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Abstract Detail

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

Waterway, Marcia J. [1], Lechowicz, Martin J. [2], Dabros, Anna [3], Guillet, Joelle [4], Martins, Kyle [2].

Ecological and evolutionary diversification within the genus Carex: consequences for community assembly.

Due to its species-richness and ecological diversity, Carex is an excellent model system for exploring questions related to ecological speciation, niche differentiation, and community assembly. Using DNA sequence data from multiple genes, we have constructed a nearly complete, well-resolved phylogenetic hypothesis for northeastern North American Carex species that allows us to identify discrete lineages and sister-species pairs, and to estimate phylogenetic distances among species. We also have sampled Carex-rich plant communities at the scale of neighborhoods of competing individuals in a variety of wetland and forest habitats, recording co-occurring Carex species as well as insolation, moisture, pH and fertility. We used both stratified random sampling across habitats and focal sampling of the communities and environments immediately surrounding individual Carex plants. The former sampling strategy allows inferences about frequency of association at varying levels of relatedness across the sampled habitat while the latter allows characterization of the environmental niche with equal sample sizes for species regardless of their frequency in the landscape. In this talk we focus on evolutionary diversification in the niches of Carex relevant to the spatial scale of plant communities where interactions among individual plants determine community composition and structure – a scale that has been called the Darwin-Hutchinson zone and is notably lacking in ecophylogenetic analyses. This is the spatial scale at which abiotic factors and interactions such as competition or facilitation among species affect community assembly conditioned by the ecological diversification in the regional species pool arising from processes of speciation and adaptive evolution. The expectation is that very closely related species should not be found together at this fine spatial scale, either because competitive exclusion would drive one to extirpation or because the two species would have diverged on at least one niche axis and hence not be found growing together. We test these expectations using patterns of species co-occurrence within and among lineages (clades) found growing in wetland and upland forest habitats sampled at scales of a few meters squared or less. Results vary among habitats and are influenced by intraspecific variance in ecological tolerances.

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1 - McGill University, Plant Science-Macdonald Campus, 21111Lakeshore, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada
2 - Mcgill University, Department Of Biology, 1205 Ave Dr. Penfield, Montreal, QC, H3A 1B1, Canada
3 - Natural Resources Canada, Science Program Branch, National Capital Region, 580 Booth St., Ottawa, ON, K1A 0E4, Canada
4 - 787 Blvd. Wilfrid Hamel, Quebec, QC, G1M 2R1, Canada

Community Assembly

Presentation Type: Symposium Presentation
Session: SY15
Location: Salon 11/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 10:15 AM
Number: SY15006
Abstract ID:1025
Candidate for Awards:None

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