Impact of sediment deposition on the distribution of plant formations in the neoformed zones of the Allal El Fassi dam

Abstract

• Sedimentation Process : The study looks at how reservoirs, especially those near the Allal El Fassi dam, are affected by sediment erosion, transit, deposition, and compaction. • Plant Community Dispersion : In nine recently created zones close to the dam, the dispersion of plant communities is influenced by sediment deposition. • Soil Properties : pH, electrical conductivity, soil texture, and the presence of trace elements like Al, B, Cu, and Zn are important environmental factors that affect the soil. • Soil Stability : Soil stability and erodibility are influenced by the fine-silt texture and high cation exchange capacity. • Floristic Composition : Of the 36 plant families found in the study, the most common were Asteraceae, Brassicaceae, and Poaceae. • Ecological Succession : Plant communities in these regions are shaped by ecological succession, as demonstrated by species such as Tamarix gallica . • Principal Component Analysis revealed a high correlation between soil properties and plant variety, with four species groupings identified, some of which were able to bioaccumulate trace elements. • Conservation and Management : The results offer important new information for soil conservation and wetland management plans. This study examines the effects of sedimentation on the distribution and diversity of plant communities in urbanized areas near the Allal El Fassi dam, aiming to elucidate how sediment properties influence local biodiversity. To achieve this, we employed a comprehensive analysis of plant and soil samples from nine neo-formed areas that exhibit diverse sedimentation characteristics. Our methodology included evaluating physicochemical parameters and conducting floristic assessments to reveal the variations in plant species diversity. The analysis identified two distinct categories of sediment: Group 1 (stations S6-S9) presented alkaline pH, conductivity above 40 μS/cm, and organic matter concentrations greater than 2.98%; Group 2 (stations S1-S5) exhibited slightly alkaline pH, conductivity below 40 μS/cm, and organic matter between 1.8% and 2.98%. Sediment composition revealed significant macroelement concentrations, influenced by mineral content and soil management practices, impacting soil fertility and nutrient availability for plants. Floristic analysis across these areas revealed a high level of biodiversity, identifying 36 plant families and 74 species adapted to the sediment conditions. The Asteraceae family was the most abundant (25.7%), represented by species such as Calendula arvensis, Carduus pycnocephalus , and Xanthium strumarium . Other families, including Brassicaceae (6.8%) with Eruca vesicaria and Nasturtium officinale , and Poaceae (5.4%) with Arundo donax and Cyanodon dactylon , further contributed to the diversity. Principal component analysis identified four species assemblages significantly influenced by soil attributes, with certain species demonstrating bioaccumulation of trace elements, underscoring their potential in soil remediation. These findings offer valuable insights for sediment manage ment and biodiversity conservation, emphasizing the critical role of sediment characteristics in supporting diverse plant communities within dam-affected regions. The study enhances our understanding of ecosystem dynamics in areas impacted by dam construction, offering guidance for sustainable ecosystem management and restoration in similar sediment-influenced environments.