Seed ecology of Captain Cook tree [Cascabela thevetia (L.) Lippold] – germination and longevityFaiz F. Bebawi A C , Shane D. Campbell A and Robert J. Mayer B
A Biosecurity Queensland, Department of Agriculture and Fisheries, Tropical Weeds Research Centre, PO Box 187, Charters Towers, Qld 4820, Australia.
B Agri-Science Queensland, Department of Agriculture and Fisheries, Maroochy Research Station, Mayers Road, Nambour, Qld 4560, Australia.
C Corresponding author. Email: Faiz.Bebawi@daf.qld.gov.au
The Rangeland Journal - https://doi.org/10.1071/RJ17025
Submitted: 4 April 2017 Accepted: 3 July 2017 Published online: 27 July 2017
Cascabela thevetia (L.) Lippold (Apocynaceae), commonly known as Captain Cook tree or yellow oleander, has established large infestations in riparian areas along several creeks and rivers in northern Queensland. To better understand the ecology of C. thevetia and the implications for its spread and management, this study reports seven experiments related to the seed ecology of its yellow and peach biotypes. We quantified its germination response to ambient (Experiment 1a and 1b), alternating and constant temperature (Experiment 2a and 2b) regimes and exposure to different light conditions (Experiment 3). Seed longevity under two soil types, two levels of pasture cover and three burial depths was also determined (Experiment 4a and 4b).
Both loose seeds and seeds still within pods (kernels) of the two biotypes of C. thevetia were able to germinate in all months of the year in northern Queensland, irrespective of the large differences in monthly ambient temperatures experienced at the Charters Towers study site. Both biotypes also germinated across a wide range of alternating day/night temperatures from 16/12°C to 47/37°C and constant temperatures from 17°C to 44.0°C. Germination of the two biotypes was significantly greater (4-fold) and faster (7 days earlier) under shade than under natural light conditions. Over all biotypes, soil types, levels of pasture cover and burial depths, no seeds of C. thevetia remained viable after 2 years: longevity was much less in many circumstances.
The results demonstrate that C. thevetia seeds can germinate over a wide temperature range, whereas the ability of seed to remain viable at low temperatures highlights the potential for expansion of its current potential distribution towards southern latitudes of the Australian continent. Across all experimental conditions, the yellow biotype displayed superior seed germination and viability traits compared with the peach biotype. Seed banks of the peach and yellow biotypes of C. thevetia are short-lived (2 years), which may be exploited when developing management strategies to reduce its impacts.
Additional keywords: biotypes, burial depth, temperature requirements, viability, yellow oleander.
ReferencesAlvarado-Cárdenas, L. O., and Ochoterena, H. (2007). A phylogenetic analysis of the Cascabela-Thevetia species complex (Plumerieae, Apocynaceae) based on morphology. Annals of the Missouri Botanical Garden 94, 298–323.
| A phylogenetic analysis of the Cascabela-Thevetia species complex (Plumerieae, Apocynaceae) based on morphology.CrossRef |
Alvarado-Cárdenas, L., Villasenor, J. L., Lopez-Mata, L., and Ortiz, E. (2017). Systematics, distribution and conservation of Cascabela (Apocynaceae: Rauvolfioideae: Plumerieae) in Mexico. Plant Systematics and Evolution 303, 337–369.
| Systematics, distribution and conservation of Cascabela (Apocynaceae: Rauvolfioideae: Plumerieae) in Mexico.CrossRef |
AVH (2017). Cascabela thevetia (L.) Lippold – yellow oleander. Australia’s Virtual Herbaria, Council of Heads of Australasian Herbaria. Available at: http://avh.chah.org.au (accessed 26 June 2017).
Baker, H. G. (1974). The evolution of weeds. Annual Review of Ecology and Systematics 5, 1–24.
| The evolution of weeds.CrossRef |
Batianoff, G. N., and Butler, D. W. (2002). Assessment of invasive naturalised plants in south-east Queensland. Plant Protection Quarterly 17, 27–34.
Bebawi, F. F., Campbell, S. D., and Lindsay, A. M. (2003). Effects of burial and age on viability of rubber vine (Cryptostegia grandiflora) seeds. Plant Protection Quarterly 18, 147–151.
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2012). Persistence of bellyache bush (Jatropha gossypifolia L.) soil seed banks. The Rangeland Journal 34, 429–438.
| Persistence of bellyache bush (Jatropha gossypifolia L.) soil seed banks.CrossRef |
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2014). Effects of light conditions and plant density on growth and reproductive biology of Cascabela thevetia (L.) Lippold. The Rangeland Journal 36, 459–467.
| Effects of light conditions and plant density on growth and reproductive biology of Cascabela thevetia (L.) Lippold.CrossRef |
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2015a). The growth, reproduction and survival of Cascabela thevetia seedlings under two levels of canopy cover. Plant Protection Quarterly 30, 21–26.
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2015b). Seed bank longevity and age to reproductive maturity of Calotropis procera (Aiton) W.T. Aiton in the dry tropics of northern Queensland. The Rangeland Journal 37, 239–247.
| Seed bank longevity and age to reproductive maturity of Calotropis procera (Aiton) W.T. Aiton in the dry tropics of northern Queensland.CrossRef |
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2016a). Seed bank persistence and germination of chinee apple (Ziziphus mauritiana Lam.). The Rangeland Journal 38, 17–25.
| Seed bank persistence and germination of chinee apple (Ziziphus mauritiana Lam.).CrossRef |
Bebawi, F. F., Campbell, S. D., and Mayer, R. J. (2016b). Seed fall, seed predation, twigging and litter fall of Cascabela thevetia (L.) Lippold. The Rangeland Journal 38, 569–577.
| Seed fall, seed predation, twigging and litter fall of Cascabela thevetia (L.) Lippold.CrossRef |
BOM (2012). Mean annual rainfall and maximum daily temperature ranges. Available at: www.bom.gov.au (accessed 22 October 2012).
