Desertification Risk Research Articles

Insight into summer drought in southern Italy: palaeohydrological evolution of Lake Pergusa (Sicily) in the last 6700 years

AbstractThe Sicily region (central Mediterranean) is at high risk of drying and desertification caused by current warming and land management. The aim of this study is to place current climatic changes within the past trajectories and natural climatic variability of the Holocene. For this we re‐examine a sediment core retrieved at Lake Pergusa covering the last ca. 6700 years. A multiproxy investigation, and in particular the oxygen isotope composition of lacustrine carbonate (δ18Oc), allowed us to reconstruct decadal‐ to centennial‐scale hydrological changes. The wettest period occurred between ca. 6700 and 6000 cal a bp. The δ18Oc record indicates a new period of wetter conditions between ca. 3700 and 2400 cal a bp. In particular, a δ18Oc minimum between 2850 and 2450 cal a bp overlaps with the period of the ‘Great Solar Minimum’ and corresponds to a dramatic reduction of arboreal pollen (AP%) and to an increase in synanthropic pollen, marking the onset of Greek colonization in the region. The longest driest interval corresponds to the Medieval Climate Anomaly, whereas the highest δ18Oc values are recorded in the last 150 years. The trend of the last 3000 years suggests that, considering future climate projections, the area will experience unprecedented drying exacerbated by human impact.

Desertification and Degradation Risks vs Poverty: A Key Topic in Mediterranean Europe

Land degradation and, subsequently, desertification processes are conditioned by biophysical factors and human impacts. Nowadays, there is an increasing interest by social scientists to assess its implications. Especially, it is relevant to the potential changes and landscape deterioration on population, economic systems and feedbacks of local societies to such adjustments. Assessing social facets should also be related to desertification risks, integrated socio-economic inputs and environmentally sustainable development perspectives. However, investigations about the effects of land degradation conditioned by global socioeconomic-factors from a holistic point of view are scarce. In this review, we pretend to discuss past and recent findings on land degradation risks related to poverty, especially based on Mediterranean Europe. To achieve this goal, we focused on key socioeconomic forces such as developmental policy, production and market structure, social change and population mobility. Our review showed that regional disparities based on complex dynamics of demographic forces (e.g. migration, fertility and ageing) and economic drivers of change (e.g. industrial concentration, urbanization, crop intensification, tourism pressure, coastalization) are keys to understand Mediterranean regions such as Southern Italy, a region exposed to high desertification risk in Europe. We concluded that the overexploitation of territories, soil and water degradation urban expansion, tourism and unplanned industrialization are some sectors and activities which can be highly affected by political and socioeconomic forces leading to unsustainable forms of land management and types of development. Special attention should be paid to social policies, education and training schemes to reduce rural migration and potentiate territorial knowledge to avoid land degradation, considering other social issues such as poverty or centralization. The potential role of win-win policies abating poverty and reducing desertification risk is evident in Mediterranean Europe and achieving land degradation neutrality necessary.

Toward a spatially explicit analysis of land vulnerability to degradation: a country-level approach supporting policy strategies.

Vulnerability to land degradation in Mediterranean Europe increased substantially in the last decades because of the latent interplay of climate and land-use change, progressive soil deterioration, and rising human pressure. The present study provides a quantitative evaluation of the intrinsic change over time in the level of vulnerability to land degradation over a representative Mediterranean area (Italy) using a normative indicator, the percentage of land classified as 'critical' in total area. This indicator derives from a spatially explicit elaboration of the ESA (Environmental Sensitive Area) Index (ESAI), a standard methodology of land classification considering different levels of vulnerability to degradation at a particularly refined spatial scale (1 km2). This indicator was calculated over a relatively long time interval (1960-2010) and aggregated at the geographical scale of administrative regions in Italy, a relevant domain in the implementation of the National Action Plan (NAP) to combat desertification and the adoption of individual Regional Action Plans (RAP). A significant - but spatially heterogeneous - increase in 'critical' land was observed in Italy, leading to distinctive dynamics in northern/central regions and southern regions. Climate aridity and anthropogenic pressure leveraged the sudden vulnerability in some marginal land of Northern Italy - a region classified as unexposed to desertification risk - paralleling the levels observed in some districts of Southern Italy, an 'affected' region to desertification risk. These results suggest a re-thinking of mitigation policies proposed in the Italian NAP and a redesign of the RAPs toward place-specific adaptation measures, especially in the 'less exposed' Northern Italian region.

