Natural Science
Seminar - Abstracts Spring 2008
Christopher Fusting
Jan. 28, 2008
Predicting
Oriental Bittersweet (Celastrus
orbiculatus)
Habitat using GIS and CART Modeling
Mentor: Dr. Mark Brenner
Abstract: Geographic
Information System (GIS) technology has become an important tool in
ecology. One application of GIS is habitat mapping and
prediction. A target species’ habitat can be sampled and then
predicted given the availability of predictor variables (data layers)
over the area of study. Oriental Bittersweet (Celastrus orbiculatus) is a
non-native, invasive woody vine common in the southeastern
Appalachians. Originally introduced from Asia for ornamental
purposes, C. orbiculatus has
spread rapidly due to poor management, prolific seed production, shade
tolerance, and a lack of natural enemies. The objective of this
study is to develop a habitat prediction model of Celastrus orbiculatus using GIS and
classification tree modeling. Presence and absence data for C. orbiculatus was gathered in the
Bent Creek Experimental Forest, NC, at 88 random plots. The
resulting habitat and non-habitat data was combined with slope, aspect,
elevation, distance to stream, and distance to roads and trails GIS
data of corresponding location. Classification and Regression
Tree modeling (CART) software was used to build a classification tree
of C. orbiculatus habitat
and non-habitat. The resulting classification tree was manually
examined and several equations were derived from it for use in habitat
and non-habitat prediction map generation. Two maps were
generated in Arcmap 9.2 and tested for accuracy using a 42 plot grid of
presence and absence habitat data of C.
orbiculatus sampled prior to the beginning of this study.
The habitat map was 5% better than random (25%) at predicting the
presence of C. orbiculatus.
The non-habitat map was 13% better than random (75%) at predicting
absence. The results indicate some success in correctly
predicting the habitat and non-habitat of C. orbiculatus. Through the
employment of this habitat prediction model, land managers could target
C. orbiculatus for removal and
develop land use policies that minimize its spread.
Moriah Floyd
February 4, 2008
Soil-management
history as a factor in Mexican bean beetle (Epilachna varivestis) preference for string
bean plants (Phaseolus vulgaris).
Mentor: Ms. Karen Joslin
Abstract: Research has shown
that the nutrient management history (NMH) of a soil can influence
insect interactions with plants grown in those soils. There are
two possible causes of this interaction: the fertilizer applied
annually, and the accumulated effects of the soil’s NMH. Research
has found that insect pest preference can be mediated by a soil’s
NMH. My objective was to determine if the soil management history
of the soils used in this study affected feeding preference and
oviposition of Mexican Bean Beetles (Epilachna
varivestis) on string beans (Phaseolus
vulgaris). Soils were collected using random representative
sampling in the spring of 2007 from two farms in Leicester, Buncombe
County, North Carolina. Soil A had been under conventional management
for 25 years, while soil B was under certified organic management for
20 years. Soils were analyzed for nutrients and 1.65kg of each was
placed in 12 plastic pots (n=24). Soil tests indicated that
fertilizer was unnecessary for either soil, but that 7.11grams of
agricultural lime per pot was required for soil B. Plants were placed
in a growth chamber with a day length of 15 hours, a daytime
temperature of 26 C, and a nighttime temperature of 20 C. Plants
were randomly arranged and received DI water initially to saturation,
followed by watering with DI for four seconds, every other day.
Planting of string beans seeds (4/pot) was followed by weeding and
thinning (1/pot), ten days post emergence. Mexican Bean Beetles were
randomly applied at a rate of 20 beetles per 24 plants when plants were
70% mature. Ovipositional data were collected only once, due to
rapid onset of plant disease. Herbivory was measured at 70% of
plant maturity. Results from the single oviposition data collection
were not enough to perform a statistical analysis. A Two-Sample
T-Test was used to analyze the herbivory data. There was no
significant difference (P=0.069) between the two soil types; soil A had
a mean of 2.83 percent defoliation and the mean of soil B was 4.83
percent defoliation. The lack of difference between the soils may
have been because their NMH’s were not very dissimilar, additionally;
the CEC of soils in the Southeast is very low, possibly reducing the
range of difference so that a statistical difference would not be found.
Virginia Wolking
February 4, 2008
Plant Species
Cover Composition in Northwest Minnesota Conservation Reserve Program
Fields
Mentor: Dr. Lou Weber
The Conservation Reserve Program was initiated in 1985 to reduce soil
erosion, protect water quality and provide wildlife habitat on erosion
prone agricultural land. Landowners receive payments for enrolled
CRP based on the agricultural rental value of the land. In order
to qualify for full monetary compensation for enrolled CRP the
landowner must follow guidelines set by local Farm Service Agency
offices. While these guidelines specify outcomes of management,
the landowner determines the practices used to sustain the CRP.
My objective is to better understand how management regimes affect
plant species in northwest Minnesota grassland CRP. CRP
Management regimes examined in this studying included mowing, aerial
application of herbicide, and cattle grazing. Seeding plans for
three CRP fields surrounding Euclid, Minnesota were obtained from the
local Farm Service Agency office. Plant species cover was
estimated using the Daubenmire method in the three fields. Each
field was sampled over a two day period from July 29th through August
12th, 2007. The Shannon-Weiner function, a measure of both plant
diversity and equitability was used to analyze plant species cover
estimates. The mowed field received a function score of 2.055,
the sprayed field scored 1.71, and the grazed field scored 3.05.
The Shannon-Weiner function score increases as plant diversity and
equitability increase, indicating that the grazed field had the highest
diversity and equitability, measures of ecosystem health. The results
suggest that disturbance in the form of cattle grazing increases plant
diversity and equitability in northwest, Minnesota CRP.
