded that other methods of providing environmental flow provide values above 25% of the mean annual flow, which provide better protection of the stream for aquatic habitats. In contrast, the River2D ecohydraulic model can provide a general idea of habitat suitability across different river basins with respect to changes in natural flow regimes and the achievement of ideal and optimal flow conditions.

The Balouchi Black bear as an endangered subspecies, has a limited distribution in Iran, including the provinces of Kerman, Sistan and Baluchestan and Hormozgan. In this study, multi-criteria evaluation method was used to model the suitability of the land as a habitat of the black bear. For this purpose, by literature reviewing and experts’ knowledge, the most important criteria for evaluating the suitability of the land as black bear habitat were identified, were standardized by fuzzy and Boolean methods and criteria weights were determined using the hierarchical analysis process (AHP) method. The highest weight is related to slope criterion. Criteria and constraints maps were prepared by satellite image interpretation and available data. Results have shown 0-20% vegetation cover crown with 6945673 ha has the highest portion in study area. The study criteria and constraints were overlaid using the Weighted Linear Combination (WLC) method and the land suitability model was produced for the Balouchi black bear. In habitat suitability map, 261615 ha were identified with very high habitat suitability for black bear. Field studies and overlaying areas with the highest habitat suitability on the suitability maps of the used criteria, show that these areas mostly include mountainous areas with wild date (Daz) and farm land date. The results of this study with producing 81% total accuracy show the capability of multi-criteria evaluation methods by producing suitability maps with considering the importance of habitat evaluation criteria in modeling the suitability black bear habitat and the possibility of trade-off the criteria which causes criteria with more importance, support lower importance criteria.

The aim of this study was to predict the habitat expansion of Festuca ovina by maximum entropy method and to determine the effective factors on its spread in the elevation gradient of Moghan-Sabalan rangelands of Ardabil province. The 28 study sites were selected and in each study site 3 transects and along each 100-meter transect 10 plots of 1 1m2 with a distance of 10 meters from each other were selected for sampling. Soil sampling in each study site was sampled from two depths of 0-15 and 15-30 cm. Soil properties using spatial statistics, topographic characteristics using digital elevation model, climatic information using meteorological data of the region, and land use measurements prepared with the help of a user map. Prediction maps related to the distribution of F.ovina were prepared using the maximum entropy modeling method. The role of environmental factors affecting the distribution of the species was investigated using the Jackknife method and response curves. Height variables, slope, patch size (coefficient of variation), potassium (15-30 cm depth), and lime (0-15cm depth) had the highest share in the model. The area under the curve index (AUC) was 0.86, which indicates the accuracy and average efficiency of the model in identifying the most desirable distribution areas. The kappa coefficient obtained from the comparison of forecast and actual maps was 0.72, which is at a very good level.

The field of ecohydraulics is rapidly growing as the society requires a better understanding of the interrelations amongst the dynamics of the physical processes pertaining to aquatic ecosystems and the modifications observed in their habitat as well as the biological responses of the organisms. Environmental flow science is a common tool for assessing the consequences of changing the flow regime of aquatic ecosystems and providing a minimum flow of aquatic species protection. Environmental Flows assessment is a global challenge involving a number of tangible and intangible segments of hydrology, hydraulics, biology, ecology, environment, socio-economics, and several other branches of engineering including water resources management. River impoundment (dams, weirs), water diversions and consequent modifications to flow regimes have highly destructive effects on aquatic species and ecosystems.    

In this research, two most common hydrologic methods Tennant and FDC Shifting were compared with a habitat simulation method i.e. PHABSIM. Tennant method is the most popular hydrological method in rivers and is based on the historic flow data. Investigation of the relationship between hydrologic approaches and physical habitat simulation approach and presentation of new recommendations based on the ecological and hydrological data can be very useful for estimating environmental flow in planning phase of river projects. We used river habitat simulation program to model the depth and velocities around boulder clusters to evaluate the habitat for Capoeta habitat in Zarrin-Gol River. The Zarrin-Gol River is one of the rivers in Golestan province in northern Iran. The statistics required for hydrologic calculations were also collected from Zarrin-Gol hydrometry station during the 42-year statistical period (1353-1395). In this regard, after the field studies and the development of the habitat suitability model for the target species, the Habitat simulation of the flow was carried out and eventually the ecological flow regime was extracted. In order to identify the important habitat variables and assess their impact, the life pattern of fish species was divided into juvenile and adult life stages.

Based on ecological assessment, the environmental water requirement of Gharahsoo river is 30% of mean annual flow for spring and summer and 10% of mean annual flow for autumn and winter seasons. It was found that application of Tennant and FDC Shifting methods led to dramatically low discharges as fixed minimum environmental flows, while habitat simulation method gave an acceptable estimation of ecological regime. However, habitat simulation technique assesses the allowable value of extraction from river flow dynamically, considering the ecological condition and average intermediate values. River conditions including flow velocity, water depth and river bed substrate are combined to form unique habitats facilitating the survival and growth of fish species populations.  Habitat forms are observed in a wide range of rivers depending on the diet and the river type such as Pool, Riffle and Run. The destruction of the Riffle substrate causes disruption and impacts the biological integrity of the current. According to the Q-WUA curve of the Riffle habitat in high waters and flood conditions, the area available for juveniles of the target species decreases because of the flood, morphology and habitat of the river, so large and continuous floods inhibit the opportunity to rebuild habitats from the river and endanger the lives of fish. One of the factors limiting the desirability of the habitat and thus reducing the available habitat in low river flows is the low flow velocity, as well as high stream flow flows. The maximum and minimum flow regime, required to maintain the Zarrin-Gol river ecosystem according to ecological needs, was 2.49 and 0.58 m3/s in April and November, respectively, with an average value of 1.25 m3/s (59 % of natural stream of the river). In the next step, habitat suitability distribution along the stream was investigated. This was performed for the full range of discharges. Habitat suitability distribution along the stream at different discharges indicated that the upstream part of the stream had the poorest habitat condition and moving towards the downstream parts, the habitat suitability condition was improved.

Application of the Tennant method based on a hydrological system can be an inappropriate choice for determining the minimum flow to maintain the ecological environment of the river. According to the results, the PHABSIM model can simulate flow, habitat suitability of target species and the habitats dynamics accurately, which is highly required to protect the proper habitat of fish in river ecosystems.