Soil management and compost amendment are the main drivers of carbon sequestration in rainfed olive trees agroecosystems: An evaluation of chemical and biological markers

Traditional olive groves are considered at high risk of erosion and desertification due to low organic matter inputs and scarce vegetation cover coupled to highly intensity tillage, leading to a further decrease in soil organic carbon contents. In a context of climate change, carbon sequestration through waste management in the framework of a circular economy becomes of primary importance for rainfed Mediterranean agricultural soils. To unveil the mechanisms of carbon sequestration in those agroecosystems, we evaluated the effect of the application of two composts (olive waste “alperujo” and biosolid) at two different doses coupled to the sustainable soil management allowing spontaneous vegetation growing on the soil surface.With this aim, solid state nuclear magnetic resonance was used to trace the evolution of the chemical composition of compost-derived and soil-derived organic matter. Successively, the activity of soil microbial community after the compost addition was monitored by measuring two enzymatic activities (β-glucosidase and dehydrogenase) and soil CO2 respiration. Lastly, the adaptation of microbial communities was quantified using the genes encoding soil enzymes associated with C cycling -glucosidase and laccase-like multicopper oxidases. The results of this study show that biosolid compost has a higher potential for C storage at mid-term (24 to 30 months after first application) than alperujo compost, yielding up to 50% net C sequestration in the topsoil in addition to the compost-derived C applied. We attribute these results to biosolid compost chemical composition, closer to that of the native organic matter, which led to a less abrupt adaptation of soil microbial functioning (lower flushes of water soluble C, lower number of copies of genes encoding enzymatic activities) to the new C source, if compared to alperujo compost. The results encourage the reduction of soil perturbation and the use of organic amendments instead of mineral fertilizers to increase carbon storage and improve sustainability of olive groves in the Mediterranean agroecosystems.

Optimal restoration of common property resources under uncertainty

Mining for minerals, while a good source of income to the local economies, results in significant environmental damages. The Aravalli Mountain Range in India protects Delhi and adjoining areas from desertification risks posed by the Thar desert through acting as a physical barrier. However, it has become degraded over time due to persistent illegal mining and encroachment by real estate developers. Restoring the Aravallis will not only reduce the threat of desertification but also help generate valuable ecosystem services, such as water supply, to the nearby cities. Yet restoration efforts undertaken thus far have remained largely unsuccessful due to a lack of sufficient financial incentives. This study asks whether financial incentives for afforestation, such as desertification prevention permits and water-based payments for ecosystem services, can promote restoration of mineral rich commons in the Aravallis. It further seeks to explore the role of risk of restoration failure in discouraging conservation effort amongst communities. We design an incentive structure through which local communities benefit from water and land based payments resulting from restoration. We develop a dynamic optimization model of afforestation decisions in presence of land use change related risk from mining and real estate mafia to derive implications for the long run sustainability of the commons. Results indicate that desertification prevention permits and water payments can be useful towards incentivizing communities to take up protection of the degraded lands. However, when presented with the threat of failure of the restoration project due to illegal mineral extraction, community's optimal afforestation level declines considerably.

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.

Identifying Degraded and Sensitive to Desertification Agricultural Soils in Thessaly, Greece, under Simulated Future Climate Scenarios

The impact of simulated future climate change on land degradation was assessed in three representative study sites of Thessaly, Greece, one of the country’s most important agronomic zones. Two possible scenarios were used for estimation of future climatic conditions, which were based on greenhouse gas emissions (RCP4.5 and RCP8.5). Three time periods were selected: the reference past period 1981–2000 for comparison, and the future periods 2041–2060 and 2081–2100. Based on soil characteristics, past and future climate conditions, type of land uses, and land management prevailing in the study area, the Environmentally Sensitive to desertification Areas (ESAs) were assessed for each period using the MEDALUS-ESAI index. Soil losses derived by water and tillage erosion were also assessed for the future periods using existing empirical equations. Furthermore, primary soil salinization risk was assessed using an algorithm of individual indicators related to the natural environment or socio-economic characteristics. The obtained data by both climatic scenarios predicted increases in mean maximum and mean minimum air temperature. Concerning annual precipitation, reductions are generally expected for the three study sites. Desertification risk in the future is expected to increase in comparison to the reference period. Soil losses are estimated to be more important in sloping areas, due especially to tillage erosion in at least one study site. Primary salinization risk is expected to be higher in one study site and in soils under poorly drainage conditions.

