Conservation translocation of the large-headed daisy to Mount Bold, South Australia

Summary

The large-headed daisy (Brachyscome diversifolia), Endangered in South Australia and known from only two small populations in the Adelaide Hills, was translocated to a historically recorded but currently unoccupied site within the Mount Bold Reservoir water catchment, chosen for its similarity in slope, aspect and vegetation to remnant habitat. Researchers from the Botanic Gardens of Adelaide raised seedlings from seed collected at the tiny (under 200 plants) Scott Creek Conservation Park population, testing whether pretreating seed with the plant-stress compound Ambiol, previously shown to aid drought tolerance in crops, could improve translocation success compared with water-soaked or untreated controls. In June 2011, ten-week-old seedlings from all three treatment groups were planted in a randomized grid pattern across six replicated quadrats on a steep, rocky south-facing slope, with survival, growth, flowering and grazing damage recorded roughly every three months. One year on, 81% of translocants survived with no significant difference among the Ambiol, water-soaked or untreated groups, most plants had flowered and set seed by five months, and about 60% showed minor invertebrate grazing damage that did not appear to threaten survival, though no new seedling recruitment was observed by the following winter. Difficulties included the steep terrain complicating planting and monitoring, ongoing invertebrate grazing that could become a longer-term problem, and the possibility that new recruits remain hidden beneath a dense herbaceous layer. The project rates itself successful, crediting careful matching of translocation-site habitat to the species' natural conditions and the use of locally sourced seed, while noting that confirming long-term viability will depend on future recruitment.