Climate change's 'thermal squeeze' - predators and climate change - hurting our birds

16 Jul, 2019 8:04am

 By: Jamie Morton

Science Reporter, NZ Herald

Some of New Zealand's most threatened birds are being backed into colder corners of our forests, through a "thermal squeeze" from pest predators and climate change.

Conservation advocates say findings of a just-published study show another reason to ramp up the war on pests, in what is expected to be a horror year for our native biodiversity.

The paper, drawing on bird distribution data captured by the Ornithological Society of New Zealand between 1969 and 1979, and again between 1999 and 2004, explored how a warming climate will heap yet more pressure on threatened species hanging on in our remaining forests.

Researchers had suspected climate change would have been worsening the toll wreaked by predators, regardless of whether it influenced pest-fuelling mast seeding events, like the record one now under way in beech forests across the country.

"We know that two key predators, ship rats and possums, do better in warmer sites," said study lead author, Dr Susan Walker, of Manaaki Whenua – Landcare Research.

"New Zealand's cool forests are mainly beech forests, which support plagues of predators in years following mast seeding, but not otherwise. In contrast, warmer forests at lower elevations support high numbers of predators every year."

Continued