Found in Complexity, Lost in Fragmentation: Putting Soil Degradation in a Landscape Ecology Perspective.

The United Nations Convention to Combat Desertification (UNCCD) assumes spatial disparities in land resources as a key driver of soil degradation and early desertification processes all over the world. Although regional divides in soil quality have been frequently observed in Mediterranean-type ecosystems, the impact of landscape configuration on the spatial distribution of sensitive soils was poorly investigated in Southern Europe, an affected region sensu UNCCD. Our study proposes a spatially explicit analysis of 16 ecological metrics (namely, patch size and shape, fragmentation, interspersion, and juxtaposition) applied to three classes of a landscape with different levels of exposure to land degradation (‘non-affected’, ‘fragile’, and ‘critical’). Land classification was based on the Environmentally Sensitive Area Index (ESAI) calculated for Italy at 3 time points along a 50-year period (1960, 1990, 2010). Ecological metrics were calculated at both landscape and class scale and summarized for each Italian province—a relevant policy scale for the Italian National Action Plan (NAP) to combat desertification. With the mean level of soil sensitivity rising over time almost everywhere in Italy, ‘non-affected’ land became more fragmented, the number of ‘fragile’ and ‘critical’ patches increased significantly, and the average patch size of both classes followed the same trend. Such dynamics resulted in intrinsically disordered landscapes, with (i) larger (and widely connected) ‘critical’ land patches, (ii) spatially diffused and convoluted ‘fragile’ land patches, and (iii) a more interspersed and heterogeneous matrix of ‘non affected’ land. Based on these results, we discussed the effects of increasing numbers and sizes of ‘critical’ patches in terms of land degradation. A sudden expansion of ‘critical’ land may determine negative environmental consequences since (i) the increasing number of these patches may trigger desertification risk and (ii) the buffering effect of neighboring, non-affected land is supposed to be less efficient, and this contains a downward spiral toward land degradation less effectively. Policy strategies proposed in the NAPs of affected countries are required to account more explicitly on the intrinsic, spatio-temporal evolution of ‘critical’ land patches in affected regions.

‘Old’ Territorial Disparities and ‘New’ Spatial Patterns: Unraveling the Latent Nexus between Sustainable Development and Desertification Risk in Italy

Although sustainable development and desertification risk are hegemonic concepts in environmental economics, their intimate relationship was occasionally studied and made spatially explicit. The present study contributes to fill this knowledge gap by delineating a statistical procedure that investigates, at the municipal scale in Italy, the association between two composite indexes of sustainable development (SDI) and desertification risk (ESAI). Based on a refined knowledge of the local context, results of a geographically weighted regression delineate two distinctive territorial models reflecting the mutual interplay of sustainable development and desertification risk in Italy. The level of sustainable development was negatively associated with desertification risk in Southern Italy, a region classified as ‘affected’ based on the Italian National Action Plan (NAP) to combat desertification. These findings document a traditional ‘downward spiral’ between local development and early desertification processes, suggesting that a high desertification risk is associated with local contexts having structural conditions that lead to unsustainable development, e.g., population growth, industrial development, tourism pressure, crop intensification, agricultural mechanization, and land abandonment. In non-affected regions such as Northern and Central Italy, the level of sustainable development was positively associated with desertification risk, indicating that sustainability conditions can be unable, at least in some local contexts, to assure a significant containment of environmental degradation. Policy strategies reconnecting local development with more specific environmental conservation targets in development countries are increasingly required to adapt to (and differentiate on the base of) heterogeneous local contexts.

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.

