Research lead author and University of Otago zoology PhD candidate Nick Foster said his new study demonstrated how mountain ranges could act as barriers to species such as stoats, hedgehogs and mice, highlighting opportunities to create sanctuaries for threatened wildlife.
Alpine ecosystems were under intense pressure from pest species, and the research showed “enormous potential” in using landscape features to naturally limit the rate of reinvasion from areas which had undergone pest eradication, he said.
“Any landforms which influence the movement of pests are incredibly valuable in pest-removal programs which take a ‘remove and protect’ approach.
“It has long been presumed that big mountains are barriers to New Zealand’s pest species, but this is the first study to analyze and really validate this strategy,” he said.
The study analyzed the movements of 10 invasive species in a 310,000ha area in the upper Mackenzie Basin, proving the effectiveness of landforms had in segregating the animals.
Mr Foster said he hoped the findings would lead pest removal groups to better understand how natural landscape barriers functioned in their areas, as well as highlight opportunities to protect upland areas in areas like the Southern Alps.
“New Zealand is plagued by a suite of invasive small mammals, each of which play a part in the ongoing degradation of native biodiversity and native species populations.
“As regional predator-free initiatives grow larger in size and ambition, larger tracts of increasingly complex and inaccessible terrain will need to be cleared of predators.
“Natural barriers will help in reducing costs and such work, and ensure success.”
In practice, this would work by removing a pest population from within an area which was defended from reinvasion by surrounding high-elevation landforms, he said.
Incursions from the area down-valley would be managed by maintaining a buffer zone of lethal devices until the reinvading population could be removed.
He was pleased the research provided some hope for those working hard to protect our native species, Mr Foster said.
“Removing pest species is a daunting task and it’s nice to know that there are things out there working in our favour.”