Natural Science Seminar

Gretchen Wilke Whipple, PhD Department of Mathematics, Warren Wilson College
Sept. 24, 2001
Tomonoids from the Deep - An Exploration of Something You Know

Abstract:  Our goal today is to explore a small corner of the world of abstract mathematics.  Thus in this presentation, we shall consider the Natural Numbers as an introduction to commutative, totally--ordered monoids, which we shall call tomonoids. We will explore a tomonoid - in this case a subset of the Natural Numbers with addition - with an odd order.  We shall note that monoids that admit these odd orders require 3 or more generators and 9 or more elements.

John W. Brock, PhD Analytical Chemistry, Warren Wilson College
October 1, 2001
Is pollution affecting your health?

Abstract:  Environmental groups and industrial associations often give conflicting views concerning the dangers of exposure to various chemicals in the environment. Debates rage over the consequences of human exposure to lead, dioxin, PCBs, DDT, and arsenic. Further, millions of dollars have been and are spent to remove these chemicals from soil, water, air, and even the bottom of the Hudson river.
    Scientists have begun to ask a series of questions about pollution and efforts to protect human health. First, what chemicals can be found in humans? Second, what is the level of this exposure in the general population? Third, what are the possible health effects of these exposures? Fourth, are these effects found in the general human population?
    For the better part of the last decade, I led a research laboratory with 8 scientist at the Centers for Disease Control (CDC) examining these questions. Further, I have collaborated with researchers from all around the world to design and implement epidemiologic studies of breast cancer, non-Hodgkins lymphoma, pancreatic cancer, male birth efects, early intelligence development. I will present an overview of this work with an emphasis on the importance of analytical chemistry in these studies.

Agatha Kaplan
October 8, 2001
Allelopathy of Rye (Secale cereale) Towards Lettuce (Lactuca Sativa)

Menror: Dr. Victoria P. Collins

Abstract: Allelopathy is a function of biochemical interactions between plants which interferes with several physiological processes of the receiving plant.  Some major agronomic crops produce allelochemicals which effect weed growth, influence the success of the following crops, and sometimes result in autotoxicity.  The purpose of this experiment was to study the persistence of the allelochemicals released from the rye residue in the Landscaping plot.  Six soil samples were taken sixty days after the rye was tilled under.  Another set of soil samples were taken from the field Big Berea, which has never been planted in rye.   The soil was placed in a funnel and washed with spring water to make an aqueous extract of the allelochemicals.  The solutions were used to dampen paper towels and ten lettuce seeds in each petri dish, which were then left for approximately five days before success of seed germination could be observed.  Two controls were used: one of water and one of Isotoic Anhydride.  The means of the number of seeds germinated per petri dish are as follows:  Landscaping plot 9.72, Big Berea 9.63,
Water 9.1, and I. A. 7.7.  Because the standard error of the I. A. control was large, the natural log of the data was taken and a one-way Analysis of Variance was run.  This test showed that the p-value was 0.0989, which is considered to be not significant.  The treatment using soil from the Landscaping plot therefore had no effect on the lettuce seed germination.  This indicates that, in this field, the rye residue was no longer toxic towards lettuce after sixty days of decomposition.

Isabel Salazar
October 8, 2001
Ocelot (Leopardalis pardalis) Habitat Evaluation In South Texas

Mentor: Dr. Lou Weber

Abstract:  Only five percent of the original habitat that ocelots use is left in South Texas, and this habitat is fragmented.  I used a Geographic Information Systems (GIS) program, Arcview to examine the total area of the fragments left.  Then I used a population viability analysis (PVA), Vortex, to examine how the populations in the fragmented habitat would react if they contained corridors compared to those populations in fragmented habitat without corridors.  I used an unpaired t-test, and found there was no significant difference between treatments (p= 0.82).   This meant, according to the PVA, that the ocelot population would become extinct in approximately fifty-five years even if fragments were connected.  Not being able to accept this, I ran another test. This one changed the mortality rate of kittens from 50% to 25%.  After using an unpaired t-test, I found there was a significant difference between treatments (p=0.0002), but the populations still went extinct in 83 years.  With this information, I concluded that adding corridors would not keep ocelot populations from going extinct.  Protecting kittens between the ages of 0-2yrs is a benefit, but other management techniques should be considered.

Laura Yetzina
Oct. 15, 2001
The analysis of fumonisin toxins in corn products

Mentor:  Dr. Victoria Collins

Abstract:  Fumonisins are mycotoxins that are found in corn and many corn-based products (Trucksess and Pholand 2001).  Mycotoxins are metabolites produced by molds or filamentous fungi such as Aspergillus, Fusarium, and Penicillum. Mycotoxins cause many health and economic problems (Sweeney and Dobson 1999). This project investigated the most common fumonisin, B1, sometimes produced by Fusarium moniliforme and Fusarium proliferatum fungi which are commonly found in corn.  Because corn is one of the major food staples for humans and animals, it is important to control and prevent this fumonisin health threat (Marasas 1995).  My objective was to isolate and quantify fumonisin B1 from various corn products including corn grown at Warren Wilson College. The method was sensitive to fumonisin levels as low as 0.0000400 ppm.   Fumonisin concentrations were highly variable ranging from 0.0000400 ppm to 0.500ppm.  Fumonisin concentrations in all corn products analyzed were below FDA guidance limits.

Vanessa Philson
Oct. 15, 2001
The Effects of Selenium and Vitamin E on the Reproductive Performance of Dairy Cattle
Mentors:  Dr. Robert Eckstein and Dr. Victoria Collins
Abstract:This study investigated the effects of vitamin E and selenium supplementation on the reproductive performance of dairy cattle.  Soils in many of the important dairy regions of the world are considered areas of selenium deficiency.  Selenium deficiency has been shown in previous studies to affect reproduction.  Dairy cattle from a farm in northwestern Pennsylvania were divided into three groups: selenium and vitamin E supplemented with MU-SE (low and high) and a non-supplemented control group.  The number of days open and the number of services per cow were compared.
    There was a significant difference found, p < 0.05, when comparing the number of days until conception.  There was no significant difference found, p > 0.05, when comparing the number of services for each animal.  Selenium and vitamin E supplementation increased the reproductive efficiency of this Pennsylvanian herd.  Further economic analysis may show whether or not supplementation is a viable method to improve reproductive efficiency versus the cost and labor of supplementation.

