Drivers and patterns of vascular plant diversity in the arid mountain Gebel Elba, Egypt

Abstract

The arid mountain Gebel Elba is situated in the south‐east corner of Egypt, nearly 15 km west of the Red Sea coast. Although this mountain is surrounded by a hyper arid desert, orographic precipitation on its northern slopes provides favourable climatic conditions for a richer growth of Afrotropical species than any similar region in Egypt. Meanwhile, a phytosociological classification of the vegetation was lacking, and its environmental drivers were mostly unknown. Additionally, plant diversity patterns for this arid mountain were not completely evaluated. Thus, this thesis aimed to provide scientific data to increase the knowledge on diversity patterns and vegetation distribution in an arid mountain ecosystem (Gebel Elba). The thesis combined ecological classification and ordination analyses with ecological modelling based on different environmental parameters. It presented an extensive and quantitative account of the vegetation composition and plant diversity of wadi systems on north-western slopes of Gebel Elba for the first time. The established vegetation-plot database covered the open desert plains and the mountainous area. It contained standardised vegetation plots along elevational gradients of four wadies, i.e., Yamib, Marafai, Acow and Kansisrob. In Chapter Two, an uncommon elevation-richness pattern was described for wadi systems of Gebel Elba. The thesis also provided the first phytosociological classification of the vegetation in Gebel Elba (Chapter Three). The vegetation classification in this study contained detailed species lists. Thus, a coherent base for future work on the Afrotropical vegetation of Gebel Elba was established and made available. Furthermore, ground truth data combined with remotely sensed information were used to produce the first model-based plant diversity maps for the arid mountain Gebel Elba (Chapter Four). The thesis focused on the Afrotropical vegetation of Egypt and filled a knowledge gap on woodlands distribution and diversity patterns in Gebel Elba region. The presented thesis indicated the high importance to conserve mountainous wadi systems of Gebel Elba especially at higher elevations.