Climate drying reduces serotinous seedbanks and threatens persistence in two fire-killed shrubs

N. J. Enright; M. C. Agne

doi:10.1071/WF24046

RESEARCH ARTICLE (Open Access)

Previous Next Contents Vol 34(2)

Climate drying reduces serotinous seedbanks and threatens persistence in two fire-killed shrubs

N. J. Enright ^A ^* and M. C. Agne ^B ^C

+ Author Affiliations

- Author Affiliations

^A Environmental and Conservation Sciences, Murdoch University, Perth, 6150, Australia.

^B School of Environmental and Forest Sciences, University of Washington, Anderson Hall, 3715 West Stevens Way NE, Seattle, WA 98195, USA.

^C Present address: USDA Forest Service Pacific Northwest Research Station, 3625 93rd Avenue SW, Olympia, WA 98512, USA.

^* Correspondence to: N.enright@murdoch.edu.au

International Journal of Wildland Fire 34, WF24046 https://doi.org/10.1071/WF24046

Submitted: 8 March 2024 Accepted: 21 January 2025 Published: 13 February 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of IAWF. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Background

Mediterranean-type ecosystems (MTEs) are experiencing declining rainfall, increasing temperature, and shifting fire regimes as climate changes. While changes in fire regimes and post-fire recruitment are widely reported, evidence for changing plant demographic rates is limited.

Aims

We hypothesised increased time to maturity and decreased serotinous seed stores available for post-fire recruitment due to declining rainfall over recent decades for two fire-killed serotinous shrubs of south-east Australian MTEs, Hakea decurrens and Banksia ornata.

Methods

Fruit and cone production for populations across time since fire chronosequences were measured in the same regions in the 1990s and in 2017.

Key results

Estimated time to 50% maturity increased from 3–15 years and 6–15 years for H. decurrens and B. ornata, respectively, while estimated canopy seed stores were 90% and 50% lower in 2017 than in the 1990s.

Conclusions

Delayed reproductive maturity and decreased total seed stores were significantly related to decreasing rainfall received by 2017 populations over their lifetimes (5–17% less than for stands in the 1990s).

Implications

Shifts in inter-fire rates of seed production and storage, combined with changes to fire regimes and post-fire recruitment conditions due to climate change may already threaten the persistence of some species.

Keywords: Banksia, chronosequence, climate change, fire, Hakea, seed storage, serotiny, shrublands.

References

Abatzoglou JT, Dobrowski SZ, Parks SA, Hegewisch KC (2018) TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958–2015. Scientific Data 5, 170191.
| Crossref | Google Scholar | PubMed |

Agne MC, Fontaine JB, Enright NJ, Harvey BJ (2022) Fire interval and post-fire climate effects on serotinous forest resilience. Fire Ecology 18, 22.
| Crossref | Google Scholar |

Bassett OD, Prior LD, Slijkerman CM, Jamieson D, Bowman DMJS (2015) Aerial sowing stopped the loss of alpine ash (Eucalyptus delegatensis) forests burnt by three short-interval fires in the Alpine National Park, Victoria, Australia. Forest Ecology and Management 342, 39-48.
| Crossref | Google Scholar |

Brooks ME, Kristensen K, van Benthem KJ, Magnusson A, Berg CW, Nielsen A, Skaug HJ, Maechler M, Bolker BM (2017) glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. The R Journal 9, 378-400.
| Crossref | Google Scholar |

Brown CD, Johnstone JF (2012) Once burned, twice shy: repeat fires reduce seed availability and alter substrate constraints on Picea mariana regeneration. Forest Ecology and Management 266, 34-41.
| Crossref | Google Scholar |

Burrows ND, Wardell-Johnson G, Ward B (2008) Post-fire juvenile period of plants in south-west Australia forests and implications for fire management. Journal of the Royal Society of Western Australia 91, 163-174.
| Google Scholar |

Coates F, Enright NJ, Miller BP, Sutter G, Carter O (2010) ‘Fire regime variability and vegetation composition in the northern Grampians.’ (Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment: Heidelberg, VIC, Australia)

Davis KT, Dobrowski SZ, Higuera PE, Holden ZA, Veblen TT, Rother MT, Parks SA, Sala A, Maneta MP (2019) Wildfires and climate change push low-elevation forests across a critical climate threshold for tree regeneration. Proceedings of the National Academy of Sciences 116, 6193-6198.
| Crossref | Google Scholar | PubMed |

Diffenbaugh NS, Field CB (2013) Changes in ecologically critical terrestrial climate conditions. Science 341, 486-492.
| Crossref | Google Scholar | PubMed |