Gretchen Schlump
October 29, 2001
Population Study of Lespedeza cuneata

Mentor: Dr. Mark Boudreau

Abstract:  Lespedeza cuneata is a perennial legume from southeast Asia.  It has spread throughout the southeastern United States after its introduction by European settlers.  The plant was used for erosion control and wildlife habitat by the state of Missouri until the early 90’s.   L. cuneata invades open spaces, including fields, prairies, meadows, and borders of ponds and wetlands.  This invasive plant encroaches even on high quality sites and develops an extensive seed bank.
    Shaw’s Nature Reserve (SNR), owned by the Missouri Botanical Garden, is located 40 miles west of St. Louis, MO.  The prairie reconstruction project at this reserve is infested with L. cuneata.  SNR uses Garlon and Roundup, applied by hand to the stems of the plant, to curb the invader.  This process is labor and chemical intensive.  Morrison (2001) proposed a study to investigate the effectiveness of non-chemical control methods—combinations of mowing and overseeding with natives—at SNR.
    Invasive exotic plants decrease species diversity (Swanson 1995, Reid and Miller 1989, Risser 1988).  Miller et. al. (1999) used diversity indices to investigate if a habitat’s diversity decreased after an L. cuneata population was eradicated with a chemical control; though the control was successful they did not see a change in diversity.
    Two transects were erected and 24 samples were taken from the transect in a high density L. cuneata site; 8 samples were taken from the low density transect.  Species were identified and percent cover was estimated for all the plots,.  An analysis of this pre-treatment data was conducted using two diversity indices, Shannon-Weiner’s and Simpson’s.  The means of the low and high plots were compared using an unpaired t-test.  The t-test for the Shannon-Weiner index did not show a significant difference with a p-value of 0.1919.  However, the Simpson’s index did show a significant difference with a p-value of 0.0074.  The methods of calculation differ; Shannon-Weiner’s index does not take into consideration that there are a finite number of species, while the Simpson’s index takes this into account.  Further research needs to be done to quantify the effects of exotic species on plant communities.

Emily Lincoln
November 5, 2001
The Effect of Sex Pheromones on the Population of  the Oriental Fruit Moth (Grapholita molesta)

Mentor: Dr. Victoria P. Collins.

Abstract The Oriental Fruit Moth (OFM) was introduced to the United States from Japan around the year 1913 on infested nursery stock (Metcalf and Flint 1962).  The OFM has infested most regions of the United States where pome and stone fruits are grown.  Conventional controls of OFM have been insecticides, mainly organophosphates and chlorinated hydrocarbons.  An alternative to insecticides is pheromone-mediated mating disruption, the controlled release of a synthetic sex pheromone that disrupts mating (Pree et al 1994).  In this study two paraffin emulsions were compared containing the same synthetic sex pheromones in the same concentrations.  7.5 acres of orchard in Fairview, NC was divided into nine 0.15-acre plots with 0.1-acre buffer between.  There were 3 replicates of each treatment.  There were three treatments the control, Confuseâ-OFM a commercial formulation, and an experimental paraffin emulsion.  Population traps were placed in the center of each plot and were monitored weekly for twenty weeks.  The cumulative trap counts were compared by 2-way ANOVA, with main effects of treatment and replicate as the variables.  The mean trap counts were 6, 20, and 27 for experimental, Confuse, and control, respectively.  The experimental formulation consistently had fewer insects, but the effect of treatment was not significant (p=0.48) probably due to the small number of replicates.  Further studies are warranted because pheromone mating disruption is an environmentally benign method of insect control.

Ben Warren
November 12, 2001
A GC/MS Analysis of  Comfrey( Symphtytum officinale) for Pyrrolizidine Alkaloids.

Mentor: Dr. Dean C. Kahl

Abstract: Comfrey (Symphytum officinale) is an herb used for its medicinal properties.   Comfrey produces pyrrolizidine alkaloids,  probably for defense.   Pyrrolizidine alkaloids are harmful to the body when digested by the liver.   The objective of this research was to develop a method for the separation and  identification of pyrrolizidine alkaloids from comfrey.  Comfrey samples were  obtained from Natural Foods store in Black Mountain,  NC as well as the WWC  Garden.  The alkaloids were extracted from the comfrey,  and then analyzed on  the gas chromatograph/mass spectrometer.  The spectra of the samples suggested  the presence of butylated hydroxytoluene(BHT,)  and stopcock grease.  BHT is  synthetic preservative,  that should not be in organic comfrey,  and the  stopcock grease probably dissolved into the sample during the extraction. The  Total Ion Chromatogram (TIC) for a sample from the Natural Foods store  suggested the presence of echimidine,  a hepatoxic pyrrolizidine alkaloid.   The method proved to be unreliable as the results did not show alkaloids in  all samples. Based on this information,  the method needs to be further  developed.

Rachel Reeser
November 19,2001
Invertebrate Densities Before and After Prescribed Burning on Jones Mountain

Mentors: Dr. Lou Weber and Ms. Dawn Nelson

Abstract: Fire is an important tool for ecosystem management in many biomes throughout the world.  The Natural Resources Crew (NRC) does prescribed burning in campus forests to combat many invasive species.  Every species reacts differently to disturbances; some benefit and some do not.  Prescribed burning in WWC forest has been determined to have a devastating effect on tree species with a smaller diameter breast height (Shaper, 1998).  Invertebrate assemblages are often useful indicators for monitoring effects of land management practices on biodiversity (Eyre, 1989).  In this study populations of 29 different invertebrates were counted and compared before and after prescribed burning on Jones Mountain, Swannanoa Valley, NC.  Ground dwelling invertebrates were sampled using pit-fall traps.  There were two control treatments, named A and C, where no burning took place, and there was one treatment, named B, that was burned by the NRC on March 14, 2001.  Each treatment had ten pit-fall traps within the area.  The pitfall taps were placed in 2-3 lines, and each trap had a 2.5 m buffer surrounding it.  Invertebrates were collected four times before burning, and then weekly for nine weeks after burning.  All found species were then counted and identified to Order or lower, if practical.  A total of 6,745 specimens were collected and identified.  To analyze the data, Community Similarity Indices were used to express relative similarities between communities.  The first two indices used, looked at all three plots together.  The Jaccard and Sorenson Coefficients (Quotients of similarity) were 0.44 and 0.61 respectively.  The proportional similarity was 72%.   Due to inadequate numbers because of weather before the burn, the last two indices look at numbers after the burn only.  Using the Bray and Curtis Index the totals for plots A versus B, and B versus C were 0.68 and 0.82 respectively.  Horns Information-Theoretic Index values for A versus B, and for B versus C were 0.83 and 0.93 respectively.  All values for indices used range from 0 (no similarity) to 1.0 (identical).  All indices suggest that burning does not alter population densities.  Further studies are warranted to sample populations for full seasons and to perform prescribed burning in the middle of a growing season.

