Desertification Hazard Research Articles

Early warning systems for desertification hazard: a review of integrated system models and risk management

Early warning systems for desertification hazard: a review of integrated system models and risk management

Assessment of desertification hazard using RS and GIS to compare the efficiency of FAO-UNEP and MEDALUS models

Assessment of desertification hazard using RS and GIS to compare the efficiency of FAO-UNEP and MEDALUS models

Desertification hazards in the middle zone of Wadi Fatimah, West Saudi Arabia

This research aims at determining and analysing the causes and consequences of desertification in the middle zone of Wadi Fatimah using satellite images, climatic data, and topographic maps. The climatic parameters such as temperature, rainfall, and global reference evapotranspiration (ET0) indicated common severe arid conditions in the study area. The CORONA images acquired in 1967 and 1979 along with the topographic map of 1971 helped define the initial morphologic features and anthropogenic regimes. Analysing the various spatial datasets implied that the inappropriate management of water resources has resulted in changes in the anthropogenic regimes in the middle zone of Wadi Fatimah. These changes have triggered a chain of desertification processes such as degradation of the vegetation biomass and wind activities. These processes have transformed 15.3 km2 of agricultural farms into abandoned lands. Nineteen km2 of bushes have disappeared as well. The degradation of both agricultural and natural vegetation has exposed soils to intense wind erosion that detaches, transports and deposits sand in areas of low elevations. Accordingly, sand accumulations have massively expanded from 16.4 km2, as monitored by 1967 CORONA images, to 40.8 km2, as monitored by SPOT in 2013. This research emphasises that the middle zone of Wadi Fatimah has been experiencing remarkable changes in its morphologic and environmental characteristics in response to serious desertification processes. These processes are strongly linked to many anthropogenic interventions. It became a necessity, then, to redefine, study and assess the various anthropogenic parameters and their relative roles in desertification processes to combat desertification hazards and enhance sustainable environmental context in the middle zone of Wadi Fatimah.

Evaluating the impacts of combating-action programs on desertification hazard trends: A case study of Taybad-Bakharz region, northeastern Iran

Abstract In Iran, desertification is usually caused by both nature and humans greedy behaviors such that, more than 75% of the country’s area is dominated by arid zones, and most of the ecosystems are being destroyed due to human activities currently known as the main environmental hazard in Taybad-Bakharz region located in northeastern Iran. Thus, the present study was conducted to evaluate the effects of these measures on the desertification phenomenon generated from climate, soil, vegetation, socio-economic, erosion, and groundwater factors in the Taybad-Bakharz region over the past 40 years (1977–2016). Besides mechanical actions e.g., the establishment of water-saving structures, gabions, and check-dams, a wide array of biological action plans was set out across the prone-regions over the last few years such as vegetation restoration plans utilizing resistant species like Haloxylon persicum and Tamarix spp. Results indicated an ascending trend in desertification hazard (from 2.17 to 2.25) despite the supports devoted to environmental protection and management of desertification. Despite partially stabilized dunes and decreased Aeolian activities, the lack of attention to the anthropogenic activities such as agricultural practices, mining, over-pumping the groundwater resources, overgrazing, etc., either directly or indirectly related to people’s livelihood has led to a rise in desertification hazard.

RETRACTED ARTICLE: Study on peak cluster-depression rocky desertification landscape evolution and human activity-influence in South of China

ABSTRACT The peak cluster depression is a concentrated distribution of karst rocky desertification hazards in southern China. Under special water and soil conditions, the bare peak cluster slopes are covered with dense evergreen forests. The traditional human farming activities have affected the forest landscape on the slopes of the peak clusters, causing the phenomenon of point-like rock exposure on the slopes of the peak clusters, which can be repaired by natural forces; modern destructive economic activities rapidly degenerate the karst forest landscape into planar rocks. The exposed landscape is superimposed on the fragile karst environment, forming a large area of rocky desertification landscape, dissipating the basic conditions for the production and living of rural communities, and forming “karst ecological poverty”. “Blocking the mountains and nourishing forests” is the best way to restore the landscape of the peak forests. “Artificial afforestation” can provide seed banks for the areas with strong rocky desertification. Appropriate development of economic forests is an important measure to increase the income of farmers.

