Ecohydrology
Group
Department
of Geography
Department of Environment and
Sustainability
How do
plants thrive in stressful
environments? As the world warms and
some regions become drier there is
pressing need for understanding the
connections between hydrology and
plant ecophysiology. Our
interdisciplinary group sits at this
nexus. We combine observations with
hard to observe processes that are
represented in simulation models. Our
models simulate plant water transport,
photosynthesis, and growth using
physical equations and biological
first principles. We use the models to
reveal the emergent traits that
underlie drought-induced tree
mortality, enhanced or suppressed
carbon cycling, and plant water
demand.
Climate
Dynamics and Tree Mortality
How
will forests fare in a warming
world? This is an urgent
question because healthy
forests are important carbon
sinks, but when trees die they
become a carbon source.
Forests also transpire 40% of
the global average
precipitation falling on land
areas, which makes forests
integral to Earth's water
cycle. Our research output
titles include:
The fate
of trees is determined largely by
the ability of their roots to access
water. Scientists have long sought
to overcome the inability to peer
into the subsurface to see how root
processes interact with other
processes occurring below ground. We
have developed a novel modeling
approach that provides a "lens" for
seeing below the surface. We ask how
does root growth prior to and during
drought allow trees to adjust their
water uptake depths to access
reliable water sources during
drought? Here you can read
about our findings so far:
Lateral
subsurface flow and saturated
soil zones play important roles
in mediating tree health, but
this hydrology has generally
been neglected when considering
the physiological responses of
plants to drought. Our work
explicitly addresses this gap by
considering the integrated
systems of plant hydraulics and
groundwater hydrology. Here you can
read about our findings so far:
Biotic and
other disturbances combine
with drought to exacerbate
forest decline and
consequent changes to
water resources. These
disturbances are an
integral part of whole
ecosystems responses. Here you
can read about our
findings so far:
Plant
traits interact with
environmental conditions
to influence plant growth
and productivity. By
examining these
interactions using crop
species and biophysical
process-based models, we
are exploring mechanisms
by manipulating both plant
traits and environment.
This enables us to use a
robust hypothesis testing
framework to study traits
that are transferable to
natural settings and novel
environmental conditions.
Here you
can read about our
findings so far:
Evapotranspiration
represents the largest
path taken by
precipitation once it
falls on terrestrial
systems, and it is
mediated by plants. We
have asked how species,
plant age, disturbance,
and gradients associated
with edaphic,
topographic, and
micrometeorologic
dynamics affect
evapotranspiration, and
how the associated
mechanisms can be used
to build robust yet
simple models. A lot
of our earlier work
(early 2000s) provided
the empirical and
theoretical foundation
for developing the
Terrestrial Regional
Ecosystem Exchange
Simulator (TREES).
Here you can read
about our findings so
far: