During 1995 the Maine Agricultural and Forest Experiment Station (MAFES) helped fund the education of nearly 90 graduate students. People outside the land-grant university setting may be unaware of the close association between its teaching and research units, but MAFES is intricately linked with students' education, both graduate and undergraduate. MAFES financial support enables these students to pursue advanced degrees, while the contributions of these students advance MAFES research.
MAFES believes that the research conducted by these students and reported in their dissertations and theses should be accessible to all who are interested. Because of the length of most dissertations and theses, however, publishing them in their entirety is impractical. Therefore, we have assembled this Miscellaneous Publication, a collection of the abstracts from each thesis or dissertation that was successfully completed during the 1995 calendar year.
The full theses and dissertations are available at Fogler Library at the University of
Maine; although they do not circulate, theses and dissertations may be copied by library
staff for the cost of photocopying. Ph.D. dissertations are available in either a
microfilm or hardcopy format from University Microfilms, Inc., 300 North Zeebe Road, Ann
Arbor, MI 48106-1346, telephone (800)521-0600.
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Stephanie S. Arnold
Master of Science in Plant, Soil, and Environmental Sciences--August 1995
An intensive Temperature Manipulation Project was designed and implemented in a coniferous forest ecosystem at the Howland Integrated Forest Study site at Howland, Maine. The purpose of the study was to investigate the effect of increased temperature on forest floor processes. As part of TeMP, this thesis project was designed to investigate the effects of increased temperature on the forest floor microbial community, specifically microbial biomass and activity.
Soil temperature was increased 5°C above ambient in two 15-m by 15-m heated with high resistance wire. Two unheated 15-m by 15-m plots served as control plots. Soil temperature and moisture, microbial biomass and activity, and soil respiration were measured monthly in the organic and mineral soil horizons during the fall of 1993 and summer of 1994. Microbial biomass was monitored using the substrate-induced respiration method and microbial activity was measured by determining dehydrogenase activity. An incubation study was designed to test the influence of three temperature regimes (5, 15, and 25°C) and four moisture regimes (20, 120, 220, and 320%) on microbial biomass, microbial activity and nitrogen mineralization rates.
Soil temperature was significantly higher, while soil moisture content and microbial biomass were significantly lower in the heated plots in the O horizon. Microbial activity was lower numerically in the heated plots but differences were not significant. Experimental warming significantly increased soil temperature in the mineral soil horizon, but soil moisture content, microbial biomass and activity were not significantly affected in this horizon. These results suggested that moisture content played an important role in controlling microbial biomass and activity. However, incubation study results for O horizon materials indicated that soil temperature played a primary role in controlling microbial biomass and activity, and soil moisture content a secondary role. This was contrary to field data. Close examination of the incubation data revealed that moisture controls microbial biomass and activity within a narrow range (20 to 120%) and moisture contents above this level have relatively little influence on microbial biomass and activity. Microbial biomass and activity were both significantly higher at the lowest temperature in the incubation study. Conclusions drawn from field and laboratory data combined suggested that as long as soil moisture contents were not limiting, increases in soil temperature may result in increased microbial biomass and decreased microbial activity.
Advisory Committee
Ivan J. Fernandez, Professor of Soil Science
Lindsey E. Rustad, Faculty Associate in Applied Ecology and Environmental Sciences
Alan S. White, Associate Professor of Forest Resources
Larry Zibilske, Associate Professor of Soil Microbiology
Bradley S. Crannell
Master of Science in Resource Utilization--May 1995
This study was designed to investigate phosphorus sorption in the presence of dissolved organic matter (DOM) extracted from common agricultural soil amendments in an acidic (pH 5.0) soil. The DOM was separated into two groups by passing half of each extract through a mixed bed resin column (+MBR) and leaving the other half unexchanged (-CTL). The + MBR treatment was used to isolate a DOM fraction from the inorganic ions present in the extracts. The + MBR treatment removed approximately 96% of the inorganic ions, 60% of the dissolved organic carbon, and 70% of the negative charge density. The negative charge density and pKa values of the DOM isolated from hairy vetch (HV) (Vivia villosa L.), crimson clover (CC) (Trifolium incarnatum L.), cattle (Bos taurus) manure (CM), and poultry (Gallus domesticus) manure (PM) were characterized by potentiometric titration. The charge densities of the DOM ranged from 4.57 to 13.44 mol(-) kg-1 C for the -CTL extracts and 0.95 to 3.56 mol(-) kg-1 C for the + MBR extracts.
Phosphorus sorption experiments were conducted at five rates of DOM (0, 5, 10, 15, 20 mmol C L-1) to determine the effect of DOM on phosphorus sorption. These experiments were conducted at 40 mmol P kg-1 soil with two timings of phosphorus addition. The sorption experiment, conducted with simultaneous addition of DOM and phosphorus, demonstrated that the unexchanged green manure DOM (HV, CC) and citric acid were able to inhibit phosphorus sorption onto acid soil. The primary mechanism proposed for this effect is the complexation of the DOM with exchangeable aluminum and iron from the soil. This complexation reaction increased the amount of aluminum and iron in solution with increased DOM additions. Complexation of the metals in solution by DOM inhibits aluminum and iron from precipitating with phosphorus. The phosphorus sorption inhibition abilities exhibited by each DOM type was not related to the negative charge density of the DOM.
When phosphorus was added six hours after DOM addition the HV-CTL, CC-CTL, and citric acid samples significantly inhibited phosphorus sorption and increased the amount of aluminum and iron in solution. Again, the amount of phosphorus sorption inhibition exhibited by each DOM type was not related to the negative charge density of the DOM. There were no significant differences between the two timings in the amount of phosphorus sorption inhibited for the HV-CTL and CC-CTL DOM. When citric acid was added six hours prior to phosphorus, less phosphorus was sorbed by the soil than with added simultaneously.
