Rare High Country snowpatch ecosystem threatened

Climate change is impacting Australia’s rare High Country snowpatch herbfield ecosystems, with lower seasonal snowfalls seeing changes to plant growth and distribution that could eventually lead to ecosystem collapse, a new study by La Trobe University has found.

The study, Early-melting snowpatch plant communities are transitioning into novel states, published in Nature Scientific Reports, found that lower snowfalls and earlier meltout has seen the ecosystem begin to transition into a new community “with an uncertain future”.

Lead researcher Dr John Morgan, Associate Professor Environment at La Trobe and a member of the Research Centre for Applied Alpine Ecology  , likened the findings to the impact of climate change on the Great Barrier Reef.

“What we are seeing is entirely expected; snowpatches are a bit like the coral reefs - one of the first places to see major change in structure and composition,” Dr Morgan said.

“We are seeing evidence for change that might ultimately lead to ecosystem collapse - so we need to better understand what can be done to save snowpatch plant communities.”

Snowpatch ecosystems occur where snow persists the longest each year, sometimes until Australia Day in Victoria, and even longer in the Kosciuszko National Park.

Dr Morgan and research asssitant Mr Zac Walker, from the Research Centre for Applied Alpine   Ecology, used a revisitation study to quantify early-melting snowpatch floristic and functional diversity change in southern Australia.

They documented any changes to shrub size distribution over time to detect encroachment into snow patches – a key prediction of climate change.

They found snowpatch vegetation had declined in area, the composition of species had changed, and shrub and tussock grass cover has increased, although changes in “functional trait diversity” were less clear.

“Many early-melting snowpatches are transitioning to a novel state with changed composition and taller vegetation structure, but there is little evidence for species loss having occurred,” the researchers found.

“Given enough time, however, the long-term loss of species is likely (i.e. biotic homogenisation) if taller shrubs outcompete short-statured snowpatch species.

“Our results provide evidence that this alpine ecosystem is forming a novel community with an uncertain future.”

Dr Morgan said the research was important given lower snowfalls are becoming more frequent in the Australian Alps, and poorer snow seasons mean “longer snow-free seasons that favour plant species that are typically limited by the snow”.

Study in Scientific Reports (Nature): Early-melting snowpatch plant communities are transitioning into novel states

Media contact: Courtney Carthy-O'Neill, c.carthy-oneill@latrobe.edu.au, +61 487 448 734