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Abstract Detail



Empirical Approaches to Phylogenetic Comparative Methods in Plant Science

Schenk, John [1].

Evolution of limited seed dispersal ability on gypsum islands.

Premise of the study:  Dispersal is a major feature of plant evolution that has many advantages, but is not always favored.  Wide dispersal, for example, leads to greater seed loss in oceanic island endemics, and evolution has favored morphologies that limit dispersal.  I tested the hypothesis that selection favored limited dispersal on gypsum islands in western North America with a phylogenetic comparative approach, where edaphic communities are sparsely vegetated except for a specialized flora that competes poorly with the surrounding flora. Methods:  I applied a series of phylogenetic comparative approaches to gypsophilic species of Mentzelia section Bartonia (Loasaceae) to investigate the evolution of limited dispersal function in seed wings, which increase primary dispersal by wind.  Through these tests, I determine whether narrowed wings were selected for in gypsophilic species. Key results:  Gypsophily was derived four to seven times.  Seed area was not significantly correlated with gypsophily or wing area.  Wing area was significantly smaller in the derived gypsum endemics, supporting the hypothesis in favor of limited dispersal function.  A model-fitting approach identified two trait optima in wing area, with gypsum endemics having a lower optimum. Conclusions:  Evolution into novel ecologies influences morphological evolution.  Morphological characters have been selected for limited dispersal following evolution onto gypsum islands.  Selection for limited dispersal ability has occurred across animals and plants, both in oceanic and terrestrial systems, suggesting reduced dispersal ability may be a general process:  selection favors limited dispersal if the difference in survival between the habitat of the parent and the surrounding area is great enough.


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Related Links:
Botany 2014 Joint Symposium & Colloquium on Phylogenetic Comparative Methods


1 - Tulane University, Department of Ecology and Evolutionary Biology, 400 Lindy Boggs Center, New Orleans, LA, 70118-5698, USA

Keywords:
seed dispersal
Mentzelia
Loasaceae
phylogenetic comparative methods
gypsophily
Ornstein-Uhlenbeck Model
functional traits.

Presentation Type: Symposium or Colloquium Presentation
Session: C1
Location: Summit/Boise Centre
Date: Monday, July 28th, 2014
Time: 2:30 PM
Number: C1005
Abstract ID:57
Candidate for Awards:None


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