Matt Drury
November 19, 2001
The Effects of Prescribed Burning on Exotic Species on Warren Wilson College Forest

Mentors: Dr. Louise Weber and Dr. William C. Davis

 Abstract:   The Natural Resources Crew has had an active burn program to control exotic species for nearly six years now.  To this point there has been no system to quantify the results of these prescribed burns, this is the motivation behind this seminar.  The objectives are to develop a system to quantify fire effects on exotic species and to test the effect of prescribed burning on Japanese spiraea (Spiraea japonica) and oriental bittersweet (Celastrus orbiculatus) after one growing season.  A BACI (Before, After, Impact, Assessment) design was used, and the impact was prescribed burning.  Three control and three impact belt transects 20 m long by 40 cm wide were used to take percent cover both pre- and post burn.  The data was represented graphically for analyses, specifically for oriental bittersweet and Japanese spiraea.  Results found that the percent cover of both oriental bittersweet and Japanese spiraea was reduced by more than half.  The data was taken in late February, the burn occurred in mid March, and the data was remeasured in mid November.  If this monitoring is continued on an appropriate timeline (i.e. monitoring in early September, burning in Feb., and monitoring again the following September,) results may be more accurately displayed.  This method effectively illustrates the effects of prescribed burning on exotic species.

Angie DeMyer
November 26, 2001

Mentor: Dr. Louise Weber

Abstract: The Nature Conservancy considers Sarracenia flava (the  yellow trumpet pitcher plant), a carnivorous plant to  be rare.  Authorities estimate that less than 5% of  the original Sarracenia stands remain in the  southeast.  Sarracenia flava stands normally occur in  the coastal regions of North Carolina.  Carnivorous  plants generally grow in nutrient poor soils.  The  plant compensates by breaking down the soft part of  the insect in order to absorb nutrients such as  phosphorous, nitrogen, and potassium from the insect.   My objective was to test a variety of horticultural  methods in hopes of bringing stands to western North  Carolina by introducing them into the future outdoor  science laboratory.  Seventy-two plants were donated.   The tallest 25% of the pitchers of each plant were  measured in centimeters once in May, June, July, and  August.  The average percent growth was calculated for  each month relative to the height in May. They were  divided into soil treatments, fertilizer treatments  and food treatments.  The food treatments seemed to  cause harm to the plants so that treatment was ended.   Using the Mann-Whitney test there was significantly  greater growth in the peat moss/perlite compared to  the clay (p-value of 0.0030).  The mean for fertilizer  was not considered significantly different from the no  fertilizer with a p-value of 0.1521.  The clay soil  found in the area behind the library did not have the  ability to hold water or to bring water up from the  bottom of the pots.  It compacted easily and was very  clumpy.  The pitchers tore and were dying off after  feeding them their supplements.  Some were exuding a  liquid from their mouth.  The plants could have been  getting to much protein because they were already  feeding on their own.  I believe that the plants were  overly secreting the digestive acids and enzymes and  therefore causing harm to themselves.

Steven Slack
November 26, 2001
Water quality analysis of Rainbow Lake, Tennessee

Mentor: Dr. Louise Weber

Abstract:  Rainbow Lake is a wilderness area within Prentice Cooper State Forest in Tennessee. The area has two streams flowing through it on which I conducted my study, Middle Creek and Bee Branch Creek. Using benthic macroinvertebrates as indicators to water quality is an effective way to qualify the health of streams and rivers. Benthic macroinvertebrates are animal groups of various taxa that live in the “benthos” or bottom sediment of the aquatic environment (Klem et al. 1990). Different types of stress will often produce different types of invertebrate communities (Klem et al. 1990). To qualify these invertebrates tolerance for stress, several “biotic indices” that give tolerance values for certain taxa have been developed. My objectives were to compare the water quality of Middle Creek to that of Bee Branch Creek using a simple t-test, and to compare the results of four different water quality assessments. Samples were collected throughout the summer of 2000. The invertebrates were then identified and the data was analyzed and given qualitative values to each sample site using EPT taxa richness, the Hilsenhoff Family Biotic Index (FBI) (Hilsenhoff 1977), the North Carolina Biotic Index (NCBI) (Lenat 1993), and the Alabama Water Watch Stream Assessment Form (AWW) (Deutsch 1993). The results of the stream comparison from all of the data had an average p-value of less than 0.89, considered not significant. Hilsenhoff’s (FBI) proved inappropriate for studies in the southeast. A drought summer had serious effects on the benthic fauna. This is a good reason why so few taxa were found and that overall numbers in the samples were low. Lenat stated that in order for the indices (biotic index) to be more valid, a higher number of individuals and taxa are needed in the samples (Lenat 1993). Therefore, the most accurate assessment of water quality was the EPT taxa richness assessment, which designated poor water quality for every sample site along Middle Creek and Bee Branch Creek.

