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

Ecological spaces play a crucial role in addressing climate change and global warming with focusing on storing and capturing CO2 from atmosphere. Consequently, quantifying and monitoring carbon storage content is the main step to toward achieving sustainable development goals. The main objective of this study is to develop a precise model for calculating carbon storage content at four pools i.e., aboveground carbon (AGC), belowground carbon (BGC), soil organic carbon (SOC) and dead organic carbon (DOC) under different land uses. For this, a site with an area extent about 243204 ha was selected from Miandoab region (West Azerbaijan Province) by the fact that it represents various land uses. Since application of integrated remotely-sensed data and novel technologies facilitates predictions as well as increases the modeling accuracy, the Google Earth Engine (GEE) platform and the InVEST model were implemented in preparing land use/land cover (LULC) maps and then carbon storage content. The prediction for 2023 showed that the total carbon storage in the aforementioned region would be approximately 11.52 × 106 ton. In addition, the detailed evaluations illustrated that the highest carbon storage content related to SOC and AGC as expected. A possible reason is that living mass is located on the surface. In terms of different land-uses without paying attention to their areas in themselves, the highest carbon storage content was for pasture, followed by tree cover, agriculture, urban area, water bodies and barren. Finally, it is concluded that applying the respective remote sensing data integrating with a suitable technique uncovers the impact of LULC changes on carbon storage with success.

Urbanization which has been considered the main contributor to climatic problems in cities, not only changed the physical environment in cities, but also has affect the characteristics of local climate zone. This study aims to investigate the relationship between surface properties of Local Climate Zones (LCZ) extracted from satellite resolution images and Land Surface Temperatures (LST) in a semi-arid region. By employing the LCZ approach, the study seeks to understand how LCZs influence LSTs in this specific environmental context. This study consisted of four main steps: Image preprocessing, LST retrieval, LCZ map preparation and spatial analysis. In this way, the LCZ scheme was used to classify the study area based on two sets of built-up types and land-cover types. Google Earth was used to specify training areas under study and to define different LCZ types. The Split Window Algorithm (SWA) was used to retrieve LST from Landsat-8 TIRS. The results showed that the built type and the land-cover type behave like two independent sets of patterns in the study area. The build type set fluctuated in a higher LST range than the cover land set (forest, farmlands and bushes). By shedding light on the relationship between the surface properties of LCZs and LSTs, the study provides valuable insights into the factors influencing thermal dynamics in semi-arid environments. Armed with this knowledge, urban planners can develop more informed strategies and interventions aimed at mitigating heat-related challenges and improving overall urban livability.

The largest part of the biodiversity of terrestrial ecosystems is in pastures and agricultural lands. In terms of biological importance, the Zagros mountain range has the richest and most diverse biodiversity, which faces the dangers of land use change and invasive species. Earthworms, soil ecosystem engineers, have been of great interest in soil physicochemical processes and evolutionary studies. Recent studies indicate the adverse effect of human activities and land use change on the diversity of earthworms. Since the identification of earthworms, using morphological methods is ambiguous; therefore, we need to use genetic methods and molecular markers to separate worms. In this study, we identified taxonomic functional units (OTUs) in earthworms using morphological information and molecular marker COI. Then, we have investigated the effect of agricultural uses on the genetic diversity of earthworms in Central Zagros, Borujerd County using multifactorial statistical analysis. We separated into 13 OTUs belonging to seven genera based on the results of the genealogical tree. The results of the comparison of wheat, alfalfa, sugar beet and clover pastures and farmlands showed that the OTUs of the farmlands all belong to the Lumbricidae family and the OTUs of the pastures, in addition to this family, were in the Megascolecida and Hormogastridae families. In total, we observed four genera of Helodrilus, Aporrectodea, Bimastos and Allolobophora in agricultural lands and six genera of Metaphire, Aporrectodea, Bimastos, Esenia, Allolobophora and Hormogaster in pastures. The results of the ranking analysis of the multifactorial analysis method in land use groups, soil physicochemical characteristics and indicators of abundance and biodiversity of earthworm OTUs with nine factors in 36 variables showed that OTUs C, H and I, all of Aporrectodea rosea species, are the most effective based on multi-factorial analysis in abundance and biodiversity. The biodiversity efficiency index of earthworms of grassland ecosystems was higher than agricultural ecosystems in all cases. Compared to other agricultural ecosystems (wheat, sugar beet and clover), alfalfa cultivation had the highest efficiency index in earthworm biodiversity and the lowest efficiency index was in wheat cultivation. Sugar beet and alfalfa croplands had more OTU diversity compared to clover and wheat croplands. The selection of alfalfa cultivation in crop rotation will increase the biodiversity of earthworms and the stability of agricultural ecosystems. Considering the importance of earthworms in providing ecosystem services and soil quality, it is necessary to conduct more research on the effect of common agricultural ecosystems on the biodiversity of earthworms.

