Composition of Wild Plants Along an Urbanization Gradient in a Mediterranean City (Témara, Morocco)

Abstract

The accelerating pace of urbanization, both locally and regionally, is undoubtedly one of the main drivers impacting the structure and diversity of vegetation cover. However, the relationship between the diversity and distribution of plant communities and the degree of urbanization remains a topic requiring further research. This contribution aims to reveal the impact of the urbanization gradient on the structure and diversity of wild flora in the urban setting of a Mediterranean city (Témara, Morocco). The study area was subdivided into three sectors according to a decreasing urbanization gradient: the first sector delimits the city center (built-up area exceeding 75%), the second covers an area with a built-up area between 50 and 75%, and the third delimits the city’s peripheral area with a built-up area of less than 50%. Each sector was surveyed using four transects, and each transect was surveyed six times, resulting in 24 surveys covering 260.5 m2 per sector. The comparative study of diversity between the three sectors was based on the calculation of alpha diversity (Shannon–Weaver index and Pielou’s evenness index) and beta diversity (Jaccard similarity index). The results showed modest specific similarity among the four transects (mean Jaccard index = 0.385) and greater floristic richness in the peripheral area than in the city center. However, no significant difference (F = 0.675, α = 0.05) was observed in specific diversity among the three sectors. In addition, the therophyte rate calculation revealed significant therophytization in the city center compared with the outskirts. Such findings may lead to a more complete understanding of the processes underlying the relationship between urbanization and plant diversity, which may have implications for the conservation of this diversity in urban settings.