Mediterranean Desertification Research Articles

Soil quality index: a tool to detect the sensitivity to soil erosion in an agricultural catchment from the Middle Atlas of Morocco.

Abstract The present paper focuses on the application of the Soil Quality Index (SQI) within the Tiguert catchment, situated in the Middle Atlas of Morocco. The studied catchment, covering approximately 10.2 km², experiences a semi-arid climate with irregular rainfall and is designated as an agricultural area, making it an ideal site for studying the intricate interactions between natural processes and human activities. The SQI developed as part of the Mediterranean Desertification and Land Use (MEDALUS) project is tailored to the unique conditions of the Mediterranean region. In the case of the Tiguert catchment, SQI is calculated using a formula that considers topographical slope, horizontal depth of soil, parental material, and soil brightness. Consequently, the results depict a promising scenario, with 61% of the soil classified as “High Quality,” indicating robust soil health and resilience despite the challenges posed by a semi-arid climate. The 31% categorized as “Moderate Quality” underscores areas requiring specific management attention, while the 8% identified as “Low Quality” signals localized challenges potentially influenced by irregular rainfall patterns. Furthermore, the SQI results are closely linked to soil erosion dynamics, with higher SQI values associated with improved resistance to erosion. The dynamic connection between precipitation patterns and SQI over a 40-year analysis indicates the impact of varying rainfall on soil health. Extreme rainfall events correspond to higher SQI percentages in the “High Quality” category, while drier periods align with lower SQI percentages, emphasizing the dynamic relationship between climate and soil quality. A comprehensive analysis of SQI across diverse ecosystems in Tiguert reveals variations in soil health, emphasizing the importance of tailored land management approaches for different land use types to optimize overall soil sustainability.

Assessing Environmental Sensitivity Areas (ESA) Using Medalus Model in Telkaif District of Northern Iraq

This study conducted in Tel Kaif district in the northern part of Nineveh Governorate, located between longitudes (˝42′33°41– ˝20′19°43) east and latitudes (˝20′23°36-˝14′54°36) north to assess its environmental sensitivity to desertification (ESA). Fifteen representative sites selected based on the agricultural uses, vegetation cover, and topography. The geographical coordinates of the study sites were determined using a GPS device, and climatic and descriptive data for the study area taken, and soil samples taken for the required laboratory analyses. The obtained data converted into weighted evidence from special tables, so that four indices were calculated, namely the Soil Quality Index (SQI), Vegetation cover Quality Index (VQI), Climate Quality Index (CQI) and Management Quality Index (MQI) required according to the requirements of achieving the Mediterranean Desertification and Land Use (MEDALUS) model. Finally, the Environmentally Sensitive Areas Index (ESAI) equation applied to classify the study area and evaluate its environmental sensitivity to desertification, and then the Kriging technique was used within GIS programs to employ the results of the study by classifying the lands and representing them cartographically. The results showed that most of the study sites have a high environmental sensitivity to desertification (ESA) of the Critical type and below the C3 type, site 15 was Critical - C2, while sites (7 and 9) were Fragile - F2, and Site 6 was Fragile - F3. Therefore, the study area is located within the areas threatened by desertification, according to the assessment of the Environmental Sensitivity to Desertification Index, which is based on the MEDALUS model.

Assessment of desertification sensitivity using an improved MEDALUS model in Northern China

Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control. Based on the Mediterranean Desertification and Land Use (MEDALUS) model, we defined four quality indicators (soil, climate, vegetation and management) to evaluate the sensitivity of land in northern China to desertification. We improved MEDALUS via excluding cities from the areas at risk of desertification by means of defining a threshold value for population density. The framework, validated in northern China, further optimizes the model to link priority areas and land restoration programmed to support desertification control. We found that the four indicators influenced and restricted each other, which jointly affected the distribution of desertification sensitivity in northern China. The spatial distribution of sensitivity in northern China showed large regional differences, with clear boundaries and concentrated distributions of regions with high and low sensitivity; the overall sensitivity decreased, with some areas rated as having moderate, severe, and extremely severe sensitivity changing to slight sensitivity; and the influence weight was much higher for the management quality index than for the climate, vegetation, and soil indexes. This suggests that management was the main factor that affected desertification sensitivity in northern China, and that climate factors exacerbated sensitivity, but the factors that are driving the spatial heterogeneity of the influencing factors need further study.

