Antarctic terrestrial ecosystems are highly specialized vegetation communities dominated by lichens and bryophytes. These ecosystems exist at the limits of survival, making them particularly vulnerable to environmental shifts. While climate change is already driving transformations in Antarctic vegetation, predicting future responses remains challenging due to the limitations of current species distribution models (SDMs). Recent studies have demonstrated that microscale terrain features such as terrain depressions, wind exposure, and biotic interactions are key determinants of moss and lichen ecological niches and spatial abundance patterns. At a broader scale, biotic interactions have been shown to enhance SDMs for Antarctic vegetation, reinforcing the need to incorporate both abiotic and biotic processes into predictive models. However, the reliability of these models is constrained by the high uncertainty associated with available climate datasets, which lack the necessary resolution for fine-scale ecological applications.

To improve SDM accuracy and predictive power, it is crucial to integrate process-explicit approaches that reflect the mechanisms driving species distributions. Incorporating microscale complexity and biotic interactions can enhance model realism, but a key missing component is a physiological link to assess how well these environmental predictors capture species’ responses to climate variability. Water availability has been identified as a fundamental driver of Antarctic vegetation patterns, yet no current SDMs incorporate physiological evidence of water stress or adaptation. Stable isotopic signatures, particularly δ¹³C, provide a direct measure of water-use efficiency and can serve as empirical indicators of vegetation responses to environmental gradients. Similarly, radiocarbon dating offers a long-term perspective on past water availability trends, helping to refine SDM predictions by assessing how species have historically responded to climate fluctuations. By integrating isotopic validation, SDMs can move beyond purely correlative approaches, allowing for more mechanistic and ecologically meaningful forecasts of vegetation dynamics in a changing climate. However, this remains an unmet challenge in Antarctic biogeography.

ISOMAP aims to develop the first process-based, high-resolution SDMs for Antarctic vegetation by integrating an ecophysiological link with stable isotope signatures, remote sensing-derived microscale non-climatic variables, and biotic interactions for four dominant species of lichens and bryophytes. The approach will couple isotopic δ¹³C signatures with environmental data and species abundances, providing an ecophysiological link to refine species niches and validate climate-driven species distribution predictions. This process-explicit modeling approach will improve the ecological realism of SDMs, making forecasts of climate change impacts more reliable. To enhance the temporal accuracy of these models, radiocarbon dating will be used to track past water availability trends and validate historical shifts in species distributions, creating a novel framework for integrating past environmental conditions into predictive models.

The research will be based on pre-collected vegetation samples spanning a regional environmental gradient in the Antarctic Peninsula from King George Island in the South Shetlands archipelago to Stonington Island in Marguerite Bay. This dataset includes community data with species abundance, samples of the target species for isotopic analysis, and temporal ultra-high-resolution remote sensing data (DEM and orthomosaic with ~2 cm resolution) for two selected areas, enabling spatial and temporal model validation. The project will employ Joint Species Distribution Models (JSDMs) to account for the influence of biotic interactions on vegetation distribution patterns. By incorporating physiological and biotic filtering mechanisms into SDMs, ISOMAP will bridge microscale terrain complexity with regional climate gradients, improving confidence in vegetation projections under climate change scenarios.

ISOMAP will pioneer the use of stable isotope validation within SDMs, enhancing our ability to model climate change impacts on Antarctic vegetation while addressing fundamental challenges in ecological modelling. The research team brings together ecological modelers, ecophysiologists, and remote sensing experts, ensuring a multidisciplinary approach to Antarctic biogeography. By integrating these methodologies, the project will contribute to a more mechanistic understanding of species distributions, setting a new standard for SDMs in extreme environments. Ultimately, ISOMAP’s findings will support conservation efforts under the Antarctic Treaty by providing high-resolution, ecologically meaningful projections of future vegetation changes, serving as a baseline for broader-scale modelling efforts across Antarctica.