The goal of the study was to collect, analyze and document environmental data for the sustainable use of Abu Dhabi's marine and coastal resources. Prior to the study there was no detailed ecological data relating to the marine environment; and with increasing development demands, and no data to assist in planning, the coastal and marine resources were under serious threat of degradation. From 1999 to 2001 extensive field research was undertaken to collect ecological data throughout the coastal and marine areas of Abu Dhabi Emirate. The program incorporated the training of UAE postgraduate students. The atlas program successfully documented data on the location and extent of coastal habitats, the distribution of marine wildlife and areas of international conservation importance throughout the Emirate of Abu Dhabi. All data was geographically corrected and checked for accuracy and completeness, and Arabic and English place names were assigned to all localities in the Emirate. The atlas program provided an opportunity for detailed scientific survey to be undertaken in an area where data generally had not been previously collected. It is envisaged that the atlas will contribute towards the protection of the marine environment, and facilitate sustainable coastal development throughout Abu Dhabi Emirate.
The United Arab Emirates (UAE) is located at the southern end of the Arabian Gulf and is situated adjacent the Straits of Hormuz; waterways which are crucial to the economic sustainability of the region and to the stability of the world's energy supplies. Each year, approximately 200,000 t of sea freight are transported through the Straits (GCC, 2006), including 2,195,000 barrels of crude oil and 509,000 barrels of refined oil per day from the UAE alone, en route to the US, Western Europe, Africa and Asia (OPEC, 2005).
In addition to its importance as a commercial transport route, the Arabian Gulf also provides a rich marine environment. The shallow water habitats in the Gulf sustain extensive ecosystems, such as sea grass and algae communities which are productive, supporting whole marine food chains, including the world's second largest population of dugong (Dugong dugon) and resident populations of killer whale (Orcinus orca), the largest predators in the sea. The presence of these large carnivores is an indication of the productivity of the shallow water habitats. The water circulation patterns in the study area are unique in that they are driven primarily by thermo-halines (Eckardt, 1999). As seawater in the shallow areas of the southern Gulf evaporates, the increased density results in subsidence, which in turn drives the local current patterns in the area. Water coming into the Arabian Gulf through the Straits of Hormuz moves south along the UAE coast and forms a clockwise gyre within the southern embayment of the Gulf along the coast of the UAE (Brown, 1986).
During the coming years, as Abu Dhabi attempts to sustain continuing rapid coastal development (Brown et al., 2006), an understanding of the effect these changes are having on the local environment, including the shallow water habitats, will be a crucial factor in planning for the environmentally responsible development of the region. This atlas is intended to provide baseline data used as a first step in formulating such an understanding.
This study was specific to Abu Dhabi Emirate, the largest of the seven Emirates of the United Arab Emirates (UAE). The aims of the study were to collect data on the location, distribution and ecology of Abu Dhabi's marine and coastal habitats and wildlife, and to help foster environmental awareness amongst the people of the UAE. The study therefore involved the training of UAE postgraduate students in coastal and marine ecology. Planning and preparations commenced in February 1999 (Loughland et al., 2004) and all of Abu Dhabi's territorial waters were surveyed from 1999 to 2001.
The study successfully documented data on the location and extent of coastal habitats, the distribution of marine wildlife and areas of international conservation importance throughout the Emirate of Abu Dhabi.
The study area
The study area encompasses all of the marine waters and coastal areas of the Arabian Gulf within Abu Dhabi Emirate (Figure 1).
Abu Dhabi Emirate has a mainland coast which when measured using remote sensed images stretches for around 960 km. The total area of Abu Dhabi's marine territorial waters is 37,616 km2. The offshore waters are generally shallow and as a result there are numerous offshore islands, with the Emirate containing over 50 islands, ranging from dramatic salt dome formations to small sandy shoals. The occurrence of an inshore network of barrier islands also provides a unique lagoon ecosystem, with protected shallow waters along the north-east coast of the Emirate.
A literature review was undertaken to obtain information on the coastal and marine areas of Abu Dhabi Emirate. The search located few data, with most records being brief reports relating to isolated field observations. Overall, there was a general lack of published material relating to the marine and coastal environment (Sheppard and Wells, 1988; Sheppard et al., 1992).