With the rapid development of society, economy and population growth, the impact of human activities on ecosystems is increasing, which has caused the relationship between human well-being and ecosystem to be in the spotlight. To that end, ecosystem services as an essential element for human development and survival emphasizes the benefits that natural ecosystems provide to humans. These services are divided into four categories based on the Millennium Ecosystem Assessment (MEA): provision, regulation, support and cultural. Cultural ecosystem services are important component of ecosystem services that refer to intangible benefits of the human beings from ecosystems and play an essential role in enhancing human well-being. Cultural ecosystem services can include the use of natural resources directly or indirectly.

The present study was conducted with the aim of modeling recreation services in Semnan province. For this purpose, the integration of the analytic hierarchy process (AHP) of one as the multicriteria decision-making methods and the recreation opportunity spectrum (ROS) model was used. In the ROS model, recreational service is estimated based on recreation potential index and accessibility- remoteness index. In the recreation potential index, three elements: the degree of naturalness, the protected regions, and the attractiveness of water bodies, and in the accessibility- remoteness index, the distance from roads and human-made areas were mapped. In this research, Sentinel-2 satellite images were used to prepare the land use map of 2021. Then, using the maximum likelihood algorithm, land use maps were prepared in 18 classes.

According to the land use map, pastures, barren lands and rainfed agriculture have the highest levels of land use in the studied area with 23.57, 22.27 and 17.31% respectively. After that, waterbodies, salt marshes and irrigated agriculture are the dominant land uses with 15.65, 10.98 and 7.84%, respectively. It is worth mentioning that the smallest area of the region is dedicated to wetlands and urban uses. Based on the results, Forest and pasture areas have the highest potential in providing recreation services in the study area. It was also seen that, the third category (low provision- difficult access) and the seventh category (high provision- easy access) respectively have the highest and lowest land surface coverage in terms of the provision of recreational ecosystem services in the province. Overall, the results showed that recreation ecosystem service is affected by various factors caused by human development, especially land cover/use changes. Considering the concentration of both variables of ecosystem service provision and urban and industrial development in the northern half of the province, it is vital to pay attention to the conflicts between the development and management of ecosystem services. If this is ignored, in addition to intensifying the instability of development, the destruction of natural assets of the province, especially forests and pastures, which are the main source of provision of various ecosystem services such as recreation, will intensify.

In general, the results indicate that most of the places in the province have a medium to low ability to provide recreation services. Considering that recreational potential is important for the well-being of urban populations, increasing urban parks and green infrastructure areas is a useful way to improve the quality of the recreational experience. Therefore, urban development strategies should increasingly aim to strengthen the natural and artificial network of green space, diversity of plant compositions and biomass structure, and proper management of green space. This is necessary for the design of green space with regard to maximizing ecosystem services in Semnan province.

The degradation of soil structure and reduced water infiltration into the soil are indicators of soil degradation, which lead to decreased stability and production quality, as well as environmental problems. Soil conservation methods are widely used to curb soil degradation processes and improve soil structure and permeability. The effectiveness of these methods in enhancing these indicators and controlling soil degradation requires further study and evaluation. This research aims to investigate the stability of soil structure and soil infiltration rate affected by various soil management and conservation operations, and to compare them in the Razin Watershed area of Kermanshah Province.