Prioritizing effective indicators of desertification hazard using factor-cluster analysis, in arid regions of Iran

Prioritizing effective indicators of desertification hazard using factor-cluster analysis, in arid regions of Iran

Desertification categorisation based on spatial analysis and remote sensing technology

This paper illustrates techniques based on multi-criteria evaluation for categorising desertification in the north-west of Iraq. Desertification is recognised as not only one of the major dilemma threatening human communities but also reduces productivity such that the whole economy is affected. The aim of this paper is to produce a desertification map for the study area that identifies risk zones through modelling and mapping by using Analytical Hierarchy Process (AHP), which is one of the Multiple Criteria Decision Making, based GIS for the selection process. In order to produce a desertification categorisation for the study area, numbers of criteria were identified depending on the questionnaires provided by experts. The produced desertification hazard map shown in ‘figure 3 indicates that 3.98% of the area is under very high sensitivity to desertification. The remaining area under high sensitivity is 7.25% and moderate sensitivity is 25.97%. The most hazardous areas are found in the middle and south parts of the study area. This paper including its methodology can be extrapolated to different desertification problems.

Quantitative mapping of desertification risk using the modified MEDALUS model: a case study in the Mazayejan Plain, Southwest Iran

This paper presents the Modified MEDALUS (MMEDALUS) approach, a quantitative assessment of desertification, in the case study area located in the Southern part of Iran. Six main factors of desertification including: soil, climate, plant cover, management, erosion state and ground water situation were considered for the model approach. Then several sub-factors determining the quality of each main factor were quantified according to their quality and weighted on a scale between 1.0 and 2.0. We used a Geographic Information System (GIS) software to analyze and prepare the spatial distribution of the factor layers. Subsequently, the final desertification hazard map was prepared by combining the different MEDALUS factors in Arc GIS 10.3 in order to define the final hazard classes on the basis of hazard scores based on the geometric mean of the main factors. The MEDALUS and MMEDALUS models show the "Desertification Potential" that in turn was validated with the current state of desertification observed in the field. The results show that the applied MMEDALUS approach yield significantly better results than the MEDALUS model in the study area. The results also show that the areas under severe and very severe hazard are the most extensive classes in the desertification map. Thus, we illustrate that most of the study area is sensitive to desertification. However, we highlight that management, climate and water table qualities were the most important indicators affecting the desertification processes, while soil quality seems to play a minor role in our study area.

Desertification Hazard Zonation in Central Iraq Using Multi-criteria Evaluation and GIS

Human communities all around the world are threatened by desertification, especially in arid and semiarid regions. Many factors affect the severity of desertification in an area such as topography, local climate, and land use. This research develops a multi-criteria evaluation method based on the analytical hierarchy process and geographic information system for assessing the desertification hazard zonation in central Iraq. Six factors including aspect, slope, rainfall, temperature, land use, and wind speed were considered in this study. Eight experts were interviewed and questioned about the importance of each indicator, and the final weights were obtained. These weights were used in GIS to obtain the desertification hazard zonation map. The results showed that 3.89%, 7.25%, and 25.97% of the study area were classified as very high, high, and moderately affected by desertification, respectively. It was concluded that rainfall, slope direction (aspect), and land use were the most important factors affecting the desertification process in the study area.

