Germination biologies and seedbank dynamics of Acacia shrubs in the Western Desert: implications for fire season impacts on recruitment
Boyd R. Wright A B C E and Peter J. Clarke D
+ Author Affiliations
- Author Affiliations
A Alice Springs Herbarium, Department of Land and Resource Management, Northern Territory Government, Alice Springs, NT 0870, Australia.
B School of Agriculture and Food Science, University of Queensland, Brisbane, Qld, 4072, Australia.
C Botany, School of Environmental and Rural Science, University of New England, Armidale, NSW 2350, Australia.
D Deceased. Formerly of Botany, School of Environmental and Rural Science, University of New England, Armidale, NSW 2350, Australia.
E Corresponding author. Email: desertecol@desertecol.com
Australian Journal of Botany 66(3) 278-285 https://doi.org/10.1071/BT18003
Submitted: 4 January 2018 Accepted: 14 May 2018 Published: 26 June 2018
Abstract
In arid Australia, fires in different seasons often result in markedly different recruitment rates of woody plants, and this can have important and long-lasting impacts on post-fire community structure and composition. The current study investigated ecological mechanisms behind this effect in four widespread arid Acacia species: Acacia aptaneura, Maslin & J.E.Reid Acacia kempeana F.Muell., Acacia maitlandii F.Muell. and Acacia melleodora Pedley. Specifically, the study examined whether increased recruitment after summer compared with winter burning relates to (1) higher soil temperatures during summer fires having increased capacity to overcome dormancy of seeds with heat-stimulated germination; (2) warmer soil temperature conditions after summer fires providing more favourable incubation temperatures for germination; and/or (3) summer fires coinciding with seasonal fluxes in seedbank densities, which may occur in response to granivory and/or rapid rates of seed deterioration after dispersal. Results supported hypotheses (1) and (2), as germination of all species responded positively to heat shock and warmer incubation temperatures. Some support was also demonstrated for hypothesis (3), as seedbank densities were shown to fluctuate seasonally, most likely in response to strong granivory. This multi-species study provides insights into mechanisms behind enhanced shrub recruitment after arid zone summer fires; and reinforces the notion that season of burn can be a strong determinant of regeneration trajectories of woody plants after fire.
Additional keywords: Acacia aneura, arid plant ecology, fire ecology, resprouter plants, seed dormancy.
References
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.| Population dynamics of the shrub Acacia suaveolens (Sm.) Willd.: fire and the transition to seedlings.Crossref | GoogleScholarGoogle Scholar |
Australian Government Bureau of Meteorology (2017) Daily rainfall totals from Glen Helen station (1941–2015). Available at http://www.bom.gov.au/jsp/ncc/cdio/weather [Verified 3 January 2018]
Berg RY (1975) Myrmecochorous plants in Australia and their dispersal by ants. Australian Journal of Botany 23, 475–508.
| Myrmecochorous plants in Australia and their dispersal by ants.Crossref | GoogleScholarGoogle Scholar |
Bond WJ (1984) Fire survival of Cape Proteaceae – influence of fire season and seed predators. Vegetatio 56, 65–74.
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.
| Soil temperatures during experimental bushfires in relation to fire intensity: consequences for legume germination and fire management in south-eastern Australia.Crossref | GoogleScholarGoogle Scholar |
Bradstock RA, Auld TD, Ellis ME, Cohn JS (1992) Soil temperatures during bushfire in semi-arid mallee shrublands. Australian Journal of Ecology 17, 433–440.
| Soil temperatures during bushfire in semi-arid mallee shrublands.Crossref | GoogleScholarGoogle Scholar |
Céspedes B, Luna B, Perez B, Urbieta IR, Moreno JM (2014) Burning season effects on the short-term post-fire vegetation dynamics of a Mediterranean heathland. Applied Vegetation Science 17, 86–96.
| Burning season effects on the short-term post-fire vegetation dynamics of a Mediterranean heathland.Crossref | GoogleScholarGoogle Scholar |
Davies SJJF (1976) Studies of the flowering season and fruit production of some arid zone shrubs in Western Australia. Journal of Ecology 64, 665–687.
| Studies of the flowering season and fruit production of some arid zone shrubs in Western Australia.Crossref | GoogleScholarGoogle Scholar |
Friedel MH, Nelson DJ, Sparrow AD, Kinloch JE, Maconochie JR (1993) What induces central Australian arid zone trees and shrubs to flower and fruit? Australian Journal of Botany 41, 307–319.
| What induces central Australian arid zone trees and shrubs to flower and fruit?Crossref | GoogleScholarGoogle Scholar |
Friedel MH, Nelson DJ, Sparrow AD, Kinloch JE, Maconochie JR (1994) Flowering and fruiting of arid zone species of Acacia in central Australia. Journal of Arid Environments 27, 221–239.