Suggestions were made to provide farmers with management handbooks,
informed county extension agents and revised guidelines on CRP
management practices.
Thomas B. Otey
February 18, 2008
Effects of
Off-Highway Vehicle (OHV) Traffic on Stream Microinvertebrate
Populations in the Tellico River Watershed
Mentor: Dr. Paul Bartels
Abstract: The Upper Tellico
Off-highway Vehicle (OHV) Area is a designated motorized vehicle
recreation area in Nantahala National Forest. The 38 miles of off-road
trails are interlaced by the headwaters of the Tellico River. Erosion
of trails and consequent sedimentation in Tellico tributaries has
caused a rise in concern regarding the environmental impacts of the OHV
Area. Stream microinvertebrate populations could be used as a means to
assess the impacts of sedimentation on aquatic ecosystems. This study
examines the effects of the Upper Tellico OHV Area on stream
microinvertebrate populations. Sediment samples were taken from two
Tellico tributaries inside of the OHV area as well as from two
reference tributaries that join the Tellico outside of the OHV Area.
Microinvertebrates were identified and counted for each stream. The
median total densities of microinvertebrates were significantly higher
in two reference streams outside of the OHV area than in one stream
inside the OHV area (Kruskal-Wallis ANOVA, P=0.001). Median Simpson’s
Diversity Index values calculated at the phylum level for the four
streams were not considered significantly different (Kruskal-Wallis
ANOVA, P=0.159). Rank/Abundance graphs suggest that phylum evenness was
similar between the two reference streams, while more variable between
the two streams inside the OHV area. Within the phylum Arthropoda, the
relative abundance of midges was higher than that of copepods within
the OHV area. This trend was reversed in the reference streams outside
of the OHV area. Due to lack of replicates and uncontrolled
environmental factors, the differences between the streams cannot be
attributed to the OHV area. However, within these specific streams, a
correlation was observed between high levels of sedimentation and
decreases in total microinvertebrate densities.
Anita
Goodrich
The Growth and
Survival of American Butternut (Juglans
cinerea)
Across a Natural Shade Gradient
February 18th 2006
Mentor: Dr. David Ellum
Abstract: Seedlings respond to
the quality and quantity of Photosynthetically Active Radiation (PAR)
through shoot elongation and expansion. Butternuts are valued as mast
producing species due to the high nutritive levels of the nuts.
They are susceptible to an introduced fungus that causes mortality in
seedlings that show no natural genetic resistance. The objective of
this study was to determine if there is a relationship between light
intensity and growth of American Butternut (Juglans cinerea). Genetically
resistant seedlings were transplanted into a preexisting canopy gap at
the Warren Wilson College Forest. A variable shade gradient
between ten and ninety percent PAR was determined for the site.
Data were collected on total height, root collar diameter and number of
stem and root before planting and at the end of a single growing
season. The final conditions of the seedlings were also measured
at the end of the growing season. Linear regression analysis was
used to identify relationships between light intensity and height
growth, root collar diameter, final condition of stem and number of
stem and root sprouts. Regression analysis identified a
correlation (r2 = 0.62) between light and the numbers of stem sprouts
produced by individuals with positive height growth. No
relationship was established between light and any of the other growth
variables. The survival rate for the site was 89% but no relationship
between survival and light was identified. The lack of relationship
between light and growth is likely related to initial transplant
shock. These seedlings will continue to be monitored as part of a
collaboration with the University of Tennessee Tree Improvement program
aimed at identifying appropriate sites for the restoration of blight
resistant American Butternut.
Liz Martin
February 25, 2008
Comparing
propagation methods for conserving an endangered woodland herb: Lysimachia fraseri, Fraser’s loosestrife
Mentor: Dr. Dave Ellum
Abstract: Fraser’s loosestrife
(Lysimachia fraseri) is an endangered herbaceous perennial native to
the Southern Appalachian mountains. There are an estimated 40 to
75 populations left throughout its range. Sexual reproduction is
the major limiting factor in the species’ success, although it
asexually reproduces by rhizome and has been successfully propagated by
rhizome. The objective of this study was to determine the most
successful propagation method for conserving Fraser’s loosestrife by
comparing stratification methods for the soil seed bank as well as
monitoring two transplanted populations of the species. Two
populations were removed from gravel road sites and transplanted to an
available field on the Warren Wilson College campus. The first
population was transplanted in May of 2007, the second in September of
2007. Soil samples and gravel samples were collected from the
site of the second transplanted population. Two treatment methods
were used to stratify the samples; treatment A went through one
freeze/thaw cycle, and treatment B went through 4 freeze/thaw
cycles. Samples were then germinated in a greenhouse for 7
weeks. There was no germination of Fraser’s loosestrife for
either soil type or stratification method, though there were many
germinants of other species for both stratification methods.
Secondary shoots were observed in October of 2007 from the first
transplanted population, and the plants were green and healthy.
Most of the transplants of the second population were not alive above
ground when observed in October, but underground rhizomes may be
viable. Results show that propagation by rhizome is a
viable conservation method, while propagating from the soil seed bank
surrounding a population may not be.
Kenmei Kato
February 25, 2008
Dragonflies (Anisoptera) and Damselflies (Zygoptera) at Warren Wilson
College
Mentor: Dr. Lou Weber
Abstract: Dragonfly
and damselfly conservation has been a growing concern
world-wide. According to the International Union for
Conservation of Nature and Natural Resources (IUCN) 33% of odonates
(dragonflies and damselflies) world-wide are of conservation concern.
