Gazelle March 2002

• Where to find us
• Jebel Ghaweel Hike
• Snakes: Cause for concern?
• Beware! Alien Invaders!
• Spiny-tail Lizards suffering from lack of rain
• Tahr on Jebel Hafit

The DNHG's monthly lectures are now held at The Emirates Academy of Hospitality Management, located opposite "Wild Wadi" near the Burj Al-Arab and the Jumeirah Beach Hotel. The Emirates Academy features a 140-seat auditorium, excellent acoustics and a built-in audio-visual system.

The auditorium is adjacent to the main entrance, on the Beach Road side. The Academy facade resembles an Arabic fortress, with four flags flying at the front gate. These are normally illuminated at night. The complex is visible from Beach Road but is set back about 100 yards from the road and is now partly obscured by construction. Direct access is currently over an open lot; for easiest access, it is best to follow the map on page 7. There is a paved parking lot within the gates.

For those coming via Sheikh Zayed Road/Abu Dhabi Highway, the best exit is flyover #4 (Al-Barsha/Dubai Police Academy).

Members who are coming to lectures directly from work may find it convenient to take advantage of the cafeteria located on the Emirates Academy premises, on the left of the outdoor courtyard behind the main lobby. Non-members are always welcome at the monthly lectures, too. Just come along. The lecture starts promptly at 8.00pm, so if you'd like to eat or chat first, come well before then.

Jebel Ghaweel is a three-peaked ridge on the mountain front east of Al-Hayer, distinctive by virtue of its summit cap of white limestone, an "exotic" block, probably a former atoll that was carried along atop the deep ocean sediments and volcanics that were bulldozed and deformed ahead of the advancing ophiolite. The triple summits are the Hajar Mountain's answer to Italy's Dolomites, complete with sheer faces and craggy spires. The summit profile is daunting and, looking up, it was hard to believe what we were going to do.

As advertised, highlights included unusual rocks and plants. On the way up we stopped to look at turbidites (deep ocean sediments deposited from turbidity currents and having a graded structure), as well as volcanic rocks identifiable by their many tiny air pockets (vesicles) filled by later stage white minerals, and, near the summit, yellow-green veins of chlorite, many of which seem to have been the site of fracturing and movement within the deformed rocks. We also saw a number of dwarf rock geckoes, Pristurus rupestris and the larger P. celerrimus, which signal with their tails. As usual, about half of these seemed to have lost and regrown their original tails.

The environment was very dry, but not devoid of botanical interest. Special attractions included the wild olive, found only at higher elevations, the sidr tree (Zizyphus spina-cristi) in fruit (but undesirably astringent, was the gastronomic verdict) as well as several of the region's hanging or climbing plants. The cliff-dwelling Capparis cartinagenia is related to the edible caper. Another prominent cliff plant, Cocculus pendulus, sported small berries. Richard Dennis was game to sample them, but Gary Feulner suggested otherwise, given that the species belongs to the curare family. The climbing milkweed Pentatropis nivalis had found its way into a small Moringa (broom tree) whereas the leafless climber Ephedra aphylla was mostly seen on Jebel Ghaweel as an erect shrub, and was found climbing into only one small Desert Thorn (Lycium shawii). We saw no goats at all, and the presence of a number of larger Desert Thorn shrubs indicates that grazing pressure may have been reduced for the past few years.

Despite the drought, we found a number of specialized plant species in flower from time to time, in favorable locations, including a thriving Euphorbia larica (the "donkey-sat-on-it" bush) and the cactus-like Caralluma arabica. Moriga peregrina, the broom tree, was in full bloom at lower elevations and Martina Fella spied a pair of Purple Sunbirds feeding on the nectar in one large tree, perhaps preparing to nest. Other bird life included a few sand partridges, Hume's wheatear in song, and, at the summit, a pale crag martin surfing enviably on the updrafts and a Bonelli's eagle soaring overhead. Encouraged by Gary, Martina also spotted the first of many of the rare bullet-shaped striped land snails, Pseudonapaeus jousseaumei, found in the wild only at higher elevations in the Hajar range and the Jebel Akhdar in Oman.

