Review of translocations of the greater stick-nest rat (Leporillus conditor): lessons learnt to facilitate ongoing recovery

Abstract

Abstract Greater stick-nest rats were widely distributed across southern Australia in pre-European times, but only survived as a single population on the Franklin Islands in South Australia. Conservation efforts since 1983 have included survey of the remaining population, establishment of a captive colony and subsequent translocations to both island and mainland sites. Translocations have met with mixed success, with four of 10 (three islands and one mainland site) successful and extant for 19–28 years, five unsuccessful (one island and four mainland sites) and one as yet indeterminate. Overall, the increase in number of populations, area of occupancy and extent of occurrence has been positive, and has resulted in a down-listing of conservation status. There are numerous plausible explanations for the lack of success at some sites, but few data to differentiate among them. These plausible explanations include: the release of stick-nest rats to habitats of poor quality; high levels of predation (perhaps hyperpredation) by native predators (chiefly monitors and predatory birds) in combination, at some sites, with predation by feral cats or foxes; and ineffective release protocols. Most extant populations have undergone substantial fluctuations over time, and some show apparent long-term declines in abundance, likely increasing their probability of local extinction over time. There is a need for regular ongoing monitoring – of stick-nest rats themselves, their habitat and their suite of potential predators – to aid interpretation of outcomes. A more experimental approach to future releases is required to adjudicate among competing explanations for such declines.