On the life cycle of Stipagrostis scoparia hillocks

Stipagrostis scoparia is a perennial grass which inhabits mobile sands in large parts of Sinai and adjacent areas of the Negev Desert. The species forms phytogenic hillocks which, according to the results of previous studies, are gradually taken over by later successional species during the course of succession. Based on information about this species from the literature, a conceptual model for the dynamics of establishment and ageing of Stipagrostis scoparia hillocks is proposed. We attempted to validate parts of the model using data collected in the Hallamish sands near Nizzana, north-western Negev. Eighty hillocks were sampled for parameters of hillock shape, vegetation cover and perennial species composition. We referred the age of hillocks as being positively correlated with perennial species richness. This assumption was found to be consistent with the proposed model. However, we conclude that further, more detailed research is needed in order to fully understand the temporal dynamics of Stipagrostis scoparia