جستجوی مقالات مرتبط با کلیدواژه « مطلوبیت زیستگاه » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

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.

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.

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

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.

To manage an animal species effectively, it is necessary to identify habitats with high suitability for it; So its population can be preserved by conserving those habitats and planning to manage them properly. For this purpose, the study was done to determine Relationship between rangeland species and habitat suitability of Gazella subgutrrosa in different seasons on the basis of dung groups in Kalmand plain of Yazd province. So, sampling was done using random steady plots with 200 meters long and 2 meters wide and with 2 replications during five field investigation in summer and autumn. Random and control plots were put in different directions and were investigated every 45 days. Finally, all maps needed and information incorporation were prepared and done in ArcGIS9.3. The results showed that there is no difference in two seasons related to dung groups' density. In terms of canopy cover percentage, Artemisia species had a significant increase in presence points compared to random points; Astragalus sp. had also a significant increase in presence points compared to control points. Onopordon sp. canopy cover in absent points and Acanthophyllum sp. in random points were higher than in presence points (p<0.01).according to the prepared map, 23% of the region has topnotch suitability and 47% has second best suitability. Rocks and the regions under human activities were identified as unsuitable habitats. According to the results, it is seems that from habitat variables, species richness, Artemisia cover percent and distance from road are effective on deer habitat.

Water resources management in the basin area is increasingly associated with the allocation of environmental flows as a tool for improving the quality of ecosystem habitats in river conservation and restortion projects. In order to facilitate the estimation of the environmental flow of the Gharasoo River in Golestan province, based on the research framework after the hydrological analysis and field studies and observations, the Habitat Suitability model of the C.Capoeta gracilis species was developed and in the next step, of the flow was performed hydrodynamic modeling of the hydraulic parameters, and Finally habitat simulation and modeling with the integration of ecological and hydrodynamic studies of the flow and extracted the ecological flow regime. Based on the results of this study, C.Capoeta gracilis species in various stages of life has shown a response to changes in hydraulic parameters (depth and velocity) and flow rate, and to conservation of the ecosystem of the Gharasoo river using River2D model and variables of Habitat physics and Habitat Suitability Index of based Weighted Usable Area, Minimum and Maximum Environmental Flows are proposed to be 0.47 m3/s for the month of September and 3.03 m3/s for month of May. Results of this study showed the use of a two-dimensional hydrodynamic model for modeling the habitat desirability of the target species can recommended a tool for improving the performance of modeling in habitat simulation and implementation of the ecological river regime in river engineering projects conservation and restoration.

Persian Gazelle (Gazella subgutturosa) with conservation status of vulnerable (VU) is one of Bovidae species living in plain and steppe regions of Iran and its population has declined dramatically. Haftad Gholleh Protected Area has been considered as one of the suitable habitats for this species for many years. However,its population faced local extinction. In order to re-introduce the species to Haftad Gholleh Protected Area, the current suitability of protected area habitats should be evaluated. Therefore, in this study, the occurrence data for gazelles was extracted by reviewing local reports and interview with experts. These occurrence data was related to the anthropogenic and topographic characteristics of the habitat in the past (30 years ago the last time gazelles were reported from the area), using maxent and logistic regression methods. Then, the developed models were projected to the current status of the protected area to estimate the present situation of suitable habitats for gazelles. Both models indicated high discrimination power with AUC greater than 80 percent. Results of both models, suggested that areas with low elevation, low slope, close to the water sources and away from roads, farms and the mines are suitable for gazelles. Current suitable maps for gazelles indicate a decrease by 13% and 16% in maxent method and logistic regression method, respectively.finally, both models predict seven percent of the protected area as suitable for gazelles. These areas are of great priority in any attempt for reintroduction of gazelles to Haftad Gholleh Protected Area.

