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Gazelle December 2000

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Contents:

Blue-tailed lizard drinking water
Backyard Terrarium
"Springtime" in Oman
Land Snails in Fox Droppings
Hajar Mountain Nature Hike
Clam shrimps found at Hatta, too
New Site for Rare Pond Snail
Shelling Report October/November 2000
Tahr on Jebel Hafit
Facts about Bats
Caralluma in Flower




Blue-tailed lizard drinking water

(Reptiles)
By Dr Reza Khan

We were out in Wadi Wurayyah earlier this year. We drove our 4WD vehicle up to the end of the wadi bottom track, past the waterfall. It was 9 in the morning when we started looking for signs of animals and noting the plant cover of the area around. Almost the entire vegetation cover of the area was dry barring a few Tephrosia, Gymnocarpus and Euphorbia larica. Reed and grass species grew along the wadi where there was water around. Dyerophytum indicum leaves had a full layer of wax and when we removed it the leaf appeared brittle.

Most of the wadi was dry except for the portions where the wadi had run deep through a very narrow gorge that is unapproachable from the topside of the wadi. At the end of the track there was a fairly big pool still receiving little water from a feebly flowing stream. There were several toads but no tadpoles and many wadi fish Garra barreimiae. There was also a swarm of whirligig beetles, diving beetles, dragonflies and larvae of both beetles and dragonflies. Many snails had accumulated on a mat of algae, partly submerged in the pool.

Close to the pool several pieces of small rocks remained misplaced due to the activities of humans or vehicular movements. Water seeped close to such stones. We saw a Blue-tailed lizard (Lacerta cyanura), a species endemic to the Hajar Mountains, walking by the side of the pool. It came close to one of the upturned stones, slowly went at its side where there was just a bit of water and seemed to sip! At this time I could go within a metre of the lizard. After a minute or so the lizard started moving away from the stone and literally ran from there to the steep side of the wadi and disappeared completely.

When we first saw the lizard we thought it was looking for insects. But this is not its usual haunt for searching food, as it prefers dry rocky areas. We followed it for over 10 minutes when it covered more than 5 metres before reaching the particular stone that had little water at its base.

The place from where it drank(!) water was shadowed. So, I could not be absolutely sure that it was sipping water. But the position I got in my picture reveals it was doing something that could be similar to drinking water. Also, the way it vanished from the site indicated that it did not come to the side of the pool looking for food. This may seem unremarkable, but it is common for arid region reptiles to satisfy all or most of their fluid needs from their food, without actually drinking. For example, there are no reported observations of mountain agamas or geckos drinking water.

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Backyard Terrarium

(Reptiles)
By Gary Feulner

Fascinated by an epidemic of amphisbaenids (legless lizards) in a neighbour's yard after recent rains, Christine Namour searched her own backyard and turned up not only an amphisbaenid, but also thread snakes (Leptotyphlops spp., true reptiles that look like spaghetti).

Under rocks, she found the small but very successful little snail Allopeas gracilis, which can also be found in grass and on the base of mossy trees. The shell of A. gracilis is a tall thin spiral typically from 0.5 to 1.0 cm long, and the aperture is U-shaped without any lip. Alive, the shell usually appears two-tone -- yellow in front and brown at the tip. The animal itself is pale yellow. A. gracilis is believed to be a native of the New World tropics but is now a cosmopolitan resident of the tropics and subtropics worldwide, due to dispersal by man and agriculture. It requires moisture, however, and is not found in the wild in the UAE.

Christine's garden pond, which filled up after recent rains, now sports a small population of dragonfly larvae, and adult dragonflies congregate in view of the back porch. She plans to keep the pond topped up and landscaped so she and the children can continue to watch the action, which has included good examples of mating, egg-laying and territorial behaviour.

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"Springtime" in Oman

(Insects) (Natural History)
Report by Gary Feulner

National Day weekend saw Gary Feulner and Geoff Cosson hiking to the top of the Saiq Plateau (2400m) in the eastern Jebel Akhdar, overlooking the Ghubrah Bowl (Wadi Mistal) between Nakhl and Rustaq. This area supports permanent springs where the relatively porous carbonate rocks of the plateau overlie impermeable older rocks. It also had healthy autumn rains this year.

This was reflected in a weekend count of 13 species of butterflies, including a Yellow Pansy and abundant Giant Skippers and Desert Orange Tips, both species rarely seen in the UAE.

The steep, north-facing slopes inside the bowl, where they are not vertical cliffs, support a veritable forest of trees such as wild olive or 'utm (Olea cf. europaea), nimt (Sageretia spiciflora), boot (Monotheca buxifolia) and others. They benefit, presumably, not only from subsurface water but also from the shade of the escarpment.

