Sabitha Sakkir

Phenology of desert plants from an arid gravel plain in eastern United Arab Emirates

Phenological events for desert plants were recorded and rainfall and temperature data were gathered over a three-year time scale at a gravel plain in the eastern region of the United Arab Emirates. Variations of phenological periods were analyzed and correlations between phenological periods and climate factors were discussed. The study showed that the growth and flowering of therophytes were significantly correlated with air temperature. The timing and abundance of rainfall came to be another factor significantly correlated with the onset and duration of chamaephyte flowering as well as the duration of therophyte growth and flowering. The variation in rainfall did not affect the onset of flowering in phanerophytes. Peak growing seasons were from November to March and flowering from November to December (also February to March depending on the availability of rainfall). Flowering in phanerophytes and chamaephytes occurs 4–6 weeks and in therophytes 4–8 weeks after rain. The results showed that variations in growth and phenology between species were correlated with environmental factors, such as temperature and rainfall or, maybe, differences in life form and photosynthetic pathways, each being adapted for utilizing a particular phase of the seasonally and yearly variable rainfall. The sequence of flowering for the species under study was more or less constant despite the difference in the amount of rainfall. The fruiting patterns of most of the species were also found parallel to their flowering patterns. Our results emphasized the need to study multiple species at many sites for the understanding and forecast of regional changes in phenology.

The coastal vegetation of the western and southern Gulf — characterisation and conservation aspects

Although we have a superficial overview of the main plant communities of coastal areas of the western and southern Gulf, in-depth studies are generally lacking, with a few notable exceptions. Coastal vegetation in the region is often equated solely to halophytic communities growing under the direct influence of salt-water, in extreme cases only to mangroves, the latter which in fact account for only a very small percentage of the total coastal vegetation. This narrow perspective has important conservation repercussions, especially given the current mass destruction of many parts of the Gulf coastline. Important speciesrich communities (flora and fauna) are being destroyed at an alarming rate without any mitigation measures, and even high-profile ecosystems, such as mangroves, are by no means immune from the on-going development frenzy. An important step towards the protection and sustainable use of environmental resources is their detailed characterisation and inventory, as well as elucidating their spatial distribution. The aims of this contribution are therefore three-fold: 1) to give an overview of the coastal vegetation of the area (Gulf coastline of the GCC countries), examining both halophytic and non-halophytic communities; 2) to highlight the most critical issues affecting coastal vegetation; and 3) to suggest conservation priorities and associated research projects. It is clear that much more detailed work is required to identify and assess remaining intact stretches of the coastline regarding their vegetation, flora and fauna.

First record of Epipactis veratrifolia Boiss. & Hohen. (Orchidaceae, Epidendroideae, Neottieae, Limodorinae) from an arid wadi in Abu Dhabi, United Arab Emirates

Epipactis veratrifolia is recorded for the first time from Jebel Hafeet, a mountain in Abu Dhabi, United Arab Emirates (UAE). This species had been previously recorded from the northern part of the UAE and other areas on the Arabian Peninsula. The occurrence of E. veratrifolia in Jebel Hafeet expands the eastern distribution limits of the species and underlines the importance of biodiversity in the region. The new record fills a gap in the distribution of this species on the Arabian Peninsula.

Floristic composition of arid off –shore islands in Abu Dhabi, United Arab Emirates

Data on flora and vegetation of 14 off-shore islands representing different habitat types were studied for investigating floristic composition, vegetation types and correlation with their habitats and ecosystem. The results demonstrate considerable plant distribution and diversity among the islands within the limited spectrum of species; encompassing a total of 47 species, belonging to 43 genera under 24 families. The most representative families were Amaranthaceae (9 species), Fabaceae (4 species), Poaceae (4 species) and Asteraceae and Aizoaceae (3 species each). Fourteen families are represented by only one species. The mangrove species, Avicennia marina, occurs throughout the coast of Abu Dhabi in discontinuous patches and in different water salinities. The studies also seek to underline that dominant species that constitutes the flora of Abu Dhabi are salt tolerant in nature. Compared to other Arabian Peninsula ecosystems, UAE perhaps has a higher coastal: mainland area ratio, which has contributed to a natural dominance of salt tolerant species among the community. The studies show 40% similarity among islands with respect to the species diversity. The floristic composition of the off-shore islands also indicates a need to consider these sites as protected sites.