Habitat degradation and habitat loss due to development have greatly
reduced suitable odonate habitat. The southern Appalachians
serve as habitat for a particularly diverse amount of odonates mainly
because of the rich habitat and steady climate. Development is
the main threat for odonates in the southern Appalachians. The
objective of my study was to conduct a survey of the dragonfly and
damselfly species on the Warren Wilson College campus and compare it to
the Great Smoky Mountains National Parks species inventory
(ATBI). The purpose was to compare the species diversity of an
ecologically protected area to the Warren Wilson College campus so that
conservation measures could be assessed and a baseline
established. Observations were conducted throughout the months of
August - December 2007 using binoculars, field guides, digital camera,
and butterfly net. With limited time and resources a genus from
every family documented by ATBI except for the Petaltail family was
observed; 23 species in total. These data suggest that there is
abundant diversity on the Warren Wilson College Campus and more
research should be conducted with the possibility of finding critically
imperiled species.
Julia Mead
March 3, 2008
Characterization
of Volatile Compounds in Clover Honey (Trifolium spp.)
by Solid-Phase Microextraction and Gas Chromatography Mass Spectrometry
Mentor: Dr. John Brock
Abstract: Honey, the natural
sweetener produced by honey bees (Apis
mellifera), is a unique mixture originating from several
sources. Volatile organic compounds (VOCs) originating from the
floral source, make up a small percentage of honey composition, but may
be used as indicators of the botanical or geographical origin of
honey. The objectives of this study were threefold: to establish
a method to characterize the VOCs in clover honey, to compare the
chemical profile of clover honey to the sensory profile, and to
determine if there is a statistical significance between the
concentrations of volatile compounds in honey from two geographical
regions. The method was executed using solid phase
microextraction (SPME), a solvent-free extraction technique, coupled
with gas chromatography mass spectrometry to separate different
volatiles. At this time, mean concentrations of two flavor
compounds, benzaldehyde and phenylacetaldehyde, have been measured in
parts per million for three clover honey samples from Northern
California. Also, a taste test was performed rating flavor,
aroma, sweetness, and color. An ANOVA test determined that no
significant difference exists between flavor (p=0.897), aroma
(p=0.347), or sweetness (0.055) ratings for the three honeys, although
the color ratings were found to be statistically significant
(p≤0.0001). Though mean concentrations of two volatiles were
found for three honey brands, it appears as though there is no
correlation between concentration of flavor compounds and sensory
perception of flavor or aroma. Future research will include a
characterization of three honey brands from the Western North Carolina
region, with mean volatile concentrations compared to those from
Northern California.
Jill Loury
March 10, 2008
The Effect of
Trout Farm Effluent on Periphyton Growth
Mentor: Dr. Mark Brenner
Abstract: For over 150 years
trout and other fish have been farmed in North America. There is
little known of the effects that trout farms have on the natural
environment, especially the communities within the water bodies they
feed into. Periphyton is a community of algae, fungi, bacteria,
and microzoans that thrive in streams. This mixture of autotrophs
and heterotrophs require different nutrients to maintain
themselves. The loading into a stream with fecal matter and
dissolved food particles from the trout farm may disrupt the natural
balance between autotrophs and heterotrophs within the periphyton
communities. A total of twenty rock samples were taken from five
sites upstream and downstream of a trout farm output at Shope Creek,
NC. The samples were analyzed for Chlorophyll a, which is a
measure of autotrophs, and Ash-Free Dry Mass, a measure of total
periphyton biomass, so that an Autotrophic Index could be made. A
nonparametric t-test, the Mann-Whitney test, was run for the Ash-free
Dry Mass, Autotrophic Index, and Chlorophyll a Analysis because they
did not pass normality tests. The AFDM P-value was 0.5476.
The Autotrophic Index P-value was 0.6905. Neither of these was
statistically significant. The Chlorophyll a Analysis had a
P-value of 0.0952, making it not quite significant. There was
very high variance within my samples, and it is suggested to try and
control for sampled substrate and depth. This experiment was
performed in the winter and will hopefully be a baseline study for
others looking at periphyton growth during different seasons.
Holly Spier
March 10, 2008
Social Comparison
and Affect Stimulation as a Motivation to Gossip
Mentor: Dr. Vicki Garlock
Abstract: Research suggests
that gossip, a common form of communication, can be used for social
comparison, social bonding, or status-enhancement. Social
comparison includes upward social comparison (gossiping for selfish
gains) and downward social comparison (gossiping for one’s pursuit of a
positive self-view). This study attempts to establish the
relationships between the tendency to gossip, the tendency to engage in
social comparison (both upward and downward), and the tendency to
respond intensely to affect-provoking stimuli. College aged
participants filled out three separate questionnaires assessing these
three constructs. A fourth measure was aimed at assessing
interest in gossip about celebrities versus peers. Results showed
several significant, positive correlations. These included
correlations between the tendency to gossip and social comparison, the
tendency to gossip and affect intensity, and the tendency to gossip and
interest in gossip. Multiple regression analyses suggest that the
variance in tendency to gossip is explained by both the variance in
social comparison scores and variance in affect intensity scores. The
findings also suggest that the motivation behind gossip is complex with
several factors playing a role.
