Fall 08

Mangrove Resources of the : Mapping and Site Survey 2011-2013

Prepared for:

United Arab Emirates

Ministry of Environment and Water

Prepared by:

Gregg E. Moore, Ph.D. Raymond E. Grizzle, Ph.D. Krystin M. Ward

Tel: 001 603 862 5138 Tel: 001 603 862 5130 Tel: 001 603 862 5128

[email protected] [email protected] [email protected]

Jackson Estuarine Laboratory, 85 Adams Point Road, Durham, NH 03824, USA

University of New Hampshire

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Mangrove Resources of the United Arab Emirates: Mapping and Site Survey 2011-2013

Cite as: Moore, G.E., Grizzle, R.E. and K.M. Ward. 2013. Mangrove resources of the United Arab Emirates: Mapping and site survey 2011-2013. Final Report to the United Arab Emirates Ministry of Environment and Water. 28pp.

On the Cover: Dense pneumatophores of gray mangrove (Avicennia marina) along a tidal creek within an extensive mangrove island in Umm Al Quwain. Photo: G.E. Moore 2013.

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Executive Summary Mangroves are the dominant coastal vegetation of the Arabian Peninsula, occupying one of the driest mangrove habitats in the world. Despite their ecological and economic importance in the United Arab Emirates (UAE), current estimates of this globally threatened resource appear incomplete and out-of-date for the country as a whole. This study was designed to fill an existing data gap in mangrove mapping for both local and international scientists and resource conservation practitioners, as well as to highlight opportunities for resource conservation, restoration and protection of critical coastal habitats in UAE. Mapping estimates were based upon remote sensing, aerial photo- interpretation, and limited field confirmations resulting in a readily transferable GIS- based digital map of mangrove coverage for the UAE. While additional fine-scale mapping and field confirmation are needed, preliminary results reveal considerably more total mangrove area than reported in published literature for and the nation as a whole (~13,615 ha in total). Each mapping estimate unit was classified into one of three descriptive density cover class categories; Low (<10%), Moderate (10-75%), and High (>75%) to facilitate interpretation of results. The high-density class most reflected prior national estimates for mangrove coverage (3,613 ha), while moderate- and low- density classes, albeit much shorter and sparse, contributed an additional 5,659 ha and 4,344 ha (respectively) to the national total estimate. Mapped mangrove habitats included fringe, basin and overwash types, which ranged in height from 3.4±0.3 m and density 61.8±5 %. The largest contiguous mangrove area polygon was 710 ha, while the smallest mapped area was 0.03 ha. Neither stand height nor density was correlated to habitat type, but fringe and basin mangroves were significantly taller and more dense than overwash mangroves. In sum, approximately 13,615 ha of mangrove area were mapped, roughly three times more than any prior estimate. Pore water salinity was 46.1±1.1 ppt and 47.5±1.1 ppt at depths of 20 cm and 50 cm, while surface water was significantly lower at 41.5±1.3 ppt; Meanwhile, pore water sulfide was 0.35±0.1 mM and 0.44±0.1 mM and redox potential was -177.1±36 mV and -218±35.2 mV over the same depth ranges. Sulfides were correlated to redox potential (p<0.001), but these parameters did not appear to influence stand height or density. While these results are preliminary, the data suggest that 1) mangrove areas are in fact increasing in total coverage as suggested by prior studies, 2) prior estimates largely excluded the smaller geographically smaller Emirates and the comparatively sparse and isolated assemblages of mangrove, and 3) the availability of higher resolution maps may allow for more complete and accurate mangrove mapping of UAE’s mangrove resources into the future. This is the first study in recent years to document the full areal extent of mangroves across the seven Emirates.

2 Introduction Mangroves are the dominant coastal vegetation of the Arabian Peninsula, occupying one of the driest mangrove habitats in the world (Dodd et al 1999). Notably sparse, these communities represent both a geographic and ecological extreme for mangroves (Duke et al. 1998, Dodd et al 1999, Polidoro 2010). In fact, the mangroves of the United Arab Emirates are comprised exclusively of the highly salt tolerant grey mangrove (Avicennia marina) (Saenger 1997, Dodd et al 1999), which has been shown to tolerate salinity twice that of seawater (Shalom-Gordon and Dubinsky 1993). Reports indicate that Rhizophora mucronata has also been planted in limited reintroduction efforts as well (FAO 2007) but were not specifically observed in the present study. Mangrove systems provide a variety of ecological functions and values from habitat for economically and ecologically valuable fisheries, birds and marine wildlife, to shoreline protection from storms, erosion, and sedimentation. Together with shellfish and seagrasses communities we noted, mangroves also serve to protect and improve the quality of coastal and nearshore waters and represent an important coastal resource for the country and the region.

