Delayed emergence and post-fire recruitment success: effects of seasonal germination, fire season and dormancy type
Mark K. J. OoiA Department of Animal and Plant Sciences, University of Sheffield, Sheffield S102TN, UK.
B Scientific Services Division, Department of Environment, Climate Change and Water NSW, PO Box 1967, Hurstville, NSW 2220, Australia.
C Corresponding author. Email: m.ooi@sheffield.ac.uk or mark.ooi@environment.nsw.gov.au
Australian Journal of Botany 58(4) 248-256 https://doi.org/10.1071/BT09228
Submitted: 4 December 2009 Accepted: 19 April 2010 Published: 22 June 2010
Abstract
Delayed seedling emergence can negatively affect plant recruitment. Recent work has shown that some species with innate seasonal requirements for germination can have seedling emergence delayed, depending on the season of fire. The impact of this delay, which is in relation to both resprouters and seedlings of species that emerge independent of season, remains unknown. I assessed delayed emergence and subsequent impacts on post-fire recruitment success of three Leucopogon species, which all display a seasonal emergence pattern related to their physiological dormancy. Intra-population comparisons showed that both small (1–6 months) and much larger (12–15 months) delays of emergence reduced seedling survival and growth, and increased the time taken for plants to reach maturity. Fire season induced delays produced very similar results, with higher mortality and slower growth after winter fires compared with post-summer fire cohorts. Seasonal emergence patterns, associated with seed dormancy and germination cues, may therefore provide a mechanism that determines the variation of recruitment success after fires in different seasons. A better understanding of the relationship between fire season and timing of emergence of physiologically dormant species would be timely considering the forecast widening of the fire season due to climate change.
Acknowledgements
Tony Auld, Rob Whelan, Emma Gorrod and two anonymous referees provided helpful comments on an original version of this manuscript. The study was completed with the financial support of the University of Sheffield’s Knowledge Transfer Projects Fund in collaboration with the Department of Environment, Climate Change and Water NSW.
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