Abstract
Lichens are one of the most iconic and ubiquitous symbioses known, widely valued as indicators of environmental quality and, more recently, climate change. Our understanding of lichen responses to climate has greatly expanded in recent decades, but some biases and constraints have shaped our present knowledge. In this review we focus on lichen ecophysiology as a key to predicting responses to present and future climates, highlighting recent advances and remaining challenges. Lichen ecophysiology is best understood through complementary whole-thallus and within-thallus scales. Water content and form (vapor or liquid) are central to whole-thallus perspectives, making vapor pressure differential (VPD) a particularly informative environmental driver. Responses to water content are further modulated by photobiont physiology and whole-thallus phenotype, providing clear links to a functional trait framework. However, this thallus-level perspective is incomplete without also considering within-thallus dynamics, such as changing proportions or even identities of symbionts in response to climate, nutrients, and other stressors. These changes provide pathways for acclimation, but their understanding is currently limited by large gaps in our understanding of carbon allocation and symbiont turnover in lichens. Lastly, the study of lichen physiology has mainly prioritized larger lichens at high latitudes, producing valuable insights but underrepresenting the range of lichenized lineages and ecologies. Key areas for future work include improving geographic and phylogenetic coverage, greater emphasis on VPD as a climatic factor, advances in the study of carbon allocation and symbiont turnover, and the incorporation of physiological theory and functional traits in our predictive models.
Original language | English (US) |
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Article number | e16131 |
Journal | American journal of botany |
Volume | 110 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2023 |
Bibliographical note
Funding Information:The authors thank Brandon Pratt for feedback on the initial outline and two anonymous reviewers for constructive feedback. D.E.S. and N.M.K. were supported by start‐up funding to D.E.S. C.C. received financial support provided by the Natural Environment Research Council (NERC) Standard Grant NE/V000764/1. A.O. was supported by the Edinburgh Earth, Ecology and Environment Doctoral Training Partnership (E4 DTP), led by the School of GeoSciences at the University of Edinburgh funded by NERC.
Publisher Copyright:
© 2023 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.
Keywords
- VPD
- acclimation
- algal physiology
- carbon balance
- climate change
- cryptogam
- functional trait
- lichen physiology
- poikilohydry
- symbiosis
- water relations
PubMed: MeSH publication types
- Journal Article
- Review
- Research Support, Non-U.S. Gov't