For this purpose, eight common reclamation and conservation operations in the study area were selected and evaluated. These operations include pit-seeding and seeding, rangeland audit plan - conversion of dryfarming to rangeland, rangeland audit plan - conversion of dryfarming to forage cultivation, almond tree planting alongside digging holes, land leveling, seedling planting, conversion of dryfarming to rangeland, forage cultivation and orchard, and forest area. For evaluation, random systematic sampling points were selected within the area of each operation and their corresponding control area for study and sampling. After digging profiles and sampling the soil, the laboratory measured and calculated soil aggregate stability indices, including Mean Weight Diameter (MWD), Geometric Mean Diameter (GMD), and the proportion of stable aggregates larger than 0.25 mm (WSA>0.25). The final infiltration rate was also measured in the operation areas and their controls using a disc infiltrometer. Finally, a statistical comparison of the mean values of MWD, GMD, WSA>0.25, and final infiltration rate in soil conservation operations and their control areas was performed using the T-test for independent samples and the Duncan test for comparing the means of these indices in various operations using SPSS software.

The evaluation results showed that the lowest MWD index was related to land leveling and sapling planting at 0.15 and 0.35 mm, respectively, while the highest values at 1.9, 1.8, and 1.6 mm were related to 20-year-old almond planting, 10-year-old almond planting, and forest areas, respectively. Additionally, the highest WSA>0.25 index values were found in fodder cultivation, orchard establishment, and 10-year-old almond planting operations, indicating the formation of large and stable aggregates due to conservation operations. Among the eight operations studied, the 20-year-old almond planting operation showed the greatest improvements in MWD and WSA>0.25 indices. The results for the final infiltration rate indicated that soil conservation operations, particularly converting low-yield rain-fed lands to sapling planting and changing rangeland use to 10-year-old almond planting, led to the highest increases in final infiltration rate, at 21.8% and 16%, respectively, compared to the control.

Overall, soil conservation operations increased the relative share of larger soil aggregates. However, the soil infiltration rate index showed conflicting results, as factors other than the evaluated conservation operations also influenced water infiltration into the soil, necessitating further studies. Consequently, examining the role of management, especially land use management, is essential for sustainable soil resource utilization.

Among natural disasters, flood is undoubtedly the most catastrophic hazard in the world. One of the basic strategies for reducing the damage caused by floods is to prepare a flood sensitivity map. Spatial prediction of the flooding probability using models created from spatial and historical data, which ultimately leads to the preparation of flood sensitivity maps is an appropriate solution for land management planners in different areas to prevent the occurrence of this phenomenon. In this research, in order to determine flood-prone areas, the hybrid model of adaptive neural and fuzzy inference and the metaexploratory optimization algorithm of imperial competition (ANFIS-ICA) and the hybrid model of adaptive neural and fuzzy inference and the metaexploratory optimization algorithm of particle swarm (ANFIS-PSO) are used.

The Zarine River watershed has an area of 4485 km2 and is located in the northwest of Kurdistan province between the longitude of 45°48ʹ30ʺand 46°48ʹ20ʺ east and the latitude of 35°42ʹ20ʺ and 36°23ʹ15ʺ north. The climate of the region is humid and the average annual rainfall is 480 mm. Locations of flood events were randomly divided into two groups: training (70%) and validation (30%). Various environmental factors (height, direction, slope, surface curvature, land use, lithology, rainfall, flow power index, distance from river and topographic wetness index) were selected as independent variables in the modeling and their digital layers were prepared. The ANFIS-ICA and ANFIS-PSO models were used in this research and their prediction results were evaluated based on the criterion (AUC) and the true skill statistic (TSS).

On the basis of these findings, in the validation stage, the model (ANFIS-PSO) with an AUC of 0.98 and a true skill statistic (TSS) of 0.89 had the highest accuracy. The results also showed that the factor of distance from the stream was identified as the most important environmental factor. In addition, ground slope and TWI were ranked second and third in importance, respectively.

Based on the results, the hybridization approach, which combines machine learning models and meta-exploratory optimization algorithms, improves the learning power as well as the predictive power of the model. The results of this research showed that the distance from the stream and the slope of the land are the most important factors affecting flooding. Based on the results and analysis, it can be concluded that machine learning models have a high capability for predicting flood potential. The flood potential maps prepared in this research can be very useful for managers and experts and can be used in planning flood prevention measures. Directing flood control facilities and measures in situations with a high flood potential will improve flood management from an economic and technical point of view.