Geoinformatics-Based Mapping of Environmental Sensitive Areas for Desertification over Satara and Sangli Districts of Maharashtra, India

Desertification processes in arid, semi-arid, and dry sub-humid conditions have been enhanced in recent decades. The geospatial database and associated satellite data can be effectively employed for regional planning to address desertification and land degradation. In this study, the Mediterranean Desertification and Land Use (MEDALUS) model has been used to map environmentally sensitive areas due to desertification in the Satara and Sangli districts of Maharashtra, India. This was achieved by combining Landsat-8 multispectral data, Census data, soil data, and climatic variables like temperature, rainfall, and evapotranspiration. The algorithm of MEDALUS is the geometric mean of four indicators, namely soil quality index (SQI), climate quality index (CQI), vegetation quality index (VQI), and socio-economic quality index (SEQI). The findings indicated that the majority of the study area comes under the potential category of desertification (60.32%) followed by fragile (27.87%) and critical (11.81%). Areas with a high propensity for desertification were found over the low to very low climatic quality and moderate to high soil quality including lower socio-economic quality. The lower socio-economic quality is mainly due to high to very high population density (>100 people/km2), low to moderate illiteracy rate (<16%), and low to moderate work participation rate (<50%) that incentivize unsustainable land use practices. The study provides a valuable tool for understanding and managing natural resources. It offers a detailed analysis of the environmental sensitivity of the study area, taking into account various factors like land use, vegetation cover, slope, and soil erosion potential. The developed comprehensive map of the area helps in identifying the most sensitive regions and developing appropriate conservation strategies. The information obtained from the study can be utilized to develop and implement successful measures to prevent or alleviate desertification, which is crucial for sustaining the health of ecosystems and the welfare of local residents.

ASSESSMENT OF SENSITIVITY TO DESERTIFICATION IN THE OUM ER-RBIA WATERSHED (UPSTREAM OF OULED SIDI DRISS) USING THE MEDALUS APPROACH

The issue of desertification is a pressing concern for many vulnerable regions, with consequences that extend far beyond their borders. It is a silent force that not only contributes to global climate change by releasing stored carbon from vegetation and soil but also compounds the ongoing environmental challenges we face on a global scale. In Morocco, the effects of these climate changes are already noticeable, particularly in terms of water scarcity due to reduced rainfall and rising temperatures. This, in turn, leads to soil drying and an increased risk of degradation. The Oum Er-Rbia watershed (upstream of Ouled Sidi Driss) is one of the basins affected by this issue, covering an area of 11,152 km² and spanning three topographic units (the Middle Atlas Mountains, the Phosphate Plateau and the Tadla Plain). This topographic diversity causes regional variation in the sensitivity to desertification. Therefore, this study aims to evaluate the sensitivity to desertification in this watershed by using the MEDALUS model (Mediterranean desertification and land use), which calculates the Desertification Sensitivity Index (DSI) through the composition of four indices: the Soil Quality Index (SQI), the Vegetation Quality Index (VQI), the Climate Quality Index (CQI) and the Land Use Quality Index (LUQI). The results show that the critical and highly sensitive zones represent 44% and are located at the northeast and west ends of the watershed. By contrast, the unaffected zones represent 12% of the total area of the watershed and correspond to the upstream area, where the climate, vegetation and land use systems are of good quality, providing effective protection for the land. To reduce the impact of this phenomenon, we have proposed some potentially impactful development actions based on land use and the results obtained.