Advisory Committee
Tsutomu Ohno, Assistant Professor of Plant and Soil Chemistry
Russell D. Briggs, Research Associate Professor of Forest Resources
Christopher S. Cronan, Professor of Plant Biology & Pathology
Thomas J. Dunn
Master of Science in Entomology--August 1995
Beauveria bassiana has great potential for controlling soil dwelling insect pests. Persistence of the fungus in the environment is dependent on its ability to survive in the soil. This study was conducted to evaluate the survival of B. bassiana propagules under a variety of soil conditions. First, experiments were conducted to determine which selective medium would most accurately recover B. bassiana from field soil. Of the six different selective media compared, Sabouraud dextrose agar (SDA) with dodine and crystal violet was the most consistent in recovering B. bassiana from sterilized and unsterilized soil solutions. Differences in recovery of colony forming units between soils from different tillage practices were minimal with this medium. Therefore, SDA with dodine and crystal violet was used for subsequent field studies.
Field studies were conducted to determine the impact of pH, nitrogen and soil moisture levels on survival of B. bassiana throughout a growing season. Plots inoculated with B. bassiana conidia were sampled every five days from June 13 to August 11 and samples were drop plated on the selective medium. B. bassiana recovery was consistently greater in the higher pH levels. Throughout most of the field season, B. bassiana recovery was greater in the low nitrogen plots, than the high nitrogen plots. Soil moisture levels (high vs. low) could not be maintained over the field season. Moisture level was used as a covariate, and was not significant.
Relative activity of fungal, bacterial and actinomycete populations were also monitored throughout the field season in these plots using a contact slide technique. Percent soil moisture did not influence the relative densities of the fungi, bacteria or actinomycetes over the period of the field season, but covers used to maintain moisture levels did impact microbial populations. Mean fungal and bacterial populations were higher in the uncovered plots, while actinomycete populations were higher in the covered plots. Soil pH level did influence the mean rank of fungi, with increasing fungi levels with increasing pH. Actinomycete populations decreased with increasing pH. Bacteria populations were not influenced by soil pH level. Soil nitrogen level had no influence on the mean rank of the microbial populations. No correlation could be found between the mean rank of fungi, bacteria, actinomycetes and B. bassiana over the period of the field season.
No differences in B. bassiana recovery were seen between soils which received synthetic fertilizer, vs. plots which received compost and manure. Recovery of B. bassiana was not influenced by various pest management practices (minimal input, conventional management and biological management).
Advisory Committee
Eleanor Groden, Associate Professor of Entomology
Larry M. Zibilske, Associate Professor of Microbiology
John B. Dimond, Professor Emeritus of Entomology
Tom A. Goodman Jr.
Master of Science in Entomology--December 1995
The interaction between the caddisfly larvae, Nemotaulius hostilis, Platycentropus radiatus (Limnephilidae), and Banksiola crotchi (Phryganeidae), and Nostoc (Cyanophyta) was observed in the field and laboratory. The life histories of the three caddis species were also studied. Nemotaulius hostilis and P. radiatus larvae had similar developmental patterns, with later instar larvae overwintering, whereas, B. crotchi larvae overwintered in a variety of instars (L1-L4). All three species were univoltine. Nemotaulius hostilis used items for case construction that were most abundant in the environment. There was some evidence that when Nostoc colonies were used by N. hostilis, particular sizes of colonies were selected. Platycentropus radiatus and B. crotchi larvae did not select particular sizes of Nostoc colonies for case construction. The silken case of N. hostilis larvae protected the larvae from predation by the fish Rhinichthys, regardless of whether Nostoc colonies were present or not.
Advisory Committee
K. Elizabeth Gibbs Professor of Entomology
Eben A. Osgood, Professor Emeritus of Entomology
Francis A. Drummond, Associate Professor of Applied Ecology and Environmental Sciences
Joyce E. Longcore, Research Assistant Professor of Plant Biology
Jaime Mena-Covarrubias
Doctor of Philosophy in Biological Sciences--May 1995
The Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) is one of the most important biological factors limiting potato production in the northeastern U.S. This study focused on the effect that nitrogen (N) fertilization of potato has on CPB performance parameters, as well as, how `Superior' potatoes respond to larval defoliation pressure.
CPB larvae have a variable growth response to potato N fertilization. CPB growth and development are related in a non-linear manner to N fertilization. Both optimal and sub-optimal responses are exhibited by CPB under similar ranges of N applied to the soil and N content of its host plant.
It was found that N plays an important role in the response of the potato plants to CPB larval defoliation. In 1991, CPB larval densities reduced potato yields. However, larval densities explained only 5.8% of the variation in tuber yield, and N fertilizer rate had no effect on the relationship between CPB density and yield. In 1992, there was no significant relationship between CPB numbers and any of the plant parameters measured. In 1993, N affected plant response to CPB defoliation. Sub-optimally N fertilized (78 kg/ha) plants show a susceptible response to larval defoliation. However, optimally N fertilized (156 kg/ha) plants produce a compensatory response. Optimally fertilized plants can tolerate 23.9 small larvae per plant without loss in yield based on an average-uniform distribution, but only 12.3 small larvae per plant considering an aggregated distribution.
Calculation of EIL for CPB larvae is also affected by N fertilization regime of potato plants. For sub-optimally fertilized potatoes, potato price is more important than beetle larval size and spatial distribution in determining the magnitude of the EIL estimates. However, for optimum N rates, the contrary is true.
It is possible to combine the EIL for small and large larvae into one EIL as a part of the decision making process for CPB control. Current economic injury levels for controlling CPB larvae in Maine are at least four to five times lower than the estimates derived from this research.
Advisory Committee
Francis A. Drummond, Associate Professor, Entomology
A. Randall Alford, Professor, Entomology
Eleanor Groden, Associate Professor, Entomology
Matthew Z. Liebman, Associate Professor, Sustainable Agriculture
Gregory A. Porter, Associate Professor, Sustainable Agriculture
Richard H. Storch, Professor, Entomology
Jean-Luc Jannick
Master of Science in Plant, Soil, and Environmental Sciences--May 1995
Interest in the use of green manures has revived because of their role in improving soil quality and their contribution to beneficial nitrogen (N) and non-nitrogen rotation effects within cropping systems. This study was conducted to evaluate the biomass production, N content, radiation interception (RI), and radiation use efficiency (RUE) of pea (Pisum sativum L.), oat (Avena sativa, L.), and hairy vetch (Vicia villosa Roth) mixtures as affected by pea genotype (a leafy pea, `Century' vs. a semi-leafless pea, 'Tipu') and pea seeding rate (0 vs. 90 vs. 224 kgha-1; oat and vetch were planted at 56 and 34 kg-ha-1, respectively).
