Abstract
In this paper, we test the mid-domain hypothesis as an explanation for observed patterns of flowering diversity in two sub-alpine communities of insect-pollinated plants. Observed species richness patterns showed an early-season increase in richness, a mid-season peak, and a late-season decrease. We show that a “mid-domain” null model can qualitatively match this pattern of flowering species richness, with R2 values typically greater than 60%. We find significant or marginally significant departures from expected patterns of diversity for only 3 out of 12 year-site combinations. On the other hand, we do find a consistent pattern of departure when comparing observed versus null-model predicted flowering diversity averaged across years. Our results therefore support the hypothesis that ecological factors shape patterns of flowering phenology, but that the strength or nature of these environmental forcings may differ between years or the two habitats we studied, or may depend on species-specific characteristics of these plant communities. We conclude that mid-domain null models provide an important baseline from which to test departure of expected patterns of flowering diversity across temporal domains. Geometric constraints should be included first in the list of factors that drive seasonal patterns of flowering diversity.
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Acknowledgements
We thank the Rocky Mountain Biological Laboratory and John Tuttle for providing access to study sites, and Rob Colwell, Bill Fagan, and Justin Calabrese for comments on earlier drafts of this paper. This material is based upon work supported by the National Science Foundation under grants DEB 94-08382, IBN-98-14509, and DEB-0238331 to D.W.I., and by assistance from Earthwatch and its Research Corps.
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Morales, M.A., Dodge, G.J. & Inouye, D.W. A phenological mid-domain effect in flowering diversity. Oecologia 142, 83–89 (2005). https://doi.org/10.1007/s00442-004-1694-0
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DOI: https://doi.org/10.1007/s00442-004-1694-0