Land degradation sensitivity and desertification risk in Harrir region, northern Iraq

Soil degradation and desertification are persistent ecological issues that present significant challenges worldwide. An accurate evaluation of land susceptibility to desertification is essential for developing suitable strategies or policies to address it on national scales. Modified Mediterranean Desertification and Land Use (MEDALUS) model is widely utilized to assess environmental and desertification sensitivity. This study employed MEDALUS model to identify environmentally sensitive areas prone to desertification in the Harrir region, northern Iraq. A total of 102 soil samples were collected from 0 to 20 cm depth covering a land area of 279.36 km2. Environmental sensitivity area index (ESAI) was used to evaluate sensitivity of the study area to environmental changes. The results indicated that ∼68.18 km2 of the study area would be exposed to land degradation and desertification. Fragile (F) regions accounted for 39.63 km2, underscoring the need for effective management and conservation practices. Only a small portion of the region (2.81 km2) was classified as ‘critical’ (C). Further analysis revealed that fragile sub-classes F1, F2, and F3 accounted for 11.84%, 17.16%, and 14.19% respectively, while critical subclass C1, C2, and C3 areas accounted for 10.97%, 9.12%, and 1.006% respectively. The remaining areas were either classified as unaffected or had potential for being influenced by environmental changes. Approximately 24.41% of the study area had the potential for being influenced by environmental sensitivity. This highlights the importance of implementing effective management and conservation practices to protect fragile regions in the study area. Policymakers and land managers can effectively prioritize and implement targeted interventions to prevent further soil degradation and desertification in the Harrir region of northern Iraq.

Assessment of Land Desertification in the Brazilian East Atlantic Region Using the Medalus Model and Google Earth Engine

Many factors drive land desertification, especially in arid and semi-arid regions. However, the sheer number of these driving factors of desertification makes analyses computer-intensive. Cloud computing offers a solution to address this problem, especially in developing countries. The objective of this work was to assess the sensitivity of the East Atlantic Basin, Brazil, to desertification using the Mediterranean Desertification and Land Use (MEDALUS) model and Google Earth Engine (GEE). The model is composed of four environmental Quality Indices (QIs) associated with soil (SQI), vegetation (VQI), climate (CQI), and management (MQI), each encompassing factors that influence the desertification process. Digital databases corresponding to these factors were pre-processed and uploaded to GEE for analysis. We report Environmentally Sensitive Areas (ESAs) and Environmentally Critical Factors (ECF) maps of the East Atlantic Basin, which show that most of the basin is in either a critical (49.4%) or fragile (35.7%) state of sensitivity. In contrast, only a smaller portion of the area is unaffected (5%) or potentially affected (10.1%). The analysis also revealed an inverse correlation between desertification sensitivity and the presence of vigorous vegetation. A joint evaluation of ESAs and ECF shed light on the importance of each factor in the sensitivity to desertification. The East Atlantic Basin shows a high degree of sensitivity to desertification, thereby demanding more attention and the establishment of measures to mitigate the negative impacts of the desertification process.

Index Integrating Soil, Vegetation, Climate and Management Qualities to Evaluate Desertification in the Northwestern Coast, Egypt

In Egypt, the phenomenon of desertification is a geographical phenomenon that is related to the decline or deterioration of the land's biological production capacity, which will eventually result in semi-desert conditions, or, in other words, the loss of fertility from productive lands. An understanding of the geographical distribution of environmentally sensitive areas (ESAs) is necessary for sustainable land use in the dry lands. The characteristics of the research region and the Mediterranean desertification and land use (MEDALUS) approach were used to evaluate the environmental sensitivity to desertification on the west-north coast of Egypt. Remote sensing images, topographic data, soils, and geological data are used to calculate desertification indicators. A hotspot of desertification risk exists on the north coast of Egypt due to soil degradation, climatic conditions, geomorphological and topographic features, soil quality and soil uses in each area. In each of these areas, these variables lead to varying levels and causes of soil degradation and desertification, as well as varying environmental, economic, and social effects. The obtained data reveal that (10.6%, 82.73%) of the west north coast are Sensitive and Very sensitive areas to desertification, About 1.22% of the research area is the moderately sensitive area, while the low sensitive and very low exhibit only (4.21,1.48) %. Remote sensing and GIS are recommended to monitor sensitivity. MEDALUS factors can be modified to obtain more reliable data at the local level.