Campbell, S. D., and Grice, A. C. (2000). Weed biology: a foundation for weed management. Tropical Grasslands 34, 271–279.
Csurhes, S. M., and Edwards, R. H. (1998). ‘Potential Environmental Weeds in Australia: Candidate Species for Preventative Control.’ (Environment Australia: Canberra, ACT.)
de Padua, L. S., Bunyaprafatsara, N., and Lemmens, R. H. M. J. (Eds) (1999). ‘Plant Resources of South-East Asia: Medicinal and Poisonous Plants.’ Vol. 1, No. 12. pp. 167–175. (Backhuys Publishers: Leiden.)
Dodd, J., and Randall, R. P. (2002). Eradication of kochia (Bassia scoparia (L.)A.J.Scott), Chenopodiaceae) in Western Australia. In: ‘Proceedings of the 13th Australian Weeds Conference’. (Eds H. Spafford Jacob, J. Dodd and J. H. Moore.) pp. 300–303. (Plant Protection Society of Western Australia: Perth.)
Everist, S. L. (1974). ‘Poisonous Plants of Australia.’ (Angus and Robertson (Publishers) Pty Ltd: Sydney.)
Genstat 8.1 Committee (2005). ‘Genstat Release 8.1 Reference Manual.’ (VSN International Ltd.: Hemel Hempstead, UK.)
Grice, A. C. (1996). Seed production, dispersal and germination in Cryptostegia grandiflora and Ziziphus mauritiana, two invasive shrubs in tropical woodlands of northern Australia. Australian Journal of Ecology 21, 324–331.
| Seed production, dispersal and germination in Cryptostegia grandiflora and Ziziphus mauritiana, two invasive shrubs in tropical woodlands of northern Australia.CrossRef |
Grice, T., and Martin, T. (2005). ‘The Management of Weeds and their Impact on Biodiversity in the Rangelands.’ (The CRC for Australian Weed Management: Townsville, Qld.)
Harper, J. L. (1977). ‘Population Biology of Plants.’ (Academic Press: London.)
Huenneke, L. F., and Vitousek, P. M. (1990). Seedling and clonal recruitment of the invasive tree Psidium cattleianum: implications for management of native Hawaiian forests. Biological Conservation 53, 199–211.
| Seedling and clonal recruitment of the invasive tree Psidium cattleianum: implications for management of native Hawaiian forests.CrossRef |
Moore, R. P. (1985). ‘Handbook of Tetrazolium Testing.’ (International Seed Testing Association: Zurich.)
Mullett, T. L. (2001). Effects of the native environmental weed Pittosporum undulatum Vent. (sweet pittosporum) on plant biodiversity. Plant Protection Quarterly 16, 117–121.
Navie, S. C., McFadyen, R. E., Panetta, F. D., and Adkins, S. W. (1996). The biology of Australian weeds. 27. Parthenium hysterophorus L. Plant Protection Quarterly 11, 76–88.
Panetta, F. D. (2004). Seed banks: the bane of the weed eradicator. In: ‘Proceedings of the 4th Australian Weeds Conference’. (Eds B. M. Sindel and S. B. Johnson.) pp. 523–526. (Weed Society of New South Wales: Sydney.)
Panetta, F. D., and Timmins, S. (2004). Evaluating the feasibility of eradication for terrestrial weed incursions. Plant Protection Quarterly 10, 5–11.
Queensland Government (2016). Fact Sheet – Captain Cook tree (Yellow oleander) Cascabela thevetia. (Biosecurity Queensland, The State of Queensland Department of Agriculture and Fisheries, Brisbane, Australia.)
Randall, R. P. (2002). ‘A Global Compendium of Weeds.’ (R.G. and F.J. Richardson: Melbourne.)
Sakai, A. K., Allendorf, F. W., Holt, J. S., Lodge, D. M., Molofsky, J., With, K. A., Baughman, S., Cabin, R. J., Cohen, J. E., Ellstrand, N. C., McCauley, D. E., O’Neil, P., Parker, I. M., Thompson, J. N., and Weller, S. G. (2001). The population biology of invasive species. Annual Review of Ecology and Systematics 32, 305–332.
| The population biology of invasive species.CrossRef |
Simpson, R. L., Leck, M. A., and Parker, V. T. (1989). Seed banks: general concepts and methodological issues. In: ‘Ecology of Soil Seed Banks’. (Eds M. A. Leck, V. T. Parker and R. L. Simpson.) pp. 3–21. (Academic Press: San Diego, CA.)
Thompson, K., Bakker, J. P., and Bekker, R. M. (1997). ‘Soil Seed Banks of NW Europe: Methodology, Density and Longevity.’ (Cambridge University Press: Cambridge, UK.)
Vivian-Smith, G., and Panetta, F. D. (2009). Lantana (Lantana camara) seed bank dynamics: seedling emergence and seed survival. Invasive Plant Science and Management 2, 141–150.
| Lantana (Lantana camara) seed bank dynamics: seedling emergence and seed survival.CrossRef |