Population ecology - Original research


, Volume 173, Issue 2, pp 421-430

First online:

Clinal variation for only some phenological traits across a species range

  • Holly R. PrendevilleAffiliated withDepartment of Biology, University of Virginia Email author 
  • , Karen Barnard-KubowAffiliated withDepartment of Biology, University of Virginia
  • , Can DaiAffiliated withDepartment of Biology, University of VirginiaSchool of Resources and Environmental Science, Hubei University
  • , Brian C. BarringerAffiliated withDepartment of Biology, University of VirginiaDepartment of Biology, University of Wisconsin - Stevens Point
  • , Laura F. GallowayAffiliated withDepartment of Biology, University of Virginia

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Phenology is the timing of life cycle events of an organism. Alterations in phenology can have profound effects on individual fitness, population growth, and community dynamics. Recent changes in climate have altered the phenology of many organisms, which may result in selection to shift phenological traits. Understanding the relationship between local climates and population differentiation in phenology will allow us to anticipate responses to novel selective environments caused by global climate change. We evaluated population differentiation in the number of days to germination, first flower, and fruit maturation for 33 populations throughout the range of Campanulastrum americanum (American Bellflower). Germination and fruit maturation had geographical clines with earlier timing in populations from northern latitudes. Northern sites were cooler and drier, suggesting potential adaptive differentiation of the shorter life cycle associated with earlier phenology. Similarly, higher elevations were cooler and had earlier fruit maturation. However, seed germination was later in higher elevation populations. Although there was substantial variation in the day to first flower, ranging 40 days between population means, it was idiosyncratic and not related to latitude, suggesting differentiation in response to selective factors distinct from those on germination and fruit maturation. Thus, germination and fruit maturation in C. americanum may shift in response to selection by rising temperatures. However, such changes are not expected for flowering time, a typical indicator of climate change.


Elevation Flowering time Latitude Phenology Population differentiation