Globally, mangrove habitats are in decline (FAO 2007, Polidoro et al. 2010) due to a number of factors including coastal development and land reclamation, aquaculture, oil spills and coastal pollution, and many other anthropogenic impacts (Ellison and Farnsworth 1996) and may face increased pressure due to climate change impacts (UNEP 1992, IPCC 2007). Despite this fact, the mangroves of the UAE appear to have increased to some extent over the last 30-40 years (Loughland et al. 2007, Howari et al. 2009) due in part to localized planting activities, alteration of shorelines and water flow patterns, and increased public awareness and conservation efforts (FOA 2007, Howari et al 2009). Although mangroves such as A. marina have one of the largest biogeographical distributions of any mangrove species (Tomlinson 1986), populations are more at risk from area declines at these extremes of their distribution where mangrove diversity is lowest (Duke et al. 1998, Polidoro 2010).

3 Recent developments in remote sensing technology have demonstrated the efficiency of mapping finer scale mangrove communities. Refined approaches may have the ability to differentiate between dominant species and stand density (Held et al. 2003). Application of such technology is particularly well suited to document vegetation change and community response to impacts, as well as to develop sustainable site-specific management strategies for coastal habitats (Dahdouh-Guebas 2002; Krause 2004, Loughland et al. 2007). Several authors have estimated the mangrove area of the UAE (Embabi 1993) or portions thereof (Althausen et al 2003, Saenger et al 2004, Loughland et al 2007, Howari 2009) using such approaches. These estimates suggest approximately 30-40 km2 of mangrove area, but these efforts were concentrated in selected areas such as Abu Dhabi Island or Khor , where significant mangrove areas are known to occur (Blasco et al 2001, Saenger et al 2004, Al Abdessalaam 2007). The published studies that cite total areal extent of mangrove were largely based upon older imagery (circa 1999-2000) and may not adequately represent diffuse, low density stands, nor the breadth of mangrove areas across the country as a whole. The discrepancy between prior and current areal extent of mangroves limits land management and conservation initiatives because the data may be incomplete or inaccurate today, in light of significant land alteration throughout the coastline of the UAE over the last 10+ years. Accordingly, we initiated the first phase of a country-wide mangrove mapping effort to document all mangrove areas, regardless of community density, under present day conditions. The survey, which was based on various aerial imagery datasets and selective field verification, compliments prior studies by improving the resolution of baseline mangrove distribution and quantification, determination of plant density and community zone composition, and identifying further mangrove mapping, research, and conservation needs in the country. Comprehensive mangrove resource mapping will facilitate repeated assessment to monitor short and long-term trends within these habitats (Ramirez-Garcia et al. 1998, Moore et al in press).

Study Area The United Arab Emirates is located on the northern coast of the Arabian Peninsula, bordered by Saudi Arabia and Oman. Encompassing 83,600 km2, it is comprised mainly of arid desert and is generally flat, aside from the eastern mountains. Six of its seven Emirates are situated on the Gulf of Arabia (Abu Dhabi, , , , Ras Al

4 Khaimah and Umm Al Quwain), while and a territory of Sharjah (Khor Kalba) occur on the Sea of Oman. The coastal areas stretch for over 850 km and include several natural plant communities including algal mats, salt marsh and mangrove. The latter are dominated by the grey mangrove (Avicennia marina) and are the subject of the present study. Published estimates suggest that the UAE has approximately 4,000 ha of mangrove, while some 2,500 ha are centered in Abu Dhabi alone (Saenger 1997), the largest of the seven Emirates. The present study has accounted for considerably more.