Delaney Burke
24 March 2008
Kleptoparasitic
attack methods by Laughing Gulls (Larus atricilla) at a seabird colony
on Eastern Egg Rock, Maine
Mentor: Dr. Lou Weber
Project Puffin maintains seven research islands in the Gulf of Maine
that are home to mixed colonies of rare seabirds. On Eastern Egg
Rock, ME, there is extensive control of predatory gulls, but minimal
control of Laughing Gulls (Larus
atricilla). The Laughing Gull population on the island has
been increasing 10% a year since 2002 and includes 1705 nesting
pairs. The problem is that Laughing Gulls are known to engage in
kleptoparasitism, the process of one organism stealing food from
another of the same or different species. This can have negative
affects on other seabird species and may be affecting endangered terns (Sterna spp.), the featured Atlantic
Puffins (Fratercula arctica),
or other species. Because little research has been done on the effect
of kleptoparasitic Laughing Gulls on the island’s other seabird
species, my objective was to determine the target hosts, the success
rate, and the method of attack. This information will be used to asses
the current Laughing Gull policy on the island in consideration of more
aggressive control. Observations were made in one to three hour blind
stints from 22 June to 18 July 2007. The time, host, method of attack,
and outcome of attack were recorded. The method of attack was
determined by the height of attack: boulder berm attacks were
less than 1 m above the rocks, aerial boulder berm attacks occurred 1 –
3 m above the boulder berm, aerial attacks were more than 3 m above the
rocky boulder berm. Results showed that Black Guillemots (Cepphus grylle) were the host
preference with 636 of 678 observed attacks, and were attacked mainly
at the boulder berm level. The overall success rate of Laughing Gulls
was 19.2%. Boulder berm and aerial boulder berm were the most common
methods. Terns, other Laughing Gulls, and Atlantic Puffins were
primarily attacked aerially. The success rate increased as the number
of gulls in the group increased, but the individual success of a gull
in a group remained constant as the group size increased. While Black
Guillemots are currently not rare, more research is needed to measure
the effects of kleptoparasitic Laughing Gulls on chick fledgling
success on Black Guillemots. Terns were victimized rarely, but an
increase in Laughing Gull numbers may provide more stress and
disturbance. A more intensive Laughing Gull control is needed on
Eastern Egg Rock to ensure the survival of the rare seabird species.
Conor McGeehan
March 30, 2008
Effect of distance
from logging roads on consumption rate and preference of Celastrus orbiculatus and Ilex opaca seed by small mammals
in the southern Appalachians
Mentor: Dr. David Ellum
Abstract: Non-native invasive
plant species pose both ecological and economic threats to native plant
communities of the southern Appalachian forests of the United States.
Oriental bittersweet (Celastrus
orbiculatus) is a non-native twining vine introduced from Asia
that is known to cause significant damage to forest systems.
Small mammals are known to be seed predators on a variety of forest
plant species. While avian species have been determined as a source of
predation and dispersal for Oriental bittersweet, little is known about
the role small mammals play in the predation and dispersal of the
species. While small mammals may offer a pathway of distribution on a
small scale, roads as biological corridors can provide a pathway for
dispersal on a much larger scale. Two objectives were defined for this
study; 1) compare the consumption of oriental bittersweet fruits and a
native species, American holly (Ilex
opaca), in relation to distance from road edge and 2) compare
small mammal abundances to forest stand structure. The study was
conducted at the Bent Creek Experimental Forest in Asheville, NC. The
first objective was tested using feeding stations that were monitored
during November and February. The second objective made use of trapping
data that was collected over 6 consecutive days in July. The Lincoln
Peterson technique was used to estimate abundance small mammals. Linear
regression analysis was used to determine relationships between small
mammal abundance and basal area, stand density and coarse woody debris.
Results showed a higher abundance of mice at distances 25m and 50m from
road, compared to the road edge. The abundance of mice was
related to both stand basal area (r2 = 0.76) and stand
density (r2 = 0.66), but not coarse woody debris. No feeding
preference between Oriental bittersweet and American holly could be
determined due to a lack of berry consumption. For the sites sampled in
this study and during that sampling period, white footed mice preferred
not to consume Oriental bittersweet and American holly berries.
Seanna
Bellinger
March 31, 2008
The Effect of
Vocal and Instrumental Music on Students’ Cognitive Performance
Mentor: Dr. Vicki Garlock
Abstract: Researchers disagree
about whether music enhances or impairs cognitive performance. This is
partly because the relationship between music and cognitive performance
can be moderated by additional factors, including personality and study
habits. My primary objective was to assess the impact of vocal
music vs. instrumental music. A secondary objective was to determine
whether musical genre and study habits influenced how music affected
performance. Participants were placed in one of five conditions
(instrumental rock, vocal rock, instrumental hip hop, vocal hip hop,
and control). Participants were given three cognitive tasks assessing
memory, spatial ability, and math ability. Participants then
completed a short questionnaire. ANOVAs on all three dependent measures
showed no statistically significant differences across the five
conditions; however, the ANOVA on the arithmetic test approached
significance (P = 0.091). Post-hoc analyses indicated a statistically
significant difference between the Hip Hop Instrumental group and the
Control (P = 0.006). Statistical tests also assessed the effects
of type of music (instrumental, vocal, control) and musical genre
(rock, hip hop, control) more generally. Math scores were lower
in the Instrumental group when compared to Control (P = 0.025) and
lower in the Hip Hop group vs. Control (P = 0.016). Analyses on
study habits showed no significant effects. My results suggest
that instrumental music and hip hop music may have more of a
debilitating effect on students’ cognitive performance, particularly
math, than vocal music or rock music. Small sample sizes may
attribute to some results corresponding with previous research better
than others.
Eliza Sydney
April 7, 2008
Ionic profile of
the
groundwater and surface water at Warren Wilson College
Mentors: Mr. Robert Hastings and Dr. Victoria Collins
Abstract: The Swannanoa River
is a surface water body that runs through Warren Wilson campus and is
part of the greater French Broad River Basin. The French Broad
River basin is a unique area of hydrologic study because over 70
percent of surface water discharge is from groundwater sources.
