Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

A technique to estimate the pre-fire depth of burial of Grevillea seeds by using seedlings after fire

Tony D. Auld A B and Andrew J. Denham A
+ Author Affiliations
- Author Affiliations

A Biodiversity Conservation Science, Department of Environment and Conservation (NSW), PO Box 1967, Hurstville, NSW 2220, Australia.

B Corresponding author. Email: tony.auld@environment.nsw.gov.au

Australian Journal of Botany 53(5) 401-405 https://doi.org/10.1071/BT04186
Submitted: 10 November 2004  Accepted: 4 April 2005   Published: 11 August 2005

Abstract

In a glasshouse experiment, we used the shrub Grevillea speciosa to examine the reliability of estimating the depth of seed burial based on the distance from the soil surface to the junction of the swollen hypocotyl with the radicle. We then examined the applicability of the technique in the field by using post-fire seedling emergence. We found that the mean length of the swollen hypocotyl in seedlings was a good predictor of the depth of seed burial (R2 = 0.97). Most variation occurred for seeds buried near the surface at 2-cm depth, where the swollen hypocotyl overestimated the depth of seed burial by about 1 cm. There was a decline in the ability of seeds to successfully emerge from soil depths below 2 cm, with seedlings of G. speciosa able to emerge from soil depths up to 8 cm in the glasshouse. This corresponds with the estimated maximum emergence depth based on seed mass. In the field, seedlings were estimated to have emerged from depths of 1–7 cm after an intense wildfire. There was an approximately normal distribution of seedling emergence depths; however, the mode of this distribution varied among locations. The technique gave comparable results to a similar technique developed for Acacia spp., allowing consideration of a greater range of species and post-fire locations. Use of the technique has the potential to provide insights into the impacts of fires below ground, including the nature of post-fire germination, residual soil seed banks, the depth-related action of fire-induced germination cues and small-scale spatial variation.


Acknowledgments

We thank Mark Tozer and Paul Mooney for help with field sampling of seedlings, Belinda Kenny for supplying seeds and the Institute for Conservation Biology, University of Wollongong, for the use of glasshouse facilities.


References


Ashcroft WJ, Murray DR (1979) The dual functions of the cotyledons of Acacia iteaphylla F.Muell. (Mimosoideae). Australian Journal of Botany 27, 343–352.

Auld TD (1986) Population dynamics of the shrub Acacia suaveolens (Sm.) Willd.: fire and the transition to seedlings. Australian Journal of Ecology 11, 373–385.

Auld TD, Denham AJ (1999) The role of ants and mammals in dispersal and post-dispersal seed predation of the shrubs Grevillea (Proteaceae). Plant Ecology 144, 201–213.
CrossRef |

Auld TD, O’Connell MA (1991) Predicting patterns of post-fire germination in 35 eastern Australian Fabaceae. Australian Journal of Ecology 16, 53–70.

Auld TD, Tozer M (1995) Patterns in emergence of Acacia and Grevillea seedlings after fire. Proceedings of the Linnean Society of New South Wales 115, 5–15.

Auld TD, Tozer MG (1999) How well do post-fire indicators provide insights into the degree of soil heating during the passage of fires? In ‘Proceedings of ‘Bushfire 99’. Australian Bushfire Conference, Albury’


Bell DT (1994) Interaction of fire, temperature and light in the germination response of 16 species from the Eucalyptus marginata forest of south-western Western Australia. Australian Journal of Botany 42, 501–509.

Bond, WJ ,  and  Van Wilgen, BW (1996). ‘Fire and plants.’ (Chapman and Hall: London)

Bond WJ, Honig M, Maze KE (1999) Seed size and seedling emergence: an allometric relationship and some ecological implications. Oecologia 120, 132–136.
CrossRef |

Bradstock RA, Auld TD (1995) Soil temperatures during experimental bushfires in relation to fire intensity: consequences for legume germination and fire management in south-eastern Australia. Journal of Applied Ecology 32, 76–84.

Brown NAC (1993) Promotion of germination of fynbos seeds by plant-derived smoke. New Phytologist 123, 575–583.

Chen H, Maun MA (1999) Effects of sand burial depth on seed germination and seedling emergence of Cirsium pitcheri. Plant Ecology 140, 53–60.
CrossRef |

Dixon KW, Roche S, Pate JS (1995) The promotive effect of smoke derived from burnt native vegetation on seed germination of Western Australian plants. Oecologia 101, 185–192.
CrossRef |

Gill AM, Ingwersen F (1976) Growth of Xanthorrhoea australis R.Br. in the relation to fire. Journal of Applied Ecology 13, 195–203.

Grant CD, Bell DT, Koch JM, Loneragan WA (1996) Implications of seedling emergence to site restoration following bauxite mining in western Australia. Restoration Ecology 4, 146–154.

Grundy AC, Mead A, Burston S (2003) Modelling the emergence response of weed seeds to burial depth: interactions with seed density, weight and shape. Journal of Applied Ecology 40, 757–770.
CrossRef |

Holmes PM (2002) Depth distribution and composition of seed-banks in alien-invaded and uninvaded fynbos vegetation. Austral Ecology 27, 110–120.
CrossRef |

Keeley JE (1987) Role of fire in seed germination of woody taxa in California chaparral. Ecology 68, 434–443.

Keith DA (1997) Combined effects of heat shock, smoke and darkness on germination of Epacris stuartii Stapf., an endangered fire-prone Australian shrub. Oecologia 112, 340–344.
CrossRef |

Kenny BJ (2000) Influence of multiple fire-related germination cues on three Sydney Grevillea (Proteaceae) species. Austral Ecology 25, 664–669.
CrossRef |

Kenny BJ (2003) Fire-related germination cues for soil-stored seedbanks of fire-prone habitats in the Sydney region, Australia. PhD Thesis (University of Technology: Sydney)

Makinson RO (2000) Grevillea. Flora of Australia 17A, 1–460.

Morris EC (2000) Germination response of seven east Australian Grevillea species (Proteaceae) to smoke, heat exposure and scarification. Australian Journal of Botany 48, 179–189.
CrossRef |

Ren J, Tao L, Liu XM (2002) Effect of sand burial depth on seed germination and seedling emergence of Calligonum L. species. Journal of Arid Environments 51, 603–611.
CrossRef |

Rokich DP (2000) Topsoil handling and storage effects on woodland restoration in Western Australia. Restoration Ecology 8, 196–208.
CrossRef |

Stone EC, Juhren G (1953) Fire stimulated germination. Californian Agriculture 7, 13–14.

Thomas PB, Morris EC, Auld TD (2003) Interactive effects of heat shock and smoke on germination of nine species forming soil seedbanks within the Sydney region. Austral Ecology 28, 674–683.
CrossRef |

Tozer MG (1998) Distribution of the soil seedbank and influence of fire on seedling emergence in Acacia saligna growing on the central coast of New South Wales. Australian Journal of Botany 46, 743–755.
CrossRef |

Underwood AJ (1981) Techniques of analysis of variance in experimental marine biology and ecology. Oceanography Marine Biological Annual Review 19, 513–605.

Whelan, RJ (1995). ‘The ecology of fire.’ (Cambridge University Press: Cambridge, UK)

Whight S, Bradstock R (1999) Indices of fire characteristics in sandstone heath near Sydney, Australia. International Journal of Wildland Fire 9, 145–153.
CrossRef |








Rent Article (via Deepdyve) Export Citation Cited By (6)