On top of the plateau the vegetation is much sparser but the views are grand for 360 degrees, one can see north to the coast and west all the way to the radar dome atop Jebel Shams. One floral constant at higher elevations was the bright yellow flowering Euryops pinifolius, a tall woody member of the daisy family.

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Land Snails in Fox Droppings

(Mammals)
Report by Gary Feulner

Examining the contents of one of a number of samples of Blanford's fox droppings he'd collected from various mountain sites around the UAE, Peter Cunningham was surprised to find no fewer than 8 small (5mm) land snail shells of three different species. Peter had never encountered this phenomenon before, nor had a European expert who was consulted.

The most likely explanation is that the fox had eaten a prey species or other food item that had run, fallen or been washed into a patch of soil and debris where the tiny shells had been washed and accumulated as flotsam, and that the fox had consumed the shells inadvertently. It is almost certainly not energy efficient for a fox to seek out and consume 5 mm snails. Alternative theories were not lacking, however. Shortly thereafter, Stephen Green found a small snail shell caught in a bit of hair from a dead goat and suggested impishly that the fox in question might have eaten a goat with snails attached.

Intriguing that the snail shells (made of calcium carbonate, CaC03) passed through the fox intact. This was unexpected since calcium carbonate dissolves readily in an acid environment like that of a mammalian digestive tract. Peter Cunningham suggests this may be due to the fox's short digestion time, implying a short residence time in the digestive tract for material consumed. But if the shells were not dissolved, could the snails themselves have survived if they had been ingested alive? And if so, is this a potentially unappreciated means of dispersal for land snails?

The episode also suggests a future for forensic malacology. It was possible to use the snail shells to identify the concerned fox dropping as having been collected in the Ru'us Al-Jibal (as confirmed by Peter's notes), since two of the three species are found only there and not further south in the UAE.

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Hajar Mountain Nature Hike

(Natural History)
Report by Gary Feulner with a little help from the editor of Gazelle

To our chairman's disappointment this nature hike was more hike than nature, because the scattered showers in September and October were not enough to make a great difference to the plant life in many areas. The plants may be dusted off, but most are not revived. The hiking area seemed to have received only a sprinkle of rain. One of the few plants seen in flower was the lavender, Lavandula subnuda, which follows a strategy of "firing" its row of buds one-at-a-time, so there's always a blossom - but often only one - on display. Another was a lone specimen of the wispy mountain morning glory, Convolvulus virgatus, perhaps fooled by the rain, which aimed three or four white, funnel-shaped flowers towards the sun.

At the start of the hike was a natural spring and pool which previous field trips have visited amidst lush vegetation of oleanders, wadi grass, reeds and rushes. Sadly, all this had been cut and burned to facilitate the construction of a concrete cistern, used as a water supply for new plantations, some two kilometres downstream. A few toads had survived the destruction, but apparently no wadi fish.

From their goal on the summit of Jebel Bulaydah, the group could see the surrounding area, including the Masafi, the Masafi-Fujairah Road and the plantations springing up along it, the white metamorphic rocks to the north, the profile of Jebel Masafi. On top of Jebel Bulaydah a lone dragonfly paid a visit, the pan-tropical Globe Skimmer (Pantala flavescens), a strong migrant.

From the ridge-top return route there were distant views of a group of four large, soaring raptors. At a guess, based on colour pattern, they were probably Booted Eagles.

To Gary's great surprise, one of the most popular photo opportunities seemed to be the mummy of a dead donkey, still resting its head on a grassy pillow.

This was a rigorous hike where the ascent seemed to go on for ever and the initial descent on loose skree was perhaps a lot faster than planned. It might have been easier to sit on a large cushion and slide down. Everyone enjoyed the day, and probably had the best night's sleep this year!

Special mention goes to Gary Feulner for ignoring the moans and groans behind him, Richard Dennis for the most spring in his step (with Alan Buck as a runner-up, at least downhill), Salah Al-Halyan for the best shortcuts, Paul Callaghan for the longest nap at lunch, Gaye Harden for the most stylish hat, and "Iron Mike" Lorrigan for best storytelling, with his recollections of DNHG field trips past.

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Clam shrimps found at Hatta, too

(Natural History)
Report by Gary Feulner

Molly McQuarrie of the ENHG in Abu Dhabi read our reports in the Gazelle about clam shrimps being found in mountain pools after recent rains in the mountains NE of Al-Ain. While showing off the Hatta area to visitors, Molly managed to find more clam shrimps in a small ephemeral pool in silt beside the main wadi, just below Hatta village. Although one may question Molly's judgment as a tour guide, this observation extends the known range of these organisms locally (it is the northernmost report) and renews the question whether the arrival of clam shrimps is recent, or whether observers have been missing them all these years. They were first reported from Jebel Hafeet in 1999.

