Fig 1 field work in the Dry Valleys

Fieldwork in the Dry Valleys. Photo: Charles Lee

Establishing sentinel sites for terrestrial Antarctic biology

21 June 2024

During the 2023-2024 Antarctic summer, our terrestrial biology research team had their first field season, where the team conducted baseline characterisation and surveys of new biological sentinel sites. Over time, these sites will provide a consistent and continuous coupled climate-biodiversity monitoring framework for land-based ecosystems.

The Ross Sea region is increasingly subject to the effects of climate change. Change may fundamentally impact its unique ecosystems by altering the physical environment in ways that can affect species distribution, abundance, and productivity. To understand these vulnerabilities, we are characterising the habitats and the biological systems, as well as the connectivity between them.

During the summer field season, a framework for future high-precision (cm-scale accuracy and reproducibility) vegetation surveys was established, which will enable robust attributions of change in Antarctic terrestrial ecosystems to climatic changes driven by anthropogenic CO2. Changes in the physiology, composition, and spatial extent of these cold-adapted and slow-growing vegetation are excellent sentinels for environmental change.

Learn more in this Radio NZ interview: Charlie Lee: Measuring Antarctic ice melt | RNZ

The researchers are also using Antarctic vegetation as a proxy for meltwater presence (because vegetation reflects moisture availability). Often, variations in meltwater flow and quantity is too subtle and ephemeral to be detected using instrumentation. This is important since glacial melt (which affects soil moisture) is a critical link between climate change and the terrestrial ecosystem response.

Fig 2 mosses

Actively growing mosses. Photo: Gabrielle Koerich

Fig 3 cyanobacterial mats

Dried cyanobacterial mats on a dry stream bed. Photo: Charles Lee

Using drones or remotely piloted aircraft systems (RPAS) equipped with multispectral and hyperspectral sensors, the team carried out high-resolution surveys of Antarctic vegetation at sites that are projected to exhibit significant changes in surface hydrology under climate warming scenarios (Trough Lake and Canada Glacier).

Recent developments in RPAS survey techniques and technologies mean we can collect baseline data at levels of resolution and precision not previously available. New collaborations around satellite remote sensing have also created novel approaches to validate our biogeographical database and ecological model.

Key achievements from the field season included:

  • the first-ever comprehensive multispectral survey of the basin in Pyramid Trough, which captured nearly all the vegetation in the flood plain upstream of the drainage into Pyramid Lake
  • a hyperspectral survey of the newly identified sentinel site for terrestrial vegetation in Pyramid Trough
  • ground-truthing spectral surveys of terrestrial vegetation that will help calibrate the detection of vegetation in Sentinel-2 satellite imagery
  • established a geodetic point (marked with a stainless-steel plaque) that will enable rapid and highly reproducible drone surveys in the future
  • a high-resolution multispectral survey of the upper reach of Canada Stream, which captured most of the visible vegetation

Assoc. Prof Charles Lee (University of Waikato) led the field team, joined by Charlotte Walshaw (University of Edinburgh), Eva Nielsen and Gabrielle Koerich (University of Canterbury).

Fig 4 drone use

Using a drone equipped with multispectral and hyperspectral sensors to carry out high-resolution surveys of Antarctic vegetation. Photos: Gabrielle Koerich, right; Eva Nielsen, left