Desertification is one of the most significant process of land degradation in all the world, especially in arid and semi-arid regions. In the United Nations Convention to Combat Desertification report (1994), Desertification is land degradation in dry-lands, resulting from various factors, including both climatic variations and human activities. This process is always associated with soil degradation, pollution and reduction of water resources, vegetation and other biological resources in natural and ecological conditions. Therefore, determining the main factors of this process can be very effective in proper land management. This research was conducted with the aim of zoning sensitivity areas to the desertification intensity based on ESAs model and providing management strategies based on scenario planning in Razavi Khorasan province.

In this research, five criteria such as climatic quality, soil, vegetation, erosion and management (human activities), and 20 indicators such as soil texture, soil depth, rock fragment, parent Material, vegetation density, fire risk, rainfall. drought, water and wind erosion, land use change, mining, livestock density in pasture, etc. were used. were used. Scoring and weighting of the indicators was done using a questionnaire and based on the expert opinions of specialists, executive managers and field experiments. The designed questionnaire included 21 questions, that classified in the form of 5 criteria of soil, climate, vegetation, erosion and management, which were distributed among the statistical population in two rounds. Management strategies and policies were also obtained in the Delphi method in the form of expert panels (brainstorming).

The results showed that the vegetation criteria with indicators such as the reduction of vegetation, the increase in the risk of fire in pastures and forests due to the continuous droughts of the past two decades and the increase in the intensity of wind and water erosion, with a value of 1.419, has had the greatest value and importance in expansion the intensity of desertification. After that, factors such as human activities (management), climate, erosion and soil respectively have had the greatest impact on the sensitivity areas to desertification in Khorasan Razavi province. In terms of the critical situation, the high percentage of the areas in the northwestern regions such as Quchan and Chenaran township due to the impacts of drought, severe changes in land use and water has become desertification. In the central, eastern and southern parts due to drought, land use changes, lack of optimal land management and wind erosion, main reason has been the expansion of desertification. Besides that, all the townships of Khorasan Razavi province have fragile conditions. This issue can be considered as an important and serious warning for the future management of Khorasan Razavi province. Therefore, in order to provide effective ways to deal with the intensity of desertification, based on the opinion of experts and specialists in the current research, by considering only the priority indicators of each of the criteria, the number of 10 cross matrix of the important indicators of each of the criteria, 20 scenarios, 6 strategies and more than 40 strategies were obtained. So that, by using the suggested strategies could be planned and managed according to regional and local conditions, to reduce the intensity of desertification.

The ESAs model uses four criteria of management, vegetation, soil quality and climate mainly to evaluate areas sensitive to desertification. So that, in this research, due to the importance of the erosion (water and wind erosion), for zoning map of sensitivity areas to desertification were used. In order to provide management plans (strategies and policy), to reduce and combat desertification in Khorasan Razavi province, management strategies such as; -sustainable management of vegetation, - water resources management and watershed management, - soil management, - livestock management and reduction of environmental hazards caused by human activities, -education, promotion and culture and sustainable management. Therefore, in this research, only the important strategies and policy that can provide a comprehensive vision of land management in Khorasan Razavi province, were suggested.

The negative effects of soil salinity on natural and human environments have turned such phenomenon into one of the serious threats to the sustainable management of arid and semi-arid areas. The present study aims to evaluate the spatial-temporal variations in land use/land cover and soil salinity in a part of Sistan basin located in the arid regions of southeastern Iran, which has been exposed to the phenomenon of soil salinity during the recent years. To this aim, land use/land cover and soil salinity maps were prepared for 1989 and 2019 using the measurements obtained from ground sampling and instruments such as remote sensing (RS) and geographic information system (GIS). Based on the results, the normalized average soil salinity was 0.322 during 1989, reaching 0.52 during 2019 with a growth of 0.188. In addition, comparing the trend of salinity increase and land use/land cover variations in the region indicates that such factors affect each other significantly. Further, the conversion of land use/land cover from irrigated agricultural uses and water bodies to bare lands, rainfed agriculture, and man-made areas has decreased the vegetation cover and water areas, leading to an increase in soil salinity due to the erosion created by the 120- day wind of Sistan and sedimentation of salt particles in the whole region. Chah-nimehs have not been able to fully compensate for the adverse effects generated by the destruction of habitats and drying up of a part of Hamun Lake and Hirmand River, despite their slight success in reducing the environmental obstacles.