Biomass production and N content of the corresponding pea sole crops were also evaluated. Treatments were planted in early June on a Caribou gravelly loam soil in Presque Isle, ME in 1993 and 1994. Biomass production and radiation interception (RI) were measured by repeated sampling using a stratified clip technique. Mixture biomass was affected by a year by pea density interaction: respective yields for mixtures containing low density and high density pea were 770 and 880 gm-2 in 1993 vs. 820 and 730 gm-2 in 1994. Mixture N content paralleled biomass production and averaged 20.9 gm-2 across all treatments. While pea sole crops did not consistently produce biomass or nitrogen equal to three-species mixtures, the two-species mixture of oat and vetch did, yielding 820 and 21.7 gm-2 of biomass and N, respectively, averaged over the two years. Multiple regression showed that 61% of the variability in mixture biomass production was accounted for by a combination of early-season pea RI and mid-season total mixture RUE. Economic analyses showed that rotations including the green manures evaluated may be economically competitive with a conventional rotation of barley (Hordeum vulgare L.) undersown with clover (Trifolium spp.) in a potato (Solanum tuberosum L.) production system.
Advisory Committee
Matt Liebman, Associate Professor of Sustainable Agriculture
Laura C. Merrick, Research Assistant Professor of Sustainable Agriculture
Francis A. Drummond, Associate Professor of Entomology
Gregory A. Porter, Associate Professor of Agronomy
Geraldine B. Opena
Master of Science in Plant, Soil and Environmental Sciences--August 1995
Rainfall distribution in Aroostook County is irregular, causing periods of both excess and deficient moisture. Improved soil management might help to provide soil conditions to enable the potato crop to tolerate periods of deficient moisture. In the present study, the effects of irrigation and soil management on potato growth and yield were determined over two growing seasons. Soil management, consisting of rotation crop (oats vs. green manure) and soil amendments (none vs. 22.4 Mg ha-1 compost and 44.9 Mg ha-1 manure) were tested in factorial combination with supplemental irrigation treatments (none, moderate and excessive in 1993, and none, reduced, moderate in 1994).
Significant amendment effects were detected on early crop growth, dry matter production and yield in 1993. Tuber size was increased, but specific gravity was reduced by the amendment treatments. Irrigation did not affect the yield. In 1994, late-season haulm vigor, dry matter production, tuber size and yields were significantly increased by irrigation, while specific gravity was reduced. Early crop growth, dry matter production, tuber size and yields were also significantly improved by the amendment treatments.
No significant effect of either amendment or irrigation on any root parameter was detected in 1993. In 1994, root length density and root dry weight were significantly affected by either irrigation and amendment. Highest root length density values were obtained when both supplemental irrigation and amendments were provided. Root/shoot ratio and root distribution among soil layers were not affected by either irrigation or amendment during the two years of the experiment. Roots were mostly (approximately 85%) concentrated in the upper 30-cm layer of the soil.
The choice of the rotation crop did not affect yields, tuber size distribution and specific gravity over the two growing seasons. The delayed vine maturity promoted by the green manure treatments did not result in enhanced tuber growth.
The long term effects of using the soil management treatments and the possible impacts of the soil amendments on disease transmission are currently being studied.
Advisory Committee
Gregory A. Porter, Associate Professor of Agronomy
Matthew Z. Liebman, Associate Professor of Sustainable Agriculture
Larry M. Zibilske, Associaciate Professor of Soil Microbiology
Marcia Siebenmann
Master of Science in Entomology--May 1995
The Narraguagus River, Maine, is experiencing declines in annual returns of adult Atlantic salmon (Salmo salar). To determine if this is due to a deterioration in water quality and availability of food for immature fish, the aquatic macroinvertebrate community at six sites was sampled in 1991 and 1992. The abundance of organisms, genus diversity, and macroinvertebrate taxa present were then compared to historic data from 1974. Ephemeroptera, Trichoptera, and Diptera were the most abundant orders, accounting for 79% of total individuals collected in 1974, 73% of total individuals in 1991, and 74% of total individuals in 1992. There was high year-to-year variation and no consistent significant changes in abundance between years at most sites. In 1991 and 1992, significant increases in Shannon's Diversity Index were observed at two sites; otherwise there were no significant differences in diversity. Nine taxa present in 1974 were absent in 1991 and 1992; 28 taxa present in 1991 and 1992 were absent in 1974. These results suggest that neither water quality nor the food base for juvenile salmon deteriorated between 1974 and 1991-1992 at these study sites in the Narraguagus River.
Advisory Committee
K. Elizabeth Gibbs, Professor of Entomology
John B. Dimond, Professor Emeritus of Entomology
William A. Halteman, Associate Professor of Mathematics
John R. Moring, Professor of Zoology
Philip A. Stack
Master of Science in Entomology--December 1995
The insidious flower bug (IFB), Orius insidiosus Say, is a natural enemy of the western flower thrips (WFT), Frankliniella occidentalis Pergande, on flowering plants throughout the eastern and midwestern US. IFB is commercially reared for release in greenhouses to control WFT on vegetable and ornamental crops. However, IFB is not recommended as a biocontrol agent in winter months because it enters a reproductive diapause in short days. This precludes its use on chrysanthemum, Dendranthema grandiflora (Ramat.) Kitamura, a valuable ornamental plant which flowers in short days. This study investigated the use of supplemental blue light to extend the daily photoperiod beyond the critical threshold for IFB diapause induction without negatively affecting flowering in chrysanthemum.
Laboratory experiments and a greenhouse validation study demonstrated that low intensity blue light (<3.5 µmolm-2s-1 and 400-500 nm) at a photoperiod of 15L:9D over a range of temperatures (19-28°C) prevented reproductive diapause in IFB. Nymphal development rate and survival, adult female preoviposition and fecundity under blue light at 24°C were comparable to what was observed under conventional long-day broad spectrum light.
