Search Results (15)

Assessing the impact of irrigated agriculture on Djorf groundwater is a fundamental key to the sustainable management of coastal freshwater resources. This study integrates Geographic Information Systems (GIS), remote sensing, and machine learning techniques to investigate the relationship between irrigated cropland in the coastal area and the water-level dynamics of the Djorf aquifer, located in the semi-arid region of southeastern Tunisia. A supervised classification using a Random Forest Model (RFM) and ground-truth GPS data was applied to detect irrigated areas in the coastal zone of Djorf. The model showed good performance, with an overall accuracy of 0.99. Moreover, the kappa values varied from 0.72 to 0.94 from 2005 to 2025. The Djorf aquifer experienced an expansion of irrigated agriculture, with an increase in area from approximately 400 ha in 2005 to 500 ha in 2015 and 1600 ha in 2025. This expansion of irrigated agriculture led to a reduction in groundwater level by 1.5 m from 2005 to 2015 and by 5 m from 2015 to 2025, as indicated by the Tajerjemet piezometric well in the southern part of the Djorf area. In the northern part, the groundwater level remained unchanged from 2005 to 2015 but decreased by 3 m from 2015 to 2025, as indicated by the Garaat Tyour piezometric well. In the center of the zone, the groundwater level decreased by 1.5 m from 2005 to 2015 and by about 9 m from 2015 to 2025, as recorded by the Henchir Arrassa piezometric well. The significant drop in groundwater levels over the last decade, from 2015 to 2025, is attributed to the substantial expansion of irrigated agriculture. The irrigated agricultural area continues to expand despite the Tunisian law classifying the Djorf zone as a restricted area for water well drilling, aimed at minimizing the degradation of groundwater in the Djorf aquifer. Alarmingly, the aquifer has resumed a rapid decrease since 2015, and urgent action is needed to prevent further degradation. Full article

Droughts are among the most critical natural hazards affecting agricultural productivity, water resources, and food security worldwide, with climate change intensifying their frequency and severity. Accurate monitoring and forecasting of drought events are therefore essential for effective risk management and sustainable resource planning. In this study, we systematically evaluated the performance of four machine learning approaches—Support Vector Regression (SVR), Random Forest (RF), K-Nearest Neighbor (kNN), and Linear Regression (LR)—for tracking and predicting the Standardized Precipitation Index (SPI) at multiple temporal scales (1, 3, 6, 9, 12, 18, and 24 months). We utilized a century-long precipitation dataset from a meteorological station in south-eastern Tunisia to compute SPI values and forecast drought occurrences. The Mann–Kendall trend test was applied to assess the presence of significant trends in the monthly SPI series. The results revealed upward trends in SPI 12, SPI 18, and SPI 24, indicating decreasing drought severity over longer time scales, while SPI 1, SPI 3, SPI 6, and SPI 9 did not exhibit statistically significant trends. Model efficacy was assessed using a suite of statistical metrics: mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and the correlation coefficient (R). While all models exhibited robust predictive performance, Support Vector Regression (SVR) proved superior, achieving the highest accuracy across both short- and long-term time horizons. These findings highlight the effectiveness of machine learning approaches in drought forecasting and provide critical insights for regional water resource management, agricultural planning, and ecological sustainability. Full article

The valorization of local plant cover, particularly through the integration of indigenous knowledge, is central to Tunisia’s economic development strategies. These approaches focus on diversifying agriculture by enhancing local natural and cultural heritage to strengthen community resilience amid environmental and socio-economic changes and to address rural exodus. This study examines the feasibility of AMP-based micro-projects in Matmata (southeastern Tunisia) by applying the Water–Energy–Food–Ecosystem (WEFE) nexus and participatory methods involving local stakeholders. Field surveys, literature reviews, and statistical analyses reveal growing youth interest in AMP ventures, driven by rising pharmaceutical and cosmetic demand. Economic viability is confirmed by internal rate of return (IRR) values of 32%, 28%, and 43%, all well above the 10% profitability threshold. Profitability index (PI) values indicate efficient investments, yielding returns of 2.64, 2.13, and 5.31 dinars per dinar invested. The initiatives also deliver socio-cultural and environmental benefits through WEFE-based resource management. Beyond profitability, the study identifies gaps and opportunities to enhance AMP biodiversity, resource management, and sustainable diversification in southern Tunisia. Further efforts are required to increase market value and ensure equitable benefit distribution. Government policies should focus on raising WEFE awareness, building capacity, and investing in climate-smart agriculture, especially in vulnerable, migration-prone regions, supported by reforms in financing, taxation, and spatial planning. Full article