Investigating changes in vegetation density and land use is one of the most important aspects of natural resource management and reviewing environmental changes. In this research, using remote sensing technique, the monitoring of changes in vegetation cover and its relationship with surface temperature and land use in Khoda Afarin and Kalibar cities were investigated using remote sensing technology during a period of 22 years (2000-2022). To perform statistical and visual analysis on satellite images, Envi 5.6 and Arc GIS 10.8 software were used. NDVI index was used to investigate changes in vegetation area and quality. Also, in order to investigate qualitative changes in vegetation, the numerical values of this index were classified into three classes: dense, semi-dense, weak or no vegetation, and the temperature changes of the earth's surface during the study period using It was calculated from Landsat satellite images and then the land use maps were extracted based on the supervised classification method and through the maximum similarity algorithm. Based on the analysis, it was determined that in the studied period, 58,196 hectares, about 15.6% of dense vegetation density, and 38,415 hectares, about 10.2% of semi-dense vegetation density, have been lost. In fact, 96,611 hectares, about 25.8% of the density of dense and semi-dense vegetation, have been converted to other uses in 22 years. The study of land use in the region showed that the changes in vegetation density are mostly related to the use of agricultural and garden lands and pastures, and during the study period, the most destruction is related to dense vegetation density. Finally, investigating the relationship between vegetation cover and land surface temperature (LST) showed that the vegetation cover index (NDVI) has a negative and inverse correlation with the land surface temperature and in most areas that have denser vegetation cover; shows a lower temperature. The results of the research show that the most important factor in the changes in vegetation density in the region is human activities such as agriculture, construction and road construction, which have caused many changes in the land surface, the analysis of the area of these land uses shows He said that the level of agricultural lands and pastures has increased significantly, which is mainly the result of the conversion of dense vegetation, especially forests, to agriculture. The results of this research can be used by the organizations of agricultural jihad, natural resources and the Ministry of Interior.

Al land use changes pose a most serious challenge to agricultural production, resulting in the loss of fertile soil and food security. The present study was conducted to investigate the challenges associated with fertile agricultural lands in Iran as an attempt to examine and identify the different aspects of the threats agricultural lands are faced with. As a second step, the laws and regulations governing land use change in different countries and in Iran were reviewed and the general policies related to the protection of agricultural lands were examined.  The review of land use laws in Iran showed that, despite their abundance, they have suffered from poor law enforcement as a result of both social and historical reasons as well as a public negligence of and non-adherence to the laws. Evaluations of temporal changes in the growth and development of metropolises as provincial centers revealed that they had greatly expanded beyond their original limits to annex fertile agricultural lands in the suburbs to these large cities. The five-year statistics of the requests submitted for land use change in each province also revealed landlords’ increasing demands submitted for land use change motivated by more profits out of their property, which result in loss of fertile soil, decreased agricultural production, and endangered food security.

Climate has an important role in agricultural activities and can be examined from two perspectives. First, what locations are suitable for a specific plant, and second, what plants are suitable for a climate. The latter approach is less considered; thus in this study, it has been investigated by introducing a standard method (Sys method). The study area is located in Mako city. Climatic suitability evaluation was performed by numerical (parametric) method using the Maku Synoptic Station data for pistachio, almond, pears, plum, sour cherry and sweet cherry. The findings showed that except for pistachio, with marginally suitable class (S3), other plants were classified as moderately suitable class (S2) but the value of climatic index for each crop was different. The introduced method made it possible to identify the most important effective climatic factors for the cultivation of each plant and determine the most limiting factor in the phenological period. Such findings showed that there is a close relationship between crops, phenological period, climatic characteristic and location. Based on this, the most suitable plant or plant species can be selected for a region, using the phenological period of the plant and climatic characteristics. However, for sustainable development, other components of the land, such as soil and/or topography, should also be evaluated. In general, the introduced approach can be used as an efficient tool, both for choosing the most suitable plants in a climate and for choosing the most suitable place (in terms of climate) for specific plants.