Figure 1. Regional context of the study area within the Middle East. The study focus on the United Arab Emirates denoted by red circle. Methodology Mangrove Mapping A combination of remote sensing and field surveys were used to estimate mangrove areal coverage (Grizzle et al 2011). Initially, we created rough mangrove estimates to focus our finer-scale mapping and site inspections from Landsat Thematic Mapper (TM5/4) and historic maps (Saenger et al 2004). Review of existing mangrove maps led to notation of additional observation areas not discerned by remote sensing and aerial photo interpretation. Landsat TM data were processed using MultiSpecCarb (v.6.28.10) and interpreted using ArcGIS software v.10.1 (ESRI 2010) which facilitated inspection of imagery for likely mangrove areas using band ratios, but the resolution (30m2) was

5 inadequate for locating small, sparse or isolated mangroves. In addition, these scenes were distributed across a range of dates from 1998 through 2010, thus lacked the temporal consistency we sought to prepare final map estimates. These classifications were then assessed using pan-sharpened Ikonos-2 imagery dated from 2000-2003. Areas classified as mangroves were then resolved from other habitat types by subsequent field verification when possible and modification of stand boundaries as needed. Ikonos-2 data had much spatial higher resolution (1-4m2), but was also dated. Thus final boundary estimates were further refined in ArcGIS using the most current collection of Bing™ Maps (Microsoft Corporation 2012) available through the ESRI ArcGIS server (circa 2010-2012), along with field-demarcated boundaries in selected areas using a Trimble Nomad 900LC GPS/Field Data Collector.

Field Survey and Ground Truth In December 2011 and May 2012, efforts were made to visit all major mangrove areas discerned from preliminary map estimate results to confirm mangrove area boundaries, collect stand characteristics data, and measure pore water chemistry. We were able to access many mangrove by sea (with assistance from the Ministry of Environment and Water), while some stands could only be accessed by walking in from the landward edge. At a minimum, we documented whether historic mangrove locations (derived from review of available maps and imagery) still contained mangroves by viewing from a distance with binoculars, as site access was often restricted. In total, site visits were conducted at approximately 45 non-contiguous mangrove areas, spanning each of the seven Emirates. These field visits included many previously unmapped, low-density areas that were discovered along our coastal route. At each mangrove area, a minimum of 50 GPS waypoints were averaged to insure accuracy of mapped data collection points. Resulting waypoints were later uploaded to ArcGIS and used to confirm, correct, or refine remotely mapped mangrove area estimates. Additional data were collected when access to the mangrove was possible. Random plots were used to collect basic data at each site. Each plot location and the ecological data therein was recorded using a Trimble Nomad downloaded to ESRI ArcGIS v.10.1 daily. Canopy height was visually estimated and plant density coverage estimates were conducted using a modified Braun Blanquet scale and subsequently characterized into three density classes; Low (<10%/m2), Moderate (10-75%/m2), and High (>75%/m2) as illustrated in Figure 2. Soil type was examined in the field and described using standard field methods (USDA- NRCS 2010).

Figure 2: Illustration of relative mangrove stand density classes from left to right illustrating low (<10%), moderate (10-75%, and high (>75%) density classes.

6 Pore Water Sampling Salinity of surface water was measured directly in the field using an Orion 5-Star Plus multimeter with DuraProbe conductivity cell. Soil pore water was sampled using the sipper method (Portnoy and Valiela1997) which extracts water trapped in pore spaces using a 1mm diameter stainless steel tube fitted with a 60cc plastic syringe. Pore water was sampled at two depths within the rhizosphere (20cm and 50cm) at each site to document salinity, redox potential, sulfide concentration and pH. Pore water salinity was determined in the field as stated above, as was redox potential using the Orion 5-Star fitted with a platinum electrode. Sulfide samples were fixed with 20% zinc acetate and determined colorimetrically in the laboratory (Cline 1969), while pH values were determined in the field using an Orion 5-Star Plus multimeter fitted with a Ross Sure- Flow temperature corrected pH triode.

Results and Discussion Mangrove Area Estimates At total of approximately 13,615 ha of mangrove area was estimated in the current study, represented in Figure 2, and individual mangrove estimation maps for each Emirate are included in Appendix A. The national total far exceeds all prior published estimates of mangrove areal extent, but is similar to areal estimates maintained by local authorities in each Emirate for all but the Khor Kalba mangrove in Sharjah (personal communication, Ministry of Environment and Water). Our estimate based on aerial mapping and field based ground truthing, found only 204 ha of forested mangrove in Khor Kalba. However, these findings are not in agreement with the recent RAMSAR designation of the Khor Kalba Protected Area, which indicates the mangrove is over 800 ha. The discrepancy between estimates may lie in the approach used to classify ‘mangrove’. Our approach included only those areas with existing mangrove plants and categorically excluded unvegetated areas. In fact, the coastal wetland area of Khor Kalba is approximately 800 ha, comprising mangrove, unvegetated mudflats, lagoon and tidal creeks, but the area presently vegetated by mangrove is a subset of the larger wetland system.

