Biodiversity and Urban Nature in Public Spaces: Inventory Strategies for Sustainable Management in Tlemcen, Algeria

Abstract Urban sprawl today constitutes one of the main factors driving landscape transformation in developing countries. This process promotes the fragmentation of natural environments, the disruption of ecological continuities, and the weakening of essential environmental functions, thereby contributing to the gradual degradation of quality of life in urban areas. In Tlemcen, Algeria, this dynamic is particularly noticeable, especially regarding green spaces, which play a decisive role in maintaining ecological balance and regulating local environmental conditions, making a precise ecological assessment of the most sensitive sites necessary. In this context, the present study aims to establish an in-depth ecological diagnosis of the example of the Jardin du Grand Bassin, a historic site representative of Tlemcen’s urban landscape, in order to evaluate its level of fragmentation, floristic composition, vegetation structure, and overall ecological condition. The methodological approach adopted is based on a comprehensive strategy combining several complementary tools. Spatial analysis using GIS allows for the examination of landscape configuration, the identification of fragmented areas, and the detection of still-functional ecological corridors, essential elements for understanding intraurban ecological dynamics. The Forest Development Type method is employed to describe vegetation stratification, characterize formation types, and identify dominant landscape structures, while a detailed floristic inventory, developed through extensive bibliographic research, organizes species according to their strata and canopies in order to apprehend the site’s plant diversity. Finally, the calculation of an ecological perturbation index (IP) complements the assessment by providing a quantitative measure of the level of environmental pressure. The results reveal that despite the presence of highly fragmented zones, several ecological corridors remain active, opening possibilities for targeted priority actions in ecological restoration. The site presents a notable floristic richness of 106 species, and the ecological perturbation index reaches 31.13%, reflecting a moderately stable ecosystem but subjected to real pressures. Analyses derived from the method show an organization of vegetation strata reflecting an exogenous horticultural heritage, characteristic of the Grand Bassin and determinant for its ecological functioning. By providing an in-depth ecological diagnosis of a major urban green space, this study fills a gap in scientific knowledge regarding the ecological condition of urban green spaces in Tlemcen and constitutes a valuable tool for urban managers. It proposes strategic orientations for sustainable management, urban biodiversity preservation, and the strengthening of ecological connectivity, positioning the Jardin du Grand Bassin as a reference model for environmental restoration initiatives and long-term ecological planning.