Translocation of the Corrigin grevillea in south Western Australia

Summary

Corrigin grevillea (Grevillea scapigera), a critically endangered shrub from the Western Australian wheatbelt, had declined to just three known wild plants by January 2008. Since 1996, the Botanic Gardens and Parks Authority has translocated clonal plants propagated from ten surviving genotypes to three sites near Corrigin, aiming to rebuild self-sustaining populations while conserving the species' remaining genetic diversity. By the time of reporting, more than 1,000 plants had established across the translocation sites, and one site alone produced over one million seeds in 2006. Genetic monitoring documented an effective founding population size of only around two, reflecting the severe historical bottleneck, yet natural seedling recruitment was confirmed occurring at two of the translocation sites, an important indicator that the populations can regenerate without ongoing human intervention. The project combined tissue culture and cutting propagation with careful site selection in remnant bushland and used monitoring to track survival, flowering, seed production, and recruitment over more than a decade. The project rated itself Successful, citing the scale of population increase from a handful of wild individuals to over a thousand translocated plants, prolific seed production, and the emergence of natural recruitment, despite the ongoing genetic vulnerability created by the species' near-extinction before translocation began.