Fire effects on plant reproductive fitness vary among individuals, reflecting pollination-dependent mechanisms

Lea K. Richardson, Jared Beck, Daniel J. Eck, Ruth Shaw, Stuart Wagenius

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Premise: Fire induces flowering in many plant species worldwide, potentially improving reproductive fitness via greater availability of resources, as evident by flowering effort, and improved pollination outcomes, as evident by seed set. Postfire increases in flowering synchrony, and thus mating opportunities, may improve pollination. However, few studies evaluate fire effects on multiple components of fitness. Consequently, the magnitude and mechanism of fire effects on reproductive fitness remain unclear. Methods: Over multiple years and prescribed burns in a prairie preserve, we counted flowering stems, flowers, fruits, and seeds of three prairie perennials, Echinacea angustifolia, Liatris aspera, and Solidago speciosa. We used aster life-history models to assess how fire and mating opportunities influenced annual maternal fitness and its components in individual plants. Results: In Echinacea and Liatris, but not in Solidago, fire increased head counts, and both fire and mating opportunities increased maternal fitness. Burned Echinacea and Liatris plants with many flower heads produced many seeds despite low seed set (fertilization rates). In contrast, plants with an average number of flower heads had high seed set and produced many seeds only when mating opportunities were abundant. Conclusions: Fire increased annual reproductive fitness via resource- and pollination-dependent mechanisms in Echinacea and Liatris but did not affect Solidago fitness. The consistent relationship between synchrony and seed set implies that temporal mating opportunities play an important role in pollination. While fire promotes flowering in many plant species, our results reveal that even closely related species exhibit differential responses to fire, which could impact the broader plant community.

Original languageEnglish (US)
Article numbere16160
JournalAmerican journal of botany
Volume110
Issue number4
DOIs
StatePublished - Apr 2023

Bibliographical note

Funding Information:
We thank members of Team Echinacea for collecting field data throughout the years. We also thank volunteers at the Chicago Botanic Garden, including especially S. Allabens, J. Bailard, and T. Dodge, for cleaning and counting the fruits and seeds. We are grateful to The Nature Conservancy for use of the field site and for conducting prescribed burns. We are also thankful for several helpful reviews that substantially improved the manuscript. We acknowledge funding from the National Science Foundation (NSF) RET award that supported L.K.R. for one summer, Northwestern University's graduate student stipend that supported L.K.R., as well as NSF awards 2051562, 2050455, 2032282, 1557075, 1555997, 1355187, and 1125997.

Funding Information:
We thank members of Team Echinacea for collecting field data throughout the years. We also thank volunteers at the Chicago Botanic Garden, including especially S. Allabens, J. Bailard, and T. Dodge, for cleaning and counting the fruits and seeds. We are grateful to The Nature Conservancy for use of the field site and for conducting prescribed burns. We are also thankful for several helpful reviews that substantially improved the manuscript. We acknowledge funding from the National Science Foundation (NSF) RET award that supported L.K.R. for one summer, Northwestern University's graduate student stipend that supported L.K.R., as well as NSF awards 2051562, 2050455, 2032282, 1557075, 1555997, 1355187, and 1125997.

Publisher Copyright:
© 2023 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.

Keywords

  • aster model
  • components of fitness
  • flowering synchrony
  • grassland
  • herbaceous perennial
  • mating opportunities
  • pollination
  • prairie
  • prescribed burn
  • seed production

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

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