IFB was an efficient predator of WFT and reproduced in a fluctuating greenhouse environment under artificial short-days with extended blue light. A simulation model of IFB development and reproduction in constant temperatures was constructed to compare with the greenhouse validation study. Although the observed densities of IFB lagged behind the simulated predator densities, the overall population growth trends were the same.
At similar light quality and intensity levels used to extend photoperiod in experiments with IFB, reproductive and vegetative responses to blue light were tested in chrysanthemum. Flower induction and development under supplemental blue light were comparable to plants exposed to conventional short-day conditions. A total energy effect (intensity x time) was observed under blue light in continuous photoperiods, with increased levels reducing flowering. A differential cultivar response to blue light was observed, particularly at higher intensities of exposure. Based on these results of the use of blue light to extend the seasonal limits of long-day insects on short-day crops, this reproductive performance enhancing technique may play a significant role in a comprehensive biological control strategy devised for greenhouse production systems.
An additional study surveyed Maine greenhouse growers over two years about the presence of WFT and the viruses vectored by WFT in their greenhouses. Over 30% of the growers reported finding WFT and of those, more than 30% also reported having plants infected with impatiens necrotic spot virus. Insecticides were the primary method of control of WFT and the majority of growers use an Integrated Pest Management strategy. Although use of biological control was negligible, most growers felt that research should focus on this pest management option.
Advisory Committee
Francis A. Drummond, Associate Professor of Entomology
James F. Dill, Professor of Entomology
David H. Lambert, Associate Professor of Plant Pathology
Richard H. Storch, Professor of Entomology
Georgette M. Trusty
Master of Science in Plant, Soil, and Environmental Sciences--August 1995
Wood ash waste, generated by Maine power plants and lumber mills, is currently being disposed of by spreading on agricultural and forest land. The effect of wood ash on forest catchment waters, soils, and ecosystems is little understood. An increase in the pH of forest soils should affect microbial populations, soil chemistry, elemental cycles, and distribution of plant species. This two part laboratory study investigates 1) the pH response of forest soil organic and mineral horizons to lime additions and 2) the effect of a sudden increase in pH on dissolved organic carbon compounds (DOC) in soil solutions.
Samples were collected from 11 forested sites, both hardwood and softwood. For the lime requirement experiment, samples were mixed with incremental amounts of lime and incubated for four months. For each soil, a regression of pH as a function of the amount of lime added allowed determination of the amount of lime required to attain a given pH. The SMP buffer method of lime requirement determination was then calibrated against this incubation lime requirement. For the DOC investigation, water extracts of limed and unlimed subsamples of the organic horizon samples were analyzed for DOC concentrations and functional group concentrations. Total luminescence fluorescence spectra were also obtained for each extract.
The SMP buffer method was an excellent predictor of lime response in organic horizons, with 98% of the variability in lime requirement explained by the buffer pH using the equation, lime requirement (LR) = -1.31(buffer pH) + 9.12. The SMP buffer was also an acceptable predictor of lime response in mineral horizons, with 84% of the variability in lime requirement explained by the buffer pH using the equation, LR = -1.05(buffer pH) + 6.71. The addition of lime to organic samples caused a 55% increase in DOC released to the water extracts. Liming had no effect on functional group concentrations of the DOC compounds, but chemical changes in DOC as a result of liming were suggested by decreased fluorescence emission and excitation wavelengths. Hardwood samples were not different from softwood samples in their ability to release DOC or in functional group concentrations. Shorter emission wavelengths in softwood than in hardwood samples suggest chemical differences due to stand type. Hardwood samples did not respond differently than softwood samples to liming.
Advisory Committee
M. Susan Erich, Associate Professor of Plant and Soil Chemistry
Russell Briggs, Associate Professor of Forest Resources
Ivan J. Fernandez, Professor of Soil Science
Peter R. Wagner
Master of Science in Plant, Soil, and Environmental Sciences--December 1995
The Moosehead Sanitary District in Greenville, Maine has irrigated municipal wastewater effluent on a somewhat poorly drained forest soil ecosystem for the past 15 years as a part of its wastewater treatment system. The effect of this treatment on soil properties focused on four areas: a forest control, an irrigated forest, an irrigated strip-cut, and an abandoned irrigated farm field. No significant differences in pH, percent organic matter, bulk density, or concentrations of total N, P, exchangeable acidity, Al, or H, or trace metals were found between irrigated forest soils and forest control soils. Significantly greater concentrations of Na (92%), Ca (54%), and Cu (79%) were found in the O horizon of treated soils. Greater amounts of N (56%) were mineralized in situ, using a buried bag incubation technique, from treated soils when compared to the control. Microbial biomass, determined by substrate induced respiration and fumigation extraction techniques, was significantly lower (46%) in treated soils when compared to the control. This decline may have been due to greater Cu concentrations or salinity in treated soils. Significantly greater concentrations of N, P, K, Fe, and Zn were found in red maple (Acer rubra L.) (37, 40, 42, 41, and 14% respectively) and balsam fir (Abies balsamea (L.) Mill.) (28, 34, 35, 23, and 10% respectively) foliage of trees grown on treated soils. Red maples were found to exhibit a mean 22% increase in radial growth response to wastewater irrigation while balsam fir showed no response. Results from this study suggest that use of the forest ecosystem was a successful tertiary component of the wastewater treatment system at the Moosehead Sanitary District, Greenville, Maine.
Advisory Committee
Ivan J. Fernandez, Professor of Soil Science
M. Susan Erich, Associate Professor of Plant and Soil Chemistry
C. Wayne Honeycutt, Faculty Associate in Applied Ecology and Environmental Sciences, New
England Plant, Soil, and Water Lab
Liquan Zhang
Master of Science in Plant, Soil and Environmental Sciences--August 1995
The effects of soil management and irrigation on potato tuber initiation, plant and tuber growth, tuber nutritional qualities (ascorbic acid and glycoalkaloid concentration), and tuber processing qualities (fructose, glucose and sucrose concentration) were evaluated on two cultivars ('Atlantic' and 'Superior') over the 1993_1994 growing seasons.