Sara Runkel
December 12, 2001
The Effects of Trout Farm Effluent on Leaf Decomposition and Periphyton Growth in Shope Creek, NC.
Mentor: Dr. Mark Brenner

Abstract: Nutrient levels within low order mountainous streams are typically low, and phosphorous is usually the limiting nutrient for primary production. However, allocthonous sources, especially the autumn leaf fall, provide most of the energy for the stream ecosystem. These streams typically have cool water temperatures and high levels of dissolved oxygen making them ideal locations for commercial trout production. The effluent from trout farms contains high levels of nutrients and organic matter from fish waste and excess feed. The objective of this study was to look at the effects of effluent from one trout farm on leaf decomposition and periphyton growth. Leaf packs and artificial substrate were placed upstream and downstream of a trout farm on Shope Creek in Buncombe Co. North Carolina. Nutrient levels at both sites were measured throughout the study. Phosphorous and ammonia levels were both significantly higher downstream (P = 0.0200 and P = 0.0004). Nitrate-N levels were not significantly different (P = 0.2303). After 47 days, leaf decomposition was significantly higher at the upstream site (P< 0.0001).  After 67 days, periphyton growth, measured as total organic matter accumulated on the artificial substrate (ash free dry mass), was significantly higher at the downstream site (P = 0.0250). Paired t-tests were used to compare phosphorous, nitrate-nitrogen, and ammonia levels at the two sites. Previous research has found phosphorous to be a limiting factor in the growth of algae and fungi. Therefore, the increased organic matter growth at the downstream site can be explained by the higher nutrient levels. Leaf decomposition appears to be inhibited by the addition of trout farm effluent to the stream. Bacteria and fungi both participate in leaf break down and their increased levels downstream suggest that leaf decomposition should also be greater at this site. One possible explanation for why this was not found is that macro-invertebrate shredders such as Plecoptera, which feed on leaves, were more abundant at the upstream site. Macroinvertebrate populations were not quantified in this study, but the leaves at the upstream site showed skeletonization typical of shredder consumption, while the downstream leaves were still intact.

Dacey Mercer
December 10, 2001
Molecular Evolution in Parasitic Finches

Mentors:  Dr. Michael Sorenson (Boston Univ.), and Dr. Jeff Holmes

Abstract: Avian brood parasites are opportunistic species with adaptations that enable them to obtain parental care, for their young, from a host species. One interesting, and less studied, group of brood parasites is the genus Vidua. The genus Vidua contains ten species of indigobird and nine species of long-tailed whydah. These species are host-specific parasites and each tends to parasitize a single species of estrildid finch. The genus has a long history of brood parasitism, and that history has been characterized by cycles of host colonization, speciation, extinction, and subsequent recolonization. This dynamic process of repeated bottlenecks may produce an increased rate of sequence evolution and a mutational bias within the lineage. This increased rate is predicted by the nearly neutral theory of molecular evolution. This theory proposes that lineages with a smaller effective population size will have a faster rate of sequence evolution than equivalent lineages with a larger effective population size. This occurs because slightly deleterious mutations are more likely to become fixed in small populations due to genetic drift. Thus, the increase will be concentrated at nucleotide sites subject to selection, creating a mutational bias. Hypotheses about the process of molecular evolution in Vidua were tested using the complete mitochondrial genome of eight different taxa. This group represented the parasitic finch lineage, its closest non-parasitic relatives, and an outgroup. Analyses indicated that the parasitic finch lineage exhibited a relatively faster rate of sequence evolution than that of estrildid hosts and other passerines. The rate of sequence evolution in the parasitic finch lineage was 30% greater than that in other lineages. In addition, Vidua accumulated a greater amount of slightly deleterious mutations than other clades. The lineage had a greater ratio of nonsynonymous to synonymous substitutions. These results are consistent with the nearly neutral theory of molecular evolution, as described by Ohta, and the evolutionary history of Vidua as a brood parasite.

Drew Walton
February 4, 2002
The antibiotic effect of an extract from shiitake mushrooms, Lentins edodes.

Mentor: Dr. Victoria P. Collins

Abstract: Shiitake mushrooms, Lentinus edodes, are a delicious and healthy food.  Shiitake are native to East Asia, but are now cultivated all over the world.  Shiitake are grown on hardwoods, but primarily white oak logs.
     Mushroom science is young, but studies on Shiitake have shown that it can boost the immune system, lower blood cholesterol levels, shrink tumors in lab studies, and act as an antibacterial agent (Manzi, 315).  The sulfur lenthionine is the principal antibacterial compound found in Shiitake.
     Lenthionine, C2H4S5, which is responsible for the strong sulfur aroma of shiitake is also the principal antibacterial component.  Lenthionine has been isolated and synthesized (Morita et al), the enzymic formation of lenthionine has been studied (Yasumoto et al), and lenthionine has also been used in studies on natural substances which prevent dental caries (Hirasawa et al).
     This study investigated the effect of a non-polar shiitake extract.  200 g (wet weight) shiitake yielded 1.5 g of oil.  The minimum inhibitory concentration of oil against Esherichia coli, Salmonella typhimurium, and Streptococcus lactis was 0.8 mg oil/ml nutrient broth and >1.12 mg oil / ml broth for Enterobacter cloacae.  The determination of a bactericidal effect vs. a bacteriostatic effect of the oil against Streptococcus lactis was inconclusive.

Amy Annino
February 4, 2002
Comparison of treatments for late blight (caused by Phytophthora infestans) on tomato (Lycopersicon esculentum).

Mentor: Dr. Mark A. Boudreau

Abstract: Late blight is a disease caused by the pathogenic protist Phytophthora infestans.   Commercial fungicides are used to manage the spread of late blight disease, which is “the cause of the largest uses of agrochemicals” according to the Global Initiative on Late Blight. As an alternative to commercial fungicides, several plant volatile oils were identified that have shown signs of being anti-fungal: Allium sativum, Allium cepa, Origanum majorana, or Thymus vulgaris. The objective of this study was to determine whether volatile oils of garlic, onion, sweet marjoram, or thyme would inhibit the growth of P. infestans in vitro.  Also, one of four oils was to be selected for a field trial with tomato against late blight.  Two in vitro trials measured how P. infestans growth would be inhibited by each essential oil as a separate treatment.  Copper sulfate was used as a positive control and water was used as a negative control.  The first in vitro trial studied the effects of the four oils at one concentration level of 1.0ml ml-1.  The second in vitro trial studied the effects of the four oils at four concentration levels: 1.6ml ml-1, 1.2ml ml-1, 0.8ml ml-1, 0.4ml ml-1.  The volatile oils were purchased from Gritman Oil Co. and were added as individual treatments to rye-b media post autoclave sterilization.  The results for trial one were that P. infestans did not grow among the four treatment plates or the positive copper sulfate control plates.  Growth did occur on the negative control plates, which also had contamination.  The results for trial two were that garlic inhibited the growth of P. infestans most successfully among treatments.  Garlic was chosen to be used in a field trial to combat the disease on tomato.  However, before the treatment applications could be given, the tomato plants contracted the disease naturally in the field.  No results were obtained.  In conclusion, in vitro trial one suggests inhibition by all treatments excluding the water control.  However, a longer growth time was needed for a more accurate assessment.  In trial two of the in vitro study, evidence suggests that garlic inhibited the growth of P. infestans.  The field study was inconclusive.

