Ali Mihi* & Juan A. Hernández-Agüero (2025) “Saharan date palm plantation doubled in Algerian over the last four decades insofar as northern plantation expanded” in Computers and Electronics in Agriculture Volume 237, Part B, October 2025, 110649 Abstract: Algeria serves as a representative country and prime example of date palm plantations (DPP) in Arab countries. Understanding the spatial distribution of date palm (Phoenix dactylifera) plantations is crucial for sustaining production levels. This study aimed to identify suitable areas for DPP and track the potential changes in DPP over space and time using freely available remote sensing data. The Maxent approach was chosen to predict suitable zones for date palm planting based on fifteen key environmental variables. In addition, Classification and Regression Trees (CART) classifier technique was applied within the Google Earth Engine (GEE) platform to quantify the spatio-temporal distribution of DPP for 1984 and 2021 using a sum of 116 USGS Landsat archive (L1T). Furthermore, change maps – Land Use Land Change Modeler (LCM) was applied to show the main changes in DPP in terms of of gains, persistence, and losses with two example type zones; zone 1 and 2. The trend of change in the DPP was mapped using the spatial trend of change LCM. The Maxent approach achieved an area under the curve (AUC) value of 0.933, while the Kappa index for CART, and the coefficient of determination (R2) indicate values greater than 80% for both years 1984 and 2021. The results show that only about 0.16% (303,644.76 ha) of Algeria’s land area is suitable for DPP. Nocturnal light and NDVI emerged as significant factors in predicting the distribution of date palms in Algeria. Over the last 37 years (1984 to 2021), DPP has doubled to 71,156.67 ha, with rate of change rate of 1923.15 ha per year, due to strategic agricultural policy programmes. Clearly, the DPP area is increasing towards the suitable area, but with a low significant rate within both zones 1 and 2. Date production is mainly concentrated in the province of Biskra, yielding 153,135.66 tonnes in 2021. The northeastern region shows a higher intensity of DPP. The results of this study can be used for management, monitoring, and future expansion efforts in DPP areas.
Juan Antonio Hernández-Agüero*, Mechthilde Falkenhahn, Jessica Hetzer, Karsten Wesche, Christiane Zarfl, Klement Tockner. (2025) “Mapping the global distribution and conservation status of oases—ecosystems of pivotal biocultural relevance” in PeerJ 13:e18884 Abstract: Background: Oases are azonal, highly productive, densely vegetated areas within drylands, often converted to agriculture, and characterized by significant biocultural diversity. Despite their importance, comprehensive information on the global distribution and biocultural diversity of oases has been lacking. Methods: To address this gap, a detailed bibliographic search and random forest modeling were combined to create a global map of oases, with a focus on Asia and North Africa (ANA). Results: In the ANA region, oases cover 1.5% of the dryland area and are populated by 150 million people, with an additional 268 million people living nearby and most likely being dependent on them. Globally, oases contain more than 8,200 vertebrate species, of which 13% are classified as threatened. However, less than 0.5% of their total area is currently under protection, making oases one of the least conserved ecosystems worldwide. These findings highlight the distinct biocultural, ecological, and geopolitical importance of oases, which are increasingly threatened by climate change and direct human impacts. Despite their significance, oases remain undervalued, emphasizing an urgent need for developing adaptative strategies to sustainably manage these pivotal ecosystems.
The Joint Aquatic Science Meeting (JASM) congress in Grand Rapids – Michigan#(US). Oral presentation “Oases: definition, distribution, and biocultural importance“#Abstract: Drylands cover about 40 % of the global land surface. Oases s.s. are#“vegetated islands”, generally fed by groundwater, embedded in drylands. Drylands,#including oases, contain a unique biological and cultural diversity, are the origin of#important crop species, and build pivotal genetic reservoirs. Hence, oases may serve as#model systems to study biocultural diversity. Here, we provide a comprehensive#definition and typology of oases, present the outcome of an extensive bibliographical#research, and introduce an open-source database (WOase) on oases. For example, we#obtained high resolution climatic, geologic, vegetation and human demographic#information from remote sensing sources – starting with data from northern Africa. Human infrastructures, spatial contrast in vegetation cover, temperature and#precipitation are the most explicative variables delineating oases, while variables such#as altitude, slope, vegetation or groundwater help to refine the definition. Furthermore, we use languages as proxy for cultural diversity, and disentangle linkages between cultural and biological diversity. Overall, oases are key ecosystems of global biological, ecological and cultural importance; at the same time they are highly threatened ecosystems that deserve major attention in future conservation and management planning. Link to presentation:
36th Congress of the International Society of Limnology (SIL100) in Berlin (Germany). Poster “S-Oases: An open-source database on the environmental and cultural state and future development of oases”. Abstract: Drylands cover 41.3% of the global land surface, containing at least 30% of the world’s cultivated plants and livestock and being considered a significant genetic reservoir. Surface water in drylands is scarce and, when available, usually proceeds from old groundwater deposits. Water availability is a precondition for the presence of oases. Oases s.str. are “intrazonal vegetation islands surrounded by drylands (AI<0.02), either natural or human-made, characterised by a persistent water supply, which make them a fertile area”. Oases per se provoque microclimates that allow their own maintenance. Water evaporation captures energy reducing temperature which produces a ring breeze circulation with the hot air from desert acting as a vertical wall avoiding moisture exchange. Oases are ecosystems of pivotal biological, ecological and cultural importance. They may serve either as climatic refugia or stepping stones, and have given shelter to civilizations since ancient times. At the same time, oases are highly threatened by human population growth, disrupting the hydrological and thermal balance. Therefore, major attention in conservation and management planning is needed. We are creating an open-source database (S-Oases: Senckenberg Oases Database), with extensive bibliographical research. The goal is to delineate oases, to assess their environmental and cultural state, and encourage oasis research and management globally. Data will be made available in an open-source database meeting the FAIR principles. We present the first map of oases in Africa and the Middle East, as well as the outcome of extensive bibliometric and data analyses.
