Student Research Programs - Office of Undergraduate and ...

HABITAT PREFERENCES OF NORTHERN FLYING SQUIRRELS IN THE EAST TAHOE BASIN:
IMPLICATIONS FOR FOREST HEALTH
Corey Milinovich
Program: NSF REU
Mentors: Lynn Zimmerman
Department: Environmental Science
University of San Francisco
Previous deforestation during the mining era followed by fire suppression in the
Tahoe Basin has resulted in unhealthy forest stands, affecting both susceptibility to
fire and habitat quality for resident wildlife. Northern Flying Squirrels (Glaucomys
sabrinus) are considered a keystone species in forested areas of northern and
western North America because they aid in the dispersal of truffles and other fungi
important for nutrient and water uptake by host trees. Because little is known
about habitat requirements of Flying Squirrels in the east Tahoe basin, I surveyed
known nesting trees as well as randomly selected neighborhood trees to identify characteristics of habitat utilized
by Flying squirrels in Lake Tahoe Nevada State Park. In this region of the east Tahoe basin, Northern Flying
Squirrels preferred taller Red Firs (Abies magnifica) with more canopy cover and witches brooms (proliferation of
twigs) than randomly selected neighborhood trees. Habitat characteristics also differed between nest tree plots
and randomly selected plots. Protecting these habitat characteristics and including them in fuel reduction
prescriptions will support Flying Squirrel populations and enhance forest health in the East Tahoe Basin.
FOULING IN FORWARD OSMOSIS
Jenny Mital
Program: NSF EPSCoR
Mentor: Amy Childress
Department: Civil and Environmental Engineering
University of Nevada, Reno
Membrane technology, specifically forward osmosis, poses a promising solution for
keeping pace with increasing water demand in its water treatment and reclamation
capabilities. Forward osmosis (FO), the newer, engineered application of osmosis,
involves the diffusion of water across the membrane from an area of low solute
concentration to an area of high solute concentration. Reverse osmosis (RO), the
more established membrane technology, utilizes hydraulic pressure to transport
treated water across the membrane. The membrane rejects almost all solute and
contaminants. Membrane fouling is one of the most detrimental factors to membrane process efficiency. There
is evidence that forward osmosis experiences less fouling or that it experiences more reversible fouling than
reverse osmosis. Higher fouling reversibility in FO may be linked to the observed cleaning effects of salt water due
to reverse salt diffusion across the membrane into the feed solution. Furthermore, it is conjectured that higher
fouling reversibility in FO is linked to the lack of hydraulic pressure. Experiments were performed to examine the
mechanisms by which forward osmosis (FO) seems to undergo more reversible fouling compared to reverse
osmosis (RO) and offer insight into the role of reverse salt diffusion and hydraulic pressure in membrane cleaning.
In these experiments, the type of salt in the FO draw solutions and the hydraulic pressure in on the RO feed
solutions were varied in order to analyze corresponding decreases or increases in flux during fouling and cleaning
experiments.
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