Environmental Factors that Influence the Spatial Distribution of Extreme Halophytes on Egypt's Northwestern Mediterranean Coast

Abstract

Climate change exerts a significant impact on coastal ecosystems, primarily through the rising sea levels, which pose a global threat to salt marshes, essential habitats for valuable halophytic plant species. Concurrently, unchecked human activities also pose a considerable risk to halophytes. Consequently, comprehending the factors that shape plant community diversity and distribution becomes pivotal for biodiversity conservation and the restoration of degraded vegetation. To address this, we selected 54 stands across the northwestern Mediterranean coast of Egypt, encompassing a salinity gradient, mirroring the global distribution of temperate salt marshes. Soil samples were collected across these 54 locations for comprehensive soil parameter assessments. The studied region was inhabited by 165 species, spread throughout 117 genera and 36 families. The most abundant families in terms of species are the Asteraceae, Poaceae, Fabaceae, and Amaranthaceae. Therophytes were the most represented life form. A multivariate analysis was applied to identify the environmental elements that might have an impact on species distribution. After using TWINSPAN and DCA as classification and ordination approaches, four vegetation groups emerged. Salinity condition influences the distribution of halophytic species, community structure, and wild community diversity. With the escalating human intervention in agricultural operations and the intensification of land usage, the seaward area has been completely degraded except for small patches and there is no possibility of rehabilitation. As a result, steps should be taken to conserve salt marsh habitats against unrestricted land use.