Analysis of spatial-temporal patterns and driving mechanisms of land desertification in China

Desertification is a major manifestation of land degradation in China. The monitoring and assessment of land desertification in China and the analysis of its driving mechanisms are crucial to the realization of the aspiration of “net zero land degradation” proposed by the United Nations Convention to Combat Desertification (UNCCD). An improved Mediterranean Desertification and Land Use (MEDALUS) model was applied to assess the multiyear spatial distribution of land desertification sensitivity across China in 2010, 2015, and 2020. A Principal Component Analysis (PCA) was used to evaluate the internal stability of the model. In addition, a Geographical Detector method was used to examine the driving mechanisms of desertification sensitivity in China. The results showed that extremely sensitive desertification areas were primarily concentrated within the Northwest Desert and Desertification Region, northern segment of the Qinghai-Tibet Plateau desert and desertification region, and western sector of the Inner Mongolia-Daxinganling Desert and Desertification Region. In addition, the proportion of land area showing an overall reduction in sensitivity (17.07 %) exceeded that showing an increase (16.56 %). This indicates an overall diminishing trend in sensitivity to land desertification across China. Land use intensity (LUI), drought resistance (DR), erosion protection (EP), and aridity index (AI) are consistently the most important drivers. From 2015 to 2020, the LUI emerged as the principal catalyst behind the transformation of land desertification sensitivity in China. Hence, emphasizing well-planned land use is vital for ensuring harmony between land utilization and ecological capacity. This study establishes a scientific basis for China's land desertification control strategy and serves as a quantitative analysis reference for the driving mechanisms.

Modelling the spatiotemporal dynamics of land susceptibility to desertification in Algeria

Desertification is a significant environmental and socioeconomic issue that requires monitoring and early detection. In this context, holistic studies are more useful than localized ones in addressing this issue. In this study, we used the desertification sensitivity index (DSI) to pinpoint regions of Algeria that are at risk of desertification and to examine significant shifts in the sensitivity of land to desertification between 2000 and 2020, as well as the primary drivers of these shifts. Unlike the standard Mediterranean Desertification and Land Use (MEDALUS) approach, which uses equal weighting of parameters and quality indicators to construct the environmental sensitivity areas, the DSI applies statistically generated weights. Our results showed that approximately 106,000 km2 of the non-desert area was extremely susceptible to desertification in 2000, 83,200 km2 in 2010, and 98,200 km2 in 2020, with critical zones mainly located in the High Plains (steppe rangelands). Our analysis revealed that climate and vegetation quality indicators were the main drivers of the DSI, which showed a nonlinear trend during the study period. The analysis of changes in land sensitivity to desertification revealed that most of the changes were negative and occurred in the High Plains, as well as certain areas of the Tell Atlas Mountain ranges and the littoral fringe. However, some positive changes occurred due to the establishment of new forest plantations and croplands. The results provide a comprehensive overview of the risk of desertification in Algeria and its main drivers and can serve as a scientific basis for the development and implementation of necessary measures to interrupt and combat this destructive environmental phenomenon.

Assessment of the desertification sensitivity of Northwestern El Minya Governorate, Egypt using MEDALUS model

Desertification leads to a decline in land production, resulting from biophysical interaction and human factors with temporal and spatial changes. This paper aims to evaluate the desertification sensitivity using Mediterranean Desertification and Land Use (MEDALUS) approach in the Northwestern El Minya Governorate in Egypt. The study area is one of the promising and important areas for land reclamation and developmental projects. Four indicators; climate, vegetation, management, and soil, were used in this study. Landsat 8 (OLI) satellite image 2021 was processed to calculate NDVI index to assess vegetation quality index. Then, it was classified into land cover classes to calculate the management quality index. ASTERDEM satellite data and the climate data were used in the climate quality index. Seventy soil samples were collected and analyzed for chemical and physical properties to be used for the retrieval of soil quality index. These indicators were integrated and used as input criteria in the model of desertification sensitivity. The physiographic unit extraction indicated that significant landforms were included in the study area namely; Old wadi Sediments, Peniplain, old river terraces, Shoulders, Sand sheets, Rock outcrops, and Sand dunes, Erosional Plains, Hill and Plain out wash. The obtained results showed that the severely sensitive area to desertification was represented by 86.7 % of the study area. The main factors affecting the sensitivity were climate conditions (arid, semi-arid), low soil quality and management in addition to the low vegetation cover. Furthermore, about 3% of the study area was located in the moderate sensitive class while the low sensitive area exhibits 1.06 %. Present study supports decision makers to reduce the constraining environmental conditions.

