From: Ecological Society of America: grants, jobs, news [[log in to unmask]] on behalf of John Stella [[log in to unmask]]
Sent: Sunday, February 12, 2017 9:21 PM
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Subject: [ECOLOG-L] PhD position to study water stress indicators of riparian forest decline using tree-rings and stable isotopes

Seeking a PhD student to work on a new NSF-funded project with field work on a
Southern California river (Santa Clara) plus dendro-isotope lab analyses. Three years of
funding minimum available, with additional years possible.

Linking basin-scale, stand-level, and individual tree water stress indicators for
groundwater-dependent riparian forests in multiple-use river basins


The PhD position is supported at SUNY-ESF, the State University of New York College
of Environmental Science and Forestry, working with Dr. John Stella and
interdisciplinary collaborators at UC Santa Barbara and The Nature Conservancy. The
position will start in fall 2017. Research questions will focus on riparian ecosystem
response to drought, climate change and groundwater extraction. Methods will include
field sampling to inventory riparian forest structure and health, collecting and analyzing
tree rings for growth trends and annual water use efficiency using carbon isotopes, and
assessing critical thresholds for riparian forest decline. Field studies will occur in the
Santa Clara River basin in Southern California with lab work at SUNY-ESF and partner
institutions. Ideal candidates will have an MS in ecology, environmental science, or a
related field; a strong quantitative and statistical background; the ability to work in
remote field settings; and interest in riparian forest ecology and tree ecophysiology in
dryland regions. The position is funded for a minimum of three years and provides a
competitive stipend, tuition and benefits. Interested candidates should send a
CV/resume (with GPA and GRE scores), a description of research interests and
experience, and names and contact information for 3 references to [log in to unmask] For
more information on how to apply, see


Linking basin-scale, stand-level, and individual tree water stress indicators for
groundwater-dependent riparian forests in multiple-use river basins
John Stella, SUNY-ESF (PI); Michael Singer, UCSB (PI); Dar Roberts, UCSB (Co-PI)

This project will develop a suite of water stress indicators at several scales to assess
the health of riparian ecosystems in response to sustained groundwater decline.
Riparian forests and woodlands are hotspots of biodiversity and support key functions
and habitats within river corridors, but they are particularly sensitive to large changes in
water supply. The study will take place in the Santa Clara River (California, USA), where
sustained groundwater pumping for irrigation during a severe drought has had negative
impacts and allows for study of riparian woodland response to short- and long-term
climate change. The project team will assess the signals and thresholds of water stress
over the last decade using high-resolution aerial imagery and tree-rings to develop
predictors of long-term impairment and collapse. This work addresses a topic of urgent
scientific and societal importance, namely how to assess and prevent negative impacts
of drought and human-induced water shortages on vulnerable, high-value riparian
ecosystems. In collaboration with The Nature Conservancy, the project team will
integrate results within statewide guidelines for protecting groundwater-dependent
riparian ecosystems mandated under California’s recent Groundwater Sustainability
Management Act. The project will engage the public in several ways, including: 1)
consulting with groundwater managers, farmers and other stakeholders through
workshops to develop effective methods for communicating results widely; (2)
mentoring early career scientists including women in STEM subjects; and 3) engaging
with K-12 student programs in diverse local communities to increase environmental
awareness in the Santa Clara basin.

As water management in multiple-use river basins around the world becomes
increasingly intertwined with large-scale ecosystem restoration, the proposed research
sits at the forefront of broader human-climate-ecosystem challenges facing societies,
businesses, and governments. The project will capitalize on extensive groundwater well
records to link water table dynamics with changes in plant water status detected at two
different scales: (1) basin-wide, high-resolution aerial imagery taken seasonally during
the drought; and (2) annual growth and carbon isotope data from tree rings covering
the same period. The study is novel, in that it integrates advanced methods in two
rapidly-emerging fields, hyperspectral remote sensing and isotope dendroecology, in
developing a holistic understanding of water stress at multiple scales of resolution. The
research is also potentially transformative in that it compares water stress indicators
that vary in their timing, strength, and rates of change, and that it enables the
assessment of warning signs and time lags between reduced growth and functioning in
individual trees, and synoptic forest decline evident throughout a river corridor. These
findings will have broad application beyond the study system, because the ecology and
functional roles of riparian trees are similar in many water-limited regions, with similar
foundational importance in groundwater-dependent ecosystems globally.