Assessing early warning for desertification hazard based on E-SMART indicators in arid regions of northeastern Iran

Desertification is a dynamic and complex system of land degradation. To understand it, physical and anthropogenic processes and their interrelations need to be identified. This study aimed to provide early warning information on desertification risk in the form of warning maps, using effective key indicators of land degradation in a 15-year period in the arid regions of northeastern Iran. E-SMART key Indicators should be E: Economic, S: Specific, M: Measurable, A: Achievable, R: Relevant, and T: Time-bound. Multiple regression analysis showed that the majority of indicators could accurately assess desertification risk at a 99% confidence level with R2 = 0.81. Furthermore, compared to the beginning of the study period, areas under desertification warning due to natural and anthropogenic factors had increased by about 78 percent in 2015. This observation is aligned with the impacts of drought, which has resulted from the continued reduction in rainfall. The expansion of at-risk areas has in turn exacerbated the adverse environmental conditions and amplified the effects of drought in the area. Spatio-temporal changes in soil salinity, groundwater quality, groundwater level, vegetation, agricultural development, and socioeconomic issues showed that the study area has suffered from land degradation and desertification between 2000 and 2015.

Natural Hazards in Sao Vicente (Cabo Verde)

Abstract São Vicente island (República de Cabo Verde) lies within the Sahelian zone and faces a number of natural hazards, of which the most significant ones are erosion and gully formation, desertification and flash flooding hazards. Based on examples, we set out to examine the main factors involved in the development of these natural hazards from a regional point of view, while simultaneously assessing the importance of anthropic action as a structural factor. The investigation of Lazareto’s gullies (located to the west of Mindelo) aimed to determine the main factors of the gullies formation. It also sought to demonstrate that the gullies’ formation is a reliable indicator of the high rates of erosion on a regional scale. The approach to the desertification hazards was based on farmers’ perception related to the evolution of agricultural production, strategies to mitigate drought and desertification issues, consequences and future prospects based on a set of interviews conducted in Ribeira da Vinha. Finally, the intense rainfall event that occurred on August 26, 2008 was analysed to identify the main vulnerability factors of the city in light of the flash flood hazard.

An applied statistical method to identify desertification indicators in northeastern Iran

BackgroundDesertification could be considered ultimate consequence of land degradation in an ecosystem. Iran with more than 75% arid and semi-arid areas involves fragile and susceptible ecosystems to desertification. We applied a statistical algorithm including regression trees and random forest techniques for determining main factors affecting desertification based on ESAs in Taybad-Bakharz region at northeastern Iran.ResultsThe results indicated a significant correlation between the desertification hazard value with variables of wind erosion, precipitation, aridity index, technology development, slope index, vegetation state and land use changes.ConclusionsRegression trees and random forest techniques in desertification hazard provide an absolute estimation of the relationship between dependent and independent variables. We can use a robust base for further investigations and refined with findings from in-depth studies carried out at the local scale.

A New Model for Desertification Assessment Using Geographic Information System (GIS) — A Case Study, Runiz Basin, Iran

The present paper attempts to evolve a new model by considering various indicators of different types of land degradation or desertification, namely, water erosion, soil salinity, vegetation degradation, and lowering of ground water table for finding areas with higher rate of degradation. The Runiz basin, located in the southern Iran, has been selected as a study area to assess the hazard of desertification. The thresholds for the severity classes of indicators were established and then the hazard map for each indicator of types of desertification has been prepared in a GIS. The risk classes of different risk maps were calculated on the basis of classification of risk scores derived by cumulative effect of all the attributes of indicators after overlying them in the GIS. It was possible to distinguish the areas under ‘actual risk’ from areas under ‘potential risk’ of desertification types. Also areas under potential risk were classified to subclasses with different probability level to show a statistical picture of risk in future. The final map of risk of desertification was produced by overlaying all four maps of degradation types. Results show that potential risk areas and areas under actual risk are almost equal, indicating further threat of desertification in future in the half of the region. Also severe condition in the half of region shows environmentally bad situation in the study area. It is hoped that this attempt using GIS will be found applicable for other regions of the world.

