Assessment of climate changes effectiveness on floristic diversity of riparian plants in the area of the first cataract islands (Sluga and gezel protected area)‎ - river Nile, upper Egypt

Abstract EN

The vegetation of Suluga and Gezel PA represents relicts of the original Nubian Riverain Vegetation, a semi-arid scrub and grassland, which have successfully survived up to the present, particularly after the construction of the Aswan old and High Dams.

112 species, representing 23 orders, 37 families and 90 genera; 29 families are Dicotyledonoae (78.4 % ) with 76 species, and 7 families are Monocotyledonous (21.6% ) with 36 species (32.1 % ).

In accordance to flora of the studied islands as a whole, 64 annuals (57.1% ) and 48 perennials (42.9% ).

With regards to most represented families are Poaceae has the highest contribution to the total flora (24 species: 21.4% ), followed by Fabaceae (17 species15.2% ), Asteraceae (12 species: 10.7% ).

The vegetation life form spectrum of Suluga and Gezel islands reflects a typical desert flora, the greater part of species are therophytes and phanerophytes (70.5% ).

The phytogeographical analysis of the 112 plant species surveyed in this study revealed that the Palaeotropical have the highest contribution (26 species: 23.2% ) followed by the Cosmopolitan (19 species: 17% ) and Pantropical (18 species: 16.1% ).

The monoregional represented by (22 species: 19.6% ) of which 19 species were Sudano-Zambezian, 2 species Mediterranean and one species Saharo-Sindian.

The bi-regional chorotype was represented by 21 species (18.8% of the total flora) of which 8 species (7.1% ) Saharo-Sindian and Sudano-Zambezian, 7 species (6.3% ) belonging to Sudano-Zambezian and Saharo-Sindian, 3 species (2.7% ) belonging to Mediterranean-Irano-Turanian chorotype, 2 species (1.8) were belonging to Sudano-Zambezian and Mediterranean and only one species (0.9% ) belonging to Mediterranean and Sudano-Zambezian chorotype.

Pluriregional represented by 6 species (5.4% ).

Species richness, Shannon-Weiner H, and Margalef indices measurements indicated that shoreline and islands banks are the most diverse habitat and followed by “mosaic pattern of vegetation” in which plant aggregates grow together forming complex stands.

These results indicate that altitudinal gradient, habitat types and edaphic conditions that control soil moisture have significant influences on species diversity.

Comparative analysis and long term analysis indicated that + 28 species (+20 % ) were lost or may be extremely very rare within 40 years.

This could be due to severe environmental conditions, climate changes and Human interface in the present study area.