Semnan plain is very susceptible to land subsidence and drought, in recent years has greatly increased the occurrence of subsidence. The aim of current research is land subsidence susceptibility assessment using frequency ratio model. At first locations of the land subsidence were specified using Landsat satellite images and field surveys. After classifying conditioning factors maps, the weight of each map was calculated using the frequency ration model. The highest weight was related to water level less than 41 meters, slope less than 2 degrees, topographic wetness index more than 12, agriculture land use type, plan curvature -0.01 to 0.01, profile curvature -0.001 to 0.001, distance less than 1260 meters of road, less than 7000 meters of faults, Quaternary formations and less than 200 meters of drainage network. Finally, by combining the weights, the final subsidence susceptibility map was prepared. The AUC for the frequency ratio model was 0.76 that showed this model is acceptable for land subsidence susceptibility mapping in the Semnan Plain. Land subsidence susceptibility maps produced in this research can be useful and functional tools for regional planners and policy makers for land use planning, resource management, and natural hazard mitigation.

Considering the role and importance of soil quality assessment in economic success and environmental sustainability, this study was conducted to evaluate the soil quality index (SQI) in different land use of Malayer province. For this purpose, 36 samples from 6 the land use were collected and 11 physical and chemical properties of soil were measured. The Soil quality index was determined based on criteria. Using the principal component analysis (PCA) method among 11 physical and chemical parameters of soil, two parameters of CaCO3 and K with a total variance justification of 63.08% as the most important parameters to evaluate the soil quality index were introduced using the Minimum Data Set (MDS) method. Finally, soil quality in different land uses was determined and compared. The results showed that the park and green spaces land use has the highest soil quality index in Malayer province, but irrigated farming and industrial land uses had the lowest soil quality, which requires management and increasing soil quality in these two land uses in order to prevent excessive soil degradation and erosion.  Considering that maintaining and increasing soil quality is one of the criteria for the sustainability of different ecosystems, the need to monitor this parameter in different land use and prone to damage in Malayer province is suggested.

The capacity of an ecosystem to ecosystem services supply depends on the structure, processes, and functions affected by interactions with socio-environmental parameters. So, considering the parameters affecting ecosystem services can be efficient in ecosystem management and improving their functions. This study aims to investigate the effective parameters of ecosystem services supply in the central part of Isfahan province. Accordingly, after a literature reviewing and considering the study area characteristics, socio-environmental parameters such as mean slope, mean height, density Population, distance from access routes, distance from the river, percentage of available land uses, and distance from the center of the largest urban area of the study area, in homogeneous areas of ecosystem services, aesthetic value, recreational value, and noise pollution reduction were extracted and evaluated using principal component analysis (PCA) method is some steps such as sample size adequacy test, standardization, evaluating the correlation matrix, calculation of eigenvalues and eigenvectors. According to the results, the value of the first component is 3.715, which justifies 57.016% of the total variance in the data. The second component also explains 19.874% of the total variance. Overall, agricultural land, residential areas, distance from roads and green spaces, and parks are the most effective parameters on ecosystem services supply justifying more than 76% of the variance of the data set. Based on the results, management measures could be taken to conserve ecosystem services based on the extracted criteria. , The results of this study lead to decision-making simplicity and land evaluation and saved time and money on land-use planning and management.

Assessment spatial distribution of the ecosystem services of nature reserves is necessary to the protection of ecological environment, promote conservation and development and land management. To that end, the present study aims to model the ecosystem services of carbon storage, habitat quality and nutrient export using the InVEST software and recreation software through the combination of several indicators in GIS software in the protected area of Maneshet and Qalarang. In addition, the service provisioning hotspots, was mapped for prioritize conservation measures, using Getis-ord Gi∗ statistics. in order to examine landscape pattern changes, landscape metrics were also used. The results Indicated that the suitability of carbon storage, habitat quality and recreation in the northern and eastern regions of the study area is more than the southern and western regions, while the nutrient exports is higher in the central regions than other regions. The highest carbon storage, habitat quality, and recreation were observed for the forest land. Likewise, it was the highest nutrient in agricultural land. Also, the results of the spatial distribution of all ecosystem services showed that hotspots are concentrated in areas with forest cover, which play the greatest role in supply ecosystem services. The results of this study, with information about the spatial distribution of services, provide the possibility of identifying the areas with the greatest benefits of ecosystem services, which can be useful in line with land use policies for sustainable development. Eventually, these results can provide some reference for Manasht and Ghalarang protected area and other nature areas to give consideration to both categories of environmental protection and development.

