Leaf stable isotopes suggest shared ancestry is an important driver of functional diversity
Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often regarded as outcomes of environmental selection. This is likely true, but the role of evolutionary history may also be important in shaping patterns of functional diversity. Here, we used leaf C and N stable isotope ratios (δ13C, δ15N) as integrators of physiological processes to assess the relative roles of phylogenetic history and environment in a diverse group of Ericaceae species native to North America. We found strong phylogenetic signal in both leaf δ13C and δ15N, suggesting that close relatives have similar physiological strategies. The signal of phylogeny was generally stronger than that of the local environment. However, within some specialized environments (e.g., wetlands, sandy soils), we found environmental effects and/or niche conservatism. Phylogenetic signal in δ13C appears to be most closely related to the constraints on metabolic demand and supply of C, and δ15N appears to be most strongly related to mycorrhizal associations within the family.
Keywordsδ13C Ericaceae Mycorrhizae δ15N Phylogenetic signal Physiological strategies
We would like to thank Kevin Nixon, Anna Stalter and the Cornell Liberty Hyde Bailey Hortorium for granting access to herbarium vouchers. We are grateful to Kim Sparks and John Pollack for technical assistance and Elizabeth Murray for statistical support.
Author contribution statement
EMG and JPS conceived and designed the project. EMG collected and analyzed the data. EMG and JPS wrote the manuscript.
This study was funded by a Kieckhefer Adirondack Research Grant to EMG.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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