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Plant Ecology

, Volume 219, Issue 5, pp 527–537 | Cite as

Fire severity drives variation in post-fire recruitment and residual seed bank size of Acacia species

  • Harrison D. Palmer
  • Andrew J. Denham
  • Mark K. J. Ooi
Article

Abstract

Very high-severity fires are a component of many fire-prone ecosystems, yet are often viewed as detrimental to vegetation. However, species in such systems are likely to have adapted to persist under a fire regime that includes high-severity fires. We examined how fire severity affects post-fire recruitment and residual seed banks of Acacia species and whether severity may affect plant responses to fire intervals. Nine sites of either high or low burn severity were identified after a large-scale mixed-severity fire in Warrumbungle National Park, south-eastern Australia. Transects were used to sample above-ground woody plant density. Seed bank size was surveyed by soil extraction from two depths and manual searching for seeds. Residual soil seed bank and recruitment were compared across the two burn severities. Acacia seedling density was higher in areas burnt at high severity, indicating that increased severity triggers increased germination from the seed bank. Size of residual seed bank was smaller after high-severity fire, but varied between species, with few Acacia cheelii seeds remaining despite high above-ground abundance. In contrast, A. penninervis retained a small residual seed bank. There was little evidence of negative effects on populations of Acacia species after high-severity burns. However, we found that high fire severity may impact on the ability of a species to persist in response to a subsequent short fire interval. Fire management for maintaining biodiversity needs to consider other key aspects of the fire regime, including severity and season, rather than focusing solely on fire frequency.

Keywords

Physical dormancy Fire severity Heat shock Acacia Recruitment Residual seed bank Obligate seeder Land management 

Notes

Acknowledgements

We thank Martin Henery and Justin Collette for field assistance, Lisa Metcalfe for laboratory assistance, Craig Wall and the National Parks and Wildlife Service Coonabarabran office for permission to work in Warrumbungle NP and Jessica Meade for assistance with drafting figures. The project was supported by funding from the NSW Office of Environment and Heritage, and as part of the Australian Government’s National Environmental Science Programme (NESP), Threatened Species Recovery Hub (1.3).

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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Centre for Mine Site RestorationCurtin UniversityPerthAustralia
  2. 2.Centre for Sustainable Ecosystem Solutions, School of Biological SciencesUniversity of WollongongWollongongAustralia
  3. 3.Ecosystem Management Science, Office of Environment and Heritage (NSW)HurstvilleAustralia
  4. 4.Centre for Ecosystem Science, School of Biological Earth and Environmental SciencesUniversity of New South WalesSydneyAustralia

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