Temperature variability drives within-species variation in germination strategy and establishment characteristics of an alpine herb
Plant establishment and subsequent persistence are strongly influenced by germination strategy, especially in temporally and spatially heterogeneous environments. Germination strategy determines the plant’s ability to synchronise germination timing and seedling emergence to a favourable growing season and thus variation in germination strategy within species may be key to persistence under more extreme and variable future climates. However, the determinants of variation in germination strategy are not well resolved. To understand the variation of germination strategy and the climate drivers, we assessed seed traits, germination patterns, and seedling establishment traits of Oreomyrrhis eriopoda from 29 populations across its range. Germination patterns were then analysed against climate data to determine the strongest climate correlates influencing the germination strategy. Oreomyrrhis eriopoda exhibits a striking range of germination strategies among populations: varying from immediate to staggered, postponed, and postponed-deep. Seeds from regions with lower temperature variability were more likely to exhibit an immediate germination strategy; however, those patterns depended on the timescale of climatic assessment. In addition, we show that these strategy differences extend to seedling establishment traits: autumn seedlings (from populations with an immediate or staggered germination strategy) exhibited a higher leaf production rate than spring seedlings (of staggered or postponed strategy). Our results demonstrate not only substantial within-species variation in germination strategy across the species distribution range, but also that this variation correlates with environmental drivers. Given that these differences also extend to establishment traits, they may reflect a critical mechanism for persistence in changing climate.
KeywordsLocal adaptation Maternal environment Plastic variation Seedling growth Reproductive ecology
We gratefully acknowledge the seed banks of the Australian National Botanic Gardens Canberra, The Royal Tasmanian Botanical Gardens, Royal Botanic Gardens Victoria, and the Australian Botanic Garden Mount Annan for providing seeds. We thank Pauline Ding and Terry Neeman (Statistical Consulting Unit ANU) for providing statistical advice, members of the Nicotra lab for useful feedback on the manuscript, ANBG staff Tom North for logistical support and Joe McAuliffe for confirming IDs on the accessions, Afiat Sukmaraga and Salamun Kaulam for the graphic editing, and especially Toton Liantoro for assistance during the experiment. The authors declare no conflict of interest. Annisa Satyanti is supported by an Australian Government Research Training Program (RTP) Scholarship.
Author contributions statement
AS designed, carried out, analysed, and wrote the manuscript. ABN advised on design and analysis. ABN and LKG advised on the draft and substantially contributed to the revisions.
Compliance with ethical standard
Conflict of interest
The authors declare no conflict of interest.
Research involving human and/or animal participants
This article does not contain any studies with human participants or animals performed by any of the authors.
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