How secure is the Lord Howe Island Woodhen? A population viability analysis using VORTEX

Abstract

The Lord Howe Island Woodhen is a flightless rail endemic to Lord Howe Island that became endangered due to human over-exploitation and predation from wild pigs. It has recently recovered from a population size of 20?30 to around 200 as a result of a captive breeding and reintroduction programme. Its classification has been downgraded from endangered to vulnerable, but no quantitative assessment of its future prospects had been undertaken. A population viability analysis (PVA) was performed on the Lord Howe Island Woodhen to project its possible fate using VORTEX, a package that realistically reflects the woodhen's recent history. Prospective analyses showed the woodhen to be acutely sensitive to minor changes in mortality and fecundity, and to catastrophes, due to exotic species, inbreeding, or disease. A remote population needs to be established if the likelihood of the woodhen's extinction is to be minimized. According to the most recent IUCN Red List categories, the woodhen satisfies the criteria for endangered status.