Abstract
Pollinator importance, the product of visitation rate and pollinator effectiveness, is a descriptive parameter of the ecology and evolution of plant–pollinator interactions. Naturally, sources of its variation should be investigated, but the SE of pollinator importance has never been properly reported. Here, a Monte Carlo simulation study and a result from mathematical statistics on the variance of the product of two random variables are used to estimate the mean and confidence limits of pollinator importance for three visitor species of the wildflower, Silene caroliniana. Both methods provided similar estimates of mean pollinator importance and its interval if the sample size of the visitation and effectiveness datasets were comparatively large. These approaches allowed us to determine that bumblebee importance was significantly greater than clearwing hawkmoth, which was significantly greater than beefly. The methods could be used to statistically quantify temporal and spatial variation in pollinator importance of particular visitor species. The approaches may be extended for estimating the variance of more than two random variables. However, unless the distribution function of the resulting statistic is known, the simulation approach is preferable for calculating the parameter’s confidence limits.
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Acknowledgements
We thank A. Royer, S. Marten-Rodriguez, and K. Barry for field assistance, W. Fagan and B. Momen for discussions of the methodology, M. Larsson for discussion of the SE of importance. We thank M. Dudash, J. Hereford, M. Rutter, A. Kula, J. Silander (AE), and two anonymous reviewers for comments on the manuscript. We also thank the National Park Service and Chesapeake & Ohio Canal National Park personnel for permitting us access to field study sites. This research was sponsored by the Washington Biologists Field Club, The Nature Conservancy’s Biodiversity Conservation Research Fund, and NSF DEB-0108285 to C. Fenster and M. Dudash.
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Communicated by John Silander.
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Reynolds, R.J., Fenster, C.B. Point and interval estimation of pollinator importance: a study using pollination data of Silene caroliniana . Oecologia 156, 325–332 (2008). https://doi.org/10.1007/s00442-008-0982-5
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DOI: https://doi.org/10.1007/s00442-008-0982-5