Assessment of desertification hazard, risk and development of management plans

About 80 percent of Iran is arid and semi-arid and about 35 percent of this area is susceptible to desertification hazard. Therefore desertification assessment and identification of the most important criteria for the assessment of risk and a basis for development of management plans is essential. This research was conducted in the semi-arid region of Agh-Band in the Golestan province, Iran with an area of 3062.5 km2 aiming at preparation of the desertification hazard and risk maps and development of various management plans to control the desertification. In this study, the IMDPA model and geomorphologic facies were used to evaluate the desertification hazard. The work units (geomorphologic facies) were defined based on geology and land use maps, satellite images and field surveys. The risk map was developed with a combination of desertification hazard intensity and hazard elements [A1] [A2] and degree of vulnerability maps using the total risk equation. Desertification management plan was developed based on four management strategies including: no plan, maintains the status quo, avoid the risk and implement the control measures. The results indicated that soil and vegetation criteria with magnitudes of 2.67 and 2.54 fall into sever desertification category (III) and other criteria are within medium class (II). The average value of degree of desertification in the study area was 2.03 (class II).

Hazard and Risk in Iran

Hazard risk needs to consider vulnerability on human activities. Risk analysis of risk, human activities at spatial and temporal scales with existing classification of hazards and map hazard map. In this study hazard risk in urban areas could be useful through considering are used to model human activities such as population, land use and strategic situation in Zayandeh Rood Basin (Z.R.B), Iran. These human, activities are classified and combined with composite classified earthquake, desertification and dryness hazards maps to drive new spatially explicit five classes of composite map of the hazards and human activities. The obtained results show that there are significantly more people potentially at risk in Center and North of the basin at high classes of risk map. The proposed maps of human activities to hazards are mainly aimed at benefiting visualization and communication of hazards risk and can be valuable in all phases of the disaster management process where knowledge of human activities is relevant for decision making.

Desertification risk assessment and management program

Risk assessment provides the possibility of planning and management to prevent and reduce the risk of desertification. The present study is aimed to assess the hazard and risk of desertification and to develop management programs in the semi-arid western regions of Golestan Province in Iran. Desertification rate was obtained using the Iranian model of desertification potential assessment. Since the rating system was considered for the indicators, data analyses were carried out according to the Mann-Whitney test. The risk of desertification was calculated based on hazard, elements at risk and vulnerability assessment maps. The intensity of desertification was estimated to be medium. Among the factors affecting desertification, agriculture by the weighted average of 3.22 had the highest effect, followed by soil, vegetation, water and wind erosion criteria by weighted averages of 2.45, 2.32, 2.15 and 1.6 respectively. Desertification risk assessment results also showed that about 78% of central and northern parts of the region, with the largest population and residential centers, surface and underground water resources, agriculture and horticulture, is confronted with a high to very high degree of risk. Management plans and control measures, based on risk values were presented in four activities (with two management priorities under critical and non-critical conditions). For the management program with the largest area. Control measures and strategies such as the establishment of halophytic and xerophytic plants, drainage networks, resilient facilities and infrastructure were proposed. Reducing the risk of desertification, could play a crucial role in the sustainable development of drylands and desert ecosystems.

The Effect of Land Use Changes on Desertification Hazard (Case Study: Maraveh Tappeh Region of Golestan Province, Iran)

Land degradation and desertification caused by land use change is mainly due to human activities in arid and semi-arid and affect on the sustainable use of lands. The aim of this study was to evaluate the effects of land use changes on the desertification hazard in Maraveh Tappeh region. In this research, land use maps of 1986, 2000 and 2014 is provided using images of MSS, ETM and OLI sensors of Landsat satellite and land use map of 2024 is predicted using Markov chain model. According to the results, dense forest area is decreased during study period and with passing time, the area of agricultural land has increased. The results for the time interval of 2014-2028, showed it is possible that will be decreased semi-dense forest and dense rangelands and will be increased other land-use areas according to results of model predictions. In the study years, desertification maps were prepared using ESAs method and with the assumption of fixed all factors other than land use factor. The results showed that there was a lack of desertification as a class in 1986, but this class has been removed in other study years and has been added the area of this class into other classes. The compare of desertification hazard classes and theirs percentage of area in studied time periods showed that critical (C3) and fragile (F3) classes had increasing trend, clearly. The difference between classes since 1986 to 2000 is clearer and more specific and destruction seem clearer.

