Plant adaptation to climate change. Photo: Stefano Manzoni.
Plant adaptation to climate change. Photo: Stefano Manzoni.


We rely on the plants that make up our planet’s ecosystems to release oxygen into the atmosphere, absorb carbon dioxide (CO2), and provide habitat and food for wildlife and humans. These services are critical in the future management of climate change, especially in terms of CO2 uptake and release, but due to the many complex, interacting processes that affect the ability of vegetation to provide these services, they remain difficult to predict.

Stefano Manzoni
Stefano Manzoni

The study is led by The International Institute for Applied Systems Analysis (IIASA) with Stefano Manzoni, The Department of Physical Geography and The Bolin Centre for Climate Research at Stockholm University, as co-author.

The results are published in the journal Nature Plants, an international team of researchers endeavored to address this problem by exploring approaches to master this complexity and improve our ability to predict vegetation dynamics. They explored key organizing principles that govern these processes – specifically, natural selection; self-organization (controlling collective behavior among individuals); and entropy maximization (controlling the outcome of a large number of random processes). In general, an organizing principle determines or constrains how components of a system, such as different plants in an ecosystem or different organs of a plant, behave together. Mathematically, such a principle can be seen as an additional equation added to a system of equations, allowing one or more previously unknown variables in the system to be determined and thereby reducing the uncertainty of the solution.

Dynamic vegetation models that combine elements

A lot of research has gone into understanding and predicting how plant processes combine to determine the dynamics of vegetation on larger scales. To integrate process understanding from different disciplines, dynamic vegetation models (DVMs) have been developed that combine elements from plant biogeography, biogeochemistry, plant physiology, and forest ecology. DVMs have been widely used in many fields including the assessment of impacts of environmental change on plants and ecosystems; land management; and feedbacks from vegetation changes to regional and global climates. However, previous attempts to improve vegetation models have mainly focused on improving realism by including more processes and more data. This has not led to the expected success because each additional process comes with uncertain parameters, which has in turn caused an accumulation of uncertainty and therefore unreliable model predictions.

- Despite the ever-increasing availability of data, and the fact that vegetation science, like many other scientific fields, is benefitting from increasing access to big data sets and new observation technologies, we also need to understand governing principles like evolution to make sense of the big data. Current models are not able to reliably predict long-term vegetation responses, explains lead author Oskar Franklin, a researcher in the IIASA Ecosystems Services and Management Program.

Better tools for understanding and managing the biosphere

The study found that by representing the principles of evolution, self-organization, and entropy maximization in models, they could better predict complex plant behavior and resulting vegetation as an emerging result of environmental conditions. Although each of these principles had previously been used to explain a particular aspect of vegetation dynamics, their combined implications were not fully understood. This approach means that a lot of complex variation and behavior at different scales, from leaves to landscapes, can now be better predicted without additional understanding of underlying details or more measurements.

The authors expect that apart from leading to better tools for understanding and managing the biosphere, the proposed "next-generation approach” may result in different trajectories of projected climate change that both policy and the general public would have to cope with.

Reference

Franklin O., Harrison S. P., Dewar R., Farrior C. E., Brännström Å., Dieckmann U., Pietsch S., Falster D., Loreau M., Wang H., Mäkelä A., Rebel K. T., Schymanski S. J., Rovenskaya E., Cramer W., Stocker B. D., Zaehle S., Manzoni S., van Oijen M., Wright I. J., Ciais P., van Bodegom P., Penuelas J., Hofhansl F., Terrer C., Soudzilovskaia N. A., Midgley G., and I. C. Prentice (2020). Organizing principles for vegetation dynamics. Nature Plants, DOI: 10.1038/s41477-020-0655-x.

Contact in Sweden:

Stefano Manzoni
stefano.manzoni@natgeo.su.se

Researcher contact for the project:

Oskar Franklin
Research scholar
Ecosystems Services and Management Program
Tel: +43 2236 807 251
franklin@iiasa.ac.at