Oil companies provided information that had been either undertaken by their organization, or by consultants on behalf of their companies. Very little of this information had been published, and was generally stored in report format in oil company libraries. The beneficial environmental data contained in these reports was usually collected in relation to a particular project, and therefore the geographical coverage of the data was often limited.
The atlas program consisted of ten research projects covering all aspects of coastal and marine habitats and wildlife. These included mangroves and saltmarsh (Saenger et al., 2004; Blasco et al., 2004), coral reefs (Loughland and Sheppard, 2001; Sheppard and Loughland, 2002; George and John, 2004), seagrass (Phillips et al., 2002; Phillips et al., 2004), intertidal and benthic communities (John and George, 2004), marine mammals (Preen et al., 2004), marine reptiles (Miller et al., 2004), marine and coastal birds (Aspinall et al., 2004), fisheries (Beech, 2004), archaeology of the coastal zone (Hellyer, 2004) and coastal mapping (Blasco et al., 2004). An international specialist headed each project, and local researchers and postgraduate students participated in each of the projects.
The methodology for determining marine mammal and reptile populations utilized aerial surveys undertaken along transects with transect markers fitted onto the aircraft to define a search area, mimicking an earlier survey undertaken by the marine mammal project leader in 1986 (Preen, 1989). This therefore allowed for comparison between the two survey periods.
Field research commenced in August 1999 and continued through to June 2001. The field research was divided into two workshop programs involving the participation of local postgraduate students.
Most of the survey was undertaken using helicopters at low altitude and speed and often the survey helicopter landed at specific sites in order to allow for closer site inspection, and field sampling. In total, 200 hours of aerial survey were undertaken. A Garmin global positioning system (GPS) in conjunction with a radio differential receiver was used to record accurate geographical positions. This data was later downloaded onto a personal computer for storage.
Marine surveys were undertaken using both small and large marine craft. The craft were directed to the study sites using GPS, and scuba survey dives were undertaken. In some cases the surveys were also undertaken using snorkel dives, especially when surveying along depth contours for continuation of sub tidal habitats (Phillips et al., 2002; Phillips et al., 2004).
Small marine craft and four wheel drive vehicles were also used to access some coastal areas for habitat surveys, however detailed shore surveys and habitat transects were most often conducted by walking and wading through shallow inshore waters.
Habitat assessment was undertaken using quadrate sampling, dumpy levels, ranging poles and 50 m tape measures (Saenger et al., 2004). Surface soil samples were collected from the coastal zone in order to determine their reflectance value, and this was later used to assist in interpreting remote sensed satellite images (Blasco et al., 2004). All zoological samples collected were preserved in 10% formaldehyde, and botanical samples were sorted, pressed and dried for later reference.
At the completion of the second student training workshop (June, 2001), all atlas project leaders had completed data collection. The data was analyzed, where earlier data existed (i.e. dugongs, Preen, 1989) data was compared, and plotted using Arc View software to illustrate the geographical extent of the data.
Additional data captured incidentally whilst collecting data for a specific project was transferred to the relevant project leader, to be incorporated into their specific data set. A quantitative analysis of all existing data was undertaken to identify ecologically important areas in the Emirate, and to determine other values of the coastal areas.
Abu Dhabi Emirate's marine and coastal areas were divided into a series of vertical zones. A practical scale of 50 km (west-east) was determined and using ERIN software a grid was overlaid on the most recently available remote sensed image of the study area (Landsat TM image 160/43, 1998), starting from the western (UAE-Saudi Arabian) border. The 50 km grid divided the study area into 7 distinct zones (Figure 2). These zones were named A-G (from west to east).
With the use of remote sensed images, atlas data, and local knowledge of the authors, coastal resource information was recorded for 16 different classes (Table 1). These classes included the location and abundance of subtidal and intertidal habitats, the presence of marine wildlife, and anthropogenic infrastructure situated along the coastline.
Results and discussion
The atlas program provided an opportunity for detailed scientific survey to be undertaken in an area where data generally had not been previously collected.
The results of this research exceeded initial expectations, indicating that Abu Dhabi Emirate contains internationally important populations of wildlife such as Dugong (Dugong dugon), and unique marine habitats. Orca (Orcinus orca) and Sooty Shearwater (Puffinus griseus) were recorded for the first time in the Arabian Gulf.
