Alpine animal species under threat

Mary Morgan-Richards and Steve Trewick have co-authored a book based on their research, titled Wild Life New Zealand. Photo: Supplied

RECENT studies have shown climate change is leading to a quarter of New Zealand’s alpine animal species to become extinct within the next 50 years.

The study, undertaken by Massey University Professors Mary Morgan-Richards, Steven Trewick and Dr Emily Koot, has shown several species which are already endangered, and other more widespread species could lose all of their current habitat in New Zealand due to global warming caused by anthropogenic climate change.

Anthropogenic climate change is essentially defined as human-caused climate change, directly linked to the burning of fossil fuels, aerosol releases, and land alteration from agriculture and deforestation, as opposed to naturally occurring climate cycles that have occurred throughout history.

The team of researchers used current niche models to project the future distribution of 12 grasshopper species on to the predicted temperature increase in New Zealand of 1degC or 3.7degC within the next 50 years, caused by global warming.

Their study concluded most of these alpine species endemic to New Zealand, would lose at least 30% of their suitable habitat.

With just a 1degC average rise in temperature, endemic species such as the green rock-hopper and the already endangered Alexandra grasshopper, would have nowhere to live.

Prof Trewick said these two species were highlighted in particular because they differed in circumstances, but their analysis showed decline of all species.

“It’s not quite the same situation for the Alexandra grasshopper because it’s not actually on a mountain, it’s in this Alexandra arid habitat which behaves a lot like an alpine environment even though it’s low down.”

“These are flightless grasshoppers so it’s not easy for them to quickly shift from one patch to the other.”

It’s possible the decline and extinction of these animals could have unpredictable effects on local ecosystems as they play a role in natural foodchains.

“Undoubtedly the dynamic starts to fall apart when you start losing species.

“We’ve got a number of graduates who are working in the field, looking at the plant/insect interactions in particular. But we know for instance, these grasshoppers and other insects in the alpine zone are the food of the birds and the reptiles up there, and to some extent other invertebrates,” Prof Trewick said.

Studies have shown the global average temperature has increased by .66degC during the past 20 years, and that without intervention the 1degC threshold will soon be passed, leading to the extinction of several species and reduced and fragmented habitats of others.

“What we’ve seen is that there’s only a limited amount of alpine habitat in New Zealand, and it’s definitely not going to increase.”

While throughout Earth’s history, species have been known to evolve and adapt to changes in their climate, though anthropogenic climate change is proving to be an altogether different beast, and the climate is changing faster than species are able to keep up with.

“It’s a complex science, because if you’re dealing with the evolutionary component you’re also trying to consider how the populations adapt to these changes. and that is a possibility.

“As far as we can tell globally, this rate of change of habitat is much faster than anything that’s happened in nature in the past, barring those catastrophic situations like volcanic eruptions or a meteorite.”

Most of our alpine animals have populations that are restricted to high-elevation and cannot jump or fly the gap to unconnected mountain habitat. This means that as the Earth warms, alpine species will find their habitat dwindling. In Aotearoa New Zealand most of our alpine plants and animals are found nowhere else in the world. When their habitat shrinks, we are set to lose a quarter of all our endemic alpine biodiversity.

“It’s easy to say mountain’, but this is an indicator and we’ve said, basically that environment is a barometer. If we can see things falling apart there, it’s just a matter of a little bit longer until things fall apart elsewhere.”

Prof Trewick said the main take home of the study was not to panic, but to recognise climate change as a real threat, and to encourage individuals to adjust their behaviours to reduce their impact on the environment.

“The positive thing is, the more we as a people and a society recognise that this is real, the more likely we’re going to be able to respond to it.

“The impact of human climate change is it is real, it is fast, and we’re going to experience it within an individual lifetime. We don’t have the excuse that we had in the past when things changed and [we said] to know it was going to change?’ We’re actually living through that now.

“I know that other things are a bit in your face at the moment, but the impacts of climate change are playing out now across the world. We’re all seeing it, we’re all seeing the storms and the extreme weather events – those are the edges of the effects.

“We’re gonna wake up one day and realise that the ecosystems that we depend on are not functioning.”