Towards species-level forecasts of drought-induced tree mortality risk

• Published in: New Phytologist
• Main Authors: De Kauwe, M.G., Sabot, M.E.B., Medlyn, B.E., Pitman, A.J., Meir, P., Cernusak, L.A., Gallagher, R.V., Ukkola, A.M., Rifai, S.W., Choat, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2022
• Subjects: Australia; cavitation resistance; drought tolerance; land surface model; plant hydraulics; species; Plant Leaves; Trees; Carbon Dioxide; Water; Droughts; Ukkola; sami
• Online Access: https://hdl.handle.net/2440/136432; https://doi.org/10.1111/nph.18129

Predicting species-level responses to drought at the landscape scale is critical to reducing uncertainty in future terrestrial carbon and water cycle projections. We embedded a stomatal optimisation model in the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model and parameterised the model for 15 canopy dominant eucalypt tree species across South-Eastern Australia (mean annual precipitation range: 344–1424 mm yr−1 ). We conducted three experiments: applying CABLE to the 2017–2019 drought; a 20% drier drought; and a 20% drier drought with a doubling of atmospheric carbon dioxide (CO2). The severity of the drought was highlighted as for at least 25% of their distribution ranges, 60% of species experienced leaf water potentials beyond the water potential at which 50% of hydraulic conductivity is lost due to embolism. We identified areas of severe hydraulic stress within-species’ ranges, but we also pinpointed resilience in species found in predominantly semiarid areas. The importance of the role of CO2 in ameliorating drought stress was consistent across species. Our results represent an important advance in our capacity to forecast the resilience of individual tree species, providing an evidence base for decision-making around the resilience of restoration plantings or net-zero emission strategies. Martin G. De Kauwe, Manon E. B. Sabot, Belinda E. Medlyn, Andrew J. Pitman, Patrick Meir, Lucas A. Cernusak, Rachael V. Gallagher, Anna M. Ukkola, Sami W. Rifai, and Brendan Choat