Pollination Dynamics in Two Subalpine Flower Meadows
Pollinator interactions were studied in two subalpine meadows to determine the role of pollination in structuring the herbaceous flower communities. The majority of the entomophllous plant species set significantly loss seed when caged to prevent visitation than when exposed to flower visitors. Visitation rate was directly related to temperature and radiation. The number of animal species visiting flowers each week was directly related to the number of plant species in bloom. Most visitor species used _f3 species of plants, while most plant species hosted 8 species of flower visitors. Floral niche breadth increased with increasing animal species diversity, but animal niche breadth was not related to flowering plant species diversity. The mean weekly visitation rate for each plant species was significantly related to floral relative density. Percent seed set was not related to visitation rate or flower density. Flowering period overlap and pollinator similarity varied for most species from one year to the next. There was no indication of competition for pollinators in either community. Supplementing the nectar of Geranium viscosissimum F.&M. resulted In a significant increase In the visitation rote and in the number of visiting species but dill not affect either aspect of visitation to the other species In flower. The introduction of 1'enstemnn cvanantllu, IlouA. did not alter the visitation patterns of the other plant species. Pollinator interactions play an indirect role in the structuring of these floral communities. Cross nollinntIon facilitates high genetic variability in subalpine plants, but does not appear to regulate the plant populations directly.
Beedlow, P.A. (1979). Pollination dynamics in two subalpine flower meadows. PhD. 188p.