Lush, green and more than 400 years old, there’s a good reason the moss beds around Casey research station have earned the nickname ‘the Daintree’ of Antarctica.

Dotted along the coast, the centimetres-high moss beds are the tallest old-growth forests in Antarctica, thriving in ice-free real estate supercharged by nutrients and water from ice melt.

For the past 25 years, Professor Sharon Robinson from the University of Wollongong has visited the site to understand the ecological roles played by moss.

This season Prof Robinson and a new team from Securing Antarctic Environmental Future (SAEF) travelled south.

The million dollar moss question … what’s changed?

“When I last visited in 2013, the samples we collected showed that the Windmill Islands region near Casey station is becoming drier,” Prof Robinson said.

“The health of the moss beds was declining and a species of moss that prefers drier conditions was more abundant than in the past.”

Watch your step

The team had their sights on two Antarctic Specially Protected Areas (ASPAs) for their field work.

But walking into the areas requires some tricky footwork to avoid damaging the fragile moss beds.

“So we ‘rock hop’ and play ‘twister’, opportunistically using rocks to place feet, knees and elbows to get up close and personal with the mosses without stepping on them,” Prof Robinson said.

After avoiding any slips, the team located the 25 cm-square ‘quadrats’ – the exact same spots under examination since 2003.

Honey, I shrunk the climate

Mosses thrive in micro-climates and inhabit their own ‘micro-topography’.

University of Wollongong researcher Krystal Randall said micro-topography is like a miniature version of mountains and valleys.

“And just as mountains and valleys can have different microclimates, the mosses can also have different microclimates depending on where they live among the micro-topography,” Ms Randall said.

Where the tiny terrain fits the bill, the team installed wires with temperature probes.

“This is very fiddly work because the aim is to insert it without causing any damage to the moss, but at the same time we are balancing on rocks – sometimes in very compromising positions!”

Spears and sponges

The team took samples to determine species and health while sponges were used to check on moisture.

“We also inserted some different sensors, which we call ‘micro-climate spears’ with a pointy end that gets inserted into the soil,” Ms Randall said.

“These probes measure soil temperature, soil moisture, ground surface temperature and air temperature near the ground.”

The combined efforts will help piece together a bigger picture of what’s happening and why.

Mapping moss

Drones also came in handy, providing a huge amount of information without disturbing the environment.

“We analyse these to see how much of the moss is green and healthy, how much is red and stressed and how much is grey, very sick or dead,” Ms Randall said.

The team partnered up with a group from the University of Tasmania to use hyperspectral cameras and sensors to look at colours of the plants.

“Some pigments are short term stress indicators, others represent a more long term stress and could be an early warning of future moss death.”

Early signs?

The team has yet to reach any conclusions from the field work but there are some early signs.

“One thing we did see immediately was that one of our quadrats had lost half its moss cover since 2013,” Ms Randall said.

“Because we haven’t been able to visit for nine years we can’t tell if this was lost two or seven years ago, but it is likely that the moss has been washed downstream by extreme spring melt flows.”

“We hypothesised that this might have happened two years ago following the heatwave at Casey.”

Samples and images collected from the field are now being analysed.

SAEF’s first year

This season is the first year of field work by SAEF – a partnership between the Australian Antarctic Program and universities and research institutions across Australia, funded by the Australian Research Council.

For fellow University of Wollongong researcher, Georgia Watson, it was also a personal milestone.

“It was my first time going to Antarctica as well as being SAEF’s first field season, so I was ecstatic to be able to be a part of the field team for the moss project,” Ms Watson said.

“It felt really momentous to be able to represent SAEF down south for the first time.”

More than moss

Mosses are the largest plants in East Antarctica, providing a home to a huge range of microscopic organisms, such as rotifers, nematodes and tardigrades.

Like ice cores, that trap CO2 bubbles and can reveal past climates, mosses fix CO2 in their cells as they grow. The age of these moss beds makes them useful proxies for recording climate history around Antarctica’s coast.

For Prof Robinson, the species are a labour of love.

“These tiny plants have been growing there for hundreds of years recording the environment around them, as well as what humans are doing across the rest of the globe,” Prof Robinson said.

“I love that with modern techniques we can interpret their stories of the past and hopefully help preserve their future environments, so that they survive the next 500 years.”