The results of the marine mammal surveys when compared with the earlier survey data (Preen, 1989) indicated a stable Dugong (Dugong dugon) population in Abu Dhabi Emirate. The same results indicated a sharp decline in the populations of certations (both porpoise and dolphin species). The central western coastal waters of the Emirate (Zone D, Figure 2) had the majority of dugong and turtle recordings (Preen et al., 2004; Miller et al., 2004). Wide scale bleaching of coral was also observed during the atlas surveys and this data is discussed by Sheppard and Loughland (2002).
Ecological hot spots
The results of this study indicated that Zones D and F were clearly the most ecologically important sites in the study area and also contained heritage (archaeological) and other anthropogenic values (Table 2). Zones D and F scored the first or second highest values for all eight ecological classes, with Zone D scoring the first value for four (50%), and Zone F scoring the first value for two (25%) of these classes. Zone D and F scored the second highest value for five (63%) of the ecological classes (Table 2).
Zone D was clearly the most important ecological area (Table 2), and was particularly important for subtidal ecosystems such as seagrass and benthic habitats. Due to these benthic habitats, Zone D also contained significant populations of wildlife, and this area is internationally important for endangered species such as dugong, because with the exception of areas in Australia, Zone D has the greatest densities of dugongs known in the world (Preen, 1989; Preen et al., 2004; Loughland and Darwish, 2004). Zone D is also an important foraging area for the endangered green and hawksbill turtles, and also provides medium density nesting sites for hawksbill turtles and very low density nesting sites for green turtles (Miller et al., 2004). This same area also contains significant international and national wintering and passage waterfowl populations (Aspinall et al., 2004) and important nesting habitat for species such as the red-billed tropic bird, and historically contained the most important Socotra cormorant colonies in the Gulf (Carp, 1976).
Carp's historical observations of many thousands of nesting Socotra cormorants in Zone D supports the results of this analysis, in that this area is rich in marine resources. During atlas aerial surveys, a pod of Orca whales with young was also observed in Zone D by the authors. This was the first such sighting of this species in the Arabian Gulf, and the presence of these top predators (males growing up to 10 m in length, and weighing up to 10 t) is testament to the high productivity and ecological value of Zone D.
Zone F occurs within the most developed area of Abu Dhabi Emirate (Capital Area), and the results of this analysis indicated that this area is still of considerable ecological importance. Zone F is particularly important for birds and coral, and also contains large areas of mangrove vegetation (Table 2). The area also contains valuable seagrass habitat, and Preen et al. (2004) reports dugong sightings within 2 km of downtown Abu Dhabi City; which is something no other world capital can boast.
The results of this analysis were strongly influenced by the ecological classes, as there were high values for the ecological classes within specific zones. The removal of the anthropogenic classes (including archaeology), or the provision of a negative value to the other anthropogenic classes, made no difference to the overall results, and had no impact on the overall ranking and rank position of Zones D and F.
The collection of baseline ecological data, and the production of a marine atlas is a major milestone towards protecting Abu Dhabi Emirate's natural resources, and the successful integration of scientific research and student training is a major achievement for capacity building in the United Arab Emirates.
The atlas provides a baseline on the state of the Emirate's marine and coastal resources, and can be considered as the benchmark on which to monitor future changes in the marine environment over time.
The atlas studies reinforced earlier work, and provided new information establishing Abu Dhabi as an area of important and extensive shallow water habitats that are utilized by a range of species including internationally significant populations of Dugong (Dugong dugon).
The results of the analysis indicated that the most important ecological zone in the Emirate occurred in the central area, in a region later designated as the Marawah Marine Protected Area, and also in the capital area, including the marine areas around Abu Dhabi Island (Capital City of the UAE). The habitats adjacent the capital area, like the Marawah habitats are also in need of formal conservation protection as urban and tourism developments are encroaching rapidly on these natural areas.
Interestingly, archaeological data had also indicated that these same areas were extensively utilized by early inhabitants. Undoubtedly this was due to the sustained ecological value and productivity of these two zones. These same ecological values persist today, and there is now a greater diversity of users including traditional stakeholders who continue to harvest fish and other resources from the area, and major offshore oil and gas operators. Due to increases in population, and particularly urban and city dwellers, these natural areas are also valuable for recreation users, and coupled with the growth in urban coastal developments and a rapidly expanding tourism industry, means that other values apart from traditional activities and oil extraction may soon become important in the study area, and the atlas baseline data will therefore be a valuable tool that may assist with sustainable coastal development.