Significant varietal differences were observed in plant growth and tuber quality. Atlantic was slower in tuberization, higher in total dry biomass and better for making fried product; however, it was significantly lower in ascorbic acid (Vc) and significantly higher in glycoalkaloid concentration compared to Superior. Applying compost and manure soil amendments slightly increase the number of stolons per plant, percentage of tuberized stolons and the total plant dry biomass production. Significant increases in stem dry matter content were observed in both years in the amended soil management system. However, no significant soil amendment effects on LAI were found. Tuber number and dry matter content were also slightly increased by amendment treatment in 1993. Tuber nutritional and processing qualities were not dramatically changed by the soil amendment treatments. Soil amendment application slightly reduced tuber Vc and glycoalkaloid concentration, but the differences were rarely significant. Soil amendments did not influence tuber reducing sugar levels during the growing season; however, significant amendment effects were detected at harvest. The effects were in opposite directions for the two experiments. Soil amendment slightly increased tuber sucrose concentration during the growing season.
Irrigation treatment tended to reduce Superior tuber Vc concentration, and the difference was significant during the 1994 harvest season. Glycoalkaloid concentration in tubers was reduced by irrigation treatment with significant effects during the 1994 harvest season. Irrigation treatment tended to increase reducing sugar levels at harvest and from January storage. Tuber sucrose concentrations were not affected by irrigation treatment during the growing season; however, they tended to be increased at harvest in the irrigation-treated plots.
Tuber Vc concentration declined over time in storage, but tuber glycoalkaloid concentration did not change over time. A negative correlation was observed between tuber fresh weight and tuber glycoalkaloid concentration.
Chip color was significantly related to reducing sugar concentration, and the relationship was slightly stronger with glucose than with fructose. The relationship between the color and sucrose concentration was not as strong. For analysis of the tuber glucose concentration, HPLC methods gave a significantly higher estimate than a YSI glucose analyzer.
Advisory Committee
Gregory A. Porter, Associate Professor of Agronomy
Rodney J. Bushway, Professor of Food Science
Timothy S. Griffin, Sustainable Agriculture Specialist and Cooperating Assistant Professor
Meng-Lan Yuan
Master of Science--December 1995
Antarctic channichthyid fishes, commonly called icefishes, have been thought to lack completely myoglobin (Mb) due to the pale coloration of their red skeletal muscle. Mb cDNA sequence of icefish Chionodraco rastrospinosus was obtained by RT-PCR and cycle sequencing, which demonstrated that Mb is present in Antarctic icefish. Previous studies (Vayda et al. 1995; Sidell et al. 1995) have shown icefishes, Chionodraco rastrospinosus, Chiondraco hamatus, Cryodraco antarcticus, Chaenodraco wilsoni, and Pseudochaenichthys georgianus, expressed both Mb mRNA and polypeptide; Pagetopsis macropterus and Chaenocephalus aceratus expressed neither Mb mRNA nor polypeptide. However, another Mb-absent species, Champsocephalus gunnari, expressed a low, but constant, level of Mb mRNA. Mb cDNA sequences of four icefish species (Pseudochaenichthys georgianus, Pagetopsis macropterus, Champsocephalus gunnari, and Cryodraco antarcticus) and two Mb-expressing nototheniid relatives (Notothenia coriiceps and Gobionotothen gibberifrons) were obtained to determine what factors in the Mb genes of these fishes could suppress the expression of Mb. Comparative analysis of Mb cDNA sequences showed a strikingly high degree of identity (92.5%) among these fishes. The 5'- and 3'-noncoding segments of Mb cDNAs were also found to have minor variations. For example, a three-base insertion was found in the 5'-untranslated regions of icefish Mb cDNA, but was absent in the nototheniid Mb cDNAs, and several base differences were scattered among the 3'-untranslated regions. The polypeptide sequences deduced from the Mb cDNAs exhibited a homology of 93.2%. Ten sequence changes observed were all conservative amino acid substitutions.
Genomic sequences of Mb-expressing Chionodraco rastrospinosus and Mb-absent Chaenocephalus aceratus were obtained to determine the gene structures of these two fishes. The genes of all the members of globin family in vertebrates possess a two intron-three exon organization, which has been conserved for 600 to 800 million years. Surprisingly, the Mb genes of Chionodraco rastrospinosus and Chaenocephalus aceratus were found to possess a three intron-four exon structure. Comparative analysis of the intron-removed genomic sequences of Chaenocephalus aceratus and the Mb cDNA sequence of Chionodraco rastrospinosus showed that numerous insertions and deletions have resulted in frame shift mutations and two in-frame termination codons in the Mb gene of Chaenocephalus aceratus. This indicates that the Mb gene of Chaenocephalus aceratus can no longer encode a functional Mb. The sequence of Chaenocephalus aceratus Mb has diverge 5.8% from the Mb cDNA sequence of other icefishes, whereas the sequence divergence between the Mb cDNAs of icefish and nototheniid species was only 2.5%. The striking degree of conservation in Mb cDNA sequence among icefish and nototheniid species suggests a strong selective pressure operating on the Mb genes of icefishes and nototheniids, implying that Mb may be functional at cold temperatures.
Thesis Advisor
Michael E. Vayda, Associate Professor of Biochemistry
Eric J. Wight
Master of Science in Bio-Resource Engineering--August 1994
Anaerobic digestion of organic wastes is a disposal alternative for both dairy farms and supermarkets faced with increased regulation and costs for waste management. The University of Maine Witter Dairy Farm has been adding vegetable waste from campus cafeterias to dairy manure influent since 1987. Interest in expanding the volume of waste to include material from local supermarkets has been expressed. However, before adding large quantities of vegetable waste, a simple but dependable digester monitoring method is required. The major focus of this thesis is to address the hypothesis that a ratio of partial to total alkalinity will be a better tool for monitoring digester stability than currently used alkalimetric methods.
A secondary goal of this thesis is to assess the potential gas yield from vegetable waste. The small vegetable loadings previously added to the digester have not provided a good evaluation of potential gas yield. Furthermore, conflicting literature reports on gas yield potential from vegetable waste require clarification for the waste product available to the Witter Farm.