Sensitivity Assessment of Land Desertification in China Based on Multi-Source Remote Sensing

Desertification, a current serious global environmental problem, has caused ecosystems and the environment to degrade. The total area of desertified land is about 1.72 million km2 in China, which is extensively affected by desertification. Estimating land desertification risks is the top priority for the sustainable development of arid and semi-arid lands in China. In this study, the Mediterranean Desertification and Land Use (MEDALUS) model was used to assess the sensitivity of land desertification in China. Based on multi-source remote sensing data, this study integrated natural and human factors, calculated the land desertification sensitivity index by overlaying four indicators (soil quality, vegetation quality, climate quality, and management quality), and explored the driving forces of desertification using a principal component and correlation analysis. It was found that the spatial distribution of desertification sensitivity areas in China shows a distribution pattern of gradually decreasing from northwest to southeast, and the areas with very high and high desertification sensitivities were about 620,629 km2 and 2,384,410 km2, respectively, which accounts for about 31.84% of the total area of the country. The very high and high desertification sensitivity areas were mainly concentrated in the desert region of northwest China. The principal component and correlation analysis of the sub-indicators in the MEDALUS model indicated that erosion protection, drought resistance, and land use were the main drivers of desertification in China. Furthermore, the aridity index, soil pH, plant coverage, soil texture, precipitation, soil depth, and evapotranspiration were the secondary drivers of desertification in China. Moreover, the desertification sensitivity caused by drought resistance, erosion protection, and land use was higher in the North China Plain region and Guanzhong Basin. The results of the quantitative analysis of the driving forces of desertification based on mathematical statistical methods in this study provide a reference for a comprehensive strategy to combat desertification in China and offer new ideas for the assessment of desertification sensitivity at macroscopic scales.

Spatial Analysis of Environmentally Sensitive Areas to Soil Degradation Using MEDALUS Model and GIS in Amazonas (Peru): An Alternative for Ecological Restoration

Land degradation is a permanent global threat that requires an interdisciplinary approach to addressing solutions in a given territory. This study, therefore, analyses environmentally sensitive areas to land degradation using the Mediterranean Desertification and Land Use (MEDALUS) and Geographic Information System (GIS) method through a multi-criteria approach in the district of Florida (Peru). For the method, we considered the main quality indicators such as: Climate Quality Index (CQI), Soil Quality Index (SQI), Vegetation Quality Index (VQI), and Management Quality Index (MQI). There were also identified groups of parameters for each of the quality indicators analyzed. The results showed that 2.96% of the study area is classified as critical; 48.85% of the surface is classified as fragile; 15.48% of the areas are potentially endangered, and 30.46% are not threatened by degradation processes. Furthermore, SQI, VQI, and MQI induced degradation processes in the area. Based on the results, five restoration proposals were made in the study area: (i) organic manure production, (ii) cultivated and improved pastures and livestock improvement, (iii) native forest restoration, (iv) construction of reservoirs in the top hills and (v) uses of new technologies. The findings and proposals can be a basic support and further improved by decision-makers when implemented in situ to mitigate degradation for a sustainable use of the territory.

Assessment of land sensitivity to degradation using MEDALUS model - a case study of Grdelica Gorge and Vranjska Valley (southeastern Serbia)

