Imagine Antarctica and your mind probably goes monochrome. But now that the sun is peeking over the horizon again, bright spots of colour emerge from the ice as the continent’s miniature meadows of mosses and lichens reawaken.
Antarctic mosses are extremophiles. They survive six months of darkness and frozen conditions in a freeze-dried state. As soon as meltwater begins to trickle, they spring back to life, but often refreeze again even during the summer months whenever overnight temperatures drop below zero.
Lichens are just as hardy, hovering in a near-dead state until sunshine and relative warmth turn on their metabolism again. Add harsh, desiccating winds to the deadly temperatures, and it’s clear survival requires finely tuned adaptations.
This is why Antarctica’s ground-hugging precious flora is particularly sensitive to change. Researchers monitoring moss beds near the Australian Casey Station are already observing a slow replacement of a moss found only in Antarctica with global species. They also found that almost half of the plants are drying out and turning red or grey as they become stressed. The cause is a combination of ozone depletion and climate change, which in this particular part of East Antarctica delivers colder summers and stronger winds.
Seeing such shifts in a well-studied and accessible site implies plant life in more remote areas may also be changing. But thankfully, drone-based remote-sensing technology is now making it easier to monitor landscape-scale environmental change far away from research stations.
Researchers are observing the slow replacement of a moss found only in Antarctica with global species.
Last summer, conservation ecologist Barbara Bollard flew drones equipped with multispectral cameras across Cape Bird, at the northern tip of Ross Island, to map plant life in a patch that is part of a New Zealand-administered network of Antarctic Specially Protected Areas (ASPAs). The camera’s sensors collect images from a broader spectrum of wavelengths than the human eye can see, which allows Bollard to analyse the data for otherwise invisible changes in the plants’ health and stress levels. The image resolution is such that even tiny changes in growth are detectable. Eventually, Bollard hopes such aerial surveys will be able to identify not just the type of vegetation but individual moss species. “We have lots of different data embedded in each pixel and a lot of mathematics goes into the analysis.”
Last summer’s survey was part of a larger project to map protected areas holding some of Antarctica’s rarest flora. Each drone flight delivers a baseline. Subsequent flyovers are planned every five years to track growth, retreat or any other changes. At this point, Bollard’s team still needs to collect samples and data on the ground as well to verify the analysis of drone images and to teach algorithms to recognise species and signals of health. But soon, nobody may need to enter protected areas on foot, she says.
She is also interested in tracking change in water availability. “We’re doing hydrology maps to look at the flow of water, how the mosses are using that water as it melts from the snow cap, and how much is required for life.”
An exciting part of the project is when old and new technology come together. Back in the 1970s and 80s, botanists used to walk through Antarctica’s mossy patches to take images and samples. From her suite of drone images, Bollard can create 3D models of the landscape and match them with the locations where the old images were taken. “We’re using the photographs from the early days of science in Antarctica to see if there have been any changes in vegetation in the past 50 years or so.”
Back then, teams would wander along transects for days to map an area. Today, one or two people spend one day surveying from above. “That’s where the technology is a game changer in minimising human impact on these really special places.”