Ilam Eyaleti Dehluran Bölgesi Abu Ghoveyr Ovası'nda çölleşme değerlendirilmesi

Assessment of desertification hazard in Abu-Ghoveyr Plain, Dehloran, Ilam Province of Iran Abstract: The present study aims to evaluate the desertification hazard and determine the effective criteria affecting desertification in Abu-Ghoveyr Plain in Ilam Province, using the 9 criteria Iranian Model of Desertification Potential Assessment (IMDPA). To this end, first, work units maps (geomorphologic facies) were created using slope, geology, and land use maps. Using this method, work units were considered as the main unit of desertification and a map was generated for each index according to assigned weights, such that the qualitative map of the desired criteria were obtained using the geometric mean of indicators. Then, through integration and determining the geometric mean of layers obtained from criteria and finally classification of the obtained maps, map of the current status of desertification in the studied area was prepared. The obtained results indicated that 31.67% of the area was in the medium class of desertification (II) and 68.33% belonged to the intense class (III). Keywords: Classification, Model, Criterion, Vegetation Cover, Work Units. Iran Ilam Eyaleti Dehluran Bolgesi Abu Ghoveyr Ovasi'nda Collesme Degerlendirilmesi Ozet: Bu calismada 9 kriter iceren Iran Collesme Potansiyel Degerlendirme Modeli kullanilarak, Ilam Eyaleti Abu-Ghoveyr Ovasi'nda collesme zararinin degerlendirilmesi ve belirlenmesi amaclanmistir. Bu amacla, oncelikle egim, jeoloji ve arazi kullanim haritalarini iceren calisma birim haritalari olusturulmustur. Bu yontem kullanilarak, calisma birimleri collesme ana unite olarak kabul edildi ve entegrasyon ve geometrik kriterler ile elde edilen tabakalarin ortalamasi alinarak calisilan alandaki collesme mevcut durumunun haritasi hazirlanmistir. Elde edilen sonuclar, alanin %31.67 sinin collesme orta (II) sinifta ve % 68.33unun ise siddetli (III) sinifta oldugunu gostermistir. Anahtar Kelimeler: Siniflandirma, Model, Olcut, Bitki Ortusu, Calisma Birimleri Received (Gelis): 15.04.2016 - Revised (Duzeltme): 20.05.2016 - Accepted (Kabul): 13.06.2016 Cite (Atif): Heidarizadi, Z., Karimi, H., Arami, S.A., 2017. Assessment of desertification hazard in Abu-Ghoveyr Plain, Dehloran, Ilam Province. Journal of the Faculty of Forestry Istanbul University 67(1): 49-64. DOI: 10.17099/jffiu.35680

Desertification assessment using the analytic hierarchy process and gis in southeast iran

Studying the factors influencing desertification progress of a region and its resulting zoning can be effective in helping to reduce the damage of this phenomenon. This study attempted to investigate the factors influencing desertification progress; hence, it proceeded to zone Sistan and Baluchestan Province using three analytic hierarchy processes, Expert Choice software and a geographic information system. First, factors affecting desertification progress were checked and they were then used to determine the most important aspects in order of priority as follows: climatic elements (temperature, evaporation, wind, precipitation and humidity), morphology (topography and slope) and human factors (land cover). Then, a zoning map of desertification‐prone lands was prepared. The results showed that, in terms of hazard progress of these lands, there were five desertification hazard regions in Sistan and Baluchestan Province with an area of about 187 502 km2 and high hazard regions covering approximately 29.2% of the province were located in the north of the province. High hazard regions with an approximate area of 3.20% of the total area of the province were mostly located in Saravan, Khash, and the surrounding areas; medium hazard regions with an approximate area of 19.6% were in Iranshahr and the southeastern part of the province; low hazard regions with an area of about 18.2% were in the southern parts of the province; and very low hazard regions with an approximate area of 12.7% were in Nikshahr and the southern parts of the province.

A case study of desertification hazard mapping using the MEDALUS (ESAs) methodology in southwest Iran

A case study of desertification hazard mapping using the MEDALUS (ESAs) methodology in southwest Iran