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Critically endangered Corrigin grevillea Grevillea scapigera. Photo: I.R. Dixon.Grevillea scapigera generally flowers in October to mid November producing copious amounts creamy white lightly scented flowers. Photo: I.R. Dixon.Project title: Translocation of the Critically Endangered Corrigin Grevillea Grevillea scapigera

Dates: 1997 - 2014

Funding: NHT Commonwealth funding and one WA State Government grant

Location: Corrigin and Bullaring about 225 km ESE of Perth, Western Australia

Research themes

  • tissue culture and seed propagation
  • genetic diversity maintenance
  • ex situ genetic material storage
  • severely degraded site management and weed control
  • self sustaining ecosystems restoration: cultural requirements and site management

Project description

Grevilliea scapigera is a critically endangered species with only a few plants remaining in the wild. The project, initiated by Dr Maurizio Rossetto for his PhD, includes propagation by tissue culture, macro-cuttings and seeds, cultivation and testing of genetic decline/stabilisation.

The first introduction studies were completed in 1996 and further introductions of micro-propagated plants have continued on an ad hoc basis.

Three translocation sites, each 0.2 ha in size, are now well established and at one stage contained over 1800 plants. Due to the short life span of the plants, these numbers have declined significantly over the last few years. Large amounts of seed have been produced at all sites, which added significantly to the soil seed bank. In 2006, one site is estimated to have produced over 1,000,000 seed.

Natural recruitment of Grevillea scapigera first occurred in 2003 and each year except 2006. In 2010, only one recruit was recorded due to one of the driest winters on record. Good winter rainfall in 2011 aided recruitment resulting in over 330 new seedlings recorded on the three sites; further recruitment occured in 2012, 2013 and 2014. Though recruitment numbers still appear to be small, when compared to the number of seed added to the soil seedbank, this species is a disturbance opportunist expected to produce higher levels of recruitment on an infrequent basis after events such as fire. Seedlings usually take at least one year to produce flowers and seed.

Most of these recruits have flowered and produced seed, leading to the long term viability of this species. Survival of seedlings over the first summer period is usually over 50%, extremely high for natural germinants. Plant material taken from cryo-storage and placed in tissue culture produced normal plants, which were planted out and produced seed. The resulting seed were sown giving excellent germination rates. The seedlings were then planted out in the winter of 2005 to check their fitness. These plants had excellent survival rates, have flowered well and produced their own seed.

The last planting, on two sites, was in 2007 and consisted of a small number of plants from a new wild clone. Management of the sites, due to better cover of indigenous species and recruitment of the Corrigin Grevillea, is now down to very basic levels. However, scientific experiments are ongoing including 50 year seed burial trials. The fourth harvest (harvested every 2 years) indicates the viability rates are still very high.

Clones of this species are held in cryo-storage to protect the gene pool for future generations and large quantities of seed are in long term storage. Information gained from this pioneering project is being used to improve translocation of other species.

Innovative scientific and experimental horticultural techniques, ongoing adequate funding, total commitment by team members, including Kings Park Voulunteer Master Gardeners, local shire assistance, Department of Parks and Wildlife and local volunteers have been successful drivers of this project.

This was the first combined scientific and horticulturally based plant translocation in Western Australia. Knowledge gained has successfully been transferred to other projects. Ad-hoc scientific experiments continue eg plant genetics and long term seed burial trials.

Key staff

Bob Dixon, Dr Eric Bunn, Dr Siegy Krauss, Kings Park Volunteer Master Gardeners

Collaborators

Dr David Merritt, Department of Parks and Wildlife Narrogin, Corrigin Shire, Bullaring Ratepayers Association

Publications

Dixon B and Krauss S (2008) Translocation of the Corrigin Grevillea in south Western Australia. In: Soorae, P.S. (ed). Global re-introduction perspectives: re-introduction case-studies from around the globe. IUCN/SSC Re-introduction Specialist Group, Abu Dhabi, UAE: 229-234.

Dixon IR (2006) Control of Arctotheca calendula amongst the critically endangered Corrigin Grevillea Grevillea scapigera on translocation sites in the Wheatbelt of Western Australia: 288-290. Proceedings of the 15th Australian Weeds Conference, eds C. Preston, J.H. Watts and N.D. Crossman (Weed Management Society of South Australia, Adelaide).

Krauss SL, Dixon B and Dixon KW (2002) Rapid genetic decline in a translocated population of the endangered plant Grevillea scapigera (Proteaceae). Conservation Biology 16: 986-994.

Presentations

Dixon B (2007) Managing translocation sites for rare species to achieve long term outcomes. Proceedings of the MEDICOS X1Sept 2007, Perth Western Australia: 75-76.