The contribution of groundwater to surface water is commonly overlooked
but is an important component of watershed hydrology. Relatively few
studies in the Southern Appalachian region have focused on groundwater
contribution to streams. Chemical analysis of natural water
requires knowledge of rock composition. To investigate the
groundwater contribution to surface water, ions released into solution
after contact with underlying geologic material should be
measured. This study had three objectives. The first was to
find the concentrations of ions in the groundwater and surface water,
the second was to investigate variability in ionic composition of
groundwater and surface water. The last objective was to
determine the relationship between base flow and total stream
flow. Ionic ratios in milliequivalents were measured and
converted to stiff diagrams to determine changes in time and
space. Though rock types in the area yield very low total ion
compositions, there are notable changes in ionic composition among the
groundwater and surface water as well as notable differences in the
surface water during periods of high and low flow. Results
suggest that groundwater and surface water are in communication and
should be viewed as one resource. As increasing development and
droughts continue in our area, knowledge of whole hydrologic systems
will be increasingly pertinent.
Eli Dwight
April 7, 2008
Comparison of
Forest Vegetation by Aspect on Suicide Ridge
Mentor: Dr. David Ellum
Abstract: Phytosociology is
the study of the composition, distributions, and interactions of plant
communities. Slope aspect is an important site variable that can
strongly influence forest structure and composition. The objectives of
this study were to: 1.) systematically compare the forest structure and
phytosociology of the North and South aspects, and 2.) to inform the
long term management of the Warren Wilson College forest.
This study was conducted on the Warren Wilson College Forest (251 ha)
in Swannanoa, NC. The forest is of the low elevation oak-hickory type,
common to the mixed mesophytic forests of the Southern
Appalachians. Data was collected on Suicide Ridge, a 51 ha stand
with well-defined northwest and southeast aspects and similar percent
slope and concavity. An area of 3.6 ha on each slope was sampled at an
intensity of 7.5% using 27 100m2 plots per site. All trees>10cm were
identified and diameter at breast height was recorded, while all small
diameter stems were identified and counted. Abundance of exotic
invasive species was estimated using 1m2 plots. Comparisons of forest
structure and composition were made based on basal area and density,
diameter distributions, species diversity and importance values and
abundance and type of invasive species
When all species were grouped, ba/ha, stems/ha, and stems<10cm/ha
did not differ significantly between the north and south aspects. The
two aspects showed low beta diversity (Sorenson’s Coefficient of
Communities 0.85) and comparable alpha diversity (Simpson’s Index of
0.59 (north) and 0.47 (south)). Analysis conducted at the species level
demonstrated greater differences between the north and south aspects.
Importance values results corresponded with life histories of species
present in a mixed mesophytic forest. There was a high density of small
diameter stems of Pinus strobus on the north side while L. tulipifera
was the most dense species on the south side. Dominance of Quercus spp.
in the overstory and the absence of individuals from the genus in the
understory may indicate a future shift in forest composition for both
aspects. Exotic invasive species were absent from the north side, while
four species were found in abundance on the south side. At least one
exotic invasive species was present in 72.2% of subplots on the south
side. It is apparent that aspect influences the structure and
composition of exotic invasives species and of trees at the species
level on Suicide Ridge.
Beth
MacLeod
April 7, 2008
Method Development
of Salicylic Acid Extraction from Cherokee Purple (Lycopersicon lycopersicum) Leaves
Mentors: Dr. Michael Torres and Dr. Joe Young
Abstract: Salicylic acid is a
colorless, crystalline organic acid. It is stored in plants as a
phytohormone, a plant hormone that helps regulate a plant’s growth.
Salicylic acid has an important role in plants as an endogenous signal
for the induction of systemic acquired resistance. Systemic acquired
resistance is defined by Ross, “..as an induced system of resistance
triggered by pathogens that cause rapid cellular necrosis of infected
tissues.” Salicylic acid also has an important role in plant
communication. Though there are already methods developed for the
extraction of salicylic acid, Warren Wilson College does not have the
required resources for these methods. Thus, the objective of my study
was to develop a method to extract salicylic acid from Cherokee Purple
using the available resources at Warren Wilson College. I extracted
salicylic acid from tomato leaves using a sochlet extraction. I
evaporated the ethanol and dried my samples using rotary evaporation. I
resuspended my samples in a sodium acetate buffer with β -glucosidase,
an enzyme which catalyzes the cleavage of individual glucose molecules.
I used high performance liquid chromatography with fluorescence for the
detection of salicylic acid. My results had a retention time of 2.478
for my 10ppm standard. My first sample had a retention time of 2.127,
my second sample had a retention time of 2.132 and my third sample had
a retention time of 2.127. I also spiked my 1st sample on two different
runs. The unspiked sample had 69.38% salicylic acid. My first run had
77.46% salicylic acid, which is an increase by 8.07%. My second run had
78.11% salicylic acid, which is an increase by 8.72%. The data of
retention times and spiking suggest that I may have found salicylic
acid. I still plan to change the wavelengths and to not add
β-glucosidase to my other examples to see if the data still points to
salicylic acid. Salicylic acid is an important molecule for the
induction of systemic acquired resistance and for plant communication.
The best part about learning if salicylic acid can have future uses as
a application on plants to improve the overall health, is knowing that
when using salicylic acid, one is using a naturally produced molecule
by the plant.
