"Nature is rife with symbiotic relationships, some of which take place out of sight, like the rich underground exchange of nutrients that occurs between trees and soil fungi"............"In North America's eastern forests, Ectomycorrhizal Mycorrhizal fungi grow on conifers such as pines, oaks and beeches and Arbuscular Mycorrhizal fungi grow on non-conifers such as maple".........."Both of these fungi drive the nutrient -carbon exchange between their respective trees and soil"........."The fungi take up carbon from tree roots and and provide soil nutrients that the trees further need to grow"..........."Scientists can measure these mycorrhizal exchanges As a way of determining the health of ecosystems during the current climate change that we are experiencing".........."Thus far, the data reveals that eastern forests are not yet shifting their range northward and/or to higher altitudes in response to warming termperatures"..........This provides some comfort that our animal, bird, reptile and amphibian suite of creatures have further time to adapt to the changes that warming temperatures will have on their survival

http://feedproxy.google.com/~r/sciencedaily/plants_animals/ecology/~3/bGCUt2u_iac/180316153852.htm?utm_source=feedburner&utm_medium=email

Soil fungi may help determine 

the resilience of forests to 

environmental change

Date:

March 16, 2018

Source:

University of California - Santa Cruz

Summary:

A major new study reveals that soil fungi
could play a significant role in the ability
 of forests to adapt to environmental change

---

This map shows the distribution
 of 'EM dominant' trees across
forest inventory plots in the

eastern United States.

Credit: Kai Zhu 

But what happens in the dark 
may have profound implications 
above ground, too: A major new 
study reveals that soil fungi could 
play a significant role in the ability 
of forests to adapt to 
environmental change.

Kai Zhu, assistant professor
of environmental studies at

UC Santa Cruz, took a unique
"big data" approach to
investigating the role of
symbiotic fungi in tree
migration in forests across
the eastern United States.

"Our climate is rapidly
 changing, and our forests
are responding, but in very
slow motion -- it's hardly
detectable," said Zhu, who
 wanted to identify factors
 that contribute to the pace
of that response.

In forests, tree growth largely
depends on the nutrients
available in the soil, while the
transfer of carbon through roots
to the soil regulates ecosystem
processes. Mycorrhizal
("MY-koe-RY-zull") fungi grow
on the roots of most plants and
drive the nutrient-carbon exchange
between plants and soil: They take
up carbon resources from their hosts
and provide soil nutrients that plants
need. The two most common fungi
associated with forest trees
 are: ectomycorrhizal (ECM), which
grow on conifers, including pines, as
well as oaks and beeches;
and arbuscular (AM), which grow
on most nonconifers, such as maples.

Zhu utilized data from the U.S.
Department of Agriculture's Forest
Inventory and Analysis program to
examine how soil carbon and nitrogen
levels differ across stands of forest
 that are characterized by "AM
dominant" trees and "ECM dominant"
 trees. He correlated the distribution
of trees with soil fungi and content,
then analyzed the distribution of trees
by fungus type. In the most significant
finding, Zhu was able to identify distinct
soil nitrogen "signatures" that impact

 soils and ecosystems in ways that may
determine the resilience of forests to the
changing climate.

Specifically, soil carbon-to-nitrogen
ratios increase with greater ECM
dominance -- even after accounting
for climate, soil texture, and foliar
nitrogen. Moreover, ECM dominance
is more associated with low soil
nitrogen rather than high soil carbon.

"These findings suggest that AM and
 ECM trees have differential success
along nitrogen fertility gradients, or
perhaps that AM and ECM trees
promote differences in cycling rates

of carbon and nitrogen because of
traits associated with nitrogen
acquisition," he said. "Both
processes may occur
\simultaneously, leading to a
self-reinforcing positive
plant-soil feedback."
Zhu's findings suggest that 

the mycorrhizal guild could
be an emerging "functional trait."

Functional traits are those
that define species in terms
of their ecological roles -- how
they interact with the environment
and with other species. As such,
they are predictable and easily
measured from the ground or by
satellite, which makes them
particularly valuable to scientists
who are monitoring environmental
responses to climate change. "They
tell us how the ecosystem is
responding," said Zhu.

"There is no evidence yet that
eastern forests are shifting their
geographic ranges to higher
latitudes in response to warming
temperatures," said Zhu. "But
understanding how mycorrhizal
relationships impact ecosystems
will help us predict how forests
will respond to global change."

Zhu's study, published in the
Journal of Ecology, is one of the
first to use the USDA's large-scale
data set to see how climate change
is impacting the ecosystem, an
approach known as "top down"

 rather than "bottom up."

As a quantitative environmental
scientist, Zhu brings the tools of
statistics and data science to the
study of global ecology. Rather than
measuring fungal traits in the soil
and scaling up, Zhu uses existing
data -- including large-scale datasets
generated by satellites -- to look at
patterns and processes playing out
on continental and global scales.
"Big data is becoming more and
more popular and powerful," he said.
"It's different from traditional research
in ecology, which takes place in a lab
or in the field."

Zhu, whose background is in physics
and systems theory, brings tremendous
 urgency to his work on climate change.
 His research focuses on four areas:
forest ecosystems, grassland, soil,
and phenology, which Zhu describes
as "nature's calendar."

Zhu is determined to make solid
contributions to a field in which
much of the evidence is incomplete
and unconvincing.

"We know the environment is changing,
 but how it impacts the Earth and its
systems is a big question," he said.
"As scientists, we have the

responsibility to correctly work out
this problem -- it's a problem that's
 important to scientists and the general
 public."

---

Story Source:

Materials provided by University 
of California - Santa Cruz. Original
written by Jennifer McNulty. Note:
 Content may be edited for style and len

---

Journal Reference:

1. Kai Zhu, M. Luke McCormack, Richard A. Lankau, J. Franklin Egan, Nina Wurzburger. Association of ectomycorrhizal trees with high carbon-to-nitrogen ratio soils across temperate forests is driven by smaller nitrogen not larger carbon stocks. Journal of Ecology, 2018; 106 (2): 524 DOI: 0.1111/1365-2745.12918
2.