Abstract Detail

Ecological diversification and niche evolution in the temperate zone’s largest genus: Carex

Pender, Jocelyn [1], Starr, Julian [2], Naczi, Robert F. C. [3], Hahn, Marlene [4], Hipp, Andrew L. [4].

Ecological niche diversification and trait evolution in North American Carex.

Species richness is not distributed evenly across the tree of life. This is exemplified by the evolutionary success of the genus Carex (sedges; Cyperaceae), the most species-rich angiosperm genus in the northern temperate zone. In this talk, we evaluate whether rates of morphological and ecological (habitat and climatic niche) trait evolution are correlated with species richness in Carex. A phylogeny of nearly all 480 North American sedge species, north of Mexico—an almost complete community sample—was constructed using four molecular markers. Morphological data was extracted from the Flora of North America, habitat data from the U.S. National Wetland Plant List, and climatic niche data from WorldClim (worldclim.org/bioclim). Using phylogenetic comparative methods for continuous traits, rates of trait evolution were estimated on the Carex phylogeny. Sister clade comparisons were used to assess statistically whether rates of trait evolution are associated with increased species richness (as a proxy for diversification). To avoid bias due to relatedness of clades, the analysis was performed using sets of non-nested sister clades. Our work demonstrates that there is a significant positive correlation between the rates of climatic niche, wetland habitat and morphological evolution and species richness. This result suggests that rates of trait evolution and species diversity are coupled in Carex, lending support to the hypothesis that organisms with the ability to evolve new morphological or ecological traits speciate more rapidly (‘evolvability’ hypothesis).

1 - University of Ottawa, Department of Biology, Room 160, Gendron Hall, 30 Marie-Curie, Ottawa, ON, K1N6N5, Canada
2 - University of Ottawa, Biology, Gendron Hall, Room 160, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
3 - The New York Botanical Garden, 2900 Southern Blvd., Bronx, NY, 0458-5126, USA
4 - The Morton Arboretum, 4100 Illinois Route 53, Lisle, IL, 60532, USA

Keywords:
Niche
Morphospace
Trait evolution
Climate
Habitat
Phylogeny
Species richness.

Presentation Type: Symposium Presentation
Session: SY15
Location: Salon 11/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:45 AM
Number: SY15003
Abstract ID:593
Candidate for Awards:None