Land degradation is a complex issue caused by diverse drivers, each of which should be considered in the analysis of land sensitivity to degradation. This study identifies the areas most sensitive to land degradation in the Grdelica Gorge and Vranjska Valley, which are unique in terms of natural and socioeconomic conditions. Land-use changes and inappropriate land management have led to serious degradation in this region. The flexible and multifactorial approach of the Mediterranean Desertification and Land Use (MEDALUS) model allowed comprehensive land degradation sensitivity analysis in the study area. The main factors driving soil degradation were assessed by estimating climate quality index, soil quality index, and vegetation quality index, and the main socioeconomic indicators by management quality index and social quality index. The results showed that forest cover is the main factor to contrast land degradation, and even minor adverse changes in forest characteristics, such as structure, canopy cover, health, and quality, could trigger degradation processes. The vegetation quality index was defined in terms of the current vegetation’s capacity to protect soil from erosion, drought resistance, and fire risk. Detailed data on forest vegetation cover was obtained from the National Forest Inventory (NFI). The environmentally sensitive area (ESA) index generated through the analysis classified 26.11% of the total study area as critical, 69.53% as fragile, and 2.70% as either prone to or unaffected by degradation processes. According to the ESA index, the areas covered by forests with optimal species composition and high canopy cover were the least susceptible to degradation. The areas under intensive agricultural production without any application of conservation measures were the most susceptible to degradation. Future strategies for optimal land-use patterns are discussed, such as the intergration of woody species in croplands to protect soil against degradation and meet human needs in the areas prone to degradation.

Land Resource Depletion, Regional Disparities, and the Claim for a Renewed ‘Sustainability Thinking’ under Early Desertification Conditions

The present contribution discusses recent findings in environmental issues dealing with desertification risk and regional disparities in the Mediterranean basin. By focusing on key socioeconomic factors underlying land and soil degradation (population growth, urban sprawl, coastalization, agricultural intensification, and land abandonment), this commentary highlights the intimate linkage between socioeconomic processes, rural poverty, and territorial disparities based on complex dynamics of demographic and economic factors. The increasing complexity in the spatial distribution of land vulnerable to degradation has also been pointed out with special reference to post-war Italy, a Mediterranean country considered as particularly affected in the UNCCD Annex IV, as the results of non-linear biophysical and socioeconomic dynamics. The lack in multi-target and multi-scale policies approaching land degradation and territorial disparities together is finally discussed as an original contribution to the study of Mediterranean desertification.

Caring of the Fringe? Mediterranean Desertification between Peri-Urban Ecology and Socioeconomics

This commentary debates on the role of multiple socioeconomic drivers of fringe land degradation (including, but not limited to, population and social dynamics, economic polarization, and developmental policies), as a novel contribution to the desertification assessment in Southern European metropolitan regions, a recognized hotspot of desertification at the global scale. Expanding rapidly all over the world, metropolitan regions are a geographical space where land degradation drivers and processes assume typical relationships that require further research supporting dedicated policy strategies. To assure a better comprehension of the environmental-economic nexus at the base of land degradation in peri-urban areas, we provided a classification of relevant socioeconomic and territorial dimensions in both macro-scale and micro-scale degradation processes. We also identified the related (contextual) factors that determine an increased risk of desertification in metropolitan regions. Micro-scale factors, such as agricultural prices and off-farm employment, reflect some potential causes of fringe land degradation, with a mostly local and on-site role. Technological change, agricultural prices, and household income influence land vulnerability, but their impact on fringe land degradation was less investigated and supposed to be quite moderate in most cases. Macro-scale factors such as population density, rural poverty, and environmental policies—being extensively studied on a qualitative base—were taken as important drivers of fringe land degradation, although their impact still remains undefined. Regional disparities in land resource distribution, rural poverty, and unsustainable management of environmental resources like soil and water were indirect consequences of land degradation in peri-urban districts. Based on a comparative review of theoretical and empirical findings, strategies mitigating degradation of fringe land and reducing desertification risk in potentially affected metropolitan regions were finally discussed for the Northern Mediterranean basin and generalized to other socioeconomic contexts.

Assessment of environmentally sensitive areas to desertification in the Blue Nile Basin driven by the MEDALUS-GEE framework

Assessing environmentally sensitive areas (ESA) to desertification and understanding their primary drivers are necessary for applying targeted management practices to combat land degradation at the basin scale. We have developed the MEditerranean Desertification And Land Use framework in the Google Earth Engine cloud platform (MEDALUS-GEE) to map and assess the ESA index at 300 m grids in the Blue Nile Basin (BNB). The ESA index was derived from elaborating 19 key indicators representing soil, climate, vegetation, and management through the geometric mean of their sensitivity scores. The results showed that 43.4%, 28.8%, and 70.4% of the entire BNB, Upper BNB, and Lower BNB, respectively, are highly susceptible to desertification, indicating appropriate land and water management measures should be urgently implemented. Our findings also showed that the main land degradation drivers are moderate to intensive cultivation across the BNB, high slope gradient and water erosion in the Upper BNB, and low soil organic matter and vegetation cover in the Lower BNB. The study presented an integrated monitoring and assessment framework for understanding desertification processes to help achieve land-related sustainable development goals.