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New Site for Rare Pond Snail

(Natural History)
Report by Gary Feulner

Bulinus wrighti is the rarest of the UAE's native freshwater snails. It represents a genus that may have originated in Arabia, although it is now centred in Africa. It has attracted particular attention because the genus is a potential host for schistosome parasites and B. wrighti itself is susceptible to most schistosome strains. As a result, it is used for medical research; specimens were collected for this purpose in September from one of two known sites in the northern Hajar Mountains.

Coincidentally, a third site was discovered in the Ru'us Al-Jibal only last month, in Wadi Naqab, just within the borders of the UAE, by a determined DNHG party consisting of Barbara Couldrey, Nick Hepher, Peter Cunningham and Gary Feulner. The site is a long pool carved in bedrock, more than 2 metres deep when full, but now reduced to a small gravel puddle the size of a drinking cup. Shells, but no live snails, were found.

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Shelling Report October/November 2000

(Marine Life)
Report by Dr. Sandy Fowler

Beryl and I checked out Rams beach on 27 October. It was in a terrible state. Garbage everywhere and almost no shells. Patricia and Robert Rosetti had the same experience the week before. We left in disgust after 2 hours.

I reported earlier taking a shell from a Khor Fakkan beach to the Natural History Museum in June this year. It was identified as Latirus turritus, not recorded before in UAE waters. I've found 3 more since, on the same beach, the latest on the DNHG field trip of 10 November 2000.

For the Field Trip 10 November, a good turnout of shelling stalwarts turned up at the beach north of Khor Fakkan, with an unlucky twosome undeterred by a puncture in Masafi. Weather conditions, a perfect tide and a good mix of shells should have let everyone collect at least 50 different species. I was lucky enough to find a specimen of Volva volva previously unrecorded in Eastern Arabia. With both ends of a beach to check out, the group quickly fragmented, and I wasn't able to check everyone's finds individually. If anyone wants help with identification, call me at home and I'll be glad to help if I can.

I checked out Hamriya beach this month. It's an easy 45-minute drive from Dubai. There was a good mix of shells (I identified about 40 separate species), and I was fascinated to see Terebralia embedded in rocks below the high water mark. Is this why we're still finding them on the beaches? Are they truly extinct within the Gulf? The hunt for live ones goes on!

One or two people have been asking for another shell workshop, where interested shellers can get together at my home, compare finds, and maybe get those stubborn shells identified. I provisionally hope to hold one in early spring. If you are interested call me and put your name down for it; I'll contact you when a date is fixed.

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Tahr on Jebel Hafit

(Mammals)
Report by Peter Cunningham

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" in the UAE (i.e. "facing an extremely high risk of extinction in the wild in the immediate future").

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 favour, 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!

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Facts about Bats

(Mammals)
Report by Peter Cunningham

Did you know:

  • Nearly 1000 kinds of bats account for almost a quarter of all mammal species and most are highly beneficial.
  • A single bat can catch up to 600 mosquitoes in just 1 hour.
  • Agricultural plants such as bananas, mangoes, dates and certain figs rely on bats for pollination and seed dispersal.
  • Bat droppings in caves support whole ecosystems of unique organisms.
  • Contrary to popular belief, bats are not blind, do not become entangled in human hair, bite only in self-defence, and seldom transmit disease to other animals.
  • Bats are exceptionally vulnerable to extinction, in part because they are the slowest reproducing mammals on earth for their size with most producing only one young per year.
  • Only one species of "vampire bat" occurs in south and Central America and does not suck blood, but makes an incision and then laps up the blood.
  • Very little scientific work has been conducted on bats from the UAE with only 8 species ever recorded although it is suspected that many more may occur.

I am busy doing some work on bat distribution in the UAE and would appreciate information regarding the following:

  • Bat roosts (i.e. caves/crevasses/ceilings, etc.)
  • Bat gatherings (i.e. frequently used feeding areas or where seen often)
  • Bat records (i.e. 16 Mouse-tailed Bats seen roosting at Abool Fort on 15 March 1999, etc.)

Any information regarding bats from the UAE & neighbouring Oman areas could be useful. Any dead specimens and sculls, etc. could also be used for identification purposes.

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Caralluma in Flower

(Botany)

With few exceptions, the showers that fell around the UAE in September, October and early November have so far made little visible difference to the parched landscape. It's nice to report, therefore, that at least a few Caralluma arabica have been seen in flower, in the east (by Geoff Cosson) and west (by Barbara Couldrey) of the Ru'us Al-Jibal. C. arabica is a succulent, leafless milkweed that is easily mistaken for a cactus. The inflorescence is a globular head of many small, deep wine-red flowers which are said to smell like rotting meat.

A second Caralluma species with yellow flowers is found occasionally in the area to the SW of Fujairah. There are no true cactuses native to the Old World, but the prickly pear cactus (Opuntia sp.)

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Patron: H.E. Sheikh Nahayan bin Mubarak Al Nahayan