7 Notwithstanding the findings at Khor Kalba, we documented three times more mangrove across the seven Emirates than that reported in the published literature. There are several factors that likely contribute to the vast discrepancy between the prior published totals and the estimate generated in the present study. Firstly, closer examination of the results show that the most dense and significant stands of mangroves are captured within the high-density classification, which includes large stands in Abu Dhabi, Umm Al Quwain, and Sharjah equaling approximately 3,615 ha, comparable to prior estimates in the published literature (~4,000 ha). These dense and often larger stands are easily observed and readily mapped, while more diffuse and scattered stands are more difficult to find, map, and document. As illustrated in Table 1, if we consider only the high density stands we mapped in Abu Dhabi (est. 2,481 ha), this is almost identical to approximately 2,500 ha totals presented by others (Saenger 1997, Saenger et al. 2004). It is possible that, given the sparse nature of many of the stands we documented, they may have been overlooked or non-existent when prior studies were undertaken (10 or more years ago). Secondly, prior estimates were largely derived from Landsat data (MMS, TM, and ETM), which do not have the spatial resolution needed to document small, isolated stands. The roughly 30m2 pixel size of imagery interpolation would inherently omit diffuse stands or patches that did not represent a majority of the cover types in an individual pixel. Finally, prior estimates used data from much older sources and commonly used remote sensing approaches only. FAO (2007) cites data from a 1978 field survey (FAO 1978) and Saenger et al. (2004) which used aerial imagery from 1999; Althausen et al. (2003) used Landsat TM (1989) and ETM (1999) data; Loughland et al (2007) used a series of aerial photos, Landsat MMS (192) TM (1984, 1985, 1988, 1996, 1998, 2000, 2002, 2003); and Howari et al. (2009) similarly used TM (1994) and ETM (2000), while their Ikonos-2 data was from 2003.

Table 1: Summary of mangrove area estimates by Emirate. Resulting totals have been grouped into simplistic density classes of Low (10%), Moderate (10-75%), and High (>75%) density to facilitate interpretation of results.

3$'%+4*%5+67+8'9:#&7+;2%:: !"#$%&' (#)*+ ,-.'$%&' /-0 1-&%2+3$'%+4*%5 !"#$%&'"( $$$$$$$$$$$$$$$$$)*+,- $$$$$$$$$$$$$$$$$.*)/- $$$$$$$$$$$$$$$$$0*12) '''''''''''''''!"#$%& !34'5 $$$$$$$$$$$$$$$$$$$$$6 $$$$$$$$$$$$$$$$$$$$-., $$$$$$$$$$$$$$$$$$$$$6 ''''''''''''''''''''!($ %#"'( $$$$$$$$$$$$$$$$$$$$$$0, $$$$$$$$$$$$$$$$$$$$$$-0 $$$$$$$$$$$$$$$$$$$$$$-) '''''''''''''''''''''')% 7#3'(8'& $$$$$$$$$$$$$$$$$$$$$6 $$$$$$$$$$$$$$$$$$$$$6 $$$$$$$$$$$$$$$$$$$$$6 '''''''''''''''''''''* 9':$!;$<&'(4'& $$$$$$$$$$$$$$$$$$$$).1 $$$$$$$$$$$$$$$$$$$$-.) $$$$$$$$$$$$$$$$$$$$$$=, ''''''''''''''''''''&$" >&'83'& $$$$$$$$$$$$$$$$$$$$-,. $$$$$$$$$$$$$$$$$$$$$$$$ 0 $$$$$$$$$$$$$$$$$$$$$$-2 ''''''''''''''''''''+"& ?44$!;$@#A'(5 $$$$$$$$$$$$$$$$$$$$2./ $$$$$$$$$$$$$$$$$$$$$$+) $$$$$$$$$$$$$$$$$-*-=2 '''''''''''''''''!#$,, $$$$$$$$$$$$$$$$$0*2-0 $$$$$$$$$$$$$$$$$.*2./ $$$$$$$$$$$$$$$$$+*0++ '''''''''''''''!%#)!) Given that several of these authors have indicated that mangrove cover has been increasing over time across a study period from roughly 1978 to 2003, it is possible that the increases in coverage we estimated is simply a continuation of that upward trend over the roughly 10+ years since prior estimates were made. The most dramatic increases we noted were in Abu Dhabi, where significant restoration plantings have been undertaken since the 1990’s (Ministry of Environment and Water 2010). Similarly, the success of

