Cowan, Peter D , Bolmgren, Kjell , Mast, Austin .
Evolution of a circular trait: Phenology in Banksia (Proteaceae).
The shrub genus Banksia Proteaceae, is comprised of 80 species. The average flowering duration for the group is 3.5 months, however, flowering onset for at least one species occurs in every month except July. This presents an interesting problem of analysis. Unlike Northern climates, where the majority of phenological studies have been undertaken, flowering time in Banksia does not have a logical starting point, such as mid-winter dormancy. To test for relationships between flowering time and other phenological traits such as shoot growth, or functional traits such as plant height, we employed circular statistics. The application of circular statistics to flowering phenology and has particular relevance for environments where a dormant season does not exist. Using Felsenstein phylogenetic independent contrasts, modified for circular variables, we tested for correlations among flowering time (onset and duration), reproductive traits (number of seed bearing follicles), and functional traits (plant height). We found significant positive relationships between number of follicles and flowering duration. We also found a negative relationship between flowering onset and number of follicles, and a relationship between plant height and flowering suggesting trade-offs between plant growth and reproductive success.
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1 - University of California, Berkeley, Integrative Biology, Integrative Biology UC Berkeley, 3060 Valley Life Sciences Bldg #3140, Berkeley, CA, 94720-3140, USA
2 - Florida State University, Department of Biological Sciences, Tallahasse, Florida, 32306-1100, USA
phylogenetic independent contrasts
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 1:30 PM