Protected areas are parts of the land that are selected and managed for effective in situ biodiversity conservation, among other important ecosystems features. With an efficient network of protected areas located in the right places to represent all ecosystems, ecological resource management can better be achieved. Gap analysis provides a tool for assessing the degree to which biodiversity is represented in conservation areas that help land managers and policy makers when they need to make appropriate decisions. In this study, the representativeness of the national parks system as part of Iran’s protected areas network, for terrestrial ecosystems was investigated. For this purpose, suitable criteria and indicators for national parks selection were identified and mapped. We developed a decision-making algorithm for assessing the representativeness of the national parks based on the set goals mentioned above. Using the algorithm, the indicators layer was overlaid with the ecosystems layer and national parks and the national parks coverage of ecosystem patches was evaluated and coded. Having calculated the coverage of the ecosystems, three scenarios were defined and their realization was assessed in each ecosystem, hence showing the lack of ecosystems’ protection. The results showed that the three scenarios have only been realized in two ecosystems of Cold & Arid Bare Mountains and Arid Scrubland & Halophytes, and in other ecosystems, the level of representativeness is not sufficient. Based on this, the area required to complete the system of national parks in terrestrial ecosystems was calculated as around 2000000 hectares. The results of this study can be a guide for land protection planners to revise the system of terrestrial national parks in Iran.

The purpose of this research was to evaluate the intensity of desertification and its impacts on the reduction of vegetation in Shir Ahmad Wildlife refuge in Sabzevar township of Razavi Khorasan Province. To evaluate the intensity of desertification, the ESAs model and the three criteria of climate quality, vegetation and human management were used. The results of this research showed that based on the ESAs model, desertification occurred in the study area during the years 2008 to 2018 and its trend was increasing. Thus, in 2008, 64.9% of Shir Ahmad region is in the severe hazard class and 35.1% of the other lands in the region are in the moderate hazard class. However, in terms of the intensity of desertification and ecological conditions in 2018 about 68.5% of lands are in the severe desertification hazard class and 31.5% are in the moderate hazard class. The results of this research showed that in the last 10 years, the continuation of the drought and changes in climatic parameters along with human activities have been the main causes of the desertification expansion and vegetation reduction in Shir Ahmad Wildlife refuge. Therefore, significant methods should be taken regarding the preservation and sustainability of this area in order to prevent the destruction of plant and animal species. Some of the measures such as reducing the grazing pressure of domestic animals from the pastures, replacing industrial animal husbandry methods instead of the traditional method, implementing land restoration programs and providing fodder for wildlife, will be among the proposed programs for the management and protection of Shir Ahmad Wildlife refuge.

Today, the destruction of natural resources is one of the most important and serious challenges facing development programs. Soil erosion is among the processes that directly and indirectly threaten our country's soil and water resources. Water erosion appears on the earth in different forms, one of the advanced forms of which is the gulies. Gully erosion is one of the important processes of soil destruction, which in different climates causes significant soil losses and the production of large amounts of sediment. The purpose of the present research is to investigate the morphological characteristics of the gullies of Khuzestan province and the role of its influencing factors in the expansion of the gully areas.

 First, by collecting available data and comparing it to satellite image and other data, the province's gullies have been defined. The first field visit focused on verifying the integrity of these areas and correcting the gullies boundaries. The total area of Khuzestan province approximately is 64000 km2 in the dry desert climate, and more than 33,862 ha of it is under the influence of gully erosion. The hot semi-arid climate also covers approximately 12,1% of the province and 16,116 ha have experienced gullies erosion. After determining the area of gullies and dividing the areas above and below 500 ha, due to the difference in appearance, topography, and vegetation, 2 and 1 representative areas were selected from the hot-dry desert and hot-semi-arid climates, respectively, and 2 replicates were selected from each representative. Longitudinal and cross-sectional profiles of representative and replicated gullies were drawn and after soil sampling, all morphological features of the gullies were measured.