8 the mangrove plantings at Ras Al Khor by the municipality of Dubai reflects a significant increase from no prior documented mangrove areas (FAO 1978), to roughly 60 ha mapped by the present effort (Table 1). Finally, variation between current and prior estimates may stem from differences in mapping approaches, minimum size requirement for inclusion, and the potential for including salt marsh and other halophyte communities along with mangrove. For example, often we found pneumatophores from black mangrove extending considerable distance into mud flats and sands beyond the drip edge of the canopy during field verification. When we were able, we mapped these aerial roots as part of the mangrove area coverage estimate, but these structures would be impossible to see in aerial imagery at even the finest scale. The results presented here, while comprehensive in geographic scope, remain as a preliminary mapping assessment. A finer-scale mapping effort is warranted to revise and improve mapping estimate over such a large and discontinuous geographic area. Additional interaction and data sharing with local authorities would also be of great benefit to improve overall estimate accuracy.

It was not surprising to find that Abu Dhabi contained the most total area of mangrove regardless of stand density, given it represents approximately 86% of the total land area of the UAE and longest extent of suitable coastal habitat (est. 495 km, excluding the offshore islands). We did not note mangrove in Fujairah, despite historic reference to some 500 ha noted by FAO (2005), although Sharjah’s discontinuous territory along the Sea of Oman may have been accidentally included in estimates for the surrounding Emirate of Fujairah. There was a general trend between total land area and mangrove area as suggested by Figure 4. However, Figure 5 represents a different perspective from a resource management point of view, illustrating total mangrove area as a function of the length of coastline for each Emirate. Umm Al Quwain has ten fold fewer kilometers of coastline (44 km) than Abu Dhabi (495 km). Yet Umm Al Quwain has considerably more mangrove area per linear kilometer of coastline, roughly double that of Abu Dhabi and three or more times more than the remaining Emirates (Figure 5).

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Figure 3: National maps of mangrove area estimates from 2011-2012. (Image source: Bing Maps) Additional maps for each Emirate are included in Appendix A, Figures A1-A7.

Figures 4 and 5: Comparison of total mangrove area by Emirate (left) versus total mangrove as a function of shoreline length by Emirate (right).

10 Stand Characteristics Three basic mangrove habitat types were observed throughout the UAE: basin, fringe, and overwash (Figure 6-8). Basin type habitats occur in the interior of larger mangrove stands and often remain flooded for extended periods (Figure 6). Basin habitats were observed in all but two Emirates (Ajman and Fujairah), while the basin formation in Dubai is marginal. Basin habitats were characterized by intermediate stand height (3.0±0.5 m) and moderate to high percent cover (67.9±9.1 %) as illustrated in Figures 9 and 10, respectively. Height and cover were not significantly different from fringe habitats, but were different from overwash habitats (p<0.001). Fringe habitats were present in all Emirates. These common habitats were characterized as the coastal edge of the mangrove where relatively tall, mature trees form a continuous linear band of forest that became flooded on daily high tides (Figure 7). Fringe habitats also included shrub and immature trees forming the same linear band and were differentiated by overwash by their more elevated position in the tidal regime. Overall, fringe habitats possessed the tallest plants (3.9±0.9 m) and were generally taller than basin. Fringe mangrove was slightly less dense (63.2±6.1 %) than basin overall, likely due to our combining dense tree-dominated with less dense shrub-dominated fringe habitats. Nonetheless, fringe habitats were significantly taller, and more dense, than overwash habitats (Figures 9 and 10). Finally, overwash habitats were observed primarily in Abu Dhabi, but were also noted in Sharjah (Khor Kalba), Umm Al Quwain, and . Overwash habitats were the shortest and least dense habitats, with a mean height of 1.5±.04 m and a percent cover of 28.7±15.9 %. These habitats are the most exposed and regularly flooded, with stands often comprised of particularly few trees (Figure 8). Some stands appeared as new colonizers, while others may have been relics of larger stands damaged by coastal storms or other impacts.

Figure 6: Examples of basin habitat within the interior of a mangrove island in Umm Al Quwain.

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Figure 7: Example of a mature fringe forest in Abu Dhabi.

Figure 8: Example of an exposed overwash habitat along the western coast of Abu Dhabi.