Dan Harper
February 11, 2002
Black Bears on Warren Wilson College Campus

Mentor: Dr. Lou Weber

Abstract: This study was initiated due to the increase of black bear sightings on Warren Wilson Campus College over the past couple of years.  The first objective of the study was to determine the causes of this recent increase in bear sightings on campus.  The second objective was to determine whether a corridor exists between the top of Suicide Ridge and Jones Mountain.  The fourth was to determine the important aspects of habitat with in the corridor and lastly to determine if bears are found foraging in the forest or if trash is their only source of food on Warren Wilson Campus.  Black bear history and distribution are important to the understanding human bear interactions on Warren Wilson campus.  According to a study done by Mark Jones in 1998 a population of 1 bear per km2 was found which is in close proximity to Warren Wilson campus, one of the most dense bear populations in the region and country.  I used a black bear sighting interview form which I sent as an All-l, email attachment.  Interviews were also conducted personally, through the campus mail, and via phone.  This data was organized into a Microsoft word database.  A Global Positioning Satellite (GPS) unit was then used to collect all bear sighting points, and other important aspects of habitat.  I performed a qualitative analysis of the black bear corridor and a qualitative analysis of two important areas of bear sightings with in the corridor.  With this data I created a Geographical Information Systems, Arcview map of all the important data.  The results show that there is a diversity of vegetative cover with in the possible black bear corridor, but rhododendron thickets are the dominant coverage type.  Important sources of soft and hard masting species were found through out the possible corridor as well as important water sources.  Signs of bear such as scat, claw scratchings, and diggings were found through out the corridor.  There was an abundance of hard masting trees as well as soft masting species with in the John Casey and Bill Davis study sites.  The reasons for bears coming onto Warren Wilson Campus are yet to be determined. Although, I have shown there is a substantial corridor from Suicide ridge to Jones Mountain with an abundance of important food sources to bears.  There are also a few bears that used Warren Wilson property for foraging.  This leads me to suggest that this corridor be protected and managed to keep bears safe on Warren Wilson’s property as long as no human bear conflict occurs.  To reduce the risk of human bear conflict I would suggest that a community wide effort to obtain bear proof trash containers be undertaken.  For further study I would suggest creating a GIS model to assess the quality of habitat for black bears on Warren Wilson Campus including Dam Pasture.  Another study would be to measure the weight of acorn mast in oaks on Warren Wilson campus.  I also suggest setting up a series of bait triggered camera stations to determine the number frequency of bears coming onto Warren Wilson property.  As a last resort to pest bears I would suggest using a taste aversion conditioning experiment on pest bears to trash.

Sharon C. Fabrega
A Correlational Analysis of Community Structure in Meiofaunal Assemblages.

February 25, 2002
Mentor:  Dr. Paul Bartels

Abstract:  Tardigrades are invertebrates and are the sole members the phylum Tardigrada.  For many years the systematics surrounding tardigrades has been debated and was often ignored, as this phylum’s relationship to other phyla was, and continues to be unclear (Kinchin 1994).  The phylum Tardigrada has however been classified as a sister group of the arthropods (Nelson and Marley 2000).  Tardigrades are hydrophilous, requiring a layer of water in which to swim and perform gas exchange.  They are considered meiofauna, benthic animals 40-50mm in size (Hauer and Lamberti 1996).  Not much has been known with regards to tardigrade representation in the Great Smoky Mountain National Park, and it is through the All Taxa Biodiversity Inventory that scientists have been able to focus on studying tardigrades in the Smokies.  By using samples collected for the Inventory, I was able to do a separate study.  The object of the study was to determine if there is a correlation between the number of tardigrades to rotifers or nematodes in a sample, and to hypothesize reasons of the correlation using other available data such as species diversity and the number of predator species present.  The Pearson’s product-moment correlation was used on Excel for the statistical analysis, and the r2 value was used to measure the percentage of variance accounted for by a correlation (Dytham 1999).  The Ho being tested is that there is no correlation in either of the three The Pearson product-moment correlation indicates an insignificant positive association between nematodes and tardigrades (r=0.111, d.f.=21, P>0.05) with r2=0.0123, a significant positive association between rotifers and tardigrades (r=0.610, d.f.=21, P<0.05) with r2=0.372, and a significant positive association between nematodes+ rotifers and tardigrades (r=0.473, d.f.=21, P<0.05) with r2=0.224.  A positive significant correlation was found between tardigrades and rotifers, and tardigrades and nematodes+rotifers.

Shannon Pack
Fatty Acid Content of Feline Diets
February 25, 2002
Mentor: Dr. Victoria Collins
Abstract: Fatty acids are incorporated into cell membranes, and are used for fuel. Essential fatty acids are required in the diet.
Some essential fatty acids (n3) confer health benefits. The purpose of this experiment was to measure and compare the relative
amounts of fatty acids in several different cat foods, and to determine whether more expensive brands contained more essential
and beneficial fatty acids.  I analyzed at least two replicates of five different cat foods. Fatty acid methyl esters (FAMEs) were
prepared by heating cat food with methanol and acetyl chloride in toluene solvent. The FAMES were separated and quantified
by Gas Chromatography. I compared five different brands of cat food. The brands differed in fatty acid composition. Science
Diet, the most expensive non-prescription brand, had the highest amounts of beneficial n3 fatty acids, and Laura Lynn Moist,
the lowest amount. Since all the cat foods contained essential fatty acids, any of them would fulfill feline nutritional needs under
normal circumstances. Science Diet, however, since it is richest in the healthiest fatty acids, may promote long and healthy life
for cats.

