, Volume 148, Issue 3, pp 365–372 | Cite as

Characterizing ecological generalization in plant-pollination systems

  • Heather F. SahliEmail author
  • Jeffrey K. Conner


Despite the development of diversity indices in community ecology that incorporate both richness and evenness, pollination biologists commonly use only pollinator richness to estimate generalization. Similarly, while pollination biologists have stressed the utility of pollinator importance, incorporating both pollinator abundance and effectiveness, importance values have not been included in estimates of generalization in pollination systems. In this study, we estimated pollinator generalization for 17 plant species using Simpson’s diversity index, which includes richness and evenness. We compared these estimates with estimates based on only pollinator richness, and compared diversity estimates calculated using importance data with those using only visitation data. We found that pollinator richness explains only 57–65% of the variation in diversity, and that, for most plant species, pollinator importance was determined primarily by differences in visitation rather than by differences in effectiveness. While simple richness may suffice for broad comparisons of pollinator generalization, measures that incorporate evenness will provide a much more accurate understanding of generalization. Although incorporating labor-intensive measurements of pollinator effectiveness are less necessary for broad surveys, effectiveness estimates will be important for detailed studies of some plant species. Unfortunately, at this point it is impossible to predict a priori which species these are.


Diversity Effectiveness Evenness Pollinator importance Specialization 



We thank S. Armbruster, C. Brassil, M. Duffy, S. Emery, C. Herrera, F. Knapczyk, A. Roles, D. Schemske, D. Vazquez, and P. Wilson for helpful comments on the manuscript. Funding was provided by a Lauff Scholarship, Sigma-Xi Grant-in-Aid, NSF DEB-9903880, and NSF DDIG DEB-0408055. This is KBS contribution no. 1214.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Kellogg Biological Station and Department of Plant BiologyMichigan State UniversityHickory CornersUSA

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