The effect of flower density on pollinator visitation rate for Caltha palustris, Aralia nudicaulis, and Syringa vulgaris in different habitats.

Abstract

We measured rates of visitation by potential pollinators and flower density for populations of Caltha palustris from a moist understory habitat and of Aralia nudicaulis from a species-rich open field habitat. Regression analysis of visitation rate as a function of flower density gave statistical data which was used to compare the effect of patch density on pollinator visitation in the two contrasting habitats. A second, more controlled study utilized artificial patches of Syringa vulgaris in order to further quantify visitation rate and density, and was analyzed in a similar fashion. The results of the study show that pollinator visitation in uniformly dispersed floral communities is more dependent on flower density, than it is in a clumped less species-diverse habitat.