Lunch was served at the summit by Martina, in true Emirates in-flight style, but we all wondered how she had managed to pack so much junk food – sausage, potato chips, candies, even Hostess twinkies -- into such a small backpack. Mike Lorrigan, for his part, served sandwiches all around, prepared in a burst of early morning Boy Scout zeal. The lunch site gave a marvelous view of the surrounding countryside, from Jebel Hatta and the Hajar range to Buraimi to the south and the desert to the west, and showed off other, smaller hills capped by similar white exotic blocks.

After summiting, we walked the summit ridge to the east end and looked back. It appeared so rugged and difficult, we could hardly believe we had been there. So, as a special treat for this strong hiking group (Martina was hiking in boots with soles taped on enroute by Richard's emergency repair tape), the decision was made to descend via a "new" route down a wadi that cut through several vertical limestone ridges. There were some second thoughts as the chute narrowed and steepened, but these passed after we saw several small cairns indicating that this had once been an "established" route. The route was in need of resurfacing, however, and we worked our way down carefully over slopes covered with bits and blocks of broken limestone. David Palmer said afterwards that he felt like he had been skiing.

We returned to the cars, about nine hours and many rolls of film after we had left them, and looked back up at the jagged skyline, now silhouetted by the dying sun. We still couldn't believe we had done "that."

Most people are more afraid of snakes than weapons or other people. This is understandable as certain snakes are venomous and can cause fatalities, but the probability of being fatally bitten by a snake is low. The following table was published in the New Scientist of 3 March 2001 and indicates potential cause of human death and the probability of being affected.

[Now of course everything is relative, for instance, if you find yourself unlucky enough to be in Angola the probability of being blown up by a landmine would be quite high]

Twenty-one species of snakes belonging to 6 families occur (including offshore) in the UAE. Of these, only four terrestrial species (Family Viperidae - True Vipers) and eight marine species (Family Hydrophiidae) are potentially dangerous.

Of the four Viper species found in the UAE the Saw-scaled Viper (Echis carinatus) is potentially the most dangerous with case fatalities reported as 5-10% in hospitalized cases. Saw-scaled Viper venom is haemotoxic or vasculotoxic causing local pain and swelling and widespread bleeding. Carpet Viper (Echis coloratus) and Sand Viper (Cerastes cerastes) venom is potentially dangerous although symptoms are less severe than for the Saw-scaled Viper and fatalities are rare. Very little is known about the False-horned Viper (Pseudocerastes persicus), a potentially dangerous snake of high altitudes, but rarely encountered. Sea snake bites are not painful and 50% of bites do not result in envenoming. The venom is neurotoxic and results in muscle paralysis.

Bites of the rear-fanged Colubrids, mildly toxic and/or harmless snakes, may occasionally result in envenoming with pain and local swelling being common. As a general rule-of-thumb in the UAE, snakes, which are long and slender, are harmless while short and stocky snakes are potentially dangerous.

Evacuation of the unfortunate person to the nearest hospital or clinic (most large hospitals and clinics have anti-venom) is advisable, especially if bitten by a potentially dangerous or unidentified snake. A pressure bandage (splint limb if possible) should be wrapped around the bitten limb and mobility restricted where possible resulting in delaying the absorption of venom. Fortunately bites of venomous snakes encountered in the UAE rarely develop irreversible life-threatening situations within six hours.

Snakes are extremely beautiful and interesting creatures certainly not out to "get" humans or afflicted with the devil. In fact most snakes I have encountered are passive and only strike or try and defend themselves when actively harassed. In all cases the snakes have always tried to escape before attempting to defend themselves. Inflating the body and rubbing the scales on the flanks together causes the early warning rasping sound used by Saw-scaled Vipers. An interesting theory exists that this warning sound has evolved in an arid environment instead of hissing, which results in the loss of water vapor. A quote by an anonymous source I came across recently sums it up: " We only conserve what we love. We only love what we know. We only know what we are taught."