| Flowering and fruiting of arid zone species of Acacia in central Australia.Crossref | GoogleScholarGoogle Scholar |
Geiger R (1959) ‘The climate near the ground.’ (Harvard University Press: Cambridge, MA, USA)
Govender N, Trollope WSW, Van Wilgen BW (2006) The effect of fire season, fire frequency, rainfall and management on fire intensity in savanna vegetation in South Africa. Journal of Applied Ecology 43, 748–758.
| The effect of fire season, fire frequency, rainfall and management on fire intensity in savanna vegetation in South Africa.Crossref | GoogleScholarGoogle Scholar |
Harrington JF (1972) Seed storage and longevity. In ‘Seed biology’. (Ed. TT Kozlowski) pp. 145–245. (Academic Press: New York)
Heelemann S, Proches S, Rebelo AG, van Wilgen BW, Porembski S, Cowling RM (2008) Fire season effects on the recruitment of non-sprouting serotinous Proteaceae in the eastern (bimodal rainfall) fynbos biome, South Africa. Austral Ecology 33, 119–127.
| Fire season effects on the recruitment of non-sprouting serotinous Proteaceae in the eastern (bimodal rainfall) fynbos biome, South Africa.Crossref | GoogleScholarGoogle Scholar |
Hodgkinson KC (1991) Shrub recruitment response to intensity and season of fire in a semi-arid woodland. Journal of Applied Ecology 28, 60–70.
| Shrub recruitment response to intensity and season of fire in a semi-arid woodland.Crossref | GoogleScholarGoogle Scholar |
Hodgkinson KC, Oxley RE (1990) Influence of fire and edaphic factors on germination of the arid zone shrubs Acacia aneura, Cassia nemophila and Dodonaea viscosa. Australian Journal of Botany 38, 269–279.
| Influence of fire and edaphic factors on germination of the arid zone shrubs Acacia aneura, Cassia nemophila and Dodonaea viscosa.Crossref | GoogleScholarGoogle Scholar |
Keith DA (2002) Population dynamics of an endangered heathland shrub, Epacris stuartii (Epacridaceae): recruitment, establishment and survival. Austral Ecology 27, 67–76.
| Population dynamics of an endangered heathland shrub, Epacris stuartii (Epacridaceae): recruitment, establishment and survival.Crossref | GoogleScholarGoogle Scholar |
Lenth RV (2016) Least-Squares Means: The R Package lsmeans. Journal of Statistical Software 69, 1–33.
| Least-Squares Means: The R Package lsmeans.Crossref | GoogleScholarGoogle Scholar |
Letnic M, Dickman CR, McNaught G (2000) Bet-hedging and germination in the Australian arid zone shrub Acacia ligulata. Austral Ecology 25, 368–374.
| Bet-hedging and germination in the Australian arid zone shrub Acacia ligulata.Crossref | GoogleScholarGoogle Scholar |
McArthur AG (1972) Fire control in the arid and semi-arid lands of Australia. The use of trees and shrubs in the dry country of Australia.’ (Australian Government Publishing Service: Canberra)
Moore RP (1985) ‘Handbook on tetrazolium testing.’ (International Seed Testing Association: Zurich, Switzerland)
Morton SR (1982) Granivory in the Australian arid zone: diversity of harvester ants and structure of their communities. In ‘Evolution of the flora and fauna of arid Australia’. (Eds WR Barker, PJM Greenslande) pp. 257–262. (Peacock Publications: Frewville, SA)
Nicholas AMM, Franklin DC, Bowman D (2011) Floristic uniformity across abrupt boundaries between Triodia hummock grassland and Acacia shrubland on an Australian desert sandplain. Journal of Arid Environments 75, 1090–1096.
| Floristic uniformity across abrupt boundaries between Triodia hummock grassland and Acacia shrubland on an Australian desert sandplain.Crossref | GoogleScholarGoogle Scholar |
Nield AP, Enright NJ, Ladd PG (2016) Fire-stimulated reproduction in the resprouting, non-serotinous conifer Podocarpous drouynianus (Podocarpaceae): the impact of a changing fire regime. Population Ecology 58, 179–187.
| Fire-stimulated reproduction in the resprouting, non-serotinous conifer Podocarpous drouynianus (Podocarpaceae): the impact of a changing fire regime.Crossref | GoogleScholarGoogle Scholar |
Ooi MKJ, Auld TD, Whelan RJ (2004) Delayed post-fire seedling emergence linked to season: a case study with Leucopogon species (Epacridaceae). Plant Ecology 174, 183–196.