Desertification risk fuels spatial polarization in \u2018affected\u2019 and \u2018unaffected\u2019 landscapes in Italy

Southern Europe is a hotspot for desertification risk because of the intimate impact of soil deterioration, landscape transformations, rising human pressure, and climate change. In this context, large-scale empirical analyses linking landscape fragmentation with desertification risk assume that increasing levels of land vulnerability to degradation are associated with significant changes in landscape structure. Using a traditional approach of landscape ecology, this study evaluates the spatial structure of a simulated landscape based on different levels of vulnerability to land degradation using 15 metrics calculated at three time points (early-1960s, early-1990s, early-2010s) in Italy. While the (average) level of land vulnerability increased over time almost in all Italian regions, vulnerable landscapes demonstrated to be increasingly fragmented, as far as the number of homogeneous patches and mean patch size are concerned. The spatial balance in affected and unaffected areas—typically observed in the 1960s—was progressively replaced with an intrinsically disordered landscape, and this process was more intense in regions exposed to higher (and increasing) levels of land degradation. The spread of larger land patches exposed to intrinsic degradation brings to important consequences since (1) the rising number of hotspots may increase the probability of local-scale degradation processes, and (2) the buffering effect of neighbouring (unaffected) land can be less effective on bigger hotspots, promoting a downward spiral toward desertification.

Density matters? Settlement expansion and land degradation in Peri-urban and rural districts of Italy

Being a relatively less known driver of land vulnerability to degradation in Southern Europe, the net impact of urban expansion on land quality depletion requires a comparative investigation in peri-urban and rural districts. An empirical approach based on the Environmentally Sensitive Area Index (ESAI) was illustrated here with the aim at assessing long-term changes in the level of land vulnerability during a time interval that reflects divergent socioeconomic dynamics in Italy, an affected country according with the United Nation Convention to Combat Desertification (UNCCD). The degree of land vulnerability increased in a spatially heterogeneous manner over the last 50 years thanks to the synergic impact of climate aridity and landscape transformations. At the same time, urbanization shaped the spatial distribution of vulnerable land at both regional and local scale. Urban-rural gradients were at the base of renewed spatial disparities in land vulnerability between Northern Italy (classified as a ‘non-vulnerable’ region in the National Action Plan to combat desertification) and Southern Italy (classified as a ‘highly vulnerable’ region). These dynamics reflect the expansion of peri-urban areas towards high-quality, productive soils less vulnerable to degradation. By documenting a complex pattern of soil depletion due to urbanization in Italy, the present study contributes to a wider knowledge of the intrinsic linkage between peri-urbanization, (un)sustainable development, and desertification risk in advanced economies.

Drivers and impacts of changes in China’s drylands

China has 6.6 million km2 of drylands that support approximately 580 million people. These drylands are at risk of desertification. In this Review, the changes observed in China’s drylands are synthesized, with a focus on their drivers and the effects of 13 large-scale land conservation and restoration programmes aimed at mitigating them, including the Three-North Shelterbelt Development Program and Grain for Green Program. After the implementation of the first large-scale restoration programme in 1978, 45.76% of China’s drylands experienced statistically significant land improvement or vegetation greenness, as identified by the Normalized Difference Vegetation Index. However, activities associated with restoration and conservation projects, such as afforestation, also impose substantial water pressure. Desertification thus remained prevalent during 1980–2015, with 11.43% drylands (especially in north-eastern and north-western drylands) experiencing land degradation or vegetation brownness. Drylands remain at risk of expansion owing to increasing aridity, particularly in semi-arid areas. Future trade-offs between the effects of CO2 fertilization and increased aridity on dryland vegetation cover are still poorly understood. Long-term experiments on the interactions between physical–chemical–biological processes across spatial and temporal scales, such as large-scale field surveys using standardized protocols, are needed to better manage drylands in China and globally. Global drylands are threatened by a combination of anthropogenic climate change and human activities, putting some locations at high risk of desertification. This Review details changes observed in the drylands of China, and the mitigating impact of large-scale restoration and conservation programmes designed to reverse them.

Spatial-temporal pattern of land use conflict in China and its multilevel driving mechanisms

Land use conflict describes the incoordination of land use structure when meeting the diverse human demands under the deterioration of natural environment, which is a sensitive indicator of human-environmental interaction. The increased demand for different land use types due to rapid population growth and urbanization in China places tremendous pressure on limited land resources, which raises great concerns about land use conflict. To solve them, nation-scale assessment is essential, but such kind of research is still lacking due to the high data requirements. Here we drew on the conceptual framework of ecological risk assessment and the theories in landscape ecology, and developed a methodology to derive the spatio-temporal patterns of land use conflict in China from 2001 to 2017. We then used multilevel regression model to identify the driving factors of land use conflict at different levels. The results showed that the areas with strong land use conflict had a higher frequency of land use change, indicating that our model based on the framework of ecological risk assessment could effectively measure land use conflict. Land use conflict showed significant differences between two sides of the Hu Huanyong line, an important division line of population density and socio-economic background. The Main types of land use conflict in China included the strong competition between the use of cultivated land and grassland, the rapid expansion of construction land and the high risk of desertification. Among the driving forces, population density had a positive impact on land use conflict at the upper level, and altitude had a negative impact at the bottom level. Our research provides essential information to solve land use conflict through scientific land use planning and management and further to achieve the sustainable use of land resources.