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Figures 9 and 10: Comparison of mean stand height (left) and percent cover (right) for mangroves by habitat category (basin, fringe and overwash). Pore Water Chemistry Pore water chemistry revealed several interesting relationships by habitat type, differing somewhat from the patterns observed for stand height and percent cover. Surface water salinity (41.4±1.3 ppt) was significantly lower than pore water salinity at both depths sampled (46.1±1.1 ppt; 47.5±1.1 ppt), presumably reflecting accumulation of salt in the rhizosphere. When pore water salinity was sorted by habitat type, the substrate in overwash habitats was significantly more saline (52±2.0 ppt) than basin (45.4±1.9 ppt) or fringe habitats (45.6±1.4 ppt); However this particularly high value was obtained from a comparatively lower sampling size. Comparison of salinity by habitat type is shown in Figure 11, while Figure 12 illustrates salt excretion and accumulation on leaves of A. marina from an overwash stand from the west coast of Abu Dhabi. The extreme conditions, and potential salt stress that may be inferred from the salinity values noted, may contribute to the short stature of plants persisting in overwash habitats.

Figures 11 and 12: Salinity by habitat type revealing significantly higher pore water values in exposed overwash habitats (left) and accumulation of salts on abaxial leaf surfaces of Avicennia marina.

13 Despite mangrove’s high tolerance of sulfide and axoxia, accumulation of sulfides in sediment affect growth, stature, and survivorship of mangroves. Significant differences were noted in pore water sulfide concentration between each of the three habitat types examined (Figure 13). Basin mangroves had the highest pore water sulfide concentrations (0.84±0.3 mM). In fact, basin habitats are often flooded for extended periods due to the relative elevation and locations within the interior of larger mangrove stands, thus typically accumulate higher sulfides due to dense peat and clay soils and the lack of regular tidal flushing. However, the concentrations noted here are not particularly high compared to mangrove elsewhere which can have values of 5 mM or higher (Moore 1997, Layman et al 2006). While differences between habitats were not significant for redox potential, basin habitats did possess the most negative redox values (-287±70 mV) (Figure 14). In contrast, overwash habitats had the lowest sulfide concentrations, (virtually zero at a mean value of 0.1±0.08). These results are likely due to the exposed nature of these habitats, the sandy substrate they occur in, and their regular daily flushing with oxygen rich ocean water.

Figures 13 and 14: Significant differences in sulfides between habitats (left) and range of Eh (right).

14 Synthesis and Conclusions Three main conclusions that have management implications can be drawn from the data collected to date. First, despite considerable land development and ecological change throughout the country over the last 10-20 years, the areal extent of mangrove appears to have increased overall as compared to all prior published studies. Moreover, this study has documented that viable mangrove communities exist in six of the seven Emirates, however disparate their size and ecological complexity. In fact, the study noted that while Abu Dhabi has the most total mangrove acreage, several of the smaller Emirates had surprisingly high mangrove area relative to their available habitat (i.e. length of shoreline). The significant increase in newly estimated areas may stem from differences in image/data quality available today, mapping approaches, and the geographic extent of the study. Closer examination of the data illustrate that while overall, the UAE gained mangrove area over the last 10+ years, losses were noted at sites within several of the Emirates, likely due to land use changes, development, or other impacts. The results of the current study, while preliminary, are based upon the most up to date aerial images and provide a basis for additional mapping and evaluation of both current conditions, but re- examination of historic mangrove estimates in key areas as well. Therefore, we propose that the Ministry consider funding a finer-scale mapping effort to better understand and document the specifics of losses and gains in mangrove area estimates to more accurately represent the UAE’s mangrove resources within a context of local, national, and international science and conservation needs.

Second, mapping the country-wide extent of mangrove resource gains and losses establishes the most up-to-date foundation to base current and future conservation, restoration and management strategies for the country. The current inventory, particularly when combined with more comprehensive ground truth and field data collection, presents an ideal opportunity to establish a rigorous monitoring program for mangroves in key locations throughout the country. While valuable, maps alone only document the results of ecological change (i.e. forest gain or loss), but provide little information on causes, contributing factors, or opportunities for adaptive management. Field data are critical to explaining past change, tracking the trajectory of current change, and exploring the factors that affect these processes into the future. We suggest the Ministry consider funding the development and implementation of a mangrove- monitoring program within selected, representative areas. Such a program may include parameters such as precise measured survey of forest boundaries and surface elevations, stand height and density measures, tidal range, and a suite of edaphic factors known to

15 influence mangrove establishment, maintenance and sustainability. Employing standard methods at each of several monitoring sites, the program could be used to train Ministry Staff or other scientists to track mangrove change over both spatial and temporal scales and provide the data needed to guide management and long term resource conservation.

