Bulletin 33 - November 1987: Botany Field Trip to Ghayl - 1st May 1987

Botany Field Trip to Ghayl - 1^st May 1987

Ten members of the ENHG drove out to the Ghayl junction on the Ras al Khaimah to Manama road on Thursday, 30^th April and set up camp in an area of gravel and sand surrounded by low craggy hills. Despite the heat and the constraints of Ramadan to fieldwork, there was sufficient light for a quick investigation of the area before settling down for a meal and the evening. The several first time campers were fortunately not over-discouraged by the odd camel spider dashing around the small wood fire. The evening was dry and clear and for an hour or so after dusk it was possible to sight several satellites bouncing their way across the stars, occasionally mistaken for aircraft flying into and out of Dubai.

The spring of 1987 had surpassed the last good rainy season in quantity (1983), and it was hoped that annuals in particular would be prolific. Hence there was a mood of anticipation as we set off early to explore the area as thoroughly as possible before the sun climbed too high. We estimated three to four hours comfortable walking and recording.

The campsite was located at approximately 25°47’N and 56°02’E, in the foothills of the Hajjar range, a region strongly influenced by the sands of the central plains as these abutted on to the hills to the east. In order to cover as much different terrain as possible, it was decided to look at four separate but adjoining areas:

1                    the immediate vicinity of the camp site

2                    the edge of the plain below and to the north

3                    the low hillocks surrounding the camp

4                    the higher hills and dunes to the south

No attempt was made to assess relative numbers, only to record species present and a subjective calculation of relative abundance. The majority of the group was unfamiliar with the common plant names and part of the exercise was to familiarize people with some of the more recognizable plants. There are repetitions in the checklists but these serve to indicate the varying habitats of some species. The checklists are in alphabetical order by family.

The Immediate Vicinity of the Camp

The campsite was at approximately 225 m elevation about five kilometers from the Ghayl-Manama junction and a few hundred meters to the north of the road. Despite the encroaching hills, we found a fairly level patch of mixed orange sand and gravel, giving the soil a coarse appearance. Most plants constituted low ground cover only, apart from a lone acacia tree, well-nibbled, which nevertheless stood some 4 m high. Most of the flowering and/or fruiting species were fairly easily identified but some of the grasses and a few other species were lacking flower or fruit or were too immature, or too old to recognize. Ground cover of annuals was thick, though many plants, up to about 75% of some species, were very young and from their desiccated appearance were already drying out before maturity and it was felt unlikely to set seed.

The Plain

The undulating plain to the north is not extensive and surrounded by ragged hills. Shallow but intricate dry wadi systems dissect the whole area, and these were lined with acacia and associated undergrowth, including the symbiotic Chenopodium murale (a common weed of inhabited areas), Lycium shawii, Pergularia tomentosa and various grasses. Between wadis the soil is frequently black with a thin vegetation cover, mainly annual grasses (notably Poa annua), though the odd Crotalaria aegyptiaca shrub was noticeable with its bright yellow blooms.

The Hills Surrounding the Camp

Botanically this was a rich area for variety, as a glance at the checklist indicates. Many of the anticipated perennials and annuals were present, particularly from the carnation and daisy families. These hills are severely eroded and niches for soil to collect in were numerous. As a result, the rocky slopes were covered with an abundance of species. Where small wadis had formed at the base of hillocks, vegetation was thicker, with Cymbopogon grass rife.

The Higher Hills and Dunes

Surprisingly, it was up here, on the sandy slopes to the south of the Ghayl road, that we came across most Rhanterium species. Although present on the plain, and recorded in flower in fairly good condition each year since 1983, individual plants were larger higher up, perhaps because there was less pressure from grazing. (A week earlier, in late April, this species had been recorded as locally prolific along the sides of wadis in Jebel Huwayyah, northeast of Buraimi.) The odd acacia tree stood out on the skyline but large clumps of Cenchrus grass and Leptadenia pryotechnica were more numerous. Banks of orange sand stretch away in all directions, broken by outcrops of rock and Euphorbia larica, and it seemed strange to see a small herd of bony cattle in this terrain. The sand is mostly stable but tends to pile up and shift with wind at the highest elevations. At lower levels, the flatter, stable dunes, more like rolling hills, were scattered with shrubs.

The following checklist is the result of only about 3-4 hours concentrated collecting; it is very probably that a number of species have been overlooked.

Checklist

Area 1 – immediate vicinity of the camp

Area 2 – the plain to the north

Area 3 – hillocks around the camp

Area 4 – higher hills and dunes to the south

Fl. – flowering

Fr.- fruiting

C – common

N – not common, but noticeable

R – rare

ER – extremely rare (maximum three recorded)

a – annual

p – perennial

It should be remembered that some annual are occasionally longer lived, up to two or even three years, depending on local conditions and rainfall patterns.