Palaeo leaf economics reveal a shift in ecosystem function associated with the end-Triassic mass extinction event

• Published in: Nature Plants
• Main Authors: Soh, W. K., Wright, I. J., Bacon, K. L., Lenz, T. I., Steinthorsdottir, M., Parnell, A. C., McElwain, J. C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: East Greenland; Greenland
• Online Access: https://researchers.mq.edu.au/en/publications/af4cde2b-b30c-401a-b102-622374ecd8c9; https://doi.org/10.1038/nplants.2017.104; http://www.scopus.com/inward/record.url?scp=85025124669&partnerID=8YFLogxK; https://doi.org/10.1038/nplants.2017.126; http://www.scopus.com/inward/record.url?scp=85063713026&partnerID=8YFLogxK

Climate change is likely to have altered the ecological functioning of past ecosystems, and is likely to alter functioning in the future; however, the magnitude and direction of such changes are difficult to predict. Here we use a deep-Time case study to evaluate the impact of a well-constrained CO 2-induced global warming event on the ecological functioning of dominant plant communities. We use leaf mass per area (LMA), a widely used trait in modern plant ecology, to infer the palaeoecological strategy of fossil plant taxa. We show that palaeo-LMA can be inferred from fossil leaf cuticles based on a tight relationship between LMA and cuticle thickness observed among extant gymnosperms. Application of this new palaeo-LMA proxy to fossil gymnosperms from East Greenland reveals significant shifts in the dominant ecological strategies of vegetation found across the Triassic-Jurassic transition. Late Triassic forests, dominated by low-LMA taxa with inferred high transpiration rates and short leaf lifespans, were replaced in the Early Jurassic by forests dominated by high-LMA taxa that were likely to have slower metabolic rates. We suggest that extreme CO 2-induced global warming selected for taxa with high LMA associated with a stress-Tolerant strategy and that adaptive plasticity in leaf functional traits such as LMA contributed to post-warming ecological success.