Functioning of terrestrial ecosystems is governed by three main factors
Study helps to better assess the capacity of global ecosystems to adapt
to climate and environmental change

Date:
September 22, 2021
Source:
German Centre for Integrative Biodiversity Research (iDiv)
Halle-Jena- Leipzig
Summary:
A large international research team has identified three key
indicators that together summarize the integrative function of
terrestrial ecosystems: 1. the capacity to maximize primary
productivity, 2. the efficiency of using water, and 3. the
efficiency of using carbon. The monitoring of these key indicators
will allow a description of ecosystem function that shapes the
ability to adapt, survive and thrive in response to climatic and
environmental changes.



FULL STORY ========================================================================== Ecosystems on Earth's land surface support multiple functions and services
that are critical for society, like biomass production, vegetation's
efficiency of using sunlight and water, water retention and climate
regulation, and ultimately food security. Climate and environmental
changes, as well as anthropogenic impacts, are continuously threatening
the provision of these functions. To understand how terrestrial ecosystems
will respond to this threat, it is crucial to know which functions are essential to obtain a good representation of the ecosystems' overall
well-being and functioning. This is particularly difficult since
ecosystems are rather complex in terms of their structure and their
responses to environmental changes.


==========================================================================
A large international network of researchers, led by Dr Mirco Migliavacca
at MPI BGC and iDiv in Germany, tackled this question by combining
multiple data streams and methods. The scientists used environmental
data from global networks of ecosystem stations, combined with satellite observations, mathematical models, and statistical and causal discovery methods. The result is strikingly simple: "We were able to identify three
key indicators that allow us to summarise how ecosystems function: the
maximum realised productivity, the efficiency of using water, and the efficiency of using carbon" says the study's first author Dr Migliavacca.

The maximum productivity indicator reflects the capacity of the given
ecosystem to uptake CO2. The water use indicator is a combination of
metrics representing the ecosystem water use efficiency, which is the
carbon taken up per quantity of water transpired by plants. The carbon use efficiency indicator reflects the use of carbon by an ecosystem, which represents the carbon respired versus carbon taken up. The surprising
findings made the team reflect on how complex ecosystems are ultimately
driven by a small set of major factors just like was found, for instance,
for leaf photosynthesis based on a handful of leaf traits.

"Using only these three major factors, we can explain almost 72 percent
of the variability within ecosystem functions," Migliavacca adds. "With water-use efficiency being the second major factor, our results emphasise
the importance of water availability for ecosystems' performance. This
will be crucial for climate change impact considerations," says
last author Prof Dr Markus Reichstein, director of the department Biogeochemical Integration at MPI BGC and iDiv.

The researchers inspected the exchange rates of carbon dioxide, water
vapour, and energy at 203 monitoring stations around the world that
belong to the FLUXNET network, a collaborative network of multiple
research teams and field sites that collect and share their data. The
selected sites cover a large variety of climate zones and vegetation
types. For each site, they calculated a set of the ecosystems' functional properties, and further included calculations on average climate and
soil water availability variables as well as vegetation characteristics
and satellite data on vegetation biomass.

The three identified functional indicators critically depend on the
structure of vegetation, that is vegetation greenness, nitrogen content
of leaves, vegetation height, and biomass. This result underlines the importance of ecosystem structure, which can be shaped by disturbances and forest management in controlling ecosystem functions. At the same time,
the water and carbon use efficiency also critically depend on climate
and partly on aridity, which points at the critical role of climate
change for future ecosystem functioning.

"Our exploratory analysis serves as a crucial step towards developing indicators for ecosystem functioning and ecosystem health,"
summarises Reichstein, "adding to a comprehensive assessment of the
world's ecosystems response to climate and environmental changes." ========================================================================== Story Source: Materials provided by German_Centre_for_Integrative_Biodiversity_Research_
(iDiv)_Halle-Jena-Leipzig. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Migliavacca, M., Musavi, T., Mahecha, M.D. et al. 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/2021/09/210922121758.htm

--- up 2 weeks, 6 days, 8 hours, 25 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)