Reproductive dynamics of four plant communities of southwestern British Columbia

A study of angiosperm reproductive biology was made in four plant communities in southwestern British Columbia. Species of all four communities have staggered, peak flowering times, resulting in phenological spectra. Anemophily is the major mode of pollination in a salt marsh, while entomophily predominates in a subalpine meadow. Two sphagnum bogs have more of a balance between wind and insect pollination. There are corresponding differences in the proportions of showy-flowered species in the communities. It is proposed that interspecific competition has greatly influenced the evolution of both species and community flowering strategies.Biotic seed dispersal prevails in the salt marsh and bogs, while most of the subalpine meadow species are wind-dispersed. Species and community modes of dispersal depend on the nature of the vegetation and the relative availability of dispersal vectors, as well as on diaspore morphology.Although vegetative reproduction and self-compatibility are fairly common, the bulk of the flora and vegetation at all four sites has breeding systems promoting outcrossing. There is little evidence that the physical environments of these communities, all harsh in at least some respects, have selectively favored autogamous or agamospermous species.