Laura
Righter
April 14, 2008
Antioxidant
Capacity for Various Varieties of Tomatoes (Lycopersicon
esculentum)
Mentor: Dr. Victoria Collins
Abstract: Research shows that
tomatoes are an important source for antioxidants. There are two lipid
soluble carotenoid antioxidants found in tomatoes, lycopene and
beta-carotene. Lycopene is responsible for the red pigments seen in
tomatoes, so red and black tomatoes have high levels of Lycopene. Beta
carotene is responsible for the yellow pigments seen in tomatoes, thus,
yellow and tangerine tomatoes have high levels of beta-carotene. Much
research has been done on the antioxidant capacity of red tomatoes, but
little has been done on tomatoes with yellow, tangerine, or black
colors. Therefore, my objective is to compare the antioxidant capacity
of several tomato varieties of different color. In addition, very
little research has been done to compare the antioxidant capacity of
hybrid to heirloom tomato varieties. Therefore, my second objective is
to compare antioxidant capacity of heirloom and hybrid varieties. This
study compared four fruits from each of eight tomato varieties.
Lycopene and beta-carotene were extracted with hexane and vacuum
concentrated to 20 ml. For every sample 100 microliter of
extract was added to 2 ml of DPPH free-radical. A spectrophotometer was
used to determine the antioxidants’ capacity to scavenge free-radicals
over duration of 30 min. Statistical analysis compared two
varieties of each of the four colors using a one-way ANOVA which found
the results to be highly significant (p< 0.001). The individual
means were compared using Tukey’s test. Pooled means of
antioxidant capacity of all 12 hybrids and all 20 heirlooms were
compared using an unpaired t test. The antioxidant capacity for
hybrid varieties did not differ from that of heirloom varieties (p=
0.867). It appears that tomatoes with pigments representing high levels
of lycopene have the highest antioxidant capacity. The
variation in antioxidant capacity among the different colors was
greater that the variation between the hybrid varieties and heirloom
varieties.
Forrest
Heacock
April 14, 2008
Heavy metals in
the Swannanoa River: Potential Pollution from a Remediated Junkyard
Mentor: Dr. John Brock
Abstract: Heavy metals, such
as chromium and lead are important environmental pollutants,
particularly in areas where anthropogenic pressures are high. Their
presence in the environment can have negative effects on all members of
an ecosystem, and their ability to be bioaccumulated by vegetation and
microbes allows for the possibility that they may be entering a human
population through its diet. Cars today contain a number of different
potentially toxic metals including zinc, chromium and copper in their
electrical components as well as a good amount of lead found in the
battery. Due to acidic rainwater runoff it is possible that the
aforementioned metals may be leeching from immobilized cars into nearby
soils. In areas where there are a great deal of immobilized cars,
namely junkyards, it is possible that the degree to which heavy metals
are entering the environment is significant. This problem becomes even
greater when the heavy metal pollution enters a waterway as the
mobility of the metals increases dramatically. This study attempts to
determine if an area which used to be a junkyard had been contributing
heavy metals to the nearby Swannanoa River by doing ICP analysis of
sediment samples.
Jodi M.
Ferrell
April 14, 2008
How Binge Drinking
Affects Risky Behaviors at Warren Wilson College
Mentor: Dr. John Brock
Abstract: Approximately four
out of five college students drink alcohol, and 40% of college students
are classified as heavy episodic drinkers. Condom use among
college students is less than 40%, and it has been found that heavy
episodic drinkers are three times more likely to have multiple sex
partners. Various surveys have been conducted at Warren Wilson
Campus in order to observe frequency of alcohol consumption, risky
behaviors, and sexually transmitted diseases (STDs). In 2007, a
zoomerang study distributed by the Office the Student Life showed that
although 17% of participants admitted to regretful behavior only 6%
reported that they considered their drinking to be problematic.
STD surveys conducted as a class project by the epidemiology course
offered at Warren Wilson College have revealed improvements in condom
use and STD prevalence on campus from 2004 to 2006. Epidemiology
is the study of human populations, which attempts to link human health
effects to a particular disease or condition. Through the use of
an epidemiological survey, the objective of the study was to analyze
the prevalence of risky behaviors as a result of binge drinking in
Warren Wilson College students. The survey was open for voluntary
participation in Canon Lounge during lunchtime at the end of the fall
semester of 2007. The participants signed a consent form before
completing the survey, and their identity was anonymous. The
sample population was 20% of the total population with the demographics
of the sample having more freshman and less sophomores, juniors, and
seniors than the total population. The main source of obtaining
alcohol for underage drinkers was reported to be from people of legal
drinking age. As a result of binge drinking, more class sessions
were missed than shifts of work. The majority of participants
consider themselves social drinkers, but 9% of seniors consider their
drinking be problematic. Condom use while binge drinking was
found to be 40%. A portion of each class reported having four to
six sexual partners while binge drinking during the fall semester of
2007, but the sophomore class had the highest value at16%. STD
cases contracted while binge drinking during the past semester was
reported to be 2%. The data collected may indicate elevated risky
behaviors while binge drinking, such as driving, engaging in
unprotected sex, and having multiple sexual
partners.
Chelsea
Peterson
April 21, 2008
Morphometric
Analysis of Retinoic Acid Treated Zebrafish
Mentor: Dr. Jeff Holmes
Abstract: Zebrafish are a
common developmental model used to study chordates. They are
coveted in the field of developmental biology because of their fast
development and transparent embryos. To study the effect of
retinoic acid in the development of zebrafish eyes, eggs were immersed
in a retinoic acid solution with a concentration of 0.05 micrograms/mL
and allowed to develop for 72 hours. A control group also
developed for 72 hours, but were immersed in tank water only. All
embryos were fixed in a 0.35% gluteraldehyde solution, then oriented
under a dissection microscope where the eye area was measured in
proportion to the swim bladder area using a C14 camera and i-Solutions
software. The eyeball and swim bladder areas of untreated embryos
were compared to eyeball and swim bladder areas of retinoic acid
treated embryos using unpaired t-tests. Retinoic acid treated
embryos had larger eyes and swim bladders with p values of
<0.0001. The eye/swim bladder ratios of retinoic acid treated
embryos were significantly larger than the ratios found in untreated
embryos with a p value of >0.0001. The techniques and
equipment used in this study demonstrated the ability to quantify
microscopic parts in embryos, and can be repeated in future studies.
