Ecosystem Management
Pantea Lotfi; Mozhgan Ahmadi Nadoushan
Abstract
Introduction: Drought is a natural phenomenon that occurs almost in most regions of the world, and due to its relationship with agricultural products and water resources, it is considered as one of the most important issues in environmental sciences. The effects of this phenomenon are greater in arid ...
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Introduction: Drought is a natural phenomenon that occurs almost in most regions of the world, and due to its relationship with agricultural products and water resources, it is considered as one of the most important issues in environmental sciences. The effects of this phenomenon are greater in arid and semi-arid regions due to their less annual rainfall. In contrast to traditional methods, the use of remote sensing techniques and satellite images has been considered as a useful tool for agricultural drought monitoring. The main objective of this study is to investigate changes in agricultural land use using normalized vegetation difference index and satellite images.Materials and Methods: In this study, Landsat satellite images were used to investigate the trend of agricultural land use changes in the Zayandeh Rood catchment during 1984-2023. To do this study, the normalized plant difference index was used for each year. Since various patterns of cultivation with different time differences are present in the study area during a year, it is not possible to use a selected image as the basis of a year, on the contrary, it is necessary to examine different images for different times of the year. To identify and specify the set of all the pixels that have gone under the cultivation surface in one crop year. Since this process would be very time-consuming, an innovative approach was used. First, in the Google Earth Engine system, all the annual Landsat images were called year by year. Then, the images with cloud cover were removed and the maximum filter was applied to the bands of the remaining images. Then, the normalized vegetation difference index of new annual images was created and by applying a threshold of 0.2, agricultural lands were separated from other lands. The extent of agricultural land was calculated in each year and the linear regression model was used to identify the change process. In other words, the extent of agricultural land was used as a dependent variable and time was used as an independent parameter on an annual scale.Results: The extent of agricultural land in 1984 was about 25 thousand hectares, which with a decreasing trend over time reached 21700 and 15180 hectares in 1994 and 2014, and finally reached its lowest value in 1401. It has reached 11.250 hectares. This trend shows a 55% reduction in the abandonment of agricultural land at this point in time. Also, the value of the normalized plant difference index in agricultural lands has experienced a decreasing trend over time, which indicates the change in the cultivation pattern towards low-density crops with low biomass such as wheat.Discussion: The results of the changes in the extent of agricultural use in the study area showed a decreasing pattern, so, there has been a loss of agricultural land, which is consistent with the decreasing pattern of the water level of the Zayandeh Rood watershed. This phenomenon can be directly attributed to the reduction of water resources in the region. In the last decade, the amount of water allocated to carry out agricultural activities in this region has decreased a lot due to the water volume of the Zayandeh Rood watershed approaching critical limits.
Ecosystem Management
Parimah Samadpoor; Shahrazad Faryadi; Lobat Zebardast
Abstract
Introduction: Natural capital is essential for human survival and achieving sustainable development goals. Therefore, a scientific framework is required to evaluate regional natural capitals consumption and their capacity to ensure sustainable development. Natural capitals represent the limiting and ...
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Introduction: Natural capital is essential for human survival and achieving sustainable development goals. Therefore, a scientific framework is required to evaluate regional natural capitals consumption and their capacity to ensure sustainable development. Natural capitals represent the limiting and irreplaceable factors in human well-being and sustainability of every developmental intervention. Degradation of the accumulation and flows of the natural capitals are the fundamental issues in the discussion of environmental sustainability. The current research has been conducted with the aim of investigating the state of ecosystem sustainability by adopting two approaches of ecological footprint and ecosystem services, and in other words, comparing the amount of demand for resources with the supply of goods and services provided by the ecosystem.Materials and Method: In this research, to investigate the sustainability of Nowshahr's natural and urban ecosystem as the case study, first, the trend of land use changes and its associated phenomena in the region have been investigated using ENVI 5.6 software for processing the satellite images. In order to investigate the change process of the study area, Landsat satellite reference images, TM, ETM+ and OLI sensors were used for the time scale of 2002, 2013 and 2020. Then, the classic ecological footprint of the region was calculated for six types of productive ecosystems, including agricultural lands, pastures, fishing areas, forests, built-up lands, and the carbon demand. The areas of these six land cover types were converted into global hectares using yield and equivalence factors. Subsequently, the maximum amount of ecosystem service flow per global hectare was estimated. And after that, the amount of consumption of natural capital accumulation and the occupation of capital flow in the region were investigated. Finally, the ecosystem stability of the study area was investigated using indicators such as the ecological pressure index (EPI), ecological sustainability index (ESI), ratio of capital stock to flows index, flow occupation ratio index, and excessive natural capital flow index.Results: According to the research results in the city of Nowshahr, during the period of 2011-2019, the amount of ecological footprint, ecological deficit and pressure have gradually increased, resulting in a reduction of the ecological balance and stability. Only the pasture, forest and fishing areas are in a stable state meaning that the supply of ecological resources is more than the demand, and the pressure is still within the carrying capacity of the ecosystem. In the period of investigation, the amount of use of stock to natural capital flow has increased and has reached almost four times of natural capital flow.Discussion: Measuring human demand for natural capital and nature's supply is essential for tracking progress, setting goals, and orientating sustainability policies. By combining the two approaches of evaluating ecosystem services and ecological footprint, it is possible to track human demand and nature's supply from a precise subset of ecosystem services, and therefore ecological balance and sustainability can be examined at the local level. Based on the results of the research, the stability of the region and the status of its ecosystem services is threatened by the cultivated land, and mainly the consumption of fossil energy. Based on the results of the research, in the period of investigation, the stability of the city of Nowshahr has decreased and the status of its ecosystem services are threatened by the cultivated land, and mainly the consumption of fossil energy. During this period and considering factors such as land use level, ecological deficit, footprint depth, ecosystem service flow, ecological pressure index, and ecological sustainability index, agricultural land use was the most unsustainable and fishing was the most sustainable use in city of Nowshahr.
