Masoumeh Sharifi; Bagher Nezami Balouchi; Javad Ramezani; Behzad Rayegani; Ali Jahani
Abstract
Introduction: The brown bear (Ursus arctos) is the largest carnivore which has a wide range of distribution but like other large carnivores, there are low frequency in the country. Habitats of this species in the country, especially at the local level are very fragmented. Therefore, investigation and ...
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Introduction: The brown bear (Ursus arctos) is the largest carnivore which has a wide range of distribution but like other large carnivores, there are low frequency in the country. Habitats of this species in the country, especially at the local level are very fragmented. Therefore, investigation and recognition of the potentially suitable habitat regions are of great importance in the conservation of this species. Also, identifying the factors affecting the selection of habitat plays an important role in describing species behavior and allows to compare different habitats in terms of their quality and to use it in the effective management. Evaluating the response of models and impacts of the biogeoclimatic factors, on habitat suitability, are the other goals of this study.Material and methods: This study was performed in the northwestern part of Iran in the Arasbaran ecoregion, which is known as the Caucasian geographical climate. The Caucasus ecoregion part of Iran has two separate plant communities, Hyrcanian and Arasbarani. The definite presence points of this species were identified by conducting field visits and collecting confirmed observations and reports of game wardens and experts and 64 points were employed in modeling after validating the obtained points and applying the buffer. Six modeling techniques were used in the BIOMOD package of software to create an efficient species distribution model and identify potentially suitable regions. Finally, the habitat suitability map was acquired from the resulting outputs using the combined Ensemble method.Results and discussion: The results from the models’ outputs and overlapping the map of the protected areas indicated that more than two-thirds of these areas are suitable for the brown bears. based on results, the variables of slop percentage and vegetation index involve the largest share in determining habitat desirability, so moderate slop and higher vegetation density will lead to more suitability for the species. In determining the desirability of the habitat of the brown bear, the variable of distance from rivers has less effect, and distance from the village did not play an important role. The flatness of areas, as it increase human access, reduced the level of security and thus reduced the suitability of the habitat of this species. There is more probability of the presence of species in the slope range of 10 to 40% and the suitability of habitat was raised in the moderate slope and increased the vegetation density. Regions with moderate rainfall and higher altitudes also play an important role in attracting bears and increasing habitat suitability. On the other hand, rising temperature, congested roads, and increasingly concentrated human activities reduce habitat desirability with an almost steep trend. 67% of the identified suitable and preferred habitats of the species have been located within the four protected areas category and 33% of them are outside of these areas, which is an acceptable level for conservation. Although a wide range of the protected areas in the study area is suitable for the species, the density of the brown bears in this part of the country is much lower than in the north and west of the country. This is maybe due to the high number of human casualties and damages in these areas and that most areas are not broad and wide enough to cover the entire home range of this species in the northwest. The most common reason for habitat fragmentation is the local road network, dispersion of rural areas and dispersed villages, and scattered individual livestock farming.Conclusion: One of the most significant conservation strategies for the large carnivorous species, such as the brown bear, with high mobility behavior, low population density, high conflict, and extensive conservation requirements is connectivity between the species habitats by defining new protected areas according to the suitable habitats maps. Also, the most important actions to reduce conflict and retaliatory measures are organizing the scattered livestock farming, implementing the educational programs, and more importantly, compensating the damages caused by bears to rural communities.
Hamid Sarkheil; Maryam Fakhari; Behzad Rayegani; Javad Bodagh Jamali
Abstract
Introduction: Tehran metropolis, with an area of 750 km2, a population of more than 8 million people, and about 4 million vehicles is associated with the problem of air pollution. A thorough study of the spatial distribution of pollutants such as CO and NO2 in Tehran is significant for identifying ...
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Introduction: Tehran metropolis, with an area of 750 km2, a population of more than 8 million people, and about 4 million vehicles is associated with the problem of air pollution. A thorough study of the spatial distribution of pollutants such as CO and NO2 in Tehran is significant for identifying the risks, probabilities, and risks of these contaminants. Therefore, mathematical and computational methods such as the confidence level method can be useful. The main goals of this research were to investigate the changes in air pollution levels in terms of CO and NO2 concentration, study the radius of impacts of fixed pollution stations, and calculate the level of reliability by investigating the probability of air pollution and the map of the risk of air pollution in different parts of the urban area of Tehran. Material and methods: In this study, Tehran's air pollution data in October, November, and December 2017 was used in spatial modeling. Using geostatistics and indicator kriging methods, data were analyzed and maps of the distribution of pollution concentration, and also two-dual maps (0 and 1) of the probability of pollution and risk of pollution in Tehran's for the study period were produced by ArcGIS Software. Results and discussion: The resulting maps showed the highest NO2 emissions areas (Ghaem Park, Razi Park, and the municipality of district 16) and areas with the least risk of NO2 pollution (Shahid Beheshti University, Pasdaran, Science, and Technology University, and Shad Abad). Moreover, the highest CO emission areas were the municipality of districts 11, 15, and 16, Ray station, Sharif University, Fatah Square, Health Park, and Razi Park). Aghdasyeh station, Shahid Beheshti University, municipality of district 2, Rose Park, Science and Technology University, Golbargh, Shad Abad, and Masoudieh had the lowest CO emissions. Conclusion: The indicator kriging was a useful method for assessing the risk of contamination by providing a possibility map. The hazardous maps produced in this study were useful tools for identifying areas with CO and NO2 contaminations. The results of this study can play an effective role in urban management decisions by correctly identifying the amount of air pollution in an appropriate spatial distribution.
