Micro‐spatial Heterogeneity and Seedling Demography in Species‐rich Grassland

It is suggested that spatial niche‐separation between grassland species occurs in the regeneration phase and that the differential response of species to micro‐variations in leaf cover may allow coexistence at high density. A technique for measuring heterogeneity in leaf‐cover on a scale of 1‐cm2 units (micro‐cover) and the demography of seedling cohorts of Reseda lutea and Anthyllis vulneraria in relation to this heterogeneity is described. Densities of seedlings were significantly higher in micro‐sites of low micro‐cover for R. lutea and for one of the three cohorts of A. vulneraria studied. No relationship was found between mortality and density of seedlings or micro‐cover. The ultimate causes of these distribution patterns of seedlings and their consequences for the maintenance of species diversity in grassland are discussed.