It is also a stronghold for many endangered endemic plant and wildlife species, such as the rock wren, which have adapted to cope with the challenges of living in alpine environments.
Temperatures range from a high of 30degC in summer to a low of minus 20degC in winter.
It is lashed by strong winds, there is a high snow load and there are limited snow-free periods, which translate to a shortened breeding season for birds and animals and a shortened growing season for plants.
The dryland zone of the central South Island is also home to 10 invasive mammalian species (stoats, weasels, possums, ferrets, hedgehogs, cats, Norway rats, mice, hares and rabbits), three of which — stoats, hares and mice — specialise in living in alpine conditions.
For the past two years Otago University PhD student Nick Foster has led a research project (funded by Te Manahuna Aoraki and Predator Free 2050 Ltd) to find out the distribution and habitat of all these invasive species within the 300,000ha Te Manahuna Aoraki landscape enhancement project area.
On 11,516 camera trap nights from the middle of summer to late autumn in 2019 and 2020, his team captured 1.7million images of predators from 176 motion-triggered camera locations.
"Finding hedgehogs so high in the alpine zone is probably one of the more interesting results, but I think equally as interesting is how the distribution of all these other pest species changed across elevations.
Mr Foster said the distribution of most species petered out at 1500m, but stoats, hares and mice were found above 2000m.
Stoats were the mostly widely-detected of the target species, occurring at 60% of the 176 sites.
They were detected at 90% of the sites between 1750m and 2000m, and most readily detected between 1750 and 2000m.
He said one stoat was even detected at 2135 metres, which was above the limits of vegetation and would be under snow for almost three-quarters of the year.
"Stoats will occur in any place that they can find available foods and so in that habitat it would be invertebrates, lizards and probably hares as well or the younger hares.
"They also don’t like being around other predators that can dominate them and in that environment they don’t have to contend with the likes of cats and ferrets."
Mr Foster said rock wren, New Zealand’s only true alpine bird, lived in patches throughout the Mackenzie Basin and were "really impacted" by stoats and mice.
"I think one member of the team found a Southern Alps gecko at 1900m — the only thing that is going to get them up there are stoats, otherwise they do not have any predators," Mr Foster said.
The University of Otago research was part of the Te Manahuna Aoraki project feasibility phase which focused on restoring the natural landscapes and threatened species of the upper Mackenzie Basin and Aoraki/Mount Cook National Park.
Te Manahuna Aoraki was founded by the Department of Conservation, Te Runanga o Arowhenua, Te Runanga o Waihao, Te Runanga o Moeraki and NEXT Foundation, and was joined by high country land owners and investors Aotearoa Foundation, Jasmine Social Investments, Global Wildlife Conservation (GWC) and Predator Free 2050 Ltd.
Spokeswoman Robyn Janes said they were undertaking several projects "to provide biodiversity gains and provide critical learning for the future to demonstrate how we can work together to ultimately secure a 310,000ha mainland island as part of a 20-year project".
Mr Foster said removing predators from such a huge area would be a challenge but it was "manageable to us with the tools that we have now".
Ms Janes said a decision on creating the 310,000ha mainland island predator-free zone in the Mackenzie Basin would be made later this year.
