Spatio-temporal changes of the flora, climate impact and biodiversity prediction in the presaharan wadis South of Djelfa (Algeria)

The pre-Saharan region of southern Algeria is a vast area with a range ecosystems, including wadis. However, it is exposed to several anthropogenic and natural environmental stresses, including climate change, which have resulted in repeated and prolonged periods of drought. Such temporal environmental changes have led to alterations in the plant cover, which has negatively impacted the biodiversity of the region, especially endemic ones. Consequently, there have been socio-economic problems. This study aims to examine the impact of climatic changes on wadi flora and biodiversity in the arid region of Oum Laadham (South of the province of Djelfa). The study involved 90 releves during the spring season of the years 2011, 2015 and 2019, with mixed sampling carried out in wadi sites. The overall composition of plant species, biological and phytochoric types, Shannon-Weaver and Pielou indices were used to assess plant diversity. Variance analysis and multiple regression were applied to floristic data to determine the impact of environmental parameters on flora and biodiversity changes. The survey results showed that the Asteraceae family was dominant, and therophytes were the most common biological types, regadless of the year. Variance analysis indicated that the ecological conditions of the site had a significant impact on both floristic richness and flora diversity with a p-value<alpha (0.05). The Multiple regression analysis showed that yearly precipitation (mm) was positively correlated with floristic richness), the global recovery of vegetation, and the Shannon-Weaver and Pielou indices, regardless the year considered. In recent years, climatic disturbance have led to changes in the flora and its distribution in the region. To effectively address these challenges, it is recommended to implement sustainable management practices that focus on water conservation and reforestation with native species, and continuous monitoring of the region's biodiversity. These efforts, combined with climate adaptation strategies, are essential for preserving the unique flora of Oum Laadham area and supporting the local communities dependent on these ecosystems.