A bench scale study was performed using three 18-liter anaerobic reactors fed liquid manure and vegetable substrates. Shock tests were performed using HCL, acetic acid, and vegetable wastes while digesters were monitored using the following alkalimetric methods: percent bicarbonate alkalinity (proposed by thesis), total alkalinity (Standard Methods 1985), partial alkalinity value at pH = 5.75 end point (Jenkins 1991), bicarbonate alkalinity value determined from total alkalinity and back titration (DiLallo 1961), and partial alkalinity to volatile fatty acid alkalinity ratio (Ripley 1986). Gas potential was recorded throughout the study to evaluate the potential yield from vegetable waste.
Comparison of the various alkalimetric monitoring methods showed that the methods proposed by DiLallo (1961) and Ripley (1986) were the most responsive. However, the coefficients of variance were large for these methods indicating lower precision. Comparison of the shock responses of the various methods in terms of number of standard deviations showed that the partial alkalinity and percent bicarbonate methods performed best. Between these two methods, the percent bicarbonate method had the advantage of being less sensitive to measurement error, and the partial alkalinity method had the advantage of being sensitive to strong acid shocks. The best solution was found to be a combination of the percent bicarbonate and partial alkalinity methods.
Gas production results support previous work by Mata-Alvarez et al. (1992) showing that a mixture of vegetable and fruit waste can produce twice as much biogas as manure on a volatile solids basis with a specific gas production of 0.85 L/gVSfed. The results from the bench scale tests correlated well with full scale data.
Advisory Committee
Edward Huff, Associate Professor of Bio-Resource Engineering
Jeffrey McBurnie, Assistant Professor of Bio-Resource Engineering
Lynn Katz, Assistant Professor of Civil Engineering
Abdulaziz I. Al-Ohaidib
Master of Science in Food Science & Human Nutrition--May 1995
Fermented sausages made from 1:1 and 3:1 mutton:fowl were compared to a fermented beef sausage as a control. All sausages were analyzed for moisture, protein, fat, ash, minerals, lactic acid, caloric content, texture, and color and compared. Sensory evaluation was performed using 65 untrained panelists.
The three types of sausages were low in fat and high in protein and mineral contents. The results indicated a direct relationship between texture (hardness and shear) and fat content as fat increased the texture decreased. Overall acceptability was highest for the 3:1 mutton:fowl sausage. This indicates that the fermentation process was effective in masking or eliminating the strong disagreeable flavor and undesirable texture of mutton and fowl.
Ash, calories and lactic acid content for the three sausage formulations were not significantly different. The fermented beef sausage was significantly redder (higher in a-value) (P # 0.05) than the mutton:fowl fermented sausages. Statistical analyses of the sensory data indicated no significant differences by judges (P # 0.05) in texture and overall acceptability. However, statistical analyses of the sensory data indicated significant differences by judges (P # 0.05) in the appearance and flavor.
Advisory Committee
Alfred A. Bushway, Professor of Food Science, Thesis Advisor
Mahmoud El-Begearmi, Cooperating Associate Professor of Food Science
Rodney J. Bushway, Professor of Food Science
Stephanie S. Baker
Master of Science in Food Science & Human Nutrition--May 1995
A study was conducted to examine the effect of harvest season, storage temperature and length of storage (in days) on the chemical, physical and microbiological characteristics of lowbush blueberries. Commercially hand-raked blueberries were sampled on three different dates, approximately two weeks apart, throughout the blueberry harvest year. These three dates represented the early, mid and late harvest seasons.
Equal amounts of berries were randomly placed into perforated plastic bags which were then stored, in three layers, at each of three temperatures: 5°C, 15°C and 25°C. Samples were taken from the top, middle and bottom layers of bags held at the three temperatures, and then analyzed on the first, third, sixth and ninth day of storage. In the case of the samples held at 25°C, the ninth day of sampling was omitted from analysis due to berry spoilage.
The stored berries were analyzed for the following variables: physical characteristics (texture, color, amount of crushed and whole berries), chemical characteristics (sugars, titratable acidity, moisture, pH, and organic acids), and microbiological characteristics (total aerobes, yeasts and molds).
Significant interactions (p<0.05) were observed between harvest season, storage day and storage temperatures for berry total sugar, glucose, and fructose levels. The mean values for total sugar were significantly higher in the early harvest season and at the 25°C storage temperature. There was a significant (p<0.05) decrease in total sugars from day 1 to day 9 of storage.
The effects of storage temperature and harvest season on mean values for glucose and fructose concentrations showed a decreasing trend as temperatures were elevated and harvest season was extended. The mean for storage days 1 and 3 were higher and significantly different (p<0.05) from the means for storage days 6 and 9.
Significant interactions (p<0.05) were observed between harvest season, storage day and storage temperatures for berry titratable acidity, berry pH and berry sugar:acid ratios. The data for titratable acidity shows no clear trends with the effects of storage days, however a significant (p<0.05) and increasing trend was observed over the range of storage temperatures. The early harvest season was significantly (p<0.05) lower than the mid and late season. Berry pH results corresponds with the titratable acidity results. Significant (p<0.05) and decreasing trends were observed for the effects of storage temperature and storage days 1 through 6 on the berry sugar:acid ratio. Between day 6 and day 9, a slight increase was observed.
Harvest season, storage day and storage temperatures exhibited significant interactions (p<0.05) for berry Hunter L-values, a-values and b-values. Significant differences (p<0.05) for temperatures were observed only at 25°C where berries were darker. A trend was observed between seasons as berries were lighter, with the late season being significantly (p<0.05) lighter. Neither storage days nor harvest season showed any distinct trends. However, storage temperature's effect showed increasing berry b-values over all three temperatures, which represents a trend toward a more yellow (less blue) color. There was a significant increase (p<0.05) between 5 and 25°C.
