Lichen Biodiversity and Climate Change Impacts

Lichens represent a symbiotic partnership between a fungal partner (mycobiont) and a photosynthetic partner (photobiont), typically an alga or cyanobacterium. They occupy virtually every terrestrial habitat, from polar deserts to tropical rainforests, and contribute to ecosystem functions such as nitrogen fixation, soil formation and provision of habitat. Biodiversity within lichens is exceptionally high, with estimates of some 20 000–30 000 species, many of which remain undescribed. However, lichens are highly sensitive to microclimatic conditions and air quality, making them important bioindicators of environmental change. Climate warming, altered precipitation regimes and increasing frequency of extreme events are driving shifts in lichen communities, leading to range contractions, phenological changes and altered physiological performance. Conservation of lichen diversity thus requires an integrated approach combining population monitoring, habitat management and mechanistic understanding of species’ climate tolerances. Recent advances in ecological niche modelling, population genomics and controlled stress experiments are refining predictions of vulnerability, while long-term inventories are tracking biogeographical shifts and emergent threats to rare and endemic taxa.

Research from Nature Portfolio

Recent studies have employed ecological niche modelling to reconstruct glacial refugia and forecast future habitat coverage of a South American lichen species. Analyses indicate that suitable habitat during the last glacial maximum was considerably more extensive than at present, with refugial areas located in cool, dry grasslands near glacier margins. Model projections under future warming scenarios suggest that overall coverage of suitable niches may remain relatively stable, although local extirpations are predicted in some peripheral zones. The integration of palaeoclimatic reconstructions with forward-looking projections has provided a nuanced understanding of past stability and future resilience in lichen distributions.

Lichen Biodiversity and Climate Change Impacts publication trend

The graph below shows the total number of articles in lichen biodiversity and climate change impacts across all publications each year (not limited to Nature Index journals).

Technical terms

Ecological niche modelling: A computational method to predict the suitable habitat of a species by relating occurrence records to environmental variables.

Glacial refugia: Areas where species persisted during periods of glacial advances, serving as sources for postglacial recolonisation.

Bioclimatic model: A statistical or mechanistic framework that correlates species distributions with climatic variables to project range changes.

Thallus: The body of a lichen, comprising both fungal and photosynthetic partners, without differentiation into stems or leaves.

Symbiosis: A close and long-term biological interaction between two different organisms, here referring to the association of fungus and alga in lichens.

References

1. Glacial refugia and the prediction of future habitat coverage of the South American lichen species Ochrolechia austroamericana. Scientific Reports (2016).
2. Role of Squalene Epoxidase Gene (SQE1) in the Response of the Lichen Lobaria pulmonaria to Temperature Stress. Journal of Fungi (2024).
3. Climate Change, Bioclimatic Models and the Risk to Lichen Diversity. Diversity (2019).
4. The impact of climate aridification on rare lichen communities. Biosystems Diversity (2024).