On the life cycle of Stipagrostis scoparia hillocks

Stipagrostis scoparia is a perennial grass which inhabits mobile sands in l arge parts of Sinai and adjacent areas of the Negev Desert. The species for ms phytogenic hillocks which, according to the results of previous studies, are gradually taken over by later successional species during the course o f succession. Based on information about this species from the literature, a conceptual model for the dynamics of establishment and ageing of Stipagro stis scoparia hillocks is proposed. We attempted to validate parts of the m odel using data collected in the Hallamish sands near Nizzana, north-wester n Negev. Eighty hillocks were sampled for parameters of hillock shape, vege tation cover and perennial species composition. We referred the age of hill ocks as being positively correlated with perennial species richness. This a ssumption was found to be consistent with the proposed model. However, we c onclude that further, more detailed research is needed in order to fully un derstand the temporal dynamics of Stipagrostis scoparia. (C) 1999 Academic Press.