Translocation of the Critically Endangered Corrigin Grevillea: Grevillea scapigera
The recovery of theCorrigin Grevillea is a joint project with the Department of Parks and Wildlife, Narrogin, Corrigin community Landcare group, the Bullaring community and other volunteers.
This species is critically endangered 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/stabilization.
By 1996 the first introduction studies had been completed. Further introductions of micro-propagated plants 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 again in 2004, 2005, 2007 and in 2008 and 2009. 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. 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 third harvest (harvested every 2 years) indicates the viability rates are still very high.
Funding has been predominantly from NHT (Natural Heritage Trust) including WWF for Nature and the Minister for Conservation Fund (State Government) for the enlargement of one site.
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.
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