Digital mapping of soil erodibility factors based on decision tree using geostatistical approaches in terrestrial ecosystem

The improper and unconscious use of the soil, a production material for humans, increases the risk of desertification and degradation. This study examines the some erosion susceptibility parameters such as soil erosion factor (USLE-K), dispersion ratio, and aggregate stability by applying various algorithms in decision trees and evaluating the spatial distribution of these properties using multiple interpolation method. While determining statistically significant correlations (P < 0.01) between aggregate stability of soils and mass fractal dimension and mean diameter weight, these features were employed as the root node and inner node in decision trees. The highest estimation rate was determined categorically with the CART algorithm in the prediction phase with decision trees. Aggregate stability was determined by applying two tree depths and mass fractal dimension and silt variables with 81.1% accuracy. In predicting the K factor, the silt and clay variables were estimated at 90.6% by forming nodes. In comparison, the dispersion ratio was calculated at 77.4% accuracy with clay, EC, and mean diameter weight. Soils categorized as moderately erodible according to the USLE-K factor were estimated at 92.3% level of accuracy with decision trees. In the predictive values obtained by numerical data, the highest aggregate stability and the USLE-K factor were obtained with the lowest prediction accuracy. This change was similar in distribution maps. The lowest root means squarer error (8.074; 5.106) was obtained by the simple kriging interpolation method in the distribution maps of the aggregate stability observed and predicted values.

Climate Change Projections of Aridity Conditions in the Iberian Peninsula

The assessment of aridity conditions is a key factor for water management and the implementation of mitigation and adaptation policies in agroforestry systems. Towards this aim, three aridity indices were computed for the Iberian Peninsula (IP): the De Martonne Index (DMI), the Pinna Combinative Index (PCI), and the Erinç Aridity Index (EAI). These three indices were first computed for the baseline period 1961–1990, using gridded observational data (E-OBS), and subsequently, for the periods 2011–2040 (short range) and 2041–2070 (medium range), using an ensemble of six regional climate model (RCM) experiments generated by the EURO-CORDEX project. Two representative concentration pathways (RCPs) were analyzed, an intermediate anthropogenic radiative forcing scenario (RCP4.5) and a fossil-intensive emission scenario (RCP8.5). Overall, the three indices disclose a strengthening of aridity and dry conditions in central and southern Iberia until 2070, mainly under RCP8.5. Strong (weak) statistically significant correlations were found between these indices and the total mean precipitation (mean temperature) along with projected significant decreasing (increasing) trends for precipitation (temperature). The prevalence of years with arid conditions (above 70% for 2041–2070 under both RCPs) are projected to have major impacts in some regions, such as southern Portugal, Extremadura, Castilla-La Mancha, Comunidad de Madrid, Andalucía, Región de Murcia, Comunidad Valenciana, and certain regions within the Aragón province. The projected increase in both the intensity and persistence of aridity conditions in a broader southern half of Iberia will exacerbate the exposure and vulnerability of this region to climate change, while the risk of multi-level desertification should be thoroughly integrated into regional and national water management and planning.

Scientific Programming Tools for Water Management

This special issue delivers a platform in which researchers expose intersections between algorithm design, software platforms, and hardware architectures to deal with emerging challenges in the scientific field of management of water and water-dependent resources. Since the call for papers was announced in June 2019, this special issue has received 10 manuscripts. After a rigorous review process, 6 papers have been finally accepted for publication. Published papers deal with groundwater quality monitoring, coastal groundwater-dependent irrigation agriculture, desertification risk, water recovery from tailings, future scenarios of water resources, and vulnerability of coastal aquifers.