Evaluation of Desertification Severity in El-Farafra Oasis, Western Desert of Egypt: Application of Modified MEDALUS Approach Using Wind Erosion Index and Factor Analysis

Desertification is a serious threat to human survival and to ecosystems, especially to inland desert oases. An assessment of desertification severity is essential to ensure national sustainable development for agricultural and land expansion processes in this region. In this study, Index of Land Susceptibility to Wind Erosion (ILSWE) was integrated with a Modified Mediterranean Desertification and Land Use (MEDALUS) method and factor analysis (FA) to develop a GIS-based model for mapping desertification severity. The model was then applied to 987.77 km2 in the El-Farafra Oasis, located in the Western Desert of Egypt, as a case study. Climate and field survey data together with remote sensing images were used to generate five quality indices (soil, climate, vegetation, land management and wind erosion). Based on the FA, a weighted value was assigned to each index. Five thematic layers representing the indices were created within the GIS environment and overlaid using the weighted sum model. The developed model showed that 59% of the total area was identified as high-critical and 38% as medium-critical. The results of an environmentally sensitive area index suggested by the original MEDALUS model indicated similar results: 18.37% of the total area was classified as high-critical and 78.73% as medium-critical. However, the sensitivity analysis indicated that weights derived from FA resulted in better performance of the developed spatial model than that derived from the original MEDALUS method. The proposed model would be a suitable tool for monitoring vulnerable zones, and could be a starting point for sustainable agricultural development in inland oases.

Assessment of desertification using modified MEDALUS model in the north Nile Delta, Egypt

Understanding spatial patterns of environmentally sensitive areas (ESAs) to desertification is essential for sustainable land use in the drylands. This work is a novel trial for integrating the erosion quality index (EQI) with a modified Mediterranean Desertification and Land Use (MEDALUS) method and factor analysis to define ESAs to desertification. The model was then applied within 8607.13 km2 (860713 ha) in the north Nile Delta of Egypt as a case study. Climate data, satellite imageries, field observations, and samples collected from 105 soil profiles were analyzed to characterize five thematic quality indices of soil, climate, vegetation, management, and erosion. These indices were weighted based on the factor analysis (FA) and superimposed under the GIS environment in a single map using the weighted sum model. The proposed model showed that 72% of the total area was classified as critical-sensitive to desertification where 70% was classified as highly-critical, while 2% as moderately-critical. No significant difference (p < 0.001) was observed between the results of the proposed model and those calculated by the geometric mean algorithm (MEDALUS model) with R2 and root mean square error of 0.88 and 0.11, respectively. The average linear sensitivity analysis showed that using weights derived from the FA could assimilate the results of the proposed model closer to reality rather than equal weights used in the MEDALUS model. The developed model would improve the insight into desertification processes in the studied area, thereby suitable conservation practices would be adopted in time.

ASSESSMENT OF ENVIRONMENTAL SENSITIVITY TO DESERTIFICATION WITH MEDALUS MODEL IN GIS IN MAYMONA PROJECT- SOUTH OF IRAQ

The objective of this study was to identify the locations sensitivity to land desertification based on the Mediterranean Desertification and Land Use (MEDALUS) approach by the Geographic Information Systems (GIS) in the south of Maysan governorate at Iraq for mapping environmentally sensitive areas to desertification. Three indicators, which included climate, vegetation, and soil, were employed to estimate the ESAI and then to classify the land in critical, fragile potentially, and non-influenced sensitive areas. The results of the soil quality index (SQI) indicated that 25% of the studied area was classified as moderate quality and 21% was low quality while 54% was very low quality. Vegetation qualities were classified into moderate and low quality 19% and 81%, respectively, and climate quality was classified as moderate.