Multi-scale habitat selection by a cryptic, critically endangered grassland bird-The Plains-wanderer (Pedionomus torquatus): Implications for habitat management and conservation

Our understanding of the habitat needs of grassland fauna is often incomplete because of their cryptic behaviour. This presents a barrier to identifying important habitat attributes, whether these change at different spatial scales, and how this informs management decisions. Here, we use a critically endangered bird, the Plains-wanderer (Pedionomus torquatus, Pedionomidae), as an exemplar of the challenge of managing grasslands for cryptic species. Until now, almost all ecological knowledge of Plains-wanderers has come from the detection of nocturnally roosting individuals and habitat assessments at fine-scales that indicate open swards are preferred habitat. We GPS-tracked 13 adult Plains-wanderers to better understand diurnal habitat utilization in native grasslands of south-eastern Australia. Using these data, we assessed whether Plains-wanderers select for different habitat attributes during the day and night, and whether this varied according to spatial scale. At the fine-scale (< 1 ha), daytime foraging occurred in denser swards than those of nocturnal roosting sites. At the patch-scale (1-50 ha), Plains-wanderers selected for denser vegetation, with higher grass and lichen cover, whilst avoiding areas where structure was impacted by a high exotic plant cover. Plains-wanderers did not select habitat based on grassland type at the landscape-scale (>100 ha). We demonstrate that Plains-wanderers require grasslands with both open and denser swards to support foraging and roosting. In doing so, we address the biases associated with habitat assessments based on roost-only locations and extend known habitat associations critical to the successful management of the species. Our findings highlight that a precautionary approach to the classification of habitat requirements is warranted when uncertainty around habitat use of cryptic grassland fauna exists.