Ocean and Coastal Management 195 (2020) 105288 Available online 17 July 2020 0964-5691/© 2020 Elsevier Ltd. All rights reserved. Evolution of mangrove research in an extreme environment: Historical trends and future opportunities in Arabia Guillermo Friis * , John A. Burt Center for Genomics and Systems Biology, New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates A R T I C L E INFO Keywords: Mangrove Persian/Arabian Gulf Red Sea Sea of Oman Arabian Sea Avicennia marina ABSTRACT Mangrove forests occur throughout the coastlines of Arabia, one of the most environmentally extreme regions of their global distribution. The gray mangrove [Avicennia marina (Forsk.) Vierh.] is the only widespread tree species in this region, providing a unique evergreen habitat that supports high mangrove-associated biodiversity and many ecosystem services of socio-economic importance. This study provides the frst literature-based analysis of the status and historical development of mangrove science in Arabia. The goal was to identify trends and gaps in regional mangrove research, providing information essential to guiding future science and conservation programs. The analyses incorporated 400 publications from over six decades since the frst article in 1955, each classifed into 11 major research topics and including studies from each of the regional seas (Red Sea, Arabian Sea, Sea of Oman, and the Persian/Arabian Gulf). The results demonstrate that there has been expo- nential growth in research on regional mangroves in recent decades (particularly around human impacts and ecology). The study further reveals knowledge gaps in important research topics and geographical areas that could be exploited to provide insights into broader biogeographic issues. These results provide a comprehensive assessment of the growing body of knowledge on regional mangroves, and provide direction for future research that can guide conservation, management and scientifc knowledge of these critical ecosystem engineers. 1. Introduction The Arabian Peninsula represents one of the most hostile terrestrial and marine environments in the world (Sheppard et al., 1992). Due to its geographic location in the northern subtropical high-pressure zone, the Arabian region is characterized by extreme aridity, with annual rainfall rarely exceeding 250 mm, and many areas experiencing <100 mm yr 1 (Almazroui et al., 2012). The limited cloud cover results in high solar irradiance, causing land surface temperatures in many places to exceed 50 � C during summer days, while winter night temperatures can plunge below freezing due to the limited availability of vegetation and soil moisture to modulate temperatures (Patlakas et al., 2019). These ex- tremes extend to the seascapes that border the region, with high evap- oration rates and limited freshwater input resulting in extreme salinity [» 40 practical salinity units (PSU)] in enclosed water bodies such as the Persian/Arabian Gulf and the northern Red Sea (Carvalho et al., 2019; Vaughan et al., 2019). The shallow nature of the Persian/Arabian Gulf and southern Red Sea also result in sea temperatures that are among the most extreme on earth, especially in areas with large temperature ranges between winter lows of 12 � C and summer highs of 36 � C (Coles, 2003; Vaughan and Burt, 2016). The Persian/Arabian Gulf in particular is the world’s hottest sea each summer, representing a signifcant thermal challenge for marine organisms (Riegl and Purkis, 2012). Coastal sys- tems of the more oceanic Arabian Sea are also subject to extremes, with sea temperature fuctuating by as much as 15 � C during summer monsoon upwelling (Salm, 1993; Coles, 1997), resulting in a unique marine biogeographic province where a ‘pseudo-high latitude’ effect causes communities to be dominated by cold-adapted species (Sheppard and Salm, 1988; Sheppard et al., 1992; Claereboudt, 2019). Despite the extremity of these terrestrial and marine environments, extensive mangrove forests occur along much of the Arabian Peninsula coastline in nearly all bordering nations. As the only natural evergreen forests in Arabia (Saito et al., 2003; Burt, 2014) mangroves represent a critically important biogenic habitat whose relevance has only recently began to draw scientifc attention in the region. Mangrove ecosystems across the Arabian region are largely domi- nated by the gray mangrove [Avicennia marina (Forsk.) Vierh.], a species that extends across the entire Indian Ocean and into the western Indo- * Corresponding author. E-mail address: gfm3@nyu.edu (G. Friis). Contents lists available at ScienceDirect Ocean and Coastal Management journal homepage: http://www.elsevier.com/locate/ocecoaman https://doi.org/10.1016/j.ocecoaman.2020.105288 Received 27 January 2020; Received in revised form 19 June 2020; Accepted 19 June 2020