Enright NJ, Goldblum D (1999) Demography of a non-sprouting and resprouting Hakea species (Proteaceae) in fire-prone Eucalyptus woodlands of southeastern Australia in relation to stand age, drought and disease. Plant Ecology 144, 71-82.
| Crossref | Google Scholar |

Enright NJ, Lamont BB, Marsula R (1996) Canopy seed bank dynamics and optimum fire regime for the highly serotinous shrub, Banksia hookeriana. Journal of Ecology 84, 9-17.
| Crossref | Google Scholar |

Enright NJ, Marsula R, Lamont BB, Wissel C (1998) The ecological significance of canopy seed storage in fire-prone environments: a model for non-sprouting shrubs. Journal of Ecology 86, 946-959.
| Crossref | Google Scholar |

Enright NJ, Fontaine JB, Bowman DM, Bradstock RA, Williams RJ (2015) Interval squeeze: altered fire regimes and demographic responses interact to threaten woody species persistence as climate changes. Frontiers in Ecology and the Environment 13, 265-272.
| Crossref | Google Scholar |

Espelta JM, Verkaik I, Eugenio M, Lloret F (2008) Recurrent wildfires constrain long-term reproduction ability in Pinus halepensis Mill. International Journal of Wildland Fire 17, 579.
| Crossref | Google Scholar |

Gill A, McMahon A (1986) A postfire chronosequence of cone, follicle and seed production in Banksia ornata. Australian Journal of Botany 34, 425-433.
| Crossref | Google Scholar |

Gill AM, Nicholls AO (1989) Monitoring fire-prone flora in reserves for nature conservation. In ‘Fire management for nature conservation. Proceedings of national workshop’. (Eds ND Burrows, WL McCaw, G Friend) pp. 137–152. (Department of Conservation and Land Management: Busselton, WA)

Gosper CR, Miller BP, Gallagher RV, Kinloch J, van Dongen R, Adams E, Barrett S, Cochrane A, Comer S, McCaw L, Miller RG, Prober SM, Yates CJ (2022) Mapping risk to plant populations from short fire intervals via relationships between maturation period and environmental productivity. Plant Ecology 223, 769-787.
| Crossref | Google Scholar |

Hansen WD, Turner MG (2019) Origins of abrupt change? Postfire subalpine conifer regeneration declines nonlinearly with warming and drying. Ecological Monographs 89, e01340.
| Crossref | Google Scholar |

Hartig F (2021) DHARMa: residual diagnostics for hierarchical (multi-level/mixed) regression models. R package version 0.4.0. Available at https://CRAN.R-project.org/package=DHARMa

Harvey BJ, Donato DC, Turner MG (2016) High and dry: post-fire tree seedling establishment in subalpine forests decreases with post-fire drought and large stand-replacing burn patches. Global Ecology and Biogeography 25, 655-669.
| Crossref | Google Scholar |

Head L, Adams M, McGregor HV, Stephanie T (2014) Climate change and Australia. WIREs Climate Change 5, 175-197.
| Crossref | Google Scholar |

Iler AM, CaraDonna PJ, Forrest JRK, Post E (2021) Demographic consequences of phenological shifts in response to climate change. Annual Review of Ecology, Evolution, and Systematics 52, 221-245.
| Crossref | Google Scholar |

IPCC (2022) Climate change 2022: impacts, adaptation, and vulnerability. In ‘Contribution of Working Group II to the Sixth Assessment of the Intergovernmental Panel on Climate Change’. (Eds H-O Pörtner, DC Roberts, M Tignor, ES Poloczanska, K Mintenbeck, A Alegría, M Craig, S Langsdorf, S Löschke, V Möller, A Okem, B Rama). PP 37–118. (Cambridge University Press)

Jolly WM, Cochrane MA, Freeborn PH, Holden ZA, Brown TJ, Williamson GJ, Bowman DM (2015) Climate-induced variations in global wildfire danger from 1979 to 2013. Nature Communications 6, 7537.
| Crossref | Google Scholar | PubMed |

Jones MW, Abatzoglou JT, Veraverbeke S, Andela N, Lasslop G, Forkel M, Smith AJP, Burton C, Betts RA, Van Der Werf GR, Sitch S, Canadell JG, Santín C, Kolden C, Doerr SH, Le Quéré C (2022) Global and regional trends and drivers of fire under climate change. Reviews of Geophysics 60, e2020RG000726.
| Crossref | Google Scholar |

Kassambara A (2020) ggpubr: “ggplot2” Based Publication Ready Plots. R package version 0.4.0. Available at https://CRAN.R-project.org/package=ggpubr

