Use of growth characteristics for predicting plant age of three obligate-seeder Proteaceae species
Meaghan E. Jenkins A D , David A. Morrison A B and Tony D. Auld CA Department of Environmental Sciences, University of Technology Sydney, Westbourne Street, Gore Hill, NSW 2065, Australia.
B Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, Uppsala 751 89, Sweden.
C Biodiversity Conservation Science, Department of Environment and Conservation (NSW), PO Box 1967, Hurstville, NSW 2220, Australia.
D Corresponding author. Present address: Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA England. Email: meaghanjenkins@hotmail.com.
Australian Journal of Botany 53(2) 101-108 https://doi.org/10.1071/BT04067
Submitted: 12 May 2004 Accepted: 21 October 2004 Published: 31 March 2005
Abstract
We tested the ability to predict plant (and hence population) age for three fire-sensitive obligate-seeder Proteaceae species (Banksia ericifolia, Banksia marginata and Petrophile pulchella) in the heath and woodland vegetation of the Sydney region. To do this we sampled the number of growth whorls, as well as other growth characteristics (stem girth and height measurements, and canopy area and volume estimates), in areas of known time since last fire (TSLF). The average number of growth whorls was a very good predictor of plant age for both Banksia species (R2 = 98%, 99%), but this needed to be corrected for linear underestimation in P. pulchella (R2 = 92%). This technique could successfully be applied to these species in similar habitats across a large spatial scale, and so this information can be used to determine the age of a population in areas of unknown TSLF. A sample size of 15 plants was sufficient for accurate age estimates of all species; however, better estimates of TSLF for a particular plant community were obtained when estimates from two or more of the species were combined. We thus provide empirical evidence for the validity and accuracy of the growth-whorl technique for predicting plant age and hence TSLF. This information will assist in informing the development of appropriate management strategies for plants in relation to fire. Of the other growth characteristics studied, stem girth was the most reliable predictor; however, in general these other characteristics had wide confidence intervals on the predictions for sites greater than 10 years TSLF, owing to a non-linear relationship with age.
Acknowledgments
Thanks go to the New South Wales National Parks and Wildlife Service for the use of facilities, and especially to Mark Ooi for his help. Kate Langdon and Simon Rowe helped with the fieldwork, and the referees provided helpful comments on the manuscript. The sampling was carried out under licences from the New South Wales National Parks and Wildlife Service and the Sydney Catchment Authority.
Abbott I
(1985) Rate of growth of Banksia grandis Willd. (Proteaceae) in Western Australian forest. Australian Journal of Botany 33, 381–391.
Benson DH
(1985) Maturation periods for fire-sensitive shrub species in Hawkesbury Sandstone vegetation. Cunninghamia 1, 339–349.
Brown MJ, Podger FD
(1982) Floristics and fire regimes of a vegetation sequence from sedgeland-heath to rainforest at Bathurst Harbour, Tasmania. Australian Journal of Botany 30, 659–676.
Cowling RM, Lamont BB
(1985) Variation in serotiny of three Banksia species along a climatic gradient. Australian Journal of Ecology 10, 345–350.
Cowling RM,
Lamont BB, Pierce SM
(1987) Seed bank dynamics of four co-occurring Banksia species. Journal of Ecology 75, 289–302.
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.
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 | GoogleScholarGoogle Scholar |
Gill, AM (1981). Adaptive responses of Australian vascular plant species to fire. In ‘Fire and the Australian biota’. pp. 243–272. (Australian Academy of Science: Canberra)
Keith, DA (1994). Ecological and environmental impacts of natural fire regimes. In ‘Bushfire! Looking to the future’. pp. 33–39. (Nature Conservation Council of New South Wales: Sydney)
Keith DA
(1996) Fire-driven extinction of plant populations: a synthesis of theory and review of evidence from Australian vegetation. Proceedings of the Linnean Society of New South Wales 116, 37–78.
Lamont, BB (1985). Fire responses of sclerophyll shrublands—a population ecology approach, with particular reference to the genus Banksia. In ‘Fire ecology and management in Western Australian ecosystems’. Curtin Environmental Studies Group Report No. 14. pp. 41–46. (Curtin University: Perth)
Lamont BB, Barker MJ
(1988) Seed bank dynamics of a serotinous, fire-sensitive Banksia species. Australian Journal of Botany 36, 193–203.
Lamont BB,
Rees RG,
Witkowski ETF, Whitten VA
(1994) Comparative size, fecundity and ecophysiology of roadside plants of Banksia hookeriana. Journal of Applied Ecology 31, 137–144.
Minitab (2000).
Rogers RW, Westman WE
(1977) Seasonal nutrient dynamics of litter in a subtropical eucalypt forest, North Stradbroke Island. Australian Journal of Botany 25, 47–58.
Specht RL,
Rayson P, Jackman ME
(1958) Dark Island Heath (Ninety-Mile Plain, South Australia). VI. Pyric succession: changes in composition, coverage, dry weight and mineral nutrient status. Australian Journal of Botany 6, 59–88.
Tapias R,
Gil L,
Fuentes-Utrilla P, Pardos JA
(2001) Canopy seed banks in Mediterranean pines of south-eastern Spain: a comparison between Pinus halepensis Mill., P. pinaster Ait., P. nigra Arn. and P. pinea L. Journal of Ecology 89, 629–638.
| Crossref | GoogleScholarGoogle Scholar |
Wills TJ
(2003) Using Banksia (Proteaceae) node counts to estimate time since fire. Australian Journal of Botany 51, 239–242.
| Crossref | GoogleScholarGoogle Scholar |
Witkowski ETF,
Lamont BB, Connell SJ
(1991) Seed bank dynamics of three co-occurring banksias in south coastal Western Australia: the role of plant age, cockatoos, senescence and interfire establishment. Australian Journal of Botany 39, 385–397.
Witkowski ETF,
Lamont BB,
Walton CS, Radford S
(1992) Leaf demography, sclerophylly and ecophysiology of two Banksias with contrasting leaf life spans. Australian Journal of Botany 40, 849–862.
Witkowski ETF,
Lamont BB, Obbens FJ
(1994) Commercial picking of Banksia hookeriana in the wild reduces subsequent shoot, flower and seed production. Journal of Applied Ecology 31, 508–520.
Zar, JH (1999).