Jeremy Fennell
March 4, 2002
An Environmental History of Warren Wilson College: Were the Seeds of Environmentalism Present Before the Late 1960s?

Mentor: Dr. William C. Davis

Abstract: Warren Wilson College has been closely tied to its land since its inception in 1894.  Until the late 1950?s and 1960?s, the farm was the major producer of food for the school. Also, lumber from the forest is still used for building and heating purposes.  In my study, I pursued two research questions.  One was to ascertain if the seeds of environmentalism were present at the school before the national environmental movement of the late 1960?s, and two if attempts at self-sufficiency represented precursors for the school?s present environmentalism.  My research methods were to first read the 3 major histories of the college, then research the farm and forest in the school?s archives, rummage through journals and files in the farm office, and finally to orally interview the ?old timers? of the school.  I found that by today?s standards of environmentalism, most evidence pointed to a lack of environmentalism prior to the late 1960?s and that the school?s early self-sufficiency did not indicate environmental precursors.  However, some environmental measures were taken.

Danna Baxley
March 11, 2002
The Effect of Tidal Inundation on The Hatch Success of Loggerhead Sea Turtles (Caretta caretta)

Mentor: Dr. Lou Weber

Abstract: Loggerhead sea turtles have been listed as a threatened species under the U.S. Endangered Species Act since 1978.  There are many threats to Loggerhead sea turtles as a species.  Some of these threats include habitat destruction, the shrimp industry, subsistence harvesting of sea turtles by developing countries and, of course, natural threats such as predation, drowning due to excess tidal inundation, and ?cooked? or melted nests during drought summers.   The overall objectives for this project were to determine if it is a feasible conservation technique to avoid relocating nests laid between the mean and spring high tide lines during a drought summer.  An additional objective was to determine whether hatch success for nests laid between the mean and spring high tide lines (that experienced tidal inundation) was higher than hatch success of nests laid above the spring high tide line.  There have been two previous research projects conducted concerning the effect of tidal inundation on nests during drought years.  One study resulted in inconclusive data with no visible trends, while the other study concluded that tidal inundation increased the hatch success of nests during a drought year.

In an attempt to prevent nests from heating up too much during the forecasted drought summer of 2000, I avoided relocating all nests laid between the mean and spring high tide lines and labeled these nests ?experimental.? The logic behind leaving nests laid between the mean and spring high tide lines in situ (not relocating these nests) is that the bi-monthly new and full moon tides would inundate the nests with water, and nest temperatures would then cool off, preventing the nests from cooking.  The nests were monitored daily, and the instances of tidal inundation were recorded for each nest.  To collect data, an inventory was conducted for each nest, and the nest contents were examined to calculate percent hatch success.  The result of this study was that the mean hatch success for nests laid above the spring high tide line was significantly higher than the mean hatch success for experimental nests (Mann Whitney p< 0.0001).

Because the results of this experiment yielded significant results, it does not appear to be a valid conservation technique to avoid relocation of loggerhead sea turtle nests laid between the mean and spring high tide lines during drought years.  Furthermore, experimental nests were more prone to predation and storm erosion.  Even if it is a drought nesting season, nests laid below the spring high tide line should be relocated in all future loggerhead management projects.

Emily Nicar
March 25, 2002
Hatchling Fitness of Loggerhead Sea Turtles from Nests with Different Incubation Durations

Mentor: Dr. Lou Weber

Abstract: Loggerhead sea turtles have been a threatened species since 1978.  There are many threats to  Loggerhead turtles such as habitat loss, beach lighting, the shrimp and fishing industry,  and natural threats such as predation.  Conservation efforts must be evaluated to improve their status. There are many beach management strategies aimed at increasing hatch success.  One of these strategies is nest relocation.  Relocation is moving nests from below the spring high tide line to a higher location on the beach to prevent flooding of the nest.  The incubation conditions of a nest are variable according to the placement on the beach.  Different incubation environments could have great impacts on developing embryos. Incubation temperatures are the main factor in determining incubation duration.  Warmer temperatures cause shorter incubation durations and cooler temperatures cause longer incubation durations.  The main objective of my research was to determine if hatchling fitness is affected by different incubation durations.  Knowing what incubation durations produce the greatest fitness in hatchlings would have many implications for management, especially in relocation efforts.

A speed test was used to compare hatchling performance as a measure of fitness.  I used 20 randomly selected hatchlings from 12 different nests throughout the summer.  I ran them on an 8-meter track split into two 4-meter sections.  Three times were taken: orientation time (the first 4 meters), speed time (the second four meters), and overall time (the full 8 meters).  Average clutch speeds were then compared.   A significant correlation was found between incubation duration and all three times: incubation duration vs. orientation time (P=0.01), incubation duration vs. speed time (P=0.04), and incubation duration vs. overall time (P=0.005).

My results show that longer incubation durations produce faster hatchlings.  This indicates that cooler incubation temperatures produce faster hatchlings.  If being fast is a fitness advantage, then it is an important factor for management to consider, especially in relocation efforts.  When nests are moved they could be moved to cooler incubation environments to increase fitness.  I am not suggesting this as a management strategy because further research must be done to determine if speed is actually a fitness advantage, and especially to assess the impacts of this strategy on sex ratio.   My research does not determine the best management strategy for relocation, but simply adds an additional factor to consider in sea turtle beach management.

Felicia Joan Collings
April 1, 2002
The Analysis of Kudzu (Pueraria lobata) Flower Fragrance By Gas Chromatography/Mass Spectrophotometry(GC/MS)

Mentor: Dr. Dean Kahl
Abstract: Kudzu (Pueraria lobata) is a weed common to the Southeastern United States as a fast-growing and somewhat pesky plant.  First imported to America in 1876, kudzu has been used for thousands of years in China for both food and medicinal purposes.  The flower of Pueraria lobata resembles a pea flower and is very aromatic; the smell resembles grape soda.

A literature search revealed that no research has yet been published on the components of the kudzu flower fragrance.  The objective of this experiment was to use a gas chromatograph/mass spectrophotometer (GC/MS) as well as a solid phase micro extractor (SPME) in order to analyze the components of the aromatic vapor of the flower.