Non-native or alien species can and do cause considerable damage to the host environment they find themselves in, usually at the expense of native wildlife. It was pointed out recently at the United Nations Biodiversity Convention in Montreal, Canada, that alien species are the second biggest threat to indigenous wild species after habitat loss. Alien species often out-compete native species for resources, introduce diseases or inter-breed resulting in a loss of species diversity and a general loss of biodiversity.

The UAE has its fair share of alien species and related problems. These range from donkeys, archaic transport, to unwanted pets released into the wild by "caring" owners such as Mollies (ornamental fish). Feral donkeys compete directly with the declining Gazelle and Tahr for grazing, which is often marginal, in mountainous areas. Feral cats and dogs also account for a substantial loss of native birds, reptiles and small mammals and is arguably not too difficult to control as other problem species.

According to the UNEP (United Nations Environment Programme) alien fish species threaten 20% of the world's freshwater fish with extinction. Locally the predatory fish, Tilapia (Oreochromis spp.), have been released as a source of food in local Wadi systems to the detriment of indigenous species such as the Arabian Killifish (Aphanius dispar), a predator of mosquito larvae.

Birds such as the Myna's of which 3-4 species are breeding residents to the Emirates, Masked, Streaked & Golden-backed Weavers, Scaly-breasted Munia, Red Avadavit and Pin-tailed Whydah, to mention but a few, often out-compete native species for food, nesting material and nesting space. Recently the beautiful and vocal Indian ring-necked parakeet has been cited as a source of influenza A viruses liable to infect chickens, mice and ultimately humans. Bird flu has caused recent human fatalities in Hong Kong (1999) and China (2000). The deadly Spanish flu epidemic in 1918 resulted in the death of 40 million people world-wide. Other flu epidemics in 1957 and 1968 killed over a million people. Unwanted pet birds should not be released into the wild so as to avoid above-mentioned disasters.

Fifteen species of introduced ants (20% of all ant species recorded in the UAE) have been recorded from the Emirates with 3 species posing potential problems as public health and nuisance pests while 2 species threaten the local entomo-fauna and biodiversity. In the southern USA an alien ant species was so successful that it almost entirely out-competed the local ant fauna and altered the local insect diversity. Controlling ants and other alien arthropods is also very difficult, time consuming and expensive.

Exotic trees such as Eucalyptus (Blue-gum spp.) generally use more water than indigenous species while exotic Prosopis spp. have the potential of invading marginal areas and ousting local flora, which is evident (in its initial phase) in the RAK and Fujairah coastal areas.

Many countries don't often realize the threats posed by alien species and that they can be eradicated. Feral cats and rats (both of which prey heavily on birds) are 2 species that have been successfully eradicated from island off South Africa and New Zealand.

Authorities should implement better monitoring, quarantine and overall environmental control to prevent exotic species from becoming a problem. "Do-gooders" should also realise that releasing those unwanted pets may cause more damage than good when released into an unfamiliar environment. Pet shop owners and other importers of exotic wildlife as well as illegal trafficking in live and other animal products should be eradicated and strictly controlled by the relevant authorities so as to avoid the type of publicity such as was recently published in New Scientist (10 March 2001). "Indian ivory joins African ivory before it goes to Japan or China. The biggest smuggling route out of India is through the UAE, and African ivory always comes that way".