Keeley JE, Ne’eman G, Fotheringham CJ (1999) Immaturity risk in a fire-dependent pine. Journal of Mediterranean Ecology 1, 41-48.
| Google Scholar |

Keith D, Lindenmayer D, Lowe A, Russell-Smith J, Barrett S, Enright N, Fox B, Guerin G, Paton D, Tozer M, Yates C (2014) Heathlands. In ‘Biodiversity and environmental change: monitoring, challenges and direction’. (Eds D Lindenmayer, E Burns, N Thurgate, A Lowe) pp. 283–334. (CSIRO Publishing: Melbourne, Australia)

Kraaij T, Baard JA, Cowling RM, van Wilgen BW, Das S (2013) Historical fire regimes in a poorly understood, fire-prone ecosystem: eastern coastal fynbos. International Journal of Wildland Fire 22, 277.
| Crossref | Google Scholar |

Kroiss SJ, HilleRisLambers J (2015) Recruitment limitation of long-lived conifers: implications for climate change responses. Ecology 96, 1286-1297.
| Crossref | Google Scholar | PubMed |

Lüdecke D (2018) ggeffects: tidy data frames of marginal effects from regression models. Journal of Open Source Software 3, 772.
| Crossref | Google Scholar |

Morgan JW, McCarthy MA, Willocks E (2021) Does intraspecific variation in demography have implications for fire management of an obligate-seeder shrub across its geographic range? Austral Ecology 46, 315-323.
| Crossref | Google Scholar |

Moritz MA, Parisien M-A, Batllori E, Krawchuk MA, Dorn JV, Ganz DJ, Hayhoe K (2012) Climate change and disruptions to global fire activity. Ecosphere 3, art49.
| Crossref | Google Scholar |

Ramsey F, Schafer D (2012) ‘The Statistical Sleuth: A Course in Methods of Data Analysis.’ 3rd edn. (Cengage Learning: Boston, MA, USA)

R Core Team (2022) ‘R: A language and environment for statistical computing.’ (R Foundation for Statistical Computing: Vienna, Austria)

Selwood KE, McGeoch MA, MacNally R (2015) The effects of climate change and land‐use change on demographic rates and population viability. Biological Reviews 90, 837-853.
| Crossref | Google Scholar | PubMed |

Shaw J (1997) A demographic study of Banksia ornata (Proteaceae). BSc Honours Thesis, Department of Geography and Environmental Studies, University of Melbourne, Victoria, Australia.

Solt F, Hu Y (2024) dotwhisker: Dot-and-Whisker Plots of Regression Results. Available at the Comprehensive R archive Network (CRAN). https://cran.r-project.org/

Stevens-Rumann CS, Kemp KB, Higuera PE, Harvey BJ, Rother MT, Donato DC, Morgan P, Veblen TT (2018) Evidence for declining forest resilience to wildfires under climate change. Ecology Letters 21, 243-252.
| Crossref | Google Scholar | PubMed |

Turner MG, Braziunas KH, Hansen WD, Harvey BJ (2019) Short-interval severe fire erodes the resilience of subalpine lodgepole pine forests. Proceedings of the National Academy of Sciences 116, 11319-11328.
| Crossref | Google Scholar | PubMed |

Vicente-Serrano SM, Lopez-Moreno J-I, Beguería S, Lorenzo-Lacruz J, Sanchez-Lorenzo A, García-Ruiz JM, Azorin-Molina C, Morán-Tejeda E, Revuelto J, Trigo R, Coelho F, Espejo F (2014) Evidence of increasing drought severity caused by temperature rise in southern Europe. Environmental Research Letters 9, 044001.
| Crossref | Google Scholar |

von Takach Dukai B, Lindenmayer DB, Banks SC (2018) Environmental influences on growth and reproductive maturation of a keystone forest tree: Implications for obligate seeder susceptibility to frequent fire. Forest Ecology and Management 411, 108-119.
| Crossref | Google Scholar |

Walsh NG, Entistle TJ (1996) ‘Flora of Victoria.’ (Inkata Press: Melbourne, Australia)

Whitman E, Parisien M-A, Thompson DK, Flannigan MD (2019) Short-interval wildfire and drought overwhelm boreal forest resilience. Scientific Reports 9, 18796.
| Crossref | Google Scholar | PubMed |

Wickham H (2016) ‘ggplot2: Elegant Graphics for Data Analysis.’ (Springer-Verlag: New York, NY, USA)

Xu T, Hutchinson MF (2013) New developments and applications in the ANUCLIM spatial climatic and bioclimatic modelling package. Environmental Modelling & Software 40, 267-279.
| Crossref | Google Scholar |