Weber, Stefan , Caruso, Christina , Maherali, Hafiz .
The role of floral traits in the assembly of spring ephemeral communities.
Although plants compete for pollination services through their flowers, floral traits are rarely considered in community-assembly theory. Plants with similar traits are likely to share ecological niches and therefore compete for space and resources.Superior competitors may exclude species with similar traits from coexisting in the same community. Because closely related species share similar traits,competitive outcomes may be predicted by phylogenetic relationships between taxa as well. We tested the hypothesis that plant communities are structured by competition for pollination by studying 52 species of early-blooming forbs. We inventoried community composition at forest sites across south-western Ontario and Michigan. We measured seven aspects of flower colour, morphology and phenology and compared similarity in these traits among co-existing species. We tested observed patterns against those generated in theoretical null communities to judge if neighbouring species were more or less similar in floral traits than expected by chance. We also measured the phylogenetic relatedness of community members to account for trait-conservatism in coexistence patterns. We found evidence that both competition for and facilitation of pollination structures spring ephemeral assemblages. Communities were composed of species with more dissimilar flower sizes than expected under the null model. This over-dispersion of flower size suggests that competition excludes species that attract similar-sized pollinators from coexisting. However, communities were composed of species that flowered more synchronously and had more similar floral hues than expected under the null model. This clustering of species with similar flowering phenology and flower color suggests that facilitation of pollination also influences community-assembly. Phylogenetic relatedness did not explain community composition, because few floral traits were conserved. Our results demonstrate that visually attractive traits promote facilitation of shared pollinators while morphological traits act to partition resources in response to competition. We suggest that pollinator attraction represents an ecological niche through which species can be sorted in a community, and that floral similarity can explain co-existence patterns among plants.
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1 - University Of Guelph, Department Of Integrative Biology, New Science Complex, 50 Stone Road East, GUELPH, ON, N1G 2W1, Canada
2 - University Of Guelph, Department Of Integrative Biology, GUELPH, ON, N1G2W1, Canada
Presentation Type: Oral Paper:Papers for Sections
Location: Portland Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 2:00 PM