This study explores the water harvesting systems of mgouds in southern Tunisia and boqueras in southeastern Spain to understand their adaptation to semi-arid conditions and geomorphic contexts. These systems use ephemeral water through medieval-origin infrastructures to increase the water supply to rainfed crops. The hypothesis is that the diversity of these systems stems from environmental rather than cultural factors. By employing a qualitative–analytical approach, this study compares concentrated runoff diversion systems to investigate the use of boqueras/mgouds in terraces and glacis in the arid and semi-arid areas of Tunisia and the southeastern Iberian Peninsula. The research involved performing detailed geomorphological and climatological analyses and comparing structural complexities and water management strategies across different regions. The results indicate significant variability in system size and complexity. Tunisian mgouds are typically simpler and more individualised, while Spanish boqueras are larger and more complex due to more frequent and intense torrential rainfall. No common patterns were identified between the two regions. This study reveals that both types of systems reflect sophisticated adaptations to manage water scarcity and mitigate the impacts of intense rainfall, with geomorphic and climatic factors playing a decisive role. The primary conclusion is that the design and functionality of these water systems are predominantly influenced by environmental conditions rather than cultural factors. This research provides insights for developing sustainable water management strategies in other semi-arid regions. Full article

Goat farming represents a critical component of rural livelihoods, food security, and cultural heritage in southeastern Tunisia. This study adopts a multi-stakeholder approach to analyze the goat value chain in Tataouine, incorporating focus groups, semi-structured questionnaires, and direct observations with 80 farmers, 3 veterinarians, 13 butchers, and 100 consumers. The findings reveal strong local demand, with 72% of consumers purchasing goat meat and 66% consuming milk. However, significant inefficiencies exist, particularly a misalignment between production and market requirements: while 92% of butchers prefer fattened animals, only 16% of farmers engage in fattening practices. Women constitute 49% of dairy processors, yet face persistent resource constraints. Climate pressures exacerbate these challenges, with 80% of farmers reporting water scarcity and 93.8% observing pasture degradation. Three strategic interventions emerge as pivotal for sustainable development: targeted support for feed-efficient fattening techniques, establishment of women-led dairy processing collectives, and implementation of climate-resilient water management systems. These measures address core constraints while leveraging existing strengths of the production system. The study presents a transferable framework for livestock value chain analysis in arid regions, demonstrating how integrated approaches can enhance both economic viability and adaptive capacity while preserving traditional pastoral systems. Full article

The southern Gabès aquifer in southeastern Tunisia faces significant stress due to unsustainable groundwater extraction. This study employs a SEAWAT model to evaluate groundwater losses, salinization mechanisms, and the interaction between the confined aquifer and the Mediterranean Sea. The model, incorporating well pumping rates, regional freshwater inflows from the Matmata Mountain Range, and the Mediterranean Sea boundary, demonstrated high accuracy in simulating hydraulic heads. Findings reveal that regional inflow is only half of the current pumping rate, indicating unsustainable groundwater use. The study also assessed salinity dynamics by modeling the Mediterranean Sea as a constant head and salinity boundary. Results suggest limited exchange between the aquifer and the sea, challenging previous assumptions. While the immediate risks of salinization are low, continued over-extraction could compromise the aquifer’s long-term sustainability. This research highlights the need for stricter local groundwater management, offers insights into regional coastal aquifer interactions, and contributes to global discussions on managing stressed aquifer systems. Full article

