Strikingly simple means of diagnosing ecosystem health uncovered

Date:
September 29, 2021
Source:
Oregon State University
Summary:
Scientists say the health of a terrestrial ecosystem can be
largely determined by three variables: vegetations' ability to
uptake carbon, its efficiency in using carbon and its efficiency
in using water.



FULL STORY ==========================================================================
An international collaboration including Oregon State University
researcher Bev Law says the health of a terrestrial ecosystem can be
largely determined by three variables: vegetations' ability to uptake
carbon, its efficiency in using carbon and its efficiency in using water.


========================================================================== Findings, published in Nature, are important because scientists and policymakers need easier, faster and less expensive ways to determine how
the ecosystems relied on by humans respond to climate and environmental changes, including impacts caused by people.

"We used these complex, continuous data to develop equations that can
be applied with fewer measurements to monitor forest response to climate
and other factors," Law said.

The team of researchers, led by the Max Planck Institute for
Biogeochemistry in Jena, Germany, used satellite observations,
mathematical models and multiple environmental data streams to determine
that those three factors combine to represent more than 70% of total
ecosystem function.

Put another way, if an ecosystem's carbon uptake, carbon-use efficiency
and water-use efficiency are all strong, that means at least 70% of
everything the ecosystem is supposed to do is being done well.

"Ecosystems on the Earth's land surface support multiple functions and
services that are critical for society," said Law, professor emeritus
in the OSU College of Forestry. "Those functions and services include
biomass production, plants' efficiency in using sunlight and water, water retention, climate regulation and, ultimately, food security. Monitoring
these key indicators allows for describing ecosystem function in a way
that summarizes its ability to adapt, survive and thrive as the climate
and environment change." Water-and carbon-use efficiency are linked
closely with climate and also with aridity, which suggests climate change
will play a big role in shaping ecosystem function over the coming years,
the scientists say.



========================================================================== Among the building blocks of the current research are data from five
semi-arid ponderosa pine sites where Law has been conducting research
for 25 years.

Those sites are in the AmeriFlux network, a collection of locations in
North, South and Central America managed by principal investigators like
Law that measure ecosystem carbon dioxide, water and energy "fluxes,"
or exchanges with the atmosphere. AmeriFlux is part of the international FLUXNET project, and data from 203 FLUXNET sites representing a variety
of climate zones and vegetation types were analyzed for the study.

Measuring ecosystem health has long been challenging given the
complexities of ecosystem structure and how systems respond to
environmental change, said Law, who has been researching the
quantification of forest health for decades.

"In the 1980s, I was working on the development of indicators including
similar carbon-use efficiency, and many of the measurements were
incorporated in the Forest Service's Forest Health Monitoring plots," Law
said. "The new flux paper shows how continuous data can be used to develop algorithms to apply in monitoring forest condition, and for evaluating
and improving ecosystem models that are used in estimating the effects
of climate on ecosystem carbon uptake and water use." The water-use
indicator is a combination of metrics that relate to an ecosystem's
water-use efficiency, which is the carbon taken up per amount of water transpired by plants through their leaves. The carbon-use efficiency
indicator compares the carbon that's respired versus carbon taken up;
plant respiration means converting into energy the sugars produced
during photosynthesis.

"Using three major factors, we can explain almost 72% of the variability
within ecosystem functions," said Mirco Migliavacca, the study's lead
author and a researcher at the Max Planck Institute for Biogeochemistry.

The three functional indicators depend heavily, Law said, on the structure
of vegetation -- greenness, nitrogen content of leaves, vegetation height
and biomass. That points to the importance of ecosystem structure,
which can be altered by disturbances such as fire and also by forest
management practices.

========================================================================== Story Source: Materials provided by Oregon_State_University. Original
written by Steve Lundeberg. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Mirco Migliavacca, Talie Musavi, Miguel D. Mahecha, Jacob A. Nelson,
Ju"rgen Knauer, Dennis D. Baldocchi, Oscar Perez-Priego, Rune
Christiansen, Jonas Peters, Karen Anderson, Michael Bahn, T. Andrew
Black, Peter D. Blanken, Damien Bonal, Nina Buchmann, Silvia
Caldararu, Arnaud Carrara, Nuno Carvalhais, Alessandro Cescatti,
Jiquan Chen, Jamie Cleverly, Edoardo Cremonese, Ankur R. Desai,
Tarek S. El-Madany, Martha M. Farella, Marcos Ferna'ndez-Marti'nez,
Gianluca Filippa, Matthias Forkel, Marta Galvagno, Ulisse Gomarasca,
Christopher M. Gough, Mathias Go"ckede, Andreas Ibrom, Hiroki Ikawa,
Ivan A. Janssens, Martin Jung, Jens Kattge, Trevor F. Keenan,
Alexander Knohl, Hideki Kobayashi, Guido Kraemer, Beverly E. Law,
Michael J. Liddell, Xuanlong Ma, Ivan Mammarella, David Martini,
Craig Macfarlane, Giorgio Matteucci, Leonardo Montagnani, Daniel
E. Pabon-Moreno, Cinzia Panigada, Dario Papale, Elise Pendall,
Josep Penuelas, Richard P. Phillips, Peter B. Reich, Micol Rossini,
Eyal Rotenberg, Russell L. Scott, Clement Stahl, Ulrich Weber,
Georg Wohlfahrt, Sebastian Wolf, Ian J. Wright, Dan Yakir, So"nke
Zaehle, Markus Reichstein. The three major axes of terrestrial
ecosystem function. Nature, 2021; DOI: 10.1038/s41586-021-03939-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210929142708.htm

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