Sarah Gaskin
April 21, 2008
Pool Leakage and
Mass Wasting Relationship on the Warren Wilson College Campus
Mentors: Robert Hastings and Dr. Mark Brenner
Abstract: Mass wasting is
defined as the downward movement of land due to gravity. There are four
main contributing factors to mass wasting: slope, water, vegetation,
and underlying rock. Mass wasting is triggered by over-steepening
slope, adding water to the system, removing vegetation, and decreasing
the internal cohesion of underlying material. Some signs may be cracks
in pavement, leaning or bowed trees, fence posts, or telephone poles,
sunken road beds, cracked building foundations, surface springs or
seeps, and out of plumb door frames. Mass wasting is occurring on
campus behind the pool at the back of the parking lot. The Warren
Wilson College pool was leaking 1800 gallons of water a day for about a
year. The objective of my study is to determine if the pool leak is
triggering land movement, or if the two are unrelated. For my methods,
I determined past land use, drilled four bore holes, installed one
monitoring well, took water samples, and surveyed the area for relative
elevations. Historic aerial photos and topography maps showed a small
stream drainage through the landslide area, that has been flattened and
filled since the 1940’s. Bore holes revealed about seven to nine feet
of fill dirt, and showed dry soil. Water samples near the pool
contained no detectable chlorine. The lack of wet soil near the pool
and lack of chlorine in my monitoring well indicates that the pool is
most likely not triggering this landslide. An over-steepened slope and
water underflow is what is contributing to the potential landslide.
Ian Martin
April 28, 2008
Structural cues
hypothesis and the home range of the Pileated Woodpecker (Dryocopus pileatus)
Mentor: Dr. Lou Weber
Abstract: The Pileated
Woodpecker is the largest woodpecker in North America and is a common
resident of deciduous/coniferous forests in the Eastern and Western
United States. The home range of the Pileated Woodpecker is defined as
the area in which it occupies and actively defends. Dead wood is the
major foraging substrate including snags, down wood and dead parts of
live trees which contain wood boring invertebrates. There are three
different hypotheses that attempt to explain the observed inverse
relationship between home range size and food abundance: Direct
Monitoring Hypothesis, Intraspecific Competition Hypothesis, and the
Structural Cues Hypothesis. The objective of my study is to test
the structural cues hypothesis by examining the relationship between
home range size and a specific structural characteristic of Pileated
Woodpecker habitat. First home range was defined and then within the
home range six 30x30m sample plots were chosen to measure the volume of
wood. Minimum sample sizes for logs were chosen based on observation
and previous research. The number of logs per hectare was much greater
and the home range was much smaller in comparison to two other studies.
The data showed volume of logs to be consistent with the two other
studies. The similarity of the log volume data in comparison to the
other two studies lends support for the structural cues hypothesis. The
consistency of this data may indicate the actual needed amount of log
volume per hectare of the Pileated Woodpecker.
Lester
Gulledge
April 28, 2008
Changes in
Asheville’s Land cover, and Resulting Effects on Air Quality
Mentor: Dr. Dean Kahl
Abstract: An urban forest is
characterized by the integration of trees within dense development.
Rapid urbanization of the United States, as well as decreasing
tree management budgets, makes protection of urban forests increasingly
important. Trees and shrubs in an urban setting have inherent aesthetic
values, as well as quantitative values, such as air quality mitigation.
The trees of an urban forest store and sequester gaseous pollutants
such as NOx, SOx, CO, O3, and pm10. Removal rates of these pollutants
vary based on tree cover, pollution concentration, and length of
leaf-in season. Canopy cover and pollutant removal rates vary based on
land use, and the historic ecotype of the area in which the forest is
located. The objective of this study was to determine if there was a
difference in canopy cover, and removal rates of gaseous and
particulate pollutants between 2002 and 2006 by the urban forest in
downtown Asheville. The objective was also to learn about the
structure and distribution of this urban forest by comparing canopy
cover, and the ratios of canopy to road and canopy to building in one
year, in differing land use types. ArcGis and CITYgreen software was
used to perform this analysis. Canopy coverage rates in 2002 and 2006
were compared using a Wilcoxon matched pairs signed ranks test, and
2002 coverage rates did not differ from those of 2006 (p=.9453). Canopy
coverage in residential zoning districts did not differ significantly
from that of commercial districts. Zoning districts that are exempt
from Asheville’s landscape and buffering standards had significantly
less canopy coverage than districts that are not exempt. Changes within
a four year period were not significant, however no increase in tree
cover was observed within study plots as the result of raster
calculations. This contradicts the Unified Development Ordinance. All
districts exhibited a high amount of statistical variance, however 95%
confidence intervals of mean tree coverage met American Forests
recommendations.
Julian Kern
April 28, 2008
Inhibitory Effects
of Allelopathic Compounds on the Seed Germination of Invasive
Non-native Plant Species.
Mentor: Dr. David Ellum
Abstract: Allelopathy is a
plants ability to create 
compounds, usually metabolic
by-products or
secondary metabolites, which directly influence another plant species.
Previous research shows that certain plants produce allelopathic
compounds that have inhibiting effects on other plant species.
