Krystin M. Ward

Current status of coral reefs in the United Arab Emirates: Distribution, extent, and community structure with implications for management

Coral reefs of the United Arab Emirates were once extensive, but have declined dramatically in recent decades. Marine management and policy have been hampered by outdated and inaccurate habitat maps and habitat quality information. We combined existing recent datasets with our newly mapped coral habitats to provide a current assessment of nation-wide extent, and performed quantitative surveys of communities at 23 sites to assess coral cover and composition. Over 132 km(2) of coral habitat was mapped, averaging 28.6 ± 3.8% live coral cover at surveyed sites. In the Arabian Gulf low cover, low richness Porites dominated communities characterized western Abu Dhabi, while reefs northeast of Abu Dhabi city generally contained higher richness and cover, and were dominated by merulinids (formerly faviids). Distinct communities occur in the Sea of Oman, where cover and richness were low. We provide management recommendations to enhance conservation of vulnerable coral reefs in the UAE.

Distribution, Pore-Water Chemistry, and Stand Characteristics of the Mangroves of the United Arab Emirates

ABSTRACT Moore, G.E.; Grizzle, R.E.; Ward, K.M., and Alshihi, R.M., 2015. Distribution, pore-water chemistry, and stand characteristics of the mangroves of the United Arab Emirates. Mangroves are the dominant coastal vegetation of the United Arab Emirates (UAE), occupying one of the driest mangrove habitats in the world. However, published estimates of mangroves do not represent current conditions for the country as a whole. This study provides an up-to-date estimate of UAEs mangroves, summarizing their habitat characteristics, stand heights, and pore-water conditions. Estimates of mangrove cover are based upon remote sensing, aerial photointerpretation, and field verification. Our results document more mangroves than previously estimated for Abu Dhabi and the nation altogether. Mapped areas were classified into three descriptive density cover classes to facilitate interpretation of the data: low (<10%), moderate (10–75%), and high (>75%). The high-density class reflects prior national estimates for mangrove coverage (roughly 3613 ha), while moderate- and low-density classes contributed an additional 5659 ha and 4344 ha (respectively) to the national total. The largest contiguous mangrove area was 710 ha, while the smallest mapped area was 0.03 ha. Mapped mangrove habitat types included fringe, basin, and overwash, with average heights of 3.36 ± 0.25 m and density of 61.83% ± 5.01%. Stand height and pore-water sulfide concentrations were significantly different between habitat types, while stand density, pore-water salinity, and redox potential were highly variable. In sum, approximately 13,616 ha of mangrove area was mapped, roughly three times more than prior estimates. This is the first study in recent years to document the full areal extent of mangroves and associated stand characteristics across the seven emirates.

Marine Molluscs in Nearshore Habitats of the United Arab Emirates: Decadal Changes and Species of Public Health Significance

ABSTRACT Grizzle, R.E.; Bricelj, V.M.; AlShihi, R.M.; Ward, K.M., and Anderson, D.M., 2018. Marine molluscs in nearshore habitats of the United Arab Emirates: Decadal changes and species of public health significance. This paper describes the results of three qualitative surveys of marine molluscs conducted in December 2010 and May 2011 and 2012 in nearshore benthic habitats along the Arabian Gulf and Gulf of Oman coasts of the United Arab Emirates. Findings are compared with historical studies, focusing on extensive surveys from the 1960s and 1970s. Molluscan species of public health significance are identified on the basis of their potential as vectors of algal toxins in light of the recent occurrence of harmful algal blooms (HABs) in the region. Habitats sampled included intertidal sand or gravel beaches, rocks and jetties, sheltered soft-sediment flats and mangroves, and shallow subtidal coral reefs. The present study showed differences in taxonomic composition and decreased species richness of gastropods compared with a previous mollusc survey conducted in the early 1970s, reflecting the probable impacts of extensive, ongoing coastal development activities, although other environmental stressors may play a contributing role. The major habitat change found in the current survey was replacement of natural “rocky” substrates with man-made jetties and breakwaters. Of the 27 live gastropod species collected, seven predatory or scavenging species were identified as potential biotoxin vectors: Thais savignyi, T. tissoti, T. lacera, Murex scolopax, Nassarius persicus, Hexaplex kuesterianus, and Rapana sp. Of the 22 live bivalve species collected, the following 11 suspension feeders were deemed to be potential vectors of HAB toxins on the basis of their body size and feeding mode: three venerid clams (Circenita callipyga and Tivela ponderosa, which are consumed locally, and Amiantis umbonella); the widespread encrusting rock oyster, Saccostrea cuccullata, also consumed locally; two pearl oyster species; Pinctada spp.; the prickly pen shell Pinna muricata; the scallop Chlamys livida; the cockle Acrosterigma lacunosa; and the facultative suspension-feeding tellinids Asaphis violascens and Hiatula rosea.