Spectral Analysis of Sandy Desertification in the Semi-Arid Zone of North Eastern Nigeria

The method of integrating remote sensing, Geographic Information System (GIS) and field survey was employed. Assessment of the rate and intensity of sand dune encroachment using multi-temporal Landsat images (Landsat.TM, 1986, Landsat.ETM, 2000 and Landsat.OLI, TIR, 2016) and GIS. The satellite images were processed by converting raw Digital Number (DNs) values to radiance images which were converted into reflectance images used for spectral analysis.The satellite images were processed accordingly for evaluating six (6) spectral indices; Crust Index (CI, Grain Size Index, Bare soil Index (BSI), Normalized Difference Sand Dune Index (NDSDI), Normalized Difference Sand Index (NDSI), Normalised Difference Soil Index (NDSLI). An aggregate index of each of the six (6) selected indices was evaluated and the long term geometric mean was determined and used for image differencing with the baseline date image. A combination of MEDALUS.ESA and Image Differencing was adopted for change detection technique. Sandy landscapes were mapped into four (4) natural classes using natural jenks classifier of the ArcGIS analytical tool based on pre-field field determination and post verification. The description of the four (4) sandy landscape classes is as follows: Active, Semi-active, Semi-fixed and Fixed sand dune/sheets. Results of overall sandy desertification based on Aggregate Sandification Index indicates that active and semi-active sandy landscapes have progressed steadily at annual rate of expansion of 1.20 and 1.28 km 2 and intensity for the of 0.13 and 0.23% respectively. This has caused a corresponding decrease in the semi-fixed and fixed sandy landscapes of 1.24 and 1.39 km 2 and intensity for the period of 0.17 and 0.47 % respectively. The highest risk of sandy desertification is in the fixed sandy landscape which is be lost an an annual rate of 1.39 km 2 and 0.47% intensity being the highest among other classes. The result of this study indicates that the natural ecology or vegetation, graze lands, irrigated lands, rainfed farmlands, settlements, infrastructure are at high risk of sandy desertification in the semi-arid zone of Nigeria. This study is also a pointer that the shelter belts have not been very effective in controlling wind erosion and thus sandy desertification. Keywords: : desertification. sandification, eco-geomorphic landscape, semi-arid, encroachment DOI: 10.7176/JNSR/12-14-06 Publication date: July 31 st 2021

Minimizing the Impacts of Desertification in an Arid Region: A Case Study of the West Desert of Iraq

Currently, desertification is a major problem in the western desert of Iraq. The harsh nature, remoteness, and size of the desert make it difficult and expensive to monitor and mitigate desertification. Therefore, this study proposed a comprehensive and cost-effective method, via the integration of geographic information systems (GISs) and remote sensing (RS) techniques to estimate the potential risk of desertification, to identify the most vulnerable areas and determine the most appropriate sites for rainwater conservation. Two indices, namely, the Normalized Differential Vegetation Index (NDVI) and Land Degradation Index (LDI), were used for a cadastral assessment of land degradation. The findings of the combined rainwater harvesting appropriateness map, and the maps of NDVI and LDI changes found that 65% of highly suitable land for rainwater harvesting lies in the large change and 35% lies in the small change of NDVI, and 85% of highly suitable land lies in areas with a moderate change and 12% lies in strong change of LDI. The adoption of the weighted linear combination (WLC) and Boolean methods within the GIS environment, and the analysis of NDVI with LDI changes can allow hydrologists, decision-makers, and planners to quickly determine and minimize the risk of desertification and to prioritize the determination of suitable sites for rainwater harvesting.

Assessing desertification sensitivity map under climate change and agricultural practices scenarios: the island of Crete case study

AbstractThe aim of this study is the assessment of desertification risk for a typical Mediterranean island, in the frame of climate change and the application of good agricultural practices. Based on the MEDALUS Environmentally Sensitive Area Index (ESAI) approach, the sensitivity in desertification is estimated by employing 15 quantitative parameters divided in to four main quality indices: climate, vegetation, soil, and management quality. The methodology applied for a baseline scenario (current conditions), two future climate change scenarios (RCP 4.5 and RCP 8.5) and a soil quality improvement scenario. According to the results, more than 13% of the island's area is characterized as critically sensitive to desertification in the current conditions. This percentage will increase in the future under both the RCP 4.5 and the RCP 8.5 climate scenarios, where the critical areas will rise above to 15%. By applying the soil quality improvement scenario simultaneously with the climate change scenarios, a slight mitigation of desertification risk in the future could be achieved. The methodology developed in this study may be used to assess desertification process under various climate, soil, and land use management scenarios in regions of the Mediterranean Sea.