Oasis Expansion and its impacts on Ecosystem Services in Southern Tunisia

Abdelaziz Ben Abdallah; Mohamed Kefi

doi:10.56027/JOASD.112026

Auteurs-es

Abdelaziz Ben Abdallah Nantes Université, 1, quai de Tourville BP 13522 44035 Nantes Cedex 1, France
Mohamed Kefi Laboratory of Georesources, Water Research and Technologies Center (CERTE), BP 273 Technopark of Borj Cedria, 8020 Soliman, Nabeul Tunisia.

DOI :

https://doi.org/10.56027/JOASD.112026

Mots-clés :

Ecosystem services, Oasis expansion, Remote sensing, Tunisia

Résumé

Many ecosystems face multiple pressures that affect their ability to provide ecosystem services. These services are commonly grouped into four categories: Provisioning, Regulating, Cultural and Supporting services. These services can lead to develop business opportunities for local communities. However, human activities and natural hazards may conduct to ecosystem degradation and loss of biodiversity and consequently, to business risks. In arid regions, oasis ecosystems have a crucial economic and social impact. However, natural and anthropogenic factors may affect oases ecosystems and their services. Therefore, the main objective of this research is to assess changes in oasis ecosystems in southern Tunisia using multi-temporal satellite images and NDVI analysis. The methodology is based on Landsat satellite data acquired between 1995 and 2025 and the calculation of NDVI. The results shows that the oasis areas in the study area increased by 42.36%. While this expansion reflects agricultural intensification, it may also lead to higher water consumption, soil degradation and biodiversity loss. This research can help local stakeholders better understand environmental risks and support the development of appropriate strategies to preserve oasis ecosystems.

Références

Benaoun, A., Elbakkeya, M., & Ferchichi, A. (2014). Change of oases farming systems and their effects on vegetable species diversity: Case of oasian agro-systems of Nefzaoua (South of Tunisia). Scientia Horticulturae, 180, 167–175.

Bolund, P., & Hunhammar, S. (1999). Ecosystem services in urban areas. Ecological Economics, 29(2), 293–301.

Campbell, J. B. (2007). Introduction to Remote Sensing (4th ed.). The Guilford Press, New York.

CDCGE (Consulting en Développement Communautaire et en Gestion d’Entreprises). (2016). Monographie des oasis traditionnelles du gouvernorat de Kebili. Projet Gestion durable des Écosystèmes Oasiens, Renforcement des capacités pour la gestion durable des écosystèmes oasiens. Ministère de l’Environnement et du Développement Durable (MEDD).

Charieg, H., Dhraief, M. Z., Gharbi, I., & Ben Saad, A. (2025). Enhancing the resilience of vulnerable social-ecological systems: Pathways toward sustainable oases in southeastern Tunisia. Frontiers in Sustainable Food Systems, 9, 1623641. https://doi.org/10.3389/fsufs.2025.1623641

Cook, B. R., & Spray, C. J. (2012). Ecosystem services and integrated water resource management: Different paths to the same end? Journal of Environmental Management, 109, 93–100.

Costanza, R., D’Arge, R., De Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., O’Neill, R. V., Paruelo, J., Raskin, R. G., Sutton, P., & Van Den Belt, M. (1997). The value of the world’s ecosystem services and natural capital. Nature, 387, 253–260.

Direction Générale des Forêts–Ministère de l’Agriculture et de l’Environnement (DGF). (2011). Note de concept Projet FAO: Appui à la promotion des micro-entreprises forestières basées sur les PFNL pour améliorer le niveau de vie des populations forestières et une gestion durable des ressources forestières tunisiennes. TCP/TUN/3304.

Egoh, B. N., O’Farrell, P. J., Charef, A., Gurney, L. J., Koellner, T., Abi, H. N., Egoh, M., & Willemen, L. (2012). An African account of ecosystem service provision: Use, threats and policy options for sustainable livelihoods. Ecosystem Services, 2, 71–81.

Han, Y., Edwin, I. E., Wang, Y., Yan, W., Luo, C., Yu, W., & Ma, X. (2025). Impact of oasis expansion on water yield services in arid inland river basins: A case study of the Ebinur Lake Basin. Land Degradation & Development, 36, 4979–4996.

Karmaoui, A., Ifaadassan, I., Messouli, M., & Yacoubi Khebiza, M. (2015). Monetarization of ecosystem services of oasean biome (case study: Provisioning services of Middle Draa Valley oases, Morocco). British Journal of Applied Science & Technology, 11(6), 1–18. Article no. BJAST.19689.

Marino, D., Palmieri, M., Marucci, A., & Tufano, M. (2021). Comparison between demand and supply of some ecosystem services in national parks: A spatial analysis conducted using Italian case studies. Conservation, 1, 36–57.

Millennium Ecosystem Assessment (MEA). (2005). Ecosystems and Human Well-being: Synthesis Report. Island Press, Washington, D.C., USA.

Salih, A., Hassaballa, A., & Rahma, E. R. (2025). Satellite-derived multi-temporal palm trees and urban cover changes to understand drivers of changes in agroecosystem in Al-Ahsa Oasis using a spectral mixture analysis (SMA) model. Agriculture, 15, 2043.

Sharafatmandrad, M., & Mashizi, A. K. (2026). Management of ecosystem service trade-offs: Integrating human activities and stakeholder perspectives. Environmental Management, 76, 2.

USGS (U.S. Geological Survey). (2025). Landsat Spectral Indices products courtesy of the U.S. Geological Survey Earth Resources Observation and Science Center. https://www.usgs.gov/landsat-missions/landsat-normalized-difference-vegetation-index (accessed 10.12.2025).