Relationships between plant diversity and ecosystem properties can be explored by classifying component species into three categories dominants subordinates and transients[ Dominants recur in particular vegetation types are relatively large exhibit coarse!grained foraging for resources and as individual species make a substantial contribution to the plant biomass[ Subordinates also show high _delity of association with particular vegetation types but they are smaller in stature forage on a more restricted scale and tend to occupy microhabitats delimited by the architecture and phenology of their associated dominants[ Transients comprise a heterogeneous assort! ment of species of low abundance and persistence^ a high proportion are juveniles of species that occur as dominants or subordinates in neighbouring ecosystems[