The objectives of this study are A) to determine if the allelopathic
compounds of tree species inhibit the seed germination of invasive
non-native plant species and B) to determine whether a compound from an
invasive non-native tree species is more inhibiting than a compound
from native tree species. Two native tree species, Robinia pseudoacacia, and Juglans nigra, and one non-native, Ailanthus altissima were used to
test allelopathic effects on the germination of two non-native species,
Lonicera japonica and Elaeagnus angustifolia. Aqueous
solutions with concentrations of 4 g/L and 10g/L were made from ground
root bark of each of the three species. Seeds were sealed in Petri
dishes after being watered with the solutions and germination was
monitored daily for 21 days. The entire experiment was replicated one
week later. Chi-squared tests were used to test for differences in
germination success between the allelopathic solutions and a D.I. water
control. L. japonica
had no germination success in any treatments groups, most likely as a
result from factors other than allelopathy. Grouped data showed
that the presence of all three allelopathic compounds had significant
negative effects on the germination of E. angustifolia. When
tested separately against the control, the presence of R. pseudoacacia (p=0.0085) and J. nigra (p=0.0085) were only
significant at high concentrations. A. altissima was significant at
both the low (p=0.0085), and high (p=0.0085) concentrations.
Results indicate that the non-native A.
altissima has a greater effect on the germination of E. angustifolia than the native
species R. pseudoacacia and J. nigra. Results also
suggest that the compounds in A.
altissima have the potential to be used as herbicides on other
invasive non-native species, while at the same time controlling the
invasive A. altissima.
Eric
Thiedich
May 5, 2008
Analysis of
Defensive Compounds in the Eastern Tent Caterpillar (Malacosoma americanum)
Mentor: Dr. Dean Kahl
Abstract: The eastern tent caterpillar and its distinctive white
silky tent are a common sight in the early spring in the Eastern United
States. The caterpillar is commonly found in the Black Cherry
tree (Prunus serotina), who’s
leaves contain high concentrations of the cyanogenic glycoside
Prunasin. The caterpillar eats the leaves of the Black Cherry and
then regurgitates a mixture containing the cyanogenic compounds as a
defense mechanism. The objective of this research was to develop
a method to analyze defensive substances in the Eastern tent
caterpillar (Malacosoma americanum).
Caterpillars were collected from Black Cherry trees and stored at -70°
C. The water in the sample was removed by placing the
caterpillars in a desiccator for one week. The dried caterpillar
were sliced up and treated with methanol for 24 hours. The
extract was analyzed using High Performance Liquid Chromatography and
three major components were observed. Through peak enhancement
and liquid chromatography mass spectrometry, one component was
identified as amygdalin, a cyanogenic glycoside found in small
concentrations in the Black Cherry leaf. The substance causing
the largest peak could not be identified. The largest peak
appeared to be benzaldehyde, based on peak enhancement. However,
this identification could not be confirmed by LC/MS.
Ari Berk
May 5, 2008
Method for Using
High Pressure Liquid Chromatography to Profile Amino Acids in Nutrient
Broth
Mentors: Dr. Jeff Holmes and Dr. Victoria Collins
Abstract: A method for HPLC
analysis of amino acids was partially adapted and redeveloped for
analysis of amino acids in nutrient broth in the Warren Wilson lab. The
method as it stands now is unable to separate most amino acids, but it
is able to produce multi-peak spectra of amino acid mixtures.
Jorge Lopez
May 12, 2008
Plant Secondary
Metabolites and Medicinal Properties
Mentor: Dr. Michael Torres
Abstract: Many of the
important drugs synthesized today originated from plants (Leslie Taylor
2000). Specifically every fourth pharmaceutical has originated from
plants (H. Simonsen 2007). Our tropics and local flora contain many
plant species that may be of benefit, but have not been studied.
Secondary metabolites are organic compounds that are not directly
involved in the normal growth, development, or reproduction of
organisms. Secondary metabolites of garlic and onions have been used
for their medicinal properties since 1550 BC (R. Muoio et al 2004).
Research has shown that the garlic and onions contain antitumor,
antibiotic, and antiplatelet aggregate properties (V. Lanzotti 2006).
Thiosulfinates or more specifically Allicin has been identified as the
main contributor of their medicinal properties (Lanzotti). In this
experiment Allium species were analysed for thiosulfinate levels using
HPLC. The Kirby Bauer method was used to view the antimicrobial
strength of five Allium species to determine any correlation between
thiosulfinate levels and antibiotic efficacy. Extracts treated with HCl
were also used in the Kirby Bauer methods to study the effects of
digestion on antibiotic strength.
Camille Prevost
May 12, 2008
Effect of two
terpenes on the hemlock woolly adelgid, Adelges tsugae.
Mentor: Dr. Dean C. Kahl
Abstract: The hemlock woolly
adelgid, Adelges tsugae, is
an invasive pest species that threatens eastern North American hemlock
forests. This pest species is also found on western hemlocks but is not
a threat. Evidence suggests that some terpenes found in Western hemlock
species may deter the hemlock woolly adelgid. Adelgid were collected,
while in the active phase, from three sites in Western North Carolina.
Ten trees were selected from each site, and four 10 cm branch samples
were taken from each tree. Samples were placed in one of three
treatment groups receiving α-pinene, or β-caryophyllene, or no
treatment. The adelgids were assessed for mortality every two days for
a 10 day period. Treatment groups were analyzed using a nonparametric
survival analysis. There was no significant difference between
treatments at the 95% confidence level. The survival analysis of 90
samples suggests that α-pinene and β-caryophyllene have no effect on
mortality of the hemlock woolly adelgid during the active phase.