Ecological requirements and relative impact of threats affecting the Austral Rail Rallus antarcticus : monitoring methodology considerations for an imperative conservation status re-evaluation

ROESLER, IGNACIO; GIUSTI, EMILIA; ROESLER, IGNACIO; GIUSTI, EMILIA; DE MIGUEL, ANDRÉS; MARTIN, LUCÍA; DE MIGUEL, ANDRÉS; MARTIN, LUCÍA; FASOLA, LAURA; COSSA, NATALIA; FASOLA, LAURA; COSSA, NATALIA

BIRD CONSERVATION INTERNATIONAL

CAMBRIDGE UNIV PRESS

Año: 2019 vol. 29 p. 586 - 597

0959-2709

Since its rediscovery in 1998, two major threats have been mentioned for the enigmatic AustralRail Rallus antarcticus: cattle management by burning grass and rushes and predation byAmerican mink Neovison vison. Added to the lack of a protocol to monitor this secretive bird,ever-growing threats make it necessary to study its global situation in depth to take accurate andurgent management decisions. We firstly studied how threats to the Austral Rail currentlyimpact their occupancy and relative density (RD) at a wetland scale and habitat features asso-ciated with its presence at survey site scale inside wetlands in Santa Cruz province, Argentina.We additionally developed a monitoring protocol to detect the rail effectively and promptlyby studying responses to playback with two different vocalisations at different times of the dayand season. Both threats evaluated were negatively related to occupancy and RD of the AustralRail, especially mink presence appearing to have an additive effect. We propose American minkcontrol as crucial for Austral Rail conservation, while it would also be necessary to conservea portion of wetlands exempt from burning and cattle presence. At survey sites, its presencewas positively related with c.1?1.5 m tall rushes, whilst rails avoided low- density rush areasthat resulted after management of rushes with fire to create pasture. To detect rails, bothvocalisations can be confidently used at any time of the day and season. The poor knowledgeabout species ecology, mismanagement of vegetation in wetlands, expansion of American minkin Patagonia, construction on two dams in the Santa Cruz river basin, added to the alreadymodified humidity conditions due to global climate change, force us to suggest that the AustralRail should be considered as globally ?Endangered? (EN), to ensure the consideration of thespecies in management decisions.