Effect of human activities on floristic composition and diversity of desert and urban vegetation in a new urbanized desert ecosystem

Abstract

Human impact in newly urbanized deserts creates new environments that may favor the establishment/dominance of certain plant species. In this study, we showed how the human activities during desert urbanization do affect distribution, composition and diversity of plant species in a new urban ecosystem. In a field study during 2015–2016 and 2017–2018 growing seasons, we investigated these vegetation criteria in three new habitats created recently due to human manipulations in addition to the old habitat of such area (i.e. the desert). We also compared vegetation criteria comprising the floristic cover, composition and diversity between the desert locations inside and on the outskirts of the city. The detrended correspondence analysis (DCA) successfully separated the different habitats studied. Besides, the floristic composition and diversity were significantly varied amongst these habitats. The canonical correspondence analysis (CCA) revealed an apparent correlation between floristic composition and soil criteria across the study area. For the desert vegetation, the cover values of both Tamarix nilotica and Zygophyllum coccineum, in addition to the whole diversity indices, were significantly suppressed in the desert fragments inside the newly constructed city in comparison with their cover in the desert adjacent to it. Moreover, the cover of both species was significantly declined in 2018 compared with their cover in 2015. On converse, the covering areas of Phragmites australis and Bassia indica were increased after intensive constructions in 2018. These results suggest that the human activities and, consequently, urbanization may influence plant life in newly urbanized desert ecosystems, leading to dispersal of new species and destruction of plant cover in some parts of the desert. Efforts and conservation strategies should be devoted to save the desert species that are vulnerable to elimination due to expansion of urbanization.