Effective land management in the Djeffara plain, southeastern Tunisia, is being constrained by increasing land degradation issues due to arid climate conditions and soil erosion. Thus, this study aims to assess the impact of the integrated control measures, namely windbreaks and controlled grazing, on the restoration of land cover dynamics in six managed rangeland areas. Land cover changes were monitored using satellite data and the derived vegetation indices (the normalized difference vegetation index (NDVI) and the soil-adjusted vegetation index (SAVI)) from Landsat 8 (OLI), both within and outside the protected areas. The findings reveal that the implemented protection measures lead to an increase in vegetation cover, diversity, and plant density. They play an important role in stabilizing the upper soil layer. The oldest protected areas, particularly those that are well-maintained with controlled seasonal grazing, experienced a reduction in sand movement. The reintroduction of grazing should, however, be controlled to prevent degradation risks. The results show strong correlations between vegetation cover and both calculated vegetation indices, (0.73 < R² < 0.91), with more accurate estimating for the SAVI. The findings of this research can guide decision-makers for restoring degraded rangelands and planning effective control measures for wind erosion. Full article

Weather parameters and soil moisture profiles were measured at an hourly time step during four agricultural years (September to October, from 2018–19 to 2021–22) in two Jessour (water harvesting cultivated terraces) of the same valley in Zmerten (southeastern Tunisia), characterized by an arid climate. One instrumented Jesr (singular of Jessour) was located upstream and the other one downstream. During each dry season, when crops experience water stress, the downstream Jesr had a higher available water content than the upstream one; in the downstream Jesr the soil profile moisture remained above the wilting point, whereas in the upstream soil surface, moisture levels decreased to below the wilting point. High accumulation/low intensity rains (causing saturation/excess runoff) flooded both upstream and downstream Jessour from 50 mm of cumulative rainfall, whereas high intensity/low accumulation rains (causing infiltration/excess runoff) activated the downstream Jesr from an intensity of 15.2 mm/h, and a combination of moderate intensity and moderate accumulation rains activated both Jessour from an intensity of 8 mm/h and a cumulative rainfall of 33 mm. We propose to set 50 mm of cumulative rainfall and/or 6.4 mm/h of intensity as threshold values for the activation of the Jessour system in Zmerten. However, significant soil moisture recharges can occur even without activation of the Jessour system. Full article

Soil organic carbon (SOC) plays an important role in the global C cycle, as well as in the maintenance and improvement of the soil quality. Over time, special attention has been paid to it in the study of the SOC reserves worldwide; however, reduced attention has been given to assessing the spatial patterns of SOC stock (SOCS) in semi-desert ecosystems. In this line, there are no conclusive studies in drylands of Africa affected by aeolian processes (semi-desert conditions) mainly due to the complexity of sample collection, and this is especially significant in some soil types such as Arenosols (AR) and Calcisols (CL). This study evaluated the spatial variability of SOC and SOCS in AR and CL with woody crops in relation to land use and management (old plantations > 100 years: centenary olive grove; new plantations < 12 years: young olive grove, almond, and pistachio) in semi-desert conditions. For this purpose, 16 soil profiles (for 0–40 and 40–100 cm depth) were selected and studied in an experimental area of Menzel Chaker-Sfax in southeastern Tunisia (North Africa). The main results indicated that the SOCS on average was higher in Old Cultivated AR (OC-AR) with 41.16 Mg ha⁻¹ compared to Newly Cultivated AR (NC-AR) with 25.13 Mg ha⁻¹. However, the SOCS decreased after a long period of cultivation in CL from 43.00 Mg ha⁻¹ (Newly Cultivated CL: NC-CL) to 32.19 Mg ha⁻¹ (Old Cultivated CL: OC-CL). This indicates that in the long term, CL has more capacity to store SOC than AR, and that in the short term, AR is more sensitive to land management than CL. Full article