A method was developed on the GC/MS that would give the most satisfactory chromatograms.  This temperature program was then used during each kudzu experiment.  The SPME was positioned above the kudzu flowers and allowed to extract the vapors of the flowers.  The SPME was then injected into the GC/MS and chromatograms of the unknown substances were obtained.  The GC/MS library, which contains 20,000 different chromatograms of known compounds, was used to identify some of the components in the unknown flower vapor.

        Though two of the kudzu experiments resulted in poor chromatograms, four chromatograms were acceptable for library searches and fragmentation pattern analysis.  Nonanal, decanal, and methyl anthranilate were identified as chemicals possibly responsible for the fragrance of kudzu.  Due to poor library matches, contamination by foreign chemicals, and variations in temperature program, many compounds remain unknown.

        The study proved successful in the development of a method for fragrance analysis as well as the identification of three chemicals in the vapor of the kudzu flower.  Additional work will be required in order to determine more of the volatile flavor components.

Martha Gross
April 1, 2002
Clover (Trifolium repens) and Arugala (Eruca vesicaria) Living Mulches in Broccoli (Brassica oleraceas) Production

Mentor:  Dr. Mark Boudreau

Abstract: The term living mulch was first coined in 1979 by Robert Sweet of Cornell University.  A living mulch is a type of intercropping that is attained by undersowing a low-growing, densely planted groundcover underneath a market crop.  Living mulches have been found to suppress weeds, reduce pest populations, increase crop yields, enhance soil organic matter, and reduce soil erosion.  The main drawback of a living mulch is that it can compete with the market crop for nutrients, water, light, and space.  The objective of my study was to determine the effects of clover and arugala living mulches on broccoli yields.  The commercial viability of living mulches and the Land Equivalence Ratio (LER) were assessed to see how applicable living mulches were to agriculture.  In the fall of 2001 broccoli was grown with a clover living mulch, an arugala living mulch, by itself and hand weeded, and by itself with no weeding.  Fresh and dry weights of broccoli yields were measured and showed that the arugala and clover living mulches had no effect on the fresh weight broccoli yields.  The arugala living mulch did significantly decrease the broccoli head dry weight.     The LER for broccoli and clover was 1.64 and 1.29 for broccoli and arugala.  Commercial viability of living mulches was not assessed because there was no significant difference in broccoli yields between the treatments.  The results of this research and prior research show promise for the application of living mulches in commercial agriculture.

Alan G. Hook
April 8, 2002
A Correlation Analysis Between the Abundance of E. Coli and the Hilsenhoff Macroinvetebrate Index for the Swannanoa River Watershed

Mentor: Dr. Mark Brenner

Abstract: In 1997, the Swannanoa River received a Good-Fair classification for swimming and recreational waters by the Division of Water Quality in the North Carolina Department of Environment and Natural Resources. In response RiverLink, a nonprofit organization addressing water quality issues, created a nonpoint source pollution management plan with grant money from Section 319d of the Federal Clean Water Act. Part of RiverLink’s management plan involved a bioassessment of the Swannanoa River Watershed. This bioassessment involved me sampling for E. coli and determining water quality based on pollution tolerance of aquatic macroinvertebrates.

This study used the data collected for E. coli and the macroinvertebrates to evaluate the relationship between E. coli levels and pollution tolerance of macroinvertebrates using the Hilsenhoff Field Biotic Index, HFBI.  I sampled nine sites from the upper watershed, in Lower Black Mountain, to the lower watershed in Biltmore Village.  I counted E. coli samples using an indicator dye method.  I sampled, identified, and scored the tolerance values for aquatic macroinvert-ebrates using the Hilsenhoff Field Biotic Index with corrections for North Carolina. I correlated these tolerance values with E. coli colony counts using a Pierson correlation analysis.  The range of E. coli colony counts were from 0.0 to 110.3 colonies per 100 mL, with a substantial number of sites having 0.0 colony counts per 100 mL.  The HFBI tolerance values ranged from 2.9, mainly intolerant species, to 6.9, signifying more tolerant species.  Results for all three sample dates were not significant and correlation values for r ranged from 0.46 to –0.66.  I found no direct relationship between the abundance of E. coli and HFBI tolerance levels for macroinvertebrates in the Swannanoa River watershed. All E. coli samples contained less than 126 colonies per 100mL, the EPA safety standard for recreational use. Tolerance values for the HFBI ranged from 2.9 to 6.9, indicating Excellent to Fairly Poor water quality for the Swannanoa River watershed.  With continuous aeration in mountain streams, the impacts of organic pollution do not adversely affect macroinvertebrates.  Also, the possible impacts of non-source pollution caused by organic pollution may be determined by other factors not related to dissolved oxygen.

Sarah Jeanette Rose
Antioxidant properties of Ginkgo biloba
April 15, 2002

Mentor: Dr. Dean C. Kahl

Abstract: Ginkgo biloba extract is an herbal supplement that is reputed to be a natural antioxidant which has a scavenging effect on free radicals.  Free radicals damage cell membranes through peroxidation of structurally important fatty acids.  Antioxidants stop these free radical reactions.  The objective of this study was to develop a method to analyze free radical trapping properties of various antioxidants.  The ultimate objective of this study was to study the antioxidant properties of Ginkgo biloba and compare to known antioxidants.

A method was adapted from Valkonen and Kuusi (1997, Journal of Lipid Research 38:823-833).  Free radicals were produced by 2,2’-azobis(methylpropionamidine) dihydrochloride.  In the presence of phosphate buffered human serum, the reaction of the radicals and 2,7-dichloroflourescein-diacetate was facilitated by the esterases in the serum to produce a colored product.  The formation of this product was observed at 504 nm with a UV/VIS spectrophotometer. According to our preliminary results the method appears promising, but more work needs to be done (1) on the effects of concentrations of AAPH, DCFH and human serum on the rate of the reaction (2) to determine the reproducibility of the results and (3) to study the effect of various antioxidants, including extracts of Ginkgo biloba.