Habitat recognition and knowledge of habitat requirements are extremely important to the wildlife conservation, particularly for endangered and vulnerable species. The purpose of the study was to determine which ecological and habitat factors contribute the distribution of black billed sandgrous (Pterocles orientalis) in Shirahmad wildlife refuge. Sampling was performed in two season (spring and summer 2010) and in eight transects. Presence points of black billed sandgrous along with human and topographic variables were mapped in GIS environment. This study employs one recently proposed modelling technique –. Maxent – to investigate the geographic distribution pattern of black billed sandgrous. The results show that the most important factors affecting on the distribution of black billed sandgrous include the distance from roads and distance from the water sources. According to the predictions, water resources and pasture have positive relationship with habitat suitability. On the other hand, habitat suitability has negative relation with the distance from the village and rivers. Results indicate that western part of Shirahmad wildlife refuge needs more attention to most effetely manage the population of this species. Furthermore, suitable habitat factors within black billed sandgrous habitat have to be improved.

Habitat associations of wild sheep, Alborz red sheep (Ovis orientalis gemelini X Ovis orientalis arkali), in Khojir and Sorkheh Hesar National Parks were studied over three seasons (Spring, autumn and winter) in 2000. The position of observed maternal groups (including ewe with lamb) and male groups (including rams, barren ewes and juveniles) were determined on topographical maps during the field work. Then, the prepared maps were digitized. Maps of slope, aspect, altitude, soil types, vegetation density, vegetation density of higher than 50 cm, density of forbs, distance to escape terrains, distance to water source and position of asphalted roads, tracks, paths and rural areas were digitized. The frequency of occurrence and density of different observed groups were compared among the classes of each information layer via Geographical Information Systems (GIS). Habitat suitability maps were subsequently prepared. The assessment of prepared maps indicates a logical relation between habitat suitability maps and filed observation Results suggest that wild sheep frequency has a relationship with slope and aspect. Notable aspect of preference of wild sheep is often eastern. In spring, male groups prefer the eastern aspect. Distribution was higher in soils with abundant gravels and high permeability. Abundance and density of wild sheep increase with density of total vegetation and forbs, and also vegetation taller than 0.5 meter, although the latter is not related to the increase of the ewes with lamb's Distance. Analysis shows a decrease in wild sheep abundance when the area is far from water sources and escape terrain and wild sheep are rarely seen to 500 meters from roads and 1000 meters from rural areas.

Isfahan wild sheep Ovis orientalis isphahanica is listed as vulnerable in the IUCN red list of threatened species. Adequate knowledge on habitat requirements and environmental factors determining the niche of a species is central to its conservation programmes. However, there is scarcity of data on habitat associations of this species in Iran. A GIS-based model, using presence-only data, was used to predict habitat suitability for this species in Mooteh Wildlife Refuge. This study has determined the most important environmental factors influencing the ecological niche of Isfahan mouflon and has identified suitable seasonal habitats in the study area. Results showed that during summer and autumn a large part of the suitable habitats of this species is covered with Artemisia aucheri, while in winter and spring areas covered with Artemisia siberi acquire the higher suitability. This is consistent with the vertical migration of the species as the results of this study revealed that in summer and autumn higher elevation has higher suitability, whereas in winter and spring the suitability of lower elevations is higher. Slopes over 30% and distance to water sources in summer were recognized as limiting factors for the distribution of this species. The influence of other factors (such as distance to roads, mines and cultivated lands) on habitat preference was negligible.

The aim of this study was to develop a methodology to identify suitable habitat of the Eurasian Nuthatch (Sitta europea) at kheyrood forest, northern Alborz, Iran. This study was carried out during spring to summer 2008. With attention to the area and topographic condition of kheyrood forest, Patom, Namkhane, Gorazbon, Cheler and Baharbon were selected as data collecting series. The present study focused on vegetation structure and floristics, as well as topographic factors (slope, elevation, and direction). In sampling stager at observation point in the line transect path, habitat parameters and presence and absence of nuthatches were recorded. In each plot all individuals that were observed or being heard, were designated as presence point and other cases were named as an absence point. Based upon this monitoring, 78 plots were collected as the presence and 20 plots were counted as absence point during spring season. Binary Logistic Regression was performed to develop the distribution model of the Eurasian Nuthatch according to habitat variables. Finally as a result, the significant parameters in this model were height, diameter, stand and type of trees. According to the results, suitable habitat for S. europaea was considered as all the forest areas where old-growth trees with large bounds are abundant. In fact habitat quality is related to the abundance of old trees. Also, the presence of Carpinus betulus and Fagus orientalis was identified as an important factor for habitat selection.