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Article
Effects of Population Size and Density On Pollinator Visitation, Pollinator Behavior, and Pollen Tube Abundance in Lupinus Perennis
International Journal of Plant Sciences
  • Christopher E. Bernhardt, University of Akron Main Campus
  • Randall J. Mitchell, University of Akron Main Campus
  • Helen J. Michaels, Bowling Green State University - Main Campus
Document Type
Article
Publication Date
1-1-2008
Disciplines
Abstract

Both the number and the density of flowering plants in a population can be important determinants of pollinator abundance and behavior. We report the joint effects of population size and density on pollinator visitation and pollination success for Lupinus perennis (Fabaceae). Focusing on five pairs of populations, we matched one small population (125-800 flowering plants) with one distinctly larger population (1000-3000 flowering plants). In these pairs, population size did not affect pollinator communities or pollination success. All measures of pollination success increased significantly with density. Only bee behavior (number of flowers probed per inflorescence) exhibited a significant interaction of size and density. Testing whether population sizes smaller than those in the paired populations might affect pollination, we gathered pollen tube samples from 14 unpaired populations (16-215 flowering plants). Combining these data with those from the paired populations revealed a significant decrease in pollination for smaller populations, indicating that effects of population size may be detectable only when populations smaller than a few hundred plants are sampled. We found that effects of density are consistent and much stronger than those of population size. Our results suggest that both size and density of natural populations should be considered in designing restoration and reintroduction programs for this threatened plant.

Citation Information
Christopher E. Bernhardt, Randall J. Mitchell and Helen J. Michaels. "Effects of Population Size and Density On Pollinator Visitation, Pollinator Behavior, and Pollen Tube Abundance in Lupinus Perennis" International Journal of Plant Sciences Vol. 169 Iss. 7 (2008) p. 944 - 953
Available at: http://works.bepress.com/randall_mitchell/2/