According to the results, most of the gullies of the province have been created in the plains with a low slope with deep soil and loamy sand texture, silt or silt loam with pasture, and sometimes agricultural land and U-shaped cross-section. Darkhazine and Sharif gullies, with 1260 and 912 cm, and Darkhazine gullies with 420 cm value have the maximum width of top, bottom and depth in the cross-section of 75%. Also, the gullies of Choghazanbil, Darkhazine and Choghazanbil with values of 30 cm have the lowest depth, top and bottom width in the cross-section area of 75%. The overall profile is scratched, and in terms of depth class, they are in the category of medium-deep gullies with a vertical top.

Intrinsic characteristics of soil, formation and geological type, climate, intensity of rainfall as natural factors, and destruction of vegetation, land use change and the lack of proper management, unprincipled road and bridge construction operations, construction and installation of oil facilities and electricity bars as human factors have played a role in the process of gully expansion. However, the diversity and change of the number and degree of influence of different factors from one point to another and the difference in their participation in the formation and expansion of the gully are based on the environmental conditions of the land. These conditions require that more research be carried out to identify as many factors as possible in the phenomenon of gully erosion and their participation in the formation and expansion of this phenomenon in different places and with different environmental conditions.

The groundwater aquifer is one of the most vital resources, being considered more important in the countries (e.g., Iran) located in hot and dry areas. One of the ways to prevent contamination of groundwater resources is to focus on their vulnerability. So, a trustworthy assessment of groundwater vulnerability is useful to determine the contamination points of the aquifer for effective protection and management of groundwater resources.

In this research, DRASTIC index was applied to evaluate groundwater susceptibility while considering effects of land use and nitrate pollution for Kerman-Baghein Plain located in Kerman Province. In this regard, seven parameters including the depth of the water table, net feeding of aquifer, aquifer texture, surface soil texture, topography, impact of the vadose zone, and hydraulic conductivity were employed to calculate the DRASTIC index. It should be noted that this index has previously been applied by researchers for assessment of the vulnerability of the aquifer against groundwater pollution in different regions. However, despite the complexities in the underground water system and the opinions of experts in assigning the rank and weight of the parameters in this index and the difference in the conditions prevailing in the studied areas, it has always prompted researchers to take practical steps to improve this index. This improvement has been carried out in a number of studies by adding other parameters (e.g., land use and the effect of nitrate) to the parameters of the DRASTIC index. Therefore, in the present research, the parameters of land use and potential risk associated with land use have been used to compute the Composite DRASTIC index (CD) and Nitrate Vulnerability Index (NVI) in the Arc/GIS software environment, respectively. In this way, the CD index was obtained by adding the land use parameter to the DRASTIC index and the NVI index by multiplying the raster map of the potential risk rating related to the land use in the DRASTIC index. It should be noted that according to the land use map evaluation, this plain includes 54% of low-density pastures, 24% of irrigated agriculture, 10% of hand-planted forests, 6% of bare and desert lands, 5% of residential areas, and 1% of claypans. After the evaluation of three vulnerability criteria using all three indices DRASTIC, CD and NVI, their correlation with Ggroundwater Contamination Risk (GCR) was also investigated.

The results revealed that the correlation of the DRASTIC index with the risk of underground water pollution is 8%, the CD index is 30% and the NVI index is 54%, with a probability of 99%, they show a significant correlation. The results indicated that the addition of the land use parameter caused to increase the correlation of vulnerability with the risk of groundwater pollution, and multiplying the potential risk associated with land use led to further increase of the correlation. As a result, the NVI index was selected as the superior index compared to the other two indices.

The results of the NVI index of Kerman-Baghin Plain indicated that this plain is divided into two categories including very low vulnerability with an area of ​​1528.07 km2 (75.52 %) having an NVI value of less than 70 and low vulnerability with an area of ​​495.33 km2 (24.48 %) having NVI value from 70 to 110. Taken together, in order to properly manage the groundwater resources and prevent the pollution of these resources, it is recommended to prohibit the establishment of industries and the cultivation of agricultural sector causing the pollution in areas with low vulnerability.