Soil erosion remains one of the principal environmental problems in arid regions. This study aims to assess and quantify the variability of soil erosion in the Koutine catchment using the RUSLE (Revised Universal Soil Loss Equation) model. The Koutine catchment is located in an arid area in southeastern Tunisia and is characterized by an annual mean precipitation of less than 200 mm. The model was used to examine the influence of topography, extreme rainstorm intensity and soil texture on soil loss. The data used for model validation were obtained from field measurements by monitoring deposited sediment in settlement basins of 25 cisterns (a traditional water harvesting and storage technique) over 4 years, from 2015 to 2018. Results showed that slope is the most controlling factor of soil loss. The average annual soil loss in monitoring sites varies between 0.01 and 12.5 t/ha/y. The storm events inducing the largest soil losses occurred in the upstream part of the Koutine catchment with a maximum value of 7.3 t/ha per event. Soil erosion is highly affected by initial and preceding soil conditions. The RUSLE model reasonably reproduced (R² = 0.81) the spatiotemporal variability of measured soil losses in the study catchment during the observation period. This study revealed the importance of using the cisterns in the data-scarce dry areas as a substitute for the classic soil erosion monitoring fields. Besides, combining modeling of outputs and field measurements could improve our physical understanding of soil erosion processes and their controlling factors in an arid catchment. The study results are beneficial for decision-makers to evaluate the existing soil conservation and water management plans, which can be further adjusted using appropriate soil erosion mitigation options based on scientific evidence. Full article

Climate change models predict an increase in aridity, especially in the regions under Mediterranean-type climates such as the Mediterranean Basin. However, there is a lack of ecophysiological studies supporting the selection of the more drought-adapted ecotypes for reforestation programs. In this study, we analyzed the anatomical and functional adaptations of 18-month-old seedlings to drought on 16 Quercus suber L. populations from the southeastern rear edge of the species distribution in northern Tunisia growing in a common garden, in order to identify the most appropriate material to use in reforestations. The results evidenced that populations from more xeric habitats displayed the highest leaf dry mass per area (LMA) and lowest leaf area (LA) values, together with the largest increase in the bulk modulus of elasticity (Δε) in response to drought (i.e., elastic adjustment). On the other hand, some populations with intermediate values of aridity, LMA and LA displayed the sharpest increase in proline concentration (ΔPro), with a concomitant increase in osmotic potential at full turgor (Δπ_o) (i.e., osmotic adjustment). Therefore, two different strategies seem to drive the within-species variation of the studied Q. suber populations in response to water scarcity: (i) a water saver strategy for improving water stress tolerance through the maximization of the elastic adjustment; and (ii) a water spender strategy for maintaining water absorption and photosynthetic activity under moderate water stress through the maximization of the osmotic adjustment. We concluded that the higher elastic adjustment, together with reduced LA and increased LMA, implied a better performance under drought stress in the populations of Q. suber from more xeric habitats, which can be considered the most drought-adapted ecotypes and, consequently, the most appropriate for reforestation programs under an eventual increase in aridity. Full article

Research Highlights: This paper compares the thermal requirements in three different olive-growing areas in the Mediterranean region (Toledo, central Spain; Lecce, southeastern Italy; Chaal, central Tunisia). A statistical method using a partial least square regression for daily temperatures has been applied to study the chilling and heat requirements over a continuous period. Background and Objectives: The olive is one of the main causes of pollen allergy for the population of Mediterranean cities. The physiological processes of the reproductive cycle that governs pollen emission are associated with temperature, and thermal requirements strongly regulate the different phases of the plant’s life cycle. However, the point when several specific processes occur—Such as the phases within the dormancy period—Is unclear, and the transition between endodormancy and ecodormancy is not easily distinguishable from an empirical point of view. This work focuses on defining the thermal accumulation periods related to the temperature balance needed to meet the chilling and heat requirements for the metabolic activation and budbreak in olive trees. Results and Conclusions: Thermal accumulation patterns in olive trees are strongly associated with the bioclimatic conditions of olive-growing areas, and the olive flowering start dates showed significant differences between the three studied stations. Our results show that the chilling requirements were fulfilled between late autumn and early winter, although the chilling accumulation period was more evident in the coldest and most continental bioclimatic areas (central Spain). The heat accumulation period (forcing period) was clearly defined and showed a close relationship with the timing of olive flowering. Heat requirements were therefore used to generate accurate forecasting models to predict the beginning of the olive bloom and subsequent olive pollen emission. A forecasting model considering both the chilling and heat requirements was generated in Toledo, where the estimated days displayed an error of 2.0 ± 1.8 days from the observed dates. For Lecce, the error was 2.7 ± 2.5 days and for Chaal, 4.2 ± 2.4 days. Full article

