Somaya Magdy M. Ghoraba, Hanan Almahasheer, Ahmed A.H. Siddig, Hisham M. Nagi, Ena Suarez

Mangroves of the Red Sea and Gulf of Aden is a regional ecosystem subgroup (level 4 unit of the IUCN Global Ecosystem Typology). It includes the marine eco-regions of Gulf of Aden, Northern and Central Red Sea, and Southern Red Sea, and extends across Saudi Arabia, Egypt, Sudan, Yemen, Eritrea, Djibouti and Somalia. The biota is characterized by two species of true mangroves namely; Avicennia marina and Rhizophora mucronata. Both are classified by IUCN as Least Concern. The Red Sea and Gulf of Aden mangroves are threatened by cattle grazing, oil and solid wastes pollution, coastal development, heat waves and sea-level rise. Aridity and drought nature of this province, along with low nutrient inputs, are expected to exacerbate the adverse impacts of climate change on mangroves. The mapped extent in 2020 was 189.2 Km2, representing 0.1 % of the global mangrove extent. However, there is uncertainty about mapped extent in 1970 based on available studies. Although the net area of mangroves has decreased by 21.7% since 1996, it has only decreased by 4.0% since 2010. This improvement may be the result of increased conservation efforts to restore mangroves in various Red Sea and Gulf of Aden countries. Under a high sea-level rise scenario (IPCC RCP8.5) ≈-67.1% of the Red Sea and Gulf of Aden mangroves would be submerged by 2060. Moreover, 1.7% of the province’s mangrove ecosystem is undergoing degradation, with the potential to increase to 5.2% within a 50-year period, based on a vegetation index decay analysis. Overall, the Red Sea and Gulf of Aden mangrove ecosystem is assessed as Endangered (EN).