Journal article
The seed ecology of two invasive Hieracium (Asteraceae) species
JL Bear, KM Giljohann, RD Cousens, NSG Williams
Australian Journal of Botany | CSIRO PUBLISHING | Published : 2012
DOI: 10.1071/BT12058
Abstract
Two highly invasive hawkweeds, Hieracium aurantiacum and H. praealtum L., have established in the Australian Alps. Our experiments aimed to provide a better understanding of the seed ecology of these species, essential if successful eradication strategies are to be developed. Results indicated that viable seeds are produced in large numbers. Seeds germinate spontaneously and synchronously with light and moisture and are killed when exposed to temperatures above 110C for 150s. No seedlings of H. aurantiacum emerged from soil samples taken from a chronosequence of known infestations, but some H. praealtum seedlings emerged from soil sampled from sites where plants flowered the preceding summer..
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Funding Acknowledgements
This research was funded by the Parks Victoria Research Partners program, the Australian Weeds Research Committee and an Australian Research Council Linkage grant with partners Parks Victoria (PV), the Victorian Department of Primary Industries and the New South Wales Department of Environment and Climate Change (DECC). We thank Charlie Pascoe, Elaine Thomas, Marie Keatley (PV), and Genevieve Wright and Jo Caldwell (DECC) for their assistance and enthusiasm towards this research and Claire Farrell and two anonymous reviewers for helpful comments on the manuscript. Figure 1 was kindly provided by Susan Johnson and Anna Koltunow of CSIRO. Kate Blood provided the initial Hieracium plants used to produce seeds while Alex Campbell and Nick Osborne from the Burnley Nursery helped grow and care for the plants. The use of the Selecta ZZ1 aspirator at the Victorian Conservation Seedbank, Royal Botanic Gardens, Melbourne, is greatly appreciated.