Impact of Climate and Soil on Plant Dynamics and Ecosystem Stability in Argan Orchards

Assessing the impact of natural disturbances on plant biodiversity is crucial amid biodiversity loss and climate change. Research highlights dynamic shifts driven by environmental factors, climate change, and human activity, emphasizing the need to maintain ecosystem stability for biodiversity conservation and sustainable development, particularly in arid and semi-arid regions. This study, conducted between 2021 and 2023, focused on the dynamics of plant communities in argan tree reserve areas. Six argan orchards were selected as study sites for detailed investigation. A total of 82 species belonging to 25 families were identified, with 23 families documented in 2021 and 21 families in 2023, including six endemic species to Morocco (Frankenialaevis subsp. velutina, Ononisnatrix subsp. arganietorum, Rumex papilio, Andryala integrifolia subsp. cedretorum, Chiliadenushesperius, and Reseda difussa). The majority of the plants present in the study area were annual and biennial herbaceous types, exhibiting minimal seasonal stability within the plant communities. However, how communities respond to the effects of fluctuating disturbances remains unclear. This study explores the indirect effects of natural disturbances on community metrics in argan orchards, assessing plant diversity, biomass, and density across different orchard types. It highlights the influence of climate, soil properties, and biotic interactions on plant community dynamics. We utilized alpha diversity indices (Shannon, Simpson, Pielou's, and Margalef's) and beta diversity indices (Jaccard and Sorenson Similarity) to examine these patterns. Seasonal changes were predominantly influenced by temperature and precipitation, while diverse soil types shaped by relief, climate, and water balance contributed to different ecological functions. The key findings indicated the highest plant diversity in "Tioughza" and the most significant plant density in "Imoulass" and "Ezzaouite". Soil nutrients (N, C, and P) showed a positive correlation with plant biomass, highlighting their vital role in biomass accumulation, whereas temperature, C/N ratio, and loam percentage were found to be crucial for plant richness. Mixed modeling revealed a significant relation between density and biomass, but no significant effect between alpha diversity (Shannon Index) and elevation. This study concludes that soil texture and climate significantly shape the relationships between diversity, biomass, and density, recommending further research into interactions among plant diversity, cover, biomass, and soil fertility to support the sustainable management of argan orchards.