Finally, the large, contiguous mangrove system in Umm Al Quwain may represent one of the most ecologically diverse of the UAE that is presently not a designated protected area. Thus complex system includes examples of basin, fringe and overwash mangrove habitats as well as extensive seagrass beds and several live coral reefs. Its unique barrier beach provides natural protection that has helped establish and maintain the various habitats within the embayment interior and further benefits from lack of large-scale development of the shoreline and nearshore waters. Although some coastal development is occurring in the general area, much of the system appears to be relatively pristine. This extensive and diverse ecosystem may well be an excellent candidate for establishment of a Marine Protected Area (MPA). In addition to communicating the ecological value of a site, MPA designation facilitates conservation through the development of short and long-term planning as well as research and monitoring to protect the coastal resources it contains.

16 Literature Cited Abo El-Nil, M.M. 2001. Growth and establishment of mangrove (Avicennia marina) on the coastlines of Kuwait. Wetland Ecology and Management 9: 421-428. Al Abdessalaam, T.Z. 2007. Coastal and marine habitats. In: Marine Resources and Environments of Abu Dhabi (2007) T.Z. Al Abdessalaam (ed) Environment Agency – Abu Dhabi (EAD), United Arab Emirates. pp. 255. Althausen, J.D., Kendal, C.G.ST.C., Lakshmi, V., Alsharhan, A.S., and G.L. Whittle. Using satellite imagery and GIS in the mapping of coastal landscapes in arid environment: Khor Al Bazam, Western Abu Dhabi, United Arab Emirates. 2003. In Desertification in the Third Millennium. A.S. Alsharha, W.W. Wood, A.S. Goudie, A. Fowler and E.M. Abdellatif (eds) 2003. A.A. Balkema/Swets & Zeitlinger, Rotterdam, The Netherlands, p.443-449. Blasco, F., Carayon, J.L. and M. Aizpuru. 2001. World mangrove resources. Glomis Electronic Journal 1(2): 1-3. Cline, J. D. 1969. Spectrophotometric determination of hydrogen sulfide in natural waters. Limnology and Oceanography 14:454-458. Dahdouh-Guebas, F. 2002. The use of remote sensing and GIS in the sustainable management of tropical coastal ecosystems. Environment, Development and Sustainability 4:93-112. Dodd, R.S., Blasco, F., Rafi, Z.A. and E. Torquebiau. 1999. Mangroves of the United Arab Emirates: ecotypic diversity in cuticular waxes at the bioclimatic extreme. Aquatic Botany 63: 291-304. Duke N.C., Ball M.C., and J.C. Ellison. 1998. Factors influencing biodiversity and distributional gradients in mangroves. Global Ecological Biogeography Letters 7: 27– 47. Ellison, A.M, and E.J. Farnsworth. 1996. Anthropogenic Disturbance of Caribbean Mangrove Ecosystems: Past Impacts, Present Trends, and Future Predictions. Biotropica. 28(4): 549-565. Embabi, N.S. 1993. Environmental aspects of geographic distribution of mangrove in the United Arab Emirates. In: Leith, H. and A. Al Masoom (eds.), Towards the Rational Use of High Salinity Tolerant Plants, Volume 1. Dordrecht, The Netherlands: Kluwer Academic Publishers. Pp. 45-58. FAO. 2005. Global forest resources assessment 2005: Thematic study on mangroves United Arab Emirates country profile. Food and Agriculture Organization of the United Nations, Rome.