Significant interactions were observed (p<0.05) between harvest season, storage day and storage temperatures for both berry total aerobe and yeast counts. Total growth in the early and mid harvest season samples was significantly lower (p<0.05) than growth in the late season, which corresponds to the similarly significantly (p<0.05) greater yeast growth in the late harvest season. Significant differences (p<0.05) with increasing trends were observed for all effects measured on yeast counts, and significant differences (p<0.05) were observed over every other measured storage day. No significant interactions was observed (p<).05) between harvest season, storage day and storage temperatures for berry mold counts. Growth peaked on the sixth day of storage, which was significantly higher (p<0.05) than all others.
Significant interactions were observed (p<0.05) between harvest season, storage day and storage temperatures for berry texture. No significant differences were observed for the effect of storage days, however, the kg force required to compress berries stored at 25°C was significantly lower (p<0.05) than the force required for berries stored at 5 or 15°C.
Although organic acids, in general, tend to diminish during senescence, they are in a constant state of flux in a postharvest plant and this was observed in the results as there were no trends evident.
Advisory Committee
Alfred Bushway, Professor of Food Science, Thesis Advisor
Mary Ellen Camire, Associate Professor of Food Science
Rodney Bushway, Professor of Food Science
Adrienne White, Associate Professor of Human Nutrition and Foods
Ranjan P. Ekanayake
Master of Science in Food Science & Human Nutrition--May 1995
The effect of dietary manganese on the aorta and liver tissues was studied in rats using electron microscopy and morphometric techniques. Weanling, male Sprague-Dawley rats (n=20) were fed a manganese-deficient diet (MnD, 0.5 ppm ± 0.05 s.e.m.) or a manganese-supplemented diet (MnS, 90 ppm ± 0.6 s.e.m.)for 15 weeks. Scanning electron microscopy of the aorta showed damage on the luminal surface of the artery with both diets. Computer-aided image analysis showed a significantly higher (206%, p # 0.01) surface damage in MnD vs. MnS rats. Transmission electron microscopy of the arterial wall showed less-dense extracellular matrix around smooth muscle cells of the MnD rats, especially in the medial layers. Qualitative assessment of the ultrastructure of the livers of MnD rats revealed reduced numbers of mitochondria and swelling of some mitochondria as well as reduced density of the mitochondrial matrix. Dietary manganese therefore, causes ultrastructural changes in both hepatic and aortic tissues of the rat.
Advisory Committee
Dorothy J. Klimis-Tavantzis, Associate Professor of Clinical Nutrition, Thesis Advisor
Richard A. Cook, Associate Professor of Food Science & Human Nutrition
Linda J. Kling, Associate Professor of Animal & Veterinary Science
Seth Tyler, Professor of Zoology and Director, Electron Microscopy Laboratory
Susan Ismail
Master of Science in Food Science--December 1995
An average of 91 million pounds of lowbush blueberries, Vaccinium angustifolium, are grown and processed annually in Maine, Atlantic Canada, and Quebec. Due to short harvest times and the inherent fragility of the fruit approximately 99.5% of the crop is individually quick frozen immediately after harvest; 15-18% of these berries are held in storage for later canning. This freezing and canning process results in a berry which is markedly softer in texture and more reddish in color than fresh blueberries. The objective of this study was to improve the texture and color of canned lowbush blueberries through the use of a water-based canning solution containing calcium salts and citric acid. Calcium and citric acid have been used as firming agents in a number of other fruits and vegetables.
A face-centered central composite design with three center points was used for each of two calcium salts. Calcium chloride dihydrate and calcium lactate pentahydrate were each added at 0, 1500 and 300 ppm Ca++ (w/v) in water. Citric acid was added at levels of 0.00, 0.25 and 0.50% (w/v) in water. Thermal processing was conducted at a local blueberry processing plant using standard industry practices. Physical and chemical analysis of the samples were conducted after 0, 6 and 12 months of storage at 20±2°C. Fruit drain weights, pH, instrumental texture and Hunter L, a, and b values were determined. Sensory analysis of the samples were conducted by a semi-trained 12 member panel after 3 and 9 months of storage at 20±2°C. Panelists evaluated the fruit for appearance, color, mouthfeel and off-flavor.
Response surface methodology analysis of the data generated in this experiment predicts an optimization region of 1000 to 3000 ppm calcium lactate in combination with 0.00 - 0.50% citric acid will produce canned blueberries with improved color and texture as compared to control (water canned) blueberries. Further research should be conducted to verify the results of these predicted optimization treatments.
Advisory Committee
Mary Ellen Camire, Associate Professor of Food Science, Thesis Advisor
Alfred A. Bushway, Professor of Food Science
William Halteman, Associate Professor of Mathematics
Jui-Lien Hsu
Master of Science in Food Science & Human Nutrition--May 1995
The behavior of two strains of Listeria monocytogenes were evaluated in different stages of salmon production. At lower temperatures (#11°C), L. monocytogenes could survive on dry wood surface for at least 3 days without added nutrients, but was unrecoverable within 2 days at room temperature. The moisture or minimal nutrients on wood surface could prevent the loss of viability of L. monocytogenes at all incubation temperatures. When large amounts of nutrients were provided, the recoveries of L. monocytogenes at lower temperatures (#11°C) were essentially unchanged over the 72-hour holding period; however, rapid growth was observed at room temperature.
In the presence of natural microflora, L. monocytogenes in sea water died off rapidly within 36 hours at room temperature. When held at #11°C, L. monocytogenes lost viability throughout storage, but was still detectable after more than 6 days of incubation. In the absence of natural microflora, both strains of L. monocytogenes were static over the holding period at all temperatures.
At lower incubation temperatures (#11°C), L. monocytogenes in non-sterile blood-water remained viable, even after 156 hours of incubation; while in sterile blood-water, growth of L. monocytogenes was observed at 7°C and 11°C. In the absence of natural microflora, L. monocytogenes showed more apparent growth than in the presence of natural microflora. In addition, L. monocytogenes 147 was more competitive with background organisms than L. monocytogenes ATCC 19111.
No L. monocytogenes could be detected in the digestive tract of salmon after 3 days of its introduction. The survival pattern of L. monocytogenes in fish digestive tract was similar, regardless whether that the fish were feeding or not. Obvious declines of the pathogen was observed as early as 3 hours of inoculation.
