Peter Grubb wrote a really important paper in 1977 (Biological Reviews 52: 107-145) on the 'regeneration niche' and how it might contribute to the maintenance of local species diversity in plant communities. It's one of those papers I think all new Post-Grads in my Lab should read, and has been central to my thinking about plant community dynamics for a long time.
Few studies in the eucalypt woodlands of south-eastern Australia have examined whether species have fundamentally different regeneration niches. Hence, it remains uncertain whether species coexistence is promoted by differences in regeneration requirements created by substrate heterogeneity.
Recently, Amber Briggs and I published a paper (Briggs & Morgan) examining this question in semi-arid woodlands in Terrick Terrick National Park. Here, biological soil crusts (a mix of lichens, liverworts and mosses) are common and have a very patchy distribution. We wondered whether groundlayer species would germinate differently in areas with different crust components.