With hot and dry summers, the Mediterranean basin is affected by recurrent fires. While drought is the major driver of the seasonal and inter-annual fire distribution in its northern and mildest climate conditions, some extreme fire events are also linked to extreme winds or heat waves. The southern part of the Mediterranean basin is located at the driest range of the Mediterranean bioclimate and is influenced by Saharan atmospheric circulations, leading to extreme hot and dry episodes, called Sirocco, and potentially acting as a major contributor to fire hazard. The recently created fire database for Tunisia was used to investigate the ±10-day pre- and post-fire timeframe of daily weather conditions associated with fire events over the 1985–2006 period. Positive anomalies in minimum and maximum temperatures, negative anomalies in air relative humidity, and a preferential south-eastern wind during fire events were identified, which were characteristic of Sirocco winds. +7 °C anomalies in air temperature and −30% in relative air humidity were the critical thresholds for the most extreme fire conditions. In addition, meteorological anomalies started two days before fire events and lasted for three days after for large fires >400 ha, which suggests that the duration of the Sirocco event is linked with fire duration and final fire size. Lastly, the yearly number of intense Sirocco events better explained the inter-annual variability of burned area over the 1950–2006 period than summer drought based on Standardized Precipitation Evaporation Index (SPEI) indices. Full article

In this paper, we quantify the water balance of Jessour at the scale of agricultural plots. Jessour (plural of Jesr) are ancestral hydro-agricultural systems in the Dahar plateau (southeastern Tunisia). They consist of small dams built across wadis and gullies, which retain rainwater and sediments, hence enabling cropping. Despite arid climate conditions, Jessour allow the culture of the olive tree beyond its ecological limits. Weather monitoring stations were set up and soil moisture sensors installed down to a depth of 1.25 m in the soil in two neighboring gullies in the village of Zammour: one with a Jesr and one without. Laser granulometry and organic matter analyses were carried out on samples collected near the soil moisture sensors. Measurements were recorded from 28 September 2017 to 21 September 2018. From 10 to 12 November 2017, the region received 123.3 mm rainfall. The Jesr retained the equivalent of 410.3 mm of soil moisture to a depth of 1.25 m whereas the value in the gully was 224.6 mm. Throughout the summer of 2018, the soil available water capacity (AWC) remained above 55 mm in the Jesr, while it dropped to zero in the gully. Jessour are thus very suitable hydro-agricultural systems to face the climate changes concerning this fragile region, located in the transition zone between the semi-arid to arid Mediterranean region and the Sahara. Full article

Arid and semi-arid regions around the world face water scarcity problems due to lack of precipitation and unpredictable rainfall patterns. For thousands of years, rainwater harvesting (RWH) techniques have been applied to cope with water scarcity. Researchers have used many different methodologies for determining suitable sites and techniques for RWH. However, limited attention has been given to the evaluation of RWH structure performance. The aim of this research was to design a scientifically-based, generally applicable methodology to better evaluate the performance of existing RWH techniques in (semi-) arid regions. The methodology integrates engineering, biophysical and socio-economic criteria using the Analytical Hierarchy Process (AHP) supported by the Geographic Information System (GIS). Jessour/Tabias are the most traditional RWH techniques in the Oum Zessar watershed in south-eastern Tunisia, which were used to test this evaluation tool. Fifty-eight RWH locations (14 jessr and 44 tabia) in three main sub-catchments of the watershed were assessed and evaluated. Based on the criteria selected, more than 95% of the assessed sites received low or moderate suitability scores, with only two sites receiving high suitability scores. This integrated methodology, which is highly flexible, saves time and costs, is easy to adapt to different regions and can support designers and decision makers aiming to improve the performance of existing and new RWH sites. Full article