COMPARATIVE PLANT SIZES AND REPRODUCTIVE STRATEGIES IN DESERT AND MEDITERRANEAN POPULATIONS OF EPHEMERAL PLANTS

ABSTRACT Plant size at anthesis was studied in wild populations of 12 species and taxa pairs of ephemeral plants from Mediterranean and desert sites in Israel. In two of the four parameters studied, plant height and above-ground biomass, Mediterranean populations showed a significantly greater variability than the corresponding desert ones. This result is possibly correlated with the Mediterranean or steppic (Irano-Turanian) origin of the majority of the species and taxa pairs studied. Intraspecific comparison of absolute reproductive output and of two “reproductive strategy indicators” was also carried out on three widespread grasses: two of Mediterranean origin (Brachypodium distachyon and Bromus fasciculatus) and one of desert origin (Stipa capensis). No clear trends were recorded across taxonomic boundaries for the absolute reproductive output. However, desert populations of the three species showed a greater reproductive effort (biomass of diaspores per biomass of above-ground vegetative parts), and ...