PLANT FUNCTIONAL TYPES ON RED SEA COASTAL SAND DUNESM. Remesh, Yahya S. Masrahi and Osama H. SayedAbstract Plant distribution on southern Red Sea coastal sand dunes was studied using plant functional types approach. Plants were surveyed for functional types defined by photosynthetic characteristics, life form, and growth habit. Work aimed to relateplant distribution to plant attributes and edaphic gradients. Results indicated that plants could be grouped into two functional groups. Functional Group I dominated by summer annuals with C3 photosynthesis was restricted to hind dune and desert plain zones. Functional Group II dominated by summer annuals with C4 photosynthesis occurred in foredune, hind dune, and desert plain. Despite heat sensitivity of C3 carbon fixation enzymes heat avoidance by short life cycles and fast transition from vegetative growth to flowering enabled occurrence of Functional Group I in hot dry hind dune and desert plain. Functional Group II occurred in all three sand dune zones due to C4 pathway high water use efficiency and tolerance to heat and salinity. Occurrence of recorded life forms and growth habits in all sand dune zones indicated that these two traits alone could not constitutea syndrome that forms functional type. For plant functional types approach to describe plant distribution it has to consider variety of plant traits including form, habit, and physiological characteristics. Results provide a model that can be applied to predict plant distribution at similar settings in different parts of the world. |