Hybridization among foundation tree species influences the structure of associated understory plant communities

L. J. Lamit, T. Wojtowicz, Z. Kovacs, S. C. Wooley, M. Zinkgraf, T. G. Whitham, R. L. Lindroth, C. A. Gehring

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Understanding how genetic identity influences community structure is a major focus in evolutionary ecology, yet few studies examine interactions among organisms in the same trophic level within this context. In a common garden containing trees from a hybrid system (Populus fremontii S. Wats. × Populus angustifolia James), we tested the hypothesis that the structure of establishing understory plant communities is influenced by genetic differences among trees and explored foliar condensed tannins (CTs) and photosynthetically active radiation (PAR) as mechanisms. Several findings support our hypothesis: (i) Understory biomass and cover increase along the genetic gradient from P. angustifolia to P. fremontii. (ii) Along the same hybridization gradient, species richness decreases and species composition shifts. (iii) Populus foliar CT concentrations and PAR decrease from P. angustifolia to P. fremontii. (iv) Understory species richness increases with foliar CTs; however, biomass, cover, and composition show no relationship with CTs, and no understory variables correlate with PAR. (v) Structural equation modeling suggests that foliar CTs are a primary mechanism linking overstory tree genetics with understory richness. Using an experimental system dominated by naturally colonizing exotic species, this study demonstrates that a genetic gradient created by tree hybridization can influence understory plants.

Original languageEnglish (US)
Pages (from-to)165-174
Number of pages10
JournalBotany
Volume89
Issue number3
DOIs
StatePublished - Mar 1 2011

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Keywords

  • Condensed tannins
  • Hybridization
  • Plant community
  • Populus
  • Structural equation model

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science

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