Competition for microsites during recruitment in semiarid annual plant communities.

The concept of microsites for recruitment is central to plant ecology, but it is unclear whether these sites are abstract constructs or real entities. I hypothesize that, in generally microsite-limited communities, microsites comprise a limiting physical resource for which different species compete. I tested this hypothesis on winter-annual communities on biocrust in the semiarid Northern Negev of Israel, in which most species are microsite-limited, while the dominant grass (Stipa capensis) has overcome this limitation by efficient microsite acquisition and a lack of secondary seed dormancy.