Leaf shape and size track habitat transitions across forest–grassland boundaries in the grass family (Poaceae)

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Gallaher, Timothy J.
Attigala, Lakshmi
Burke, Sean V.
Craine, Joseph M.
Duvall, Melvin R.
Klahs, Phillip C.
Sherratt, Emma
Wysocki, William P.
Clark, Lynn G.
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© 2019 The Author(s). Evolution © 2019 The Society for the Study of Evolution.
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Ecology, Evolution and Organismal Biology

The Department of Ecology, Evolution, and Organismal Biology seeks to teach the studies of ecology (organisms and their environment), evolutionary theory (the origin and interrelationships of organisms), and organismal biology (the structure, function, and biodiversity of organisms). In doing this, it offers several majors which are codirected with other departments, including biology, genetics, and environmental sciences.

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Plant Sciences Institute
The Plant Sciences Institute is dedicated to enhancing Iowa State University's international prominence in the plant sciences. Our research focus is to understand the effects of genotype and environment on phenotypes (traits) sufficiently well that we will be able to predict phenotype of a given genotype in a given environment (i.e., predictive phenomics)
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Grass leaf shape is a strong indicator of their habitat with linear leaves predominating in open areas and ovate leaves distinguishing forest-associated grasses. This pattern among extant species suggests that ancestral shifts between forest and open habitats may have coincided with changes in leaf shape or size. We tested relationships between habitat, climate, photosynthetic pathway and leaf shape and size in a phylogenetic framework to evaluate drivers of leaf shape and size variation over the evolutionary history of the family. We also estimated the ancestral habitat of Poaceae and tested whether forest margins served as transitional zones for shifts between forests and grasslands. We found that grass leaf shape is converging towards different shape optima in the forest understory, forest margins and open habitats. Leaf size also varies with habitat. Grasses have smaller leaves in open and drier areas, and in areas with high solar irradiance. Direct transitions between linear and ovate leaves are rare as are direct shifts between forest and open habitats. The most likely ancestral habitat of the family was the forest understory and forest margins along with an intermediate leaf shape served as important transitional habitat and morphology respectively for subsequent shifts across forest-grassland biome boundaries.
This is the peer reviewed version of the following article: Gallaher, Timothy J., Dean C. Adams, Lakshmi Attigala, Sean V. Burke, Joseph M. Craine, Melvin R. Duvall, Phillip C. Klahs, Emma Sherratt, William P. Wysocki, and Lynn G. Clark. "Leaf shape and size track habitat transitions across forest–grassland boundaries in the grass family (Poaceae)." Evolution 73, no. 5 (2019): 927-946, which has been published in final form at DOI:10.1111/evo.13722. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.