| Delayed post-fire seedling emergence linked to season: a case study with Leucopogon species (Epacridaceae).Crossref | GoogleScholarGoogle Scholar |
Pound LM, Ainsley PJ, Facelli JM (2014) Dormancy-breaking and germination requirements for seeds of Acacia papyrocarpa, Acacia oswaldii and Senna artemisioides ssp. × coriacea, three Australian arid-zone Fabaceae species. Australian Journal of Botany 62, 546–557.
| Dormancy-breaking and germination requirements for seeds of Acacia papyrocarpa, Acacia oswaldii and Senna artemisioides ssp. × coriacea, three Australian arid-zone Fabaceae species.Crossref | GoogleScholarGoogle Scholar |
R Core Team (2016) ‘R: A language and environment for statistical computing.’ (R Foundation for Statistical Computing: Vienna, Austria) Available at http://www.R-project.org/ [Verified 6 May 2017]
Simpson B (1999) Rehabilitation of the granites gold mine: a study of unmined vegetation and seed banks. BSc Honours thesis, Flinders University, Adelaide.
Suppiah R (1993) ENSO phenomenon and 30–50 day variability in the Australian summer monsoon rainfall. International Journal of Climatology 13, 837–851.
| ENSO phenomenon and 30–50 day variability in the Australian summer monsoon rainfall.Crossref | GoogleScholarGoogle Scholar |
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.
| Distribution of the soil seedbank and influence of fire on seedling emergence in Acacia saligna growing on the central coast of New South Wales.Crossref | GoogleScholarGoogle Scholar |
Whelan RJ (1995) ‘The ecology of fire.’ (Cambridge University Press: Cambridge, UK)
Williams PR, Congdon RA, Grice AC, Clarke PJ (2004) Soil temperature and depth of legume germination during early and late dry season fires in a tropical eucalypt savanna of north-eastern Australia. Austral Ecology 29, 258–263.
| Soil temperature and depth of legume germination during early and late dry season fires in a tropical eucalypt savanna of north-eastern Australia.Crossref | GoogleScholarGoogle Scholar |
Wright BR, Clarke PJ (2007a) Fire regime (recency, interval and season) changes the composition of spinifex (Triodia spp.)-dominated desert dunes. Australian Journal of Botany 55, 709–724.
| Fire regime (recency, interval and season) changes the composition of spinifex (Triodia spp.)-dominated desert dunes.Crossref | GoogleScholarGoogle Scholar |
Wright BR, Clarke PJ (2007b) Resprouting responses of Acacia shrubs in the Western Desert of Australia – fire severity, interval and season influence survival. International Journal of Wildland Fire 16, 317–323.
| Resprouting responses of Acacia shrubs in the Western Desert of Australia – fire severity, interval and season influence survival.Crossref | GoogleScholarGoogle Scholar |
Wright BR, Clarke PJ (2008) Relationships between soil temperatures and properties of fire in feathertop spinifex (Triodia schinzii (Henrard) Lazarides) sandridge desert in central Australia. The Rangeland Journal 30, 317–325.
| Relationships between soil temperatures and properties of fire in feathertop spinifex (Triodia schinzii (Henrard) Lazarides) sandridge desert in central Australia.Crossref | GoogleScholarGoogle Scholar |
Wright BR, Fensham RJ (2016) Relationships between fire severity and recruitment in arid grassland dominated by the obligate-seeding soft spinifex (Triodia pungens). International Journal of Wildland Fire 25, 1264–1272.
| Relationships between fire severity and recruitment in arid grassland dominated by the obligate-seeding soft spinifex (Triodia pungens).Crossref | GoogleScholarGoogle Scholar |
Wright BR, Fensham RJ (2017) Fire after a mast year triggers mass recruitment of slender mulga (Acacia aptaneura), a desert shrub with heat-stimulated germination. American Journal of Botany 104, 1474–1483.
| Fire after a mast year triggers mass recruitment of slender mulga (Acacia aptaneura), a desert shrub with heat-stimulated germination.Crossref | GoogleScholarGoogle Scholar |
Yadegarnejad SA, Jafarabad MD, Savadkoohi NM (2015) Surface wildfire in conifer broad-leaved forests of the Hyrcanian region of Iran: short-term effect on regeneration and damage to trees. Journal of Forest Research 26, 425–434.
| Surface wildfire in conifer broad-leaved forests of the Hyrcanian region of Iran: short-term effect on regeneration and damage to trees.Crossref | GoogleScholarGoogle Scholar |
Zuur AF, Leno EN, Elphick CS (2010) A protocol for data exploration to avoid common statistical problems. Methods in Ecology and Evolution 1, 3–14.
| A protocol for data exploration to avoid common statistical problems.Crossref | GoogleScholarGoogle Scholar |