17 FAO. 2007. The world's mangroves, 1980-2005 : A thematic study in the framework of the Global Forest Resources Assessment 2005 Food and Agriculture Organization of the United Nations, Rome. Grizzle, R.E., Moore, G.E. and J.A. Burt. 2011. Mapping coral and mangrove habitats in the United Arab Emirates. Report to the Ministry of Environment and Water. 22pp. Held, A., Ticehurst, C., Lymburner, L., and N. Williams. 2003. High resolution mapping of tropical mangrove ecosystems using hyperspectral and radar remote sensing. International Journal of Remote Sensing 24(13): 2739-2759. Howari, F.M., Jordan, B.R., Bouchouche, N., and S. Wyllie-Echeverria. 2009. Field and remote sensing assessment of mangrove forests and seagrass beds in the Northwest part of the United Arab Emirates. Journal of Coastal Research 25(1): 48-56. IPCC. 2007. Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (Eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Krause, G. 2004. Mapping land cover and mangrove structures with remote sensing techniques: a contribution to a synoptic GIS in support of coastal management in northern Brazil. Environmental Management 34(3):429-440. Layman, C., Moore, G., Dalhgren, C., and P. Kramer. 2006. Grenada and Grenadines wetland assessment. Technical Report prepared for The Nature Conservancy, Eastern Caribbean Program, St. Croix. 40pp. Loughland, R.A., Saenger, P. Luker, G., Siddiqui, K. Saji, B., Belt, M., and K. Crawford. 2007. Changes in the coastal zone of Abu Dhabi determined using satellite images (1972-2003). Aquatic Ecosystem Health and Management 10(3): 301-308. Ministry of Environment and Water. 2010. Summary of mangroves of the United Arab Emriates. http://uaeagricent.moew.gov.ae/Fisheries/Impmangrove_e.stm. Moore, G.E. 1997. Effect of soil hydrogen sulfide on growth and survivorship of transplanted Rhizophora mangle and Avicennia germinans under varying substrate types and environmental conditions in the Bahamas. Master’s Thesis, Boston University Department of Biology. Moore, G.E., B.F. Gilmer and S.R. Schill. In Press. Mangrove resources of Grenada and the Grenadines. Journal of Coastal Research. Polidoro, B., Carpenter, K., Collins, L., Duke, N., Ellison, A., Ellison, J., Farnsworth, E., Fernando, E., Kathiresan, K., Koedam, N., Livingstone, S., Miyagi, T., Moore, G., Nam, V., Ong, J., Primavera, J., Salmo, S., Sanciangco, J., Sukardjo, S., Wang, Y., and J. Yong. 2010. The Loss of Species: Mangrove Extinction Risk and Failure of Critical Ecosystem Services. Public Library of Science One 5(4): 1-10.

18 Portnoy, J.W. and I. Valiela. 1997. Short-term effects of salinity reduction and drainage on salt-marsh biogeochemical cycling and Spartina (cordgrass) production. Estuaries 20:569–578. Ramirez-Garcia, P., Lopez-Blanco, J. et al. 1998. Mangrove vegetation assessment in the Santiago River Mouth, Mexico, by means of supervised classification using Landsat TM imagery. Forest Ecology and Management 105:217-229. Saenger, P. 1997. Biogeography of mangrove species. In: Spaulding, M., Field, C., Blasco, F. (eds), The World Atlas of Mangroves. Samara Publishers, Cambridge. Saenger, P., Blasco, F., Yousseff, A.M.M., and R.A. Loughland. 2004. Mangroves of the United Arab Emirates with particular emphasis on those of Abu Dhabi Emirate, In: Loughland, R.A., Al Muhairi, F.S., Fadel, S.S., Al Mehdi, A.M. and P. Hellyer (eds), Marine Atlas of Abu Dhabi, Emirates Heritage Club, Abu Dhabi. pp. 58-69. Shalom-Gordon, N., and N. Dubinsky. 1993. Diurnal pattern of salt secretion in leaves of black mangrove (Avicennia marina) on the Sinai coast of the Red Sea. Pacific Science 47: 51-58. UNEP/UNESCO. 1992. Report of the First Meeting of the UNEP/UNESCO Task Team on the Impact of Expected Climatic Change on Mangroves. Rio de Janeiro, 1-3 June 1992. UNEP/UN-ESCO Paris, 31pp.

19 Appendix A

Figure A1: Mangrove area estimates for Abu Dhabi 2011-2013. Figure A2: Mangrove area estimates for Ajman 2011-2013. Figure A3: Mangrove area estimates for Dubai 2011-2013. Figure A4: Mangrove area estimates for Ras Al Khaimah 2011-2013. Figure A5: Mangrove area estimates for Sharjah (Arabian Gulf) 2011-2013. Figure A6: Mangrove area estimates for Sharjah (Sea of Oman) 2011-2013. Figure A7: Mangrove area estimates for Umm Al Quwain 2011-2013.

20 Figure A1: Mangrove area estimates for Abu Dhabi for 2011-2013.

Figure A2: Mangrove area estimates for Ajman for 2011-2013. Figure A3: Mangrove area estimates for Dubai for 2011-2013.

Figure A4: Mangrove area estimates for Ras Al Khaimah for 2011-2013.

Figure A5: Mangrove area estimates for Sharjah along the Arabian Gulf for 2011-2013.

Figure A6: Mangrove area estimates for Sharjah (Khor Kalba) along the Sea of Oman for 2011-2013. Figure A7: Mangrove area estimates for Umm Al Quwain for 2011-2013.