Monitoring the Abundance of Wild and Reintroduced Bilby Populations

Abstract

ABSTRACTMonitoring techniques that are non‐invasive and use evidence of target species presence are particularly useful, especially for rare or highly dispersed species. We developed and tested a technique using DNA extracted from scats in conjunction with spatially explicit capture‐recapture (SECR) analyses to monitor the abundance of greater bilbies (Macrotis lagotis) within wild and reintroduced populations in Western Australia, and verified its application against a recently reintroduced founding population. The greater bilby is an iconic threatened species and the focus of conservation management, but no efficient and reliable method to monitor their abundance has been implemented. Estimated abundance using our method (21 ± 5 [SE]), was close to the founding population at Mount Gibson (16). Wild populations monitored from 2013–2018 were relatively small, isolated, and particularly vulnerable to threats; 2 populations were extirpated during this study. A reintroduced population at Matuwa increased sevenfold over 9 years. We demonstrate that when threats are managed appropriately across a large area, and bilbies are reintroduced, they can rapidly increase in number without the need for predator exclusion fencing. © 2020 The Wildlife Society.