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Can predator presence help native species survive?

A study by The University of Western Australia found that maintaining some predation pressure in havens gave native fauna improved chances of survival when they were released into the wild.

Dr. Natasha Harrison, from UWA's School of Biological Sciences, led the study in collaboration with the Department of Biodiversity, Conservation, and Attractions, which was in the Journal of Applied Ecology.

"Invasive predators drive global biodiversity loss and predator-free havens continue to be established to recover threatened fauna," Dr. Harrison said.

"An unintended consequence of these efforts is that havened populations can lose anti-predator traits, making them poorly suited for reintroduction into landscapes that contain predators."

The study reintroduced semi-havened woylies—individuals that had been isolated from invasive predators but exposed to chuditch (western quoll)—and woylies that had not been havened into bushland containing chuditch, and controlled levels of foxes and feral cats.

Researchers monitored woylie survival, reproduction and anti-predator traits before and for 10 months after release into Dryandra Woodland National Park south-east of Perth.

The findings suggested sustained pressure from chuditch inside the haven had been effective in maintaining the woylies' anti-predator responses.

"Predation pressure from chuditch in havens may increase a woylie's ability to respond adaptively to new invasive predators after conservation translocation," Dr. Harrison said.

"However, it is crucial to understand thresholds of predation pressure that havened fauna can withstand in varying contexts before recommending broad-scale adoption of this strategy."

The study concluded monitoring translocated individuals from different backgrounds provided valuable information, not only on the effect of havening but also on survival and the strength of natural selection on different populations.

"Replicating this type of research across species, havens and environments will help build our understanding of how to best manage our havened populations to maximize the conservation benefits," Dr. Harrison said.