Ecosystem Management
Vahid Mirzaeizadeh; Ali Mahdavi; Hamidreza Naji; Hamzeh Ahmadi
Abstract
Introduction: In recent years, attention has been paid to the effects of global climate change on different species and ecosystems. Among these, three important issues of increasing air temperature, change in carbon dioxide concentration and nitrogen deposition in relation to environmental changes and ...
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Introduction: In recent years, attention has been paid to the effects of global climate change on different species and ecosystems. Among these, three important issues of increasing air temperature, change in carbon dioxide concentration and nitrogen deposition in relation to environmental changes and the response of plants to them, have been widely studied in many places around the world. and is often related to climate change. Climate change can cause an increase in the growing season or a change in rainfall. The greatest effect of climate on tree growth can be seen in the width of annual tree rings. The formation of annual rings of a tree is affected by many different environmental and physiological factors, among which climate changes play a special role. The change in the growth and development of trees is one of the first reactions of trees to climate change. This study was conducted with the aim of monitoring the effect of climatic variables on the growth and distribution range of Pistacia atlantica tree species in Zagros forests in Ilam province using tree chronology.Materials and methods: For this purpose, sampling was carried out using an upgraded annunciator drill from 23 trees according to the extent of each climatic class using the Demartin method in Ilam province. After preparing the samples, the width of the annual vegetation rings was measured using Motic image software with high accuracy for a period of 30 years (1991 to 2022).Results: Based on the results of the average growth of each station, it was determined that Haft Cheshme station located in the Mediterranean climate class of Dumarten with an average growth of 1.13 mm has the highest growth and Manshet station located in the semi-humid climate class of Dumarten with an average growth of 0.83 has the lowest growth. In general, regions with Mediterranean climate have higher growth rate and semi-humid and semi-arid climates are in the next ranks respectively. Meteorological data from WorldClim station were used to understand the relationship between growth and climate. The Pearson correlation results of climatic variables with the growth of Bene species in the sampled stations showed that in the semi-arid climate, with the decrease in altitude above sea level, diameter growth has the highest correlation with the average maximum temperature variable, and with the increase of altitude above sea level, it has the highest correlation with the variable Precipitation is dependent, and in the Mediterranean climate, growth in higher areas has the highest correlation with the variable of precipitation, and with the decrease in altitude, growth is dependent on the average maximum temperature variable. Also, in semi-humid climates, growth has the highest correlation with the average maximum temperature variable, and with the increase in altitude The degree of correlation decreases from sea level.Discussion: The results show that the growth of areas with an altitude higher than 1700 and an altitude lower than 1000 is more affected by the average maximum temperature, and the changes in the maximum temperature are the main factor limiting the distribution of Beneh species in Ilam province, so that with the increase in temperature, the species moves towards the heights. And the regions with Mediterranean climate will migrate to reduce the effects of the maximum temperature factor, and as a result, with the passage of time, the distribution range of Beneh species will also decrease in these borders.
Ecosystem Management
Somayeh Arazi
Abstract
This study was conducted to identify and investigate changes in the size, type and number of habitat patchs in Mashkid Wetland in 2010 and 2020. For this purpose, in the spring of 2020, habitat patchs were identified through field operations and by objective observation. Ground control points were prepared ...
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This study was conducted to identify and investigate changes in the size, type and number of habitat patchs in Mashkid Wetland in 2010 and 2020. For this purpose, in the spring of 2020, habitat patchs were identified through field operations and by objective observation. Ground control points were prepared with the aim of assessing the accuracy of the final classification maps by recording land cover information and location of each type of patchs using a global positioning device. Landscape structure map was drawn through visual interpretation of phenomena using Google Earth satellite images. Arc GIS 10.3 software was used to prepare the final land use structure classification map and calculate the area of the patchs. The percentage of each patch in the heterogeneous land was determined by Excel 2013 software. According to the results, the landscape mosaic of the region in the spring of 2010 had habitat types of plants, rocks and alluvial areas and in the spring of 2020 consisted of habitats of plants, shrubs, rocks and water surfaces. A total of 131 patchs were identified and counted in 2020 and 40 habitat patchs in the landscape structure of the region in 2010. In 2010, poor vegetation patch had the highest percentage of area compared to the whole region and in 2020, water patch had the highest percentage of share. Overall, the results indicate significant changes in the size, variety and number of habitat patchs over time.