Spiny-tail Lizards suffering from lack of rain

Peter Cunningham has monitored twenty Spiny-tail Lizard individuals since May 1999 in the Al Ain area as part of his requirements for a Ph.D. study on the conservation ecology of the species that he is currently busy with. Since the start of the study no rain has fallen in the study area. This, coupled with a large number of camels in the area, has resulted in the visible decline of the desert vegetation. The coarse desert grass, Pennisetum divisum, which is a favored plant utilized by the Spiny-tail's, have been particularly badly affected. Between May 1999 and June 2000 11 individuals had succumbed indicating a 55% mortality rate over a 1-year period. In another study area where Moltkiopsis ciliata, of the Borage family, is the dominant plant, the Spiny-tail's are faring much better with no fatalities since January 2000. Moltkiopsis ciliata is closely cropped through active browsing by Spiny-tail's making it unavailable to camels. The Moltkiopsis area is a favoured habitat with a high density (±10 individuals per hectare) of Spiny-tail's in the area.

Very little work has been done on the diet of Spiny-tail Lizards throughout their range. During my current research, ten perennial plant species from 8 different families have been identified as being included in their diet. These include species from the Milkweed, Pea and Gourd family, to name but a few. Interestingly the Desert Squash, Citrullus colocynthis, is also eaten. It is expected that many more plant species, especially annuals, would be consumed once (if) the rains arrive.

Another interesting aspect is that the majority of burrows face in a southerly and easterly direction. During summer this makes sense as burrows facing in a northerly and westerly direction would be warmer and receive more windblown sand, as the prevailing wind is northwest during summer.

It has also been determined that the burrow temperatures are on average 6°C cooler than the ambient temperature 30cm below ground. This is significant when ambient temperatures are regularly in the mid-to-high 40°C during summer with soil temperatures above 60°C.

The author would welcome any other interesting data concerning Spiny-tail Lizards as observed by members. If any Spiny-tail Lizard road-kills are encountered please collect, freeze and inform Peter whereupon he will come and collect it.

Tahr on Jebel Hafit

During a hike up to the summit wadi's on Jebel Hafit during October I witnessed a rare event that made the unusual heat for this time of the year more bearable. An adult male Tahr emerged unexpectedly out of a gully approximately 100m ahead of me. Recognizing it immediately I knew how privileged I was to see this rare ungulate in its natural environment.

Arabian Tahr, Hemitragus jayakari, are endemic to the Arabian Peninsula and occur in mountainous terrain throughout the eastern UAE and northern Oman, from the Musandam in the north to the mountains bordering the Wahiba Sands in the south. The well-known Arabian explorer, Wilfred Thesiger, first documented them from Jebel Hafit in 1949 and mentions them being regularly hunted by local Bedu during that time. According to a study conducted on this species in Oman in the late 70's, the Arabian Tahr world population did not exceed 2000 animals. A helicopter survey of Jebel Hafit in 1980 sighted only 5 animals. During the 80's they were thought to be extinct on Jebel Hafit as no sightings were reported. Confirmed sightings are infrequent and they are classified as "critically endangered" (i.e. "facing an extremely high risk of extinction in the wild in the immediate future") in the UAE.

This little known species is in direct competition with domestic and feral goats for the available food. They are highly selective feeders mainly utilizing the growth tips and fruits of certain shrubs. The carrying capacity of mountains such as Jebel Hafit is generally low and the extra pressure of hunting (now illegal although not enforced) and excessive goat numbers could lead to the demise of this species in the wild if something drastic is not done to protect them.

The individual I encountered was typical of males of the species with its well-developed forequarters, prominent facial stripe, thick slightly curved horns and dark-brown shaggy coat [A previous sighting I had of a female in the Central Hajar Mountains had an overall slender build and "blonder" appearance]. Initially it was unaware of me as I had the wind in my favor and had approached the rise I was on with care. As soon as I moved to get my camera from my backpack it sensed me and loped off - not fleeing in fear - up the mountain towards some inaccessible cliffs where I could not follow. As I was not expecting to stumble upon Tahr, I was unprepared, but did eventually (after having to change lenses in haste) get two photos of the Tahr just before it disappeared over the crest. Unfortunately the distance involved as well as midday lighting did not make for a great photo and I am now trying to get the subject enlarged. Although not detracting from the actual encounter of observing Tahr at such close quarters, one thing I did however learn is to always be prepared for the unexpected - next time!