Climate change threatens movement of birds through northern Australia

Habitat degradation and erratic rainfall conditions are impacting the movement of birds through northern Australia's fragmented landscape, a new study by Monash University has found.

Analyzing 17 years of data about the movement of nearly 800 endangered purple-crowned fairy-wrens in north-west Western Australia, researchers have for the first time been able to identify exactly how human-induced habitat degradation and climate change are impacting the movement of birds who live alongside creeks and rivers in northern Australia.

These birds often move from their birthplace to a new location to raise a family, a process known as "dispersal."

Those born in low-quality habitats were found to travel further distances in search of a better patch to settle and breed, but their ability to do so is threatened by population declines and changing climatic conditions like drought.

The study, published in the Journal of Applied Ecology, was conducted by researchers from Monash University School of Biological Sciences and Wageningen University & Research in The Netherlands at Australian Wildlife Conservancy's Mornington Wildlife Sanctuary in Western Australia's Kimberley region, on the traditional lands of the Kija and Bunuba people.

Lead researcher and Monash Research Fellow Dr. Niki Teunissen said it was important to implement conservation actions that stimulate dispersal to keep populations connected so they can persist.

"Without conservation action, these birds are expected to experience population declines due to climate change, reducing connectivity and putting them at increased risk of extinction," Dr. Teunissen said.

"It's a sobering reminder of the impact of our changing climate, and highlights the urgent need for conservation through interventions like improving habitat quality to boost population numbers, by reducing the density of introduced herbivores like cattle near waterways, and by managing fire effectively through the use of prescribed burning.

"We encourage conservation managers to work on increasing population density, because having large healthy populations of purple-crowned fairy-wrens will encourage more birds to disperse out of those populations into other ones when conditions are right.

"Further climate change seems inevitable, and we can't control erratic rainfall, so finding innovative and evidence-based solutions like those we are recommending are critical."

Professor Anne Peters, Deputy Head of Monash School of Biological Sciences, said understanding how dispersal is affected by environmental changes is critical for conservation planning.

"Dispersal is a vital ecological process that is essential for populations and species to persist, especially in the face of climate change and habitat modification, which are two of the biggest threats to biodiversity worldwide," Professor Peters said.

"These birds provide a unique opportunity to study dispersal because they only live along waterways and respond strongly to song playback, making it possible for us to find all birds that move, even if they go very far.

"The furthest dispersal recorded was 68 kilometers, which is pretty far for a 10-gram bird that spends most of its life in a small territory occupying perhaps a few hundred meters of creek line."

Australian Wildlife Conservancy Chief Science Officer Dr. John Kanowski said the research was important to conservationists' understanding of the threatened bird.

"As conservationists, understanding dispersal behavior of the fairy-wrens helps us to manage habitat in a way that contributes to their conservation," he said.