Advisory Committee
Bohdan M. Slabyj, Professor of Food Science, Thesis Advisor
Alfred A. Bushway, Professor of Food Science
Hsiang-Tai Cheng, Associate Professor of Resource Economics and Policy and Cooperating
Associate Professor of Food Science and Human Nutrition
Susan S. Stephenson
Master of Science in Food Science & Human Nutrition--August 1995
The goal was to monitor cardiovascular nutrition knowledge and self-perceived food practices during a year-long field test of a curriculum based on the Activated Health Education model. The study design was pre-, post I-, post II- assessments in treatment and control schools. Treatment adolescents (n=139; mean age 15±0.7) participated in a two and one-half week intensive intervention and four monthly follow-up sessions delivered in health classes by workshop-trained high school educators. Control adolescents (n=112; mean age 16±1.0) received no intervention. Assessments included a 30-item multiple choice questionnaire (Cardiovascular Nutrition Knowledge Questionnaire) and a 12-item Likert scale (Self-Perceived Food Practices Questionnaire) to assess perception of adherence to recommended food practices (pre-assessment =.69 and -.76, respectively). At pre-assessment, cardiovascular nutrition knowledge was low, 60% and 57% correct for control and treatment groups, respectively. Treatment females scored higher (p=0.03) than males. In assessing change in knowledge at pre, post I, and post II-assessments, there was a significant group by time interaction between control and treatment groups (p=0.000) and between control and treatment males (p=0.02) and control and treatment females (p=0.002) due to the decrease in knowledge that occurred within the control group. The increase (p=0.000) in knowledge for control girls at post I-assessment was not maintained (p=0.000) at Post II-assessment. Treatment females increased (p=0.000) knowledge at post I-assessment and maintained (p=0.000) that level at post II. At pre-assessment, the control group reported better (p=0.001) food practices than the treatment group; control females reported better (p=0.02) practices than control males. Based on mean scores, both control and treatment groups perceived that it was sometimes to almost true that they ate according to recommended food practices. In assessing changes in self-perceived food practices over time, no changes within groups was noted. The control group had significantly (p=0.000) better food practices than the treatment group. While there was no difference in food practices of control and treatment males, control females had significantly (p=0.000) better self-perceived food practices than treatment females. The need continues for school-based interventions that emphasize personalization and perceived benefit of making heart-healthy food choices to reduce cardiovascular disease risk of adolescents.
Advisory Committee
Adrienne A. White, Associate Professor of Human Nutrition & Foods, Thesis Advisor
Dorothy J. Klimis-Tavantzis, Associate Professor of Clinical Nutrition
Richard A. Cook, Associate Professor of Human Nutrition
Annie E. S. Hager
Master of Science--August 1995
Predictions of the effects of climate change on forest ecosystems are often based on the predictions of computer models, which are in turn based on assumptions about forest ecosystem processes. One of the assumptions commonly employed by "gap" models is that the effect of temperature on tree growth can be represented as a parabolic curve relating heat sum during the growing season to radial growth of individual trees.
In order to test the validity of the gap models' assumption of temperature effects on tree growth, I collected tree-cores from several stands of pitch pine (Pinus rigida) in New England and New York. I examined the relationship between radial growth of pitch pine and climate in two different ways: first, I used the standard dendroclimatological technique of the response function to correlate radial growth to monthly average temperature and monthly total precipitation over the period 1935-1992 for four sites. Second, I compared average radial growth to growing season temperature sum (DEGD) at six sites.
Neither monthly average temperature and monthly total precipitation nor DEGD were strong, consistent predictors of radial growth. Radial growth of the Long Island stand showed significant positive responses to February temperature and June precipitation in the year of growth. None of the other three sites analyzed showed any significant response to monthly temperature or precipitation. Two sites from Massachusetts showed a positive correlation between DEGD and radial growth, two sites from Maine showed a negative correlation, and sites from Albany and Long Island, New York both showed no significant correlation.
While it is still unclear how climate influences yearly ring-width patterns in pitch pine, it appears from this study that the assumption made by gap models, that temperature has a predictable, parabolically shaped effect on annual radial growth, is inaccurate for this species.
Advisory Committee
Alan S. White, Associate Professor of Forest Resources, Advisor
Robert Seymour, Curtis Hutchins Associate Professor of Forest Resources
George Jacobson, Director, Institute for Quaternary Studies and Professor of Botany and
Quaternary Studies
Djoko Iriantono
Master of Science--December 1995
A progeny test of black spruce from throughout Maine has been established for 13 years. In this study, the height growth of these trees was analyzed to estimate heritability and expected gain, to detect genotype x environment (GE) interaction significance, to examine age-age correlation effects, and to identify parent-tree class and parental stand effects. In addition to height growth, cone yield and seed viability of these 13-year-old black spruce were examined in this study.
The heritability and expected gain may be higher than expected. Individual and family heritability are 0.20±0.02 and 0.55±0.21, respectively. These fairly high heritability estimates resulted after eliminating interactive families detected from the examination of GE interaction. As a result of this high heritability, 0.67_2.67% of additional expected gain may be obtained by applying a given selection strategy.
Examination of age-age correlation indicates that selection at a young age may not be effective in identifying genotypes for height growth. The significant parent-tree class and parental stand effects coupled with environment effects during 13 years may account for low juvenile-mature correlation.
Another finding of this study is that selection for height growth tends to also select genotypes superior in cone yield. These selected genotypes also bear seeds with a fairly high germination percentage (ranging from 77 to 80% for the top 4 selected families).
These findings are valuable for tree breeders and forest managers. The tree breeders can use the genetically improved materials for advanced generations, while the managers can use seeds from the genetically selected trees for reforestation activities.
Advisory Committee
Katherine K. Carter, Associate Professor of Forest Resources, Advisor
William D. Ostrofsky, Associate Research Professor and Cooperating Associate Professor,
Forest Ecosystem Science: CFRU Leader
John M. Smagula, Professor of Horticulture
Christina L. Malitz
Master of Science--August 1995
Maine's papermill and electricity generating facilities generate 1.2 million tons of processing residues a year. The by-products generated are frequently treated as municipal waste and landfilled. A study was initiated