Juniper McClellan
A Comparative Study of Nitrogen, Phosphorus, and Phytoplankton between the Wildlife and Swim Ponds
April 22, 2002

Mentor: Dr. Mark V. Brenner

Abstract: The Wildlife and Swim ponds here at Warren Wilson College have different ecology and history. The Wildlife pond is between Charlie?s Pasture and S-field which both receive added fertilizers every one to three years. The cows also spend considerable amount of time near, but not in, the Wildlife pond. It was made in fall 1999 because it was a naturally wet area due to groundwater and runoff from the fields.  The Swim pond was built approximately 1945, is far from the fields and receives most of its water from a forested watershed, Kittredge parking lot and Warren Wilson Road.  The objective of this study was to test for total nitrogen, total phosphorus and phytoplankton in order to determine the ponds current trophic status and hypothesize about future conditions.  A random number generator was used to select three collection sites from each pond. Three samples from different areas in the pond were collected on six different days.  The nutrients were tested using HACH Test in Tube Method.  The technique involves digestion of the sample the reading the wavelength from a spectrophotometer. The phytoplankton was measured by concentration of chlorophyll-a using Monochromatic Method. This was also measured on the spectrophotometer. A paired t-test showed there was no significant difference between the ponds for the three parameters measured Chl-a p=0.44, total nitrogen p=0.096, total phosphorus p=0.36.  According to trophic standards both ponds classified as having hypertrophic amounts of nitrogen and phosphorus and mesotrophic levels of phytoplankton. There was large variation in my results, including some negative numbers and some that were ?over range? which means they were too high for the spectrophotometer to read.  Visually the ponds appear to be in good condition; both contain fish and there is low turbidity. The Wildlife pond does have a considerably large amount of macrophytes, which can use up phosphorus and nitrogen, and the Swim pond does not.  While the ponds seem to have higher concentration in nutrients than lakes, they may be at high risk of volume loss by the fill in of sediments from algae and macrophytes.

Erin N Fletcher
April 22, 2002

Mentor: Dr. Lou Weber
Abstract: In the summer of 2000 Warren Wilson College cut a 1 ha stand of white pine (Pinus strubus) on North Lane because of a southern pine beetle (Dendroctonus frontalis) outbreak.  It was a total overstory removal.  This created heated controversy among the student body.  I wanted to see if there was a difference in winter bird diversity in this opening than in an unthinned pine forest.  Most of the research I could find was in hardwood forests and on neo-tropical and breeding bird populations.  In the months of November and December I observed the species of birds that used the North Lane beetle kill area versus the species that were present in an unthinned white pine stand behind the pump house.  I counted a total of 13 bird species in all.  Eleven of these species were present at North Lane and three were in the Pump House stand.  I found that North Lane had a higher average cover board index (355.75), lower forest canopy density (2.86%), and a lower average height (not including residuals) (2 meters).  The Pump House stand had an average cover board index of 136, a full overstory canopy (63.18%), and an average tree height of 26 meters.  This suggests that winter bird populations at Warren Wilson prefer forest openings to pure pine stands.  These data suggest that even-aged management is beneficial to some birds.

Pamela S. Fairchild
Environmental enrichment of captive red wolves (Canis rufus) at the Western North Carolina Nature Center
April 29, 2002

Mentor: Dr. Robert A. Eckstein

Abstract: With the goal of enhancing psychological well-being, I developed an environmental enrichment program for four red wolves at the Western North Carolina Nature Center.  I hypothesized that the environmental enrichment would illicit a change in the behavioral time budget of the wolves.  I used four different enrichment items: smashed heads of garlic; peppermint oil emulsion; rosemary tea; and chopped rawhide. The subjects were exposed to each of the four enrichments on three occasions, for a total of 12 enrichment sessions over the course of a two month study period. These sessions were preceded by 12 control sessions in which no enrichment was present.  The wolves spent a significantly larger percentage of time in sight when enrichment was present.   I did not find a statistically significant reduction in the percentage of time engaged in the performance of stereotypic behavior for individual wolves or time spent inactive vs. active for all wolves.  Environmental enrichment promoted increased time in sight in the sample group.  This may indicate an interest in the enrichment which is important for determining effective enrichment techniques.  The small sample size, lack of stereotypies, and timing of enrichment may have negatively impacted the results.  Future studies should assess whether stereotypies are more like to occur at different times of day and determine the efficacy of specific enrichment techniques.

Dana Marsh,
The importance of pasture size in the formation of ungrazed eliminative areas in horse fields.
April 29, 2002

Mentor: Dr. Robert A. Eckstein

Abstract: Fields that are grazed only by horses tend to develop an overall pattern in their appearances after an undisturbed time period consisting of little pasture management  (Odberg and Francis-Smith, 1976, Equine Veterinary Journal 8:147-149).  My objective was to compare the distribution of fecal piles in two different sized fields to a random distribution, as well as to look at the trends in the distributions between the two fields.  The distribution of fecal piles was studied in a field measuring 72 x 36 meters, and a field measuring 30 x 50 meters.  Four horses were used in this study, with two horses being housed in the large field and two horses being housed in the small field.  The study was conducted for a total of ten days.  The statistical analysis involved usage of the Poisson distribution to analyze the dispersion of the fecal piles in each sized field.  Upon completion of the study it was determined that both the large and the small sized field showed clustered distribution of fecal piles.  The chi-square statistic supported these conclusions.

Indika Somaratne
May 06, 2002
Moss Height and Tardigrade Species Diversity

Mentor: Dr. Paul J. Bartels


Abstract: Tardigrades are a phylum of microinvertebrates that were discovered in 1773.  My study was about terrestrial tardigrades that live on mosses.  According to a previous study different species of tardigrades prefer to live in different parts of the moss. My hypothesis was that as the moss height increases the tradigrade diversity also increase. I did my research as an extension of my mentor’s ATBI research project. Moss samples from the Great Smoky Mountain National Park were collected and tardigrdes were separated from those samples. Then 50 microscope slides from each sample was made from tardigrades living on short and tall mosses. Then these slides were identified with the  help of Dr. Diane Nelson at East Tennessee University. I compared the species richness and the Shannon-Wiener Diversity Index on short moss vs. tall mosses.  When I performed a Mann-Whitney U  test on my results I found that the P value was not significant, so I was unable to reject my null hypothesis. In my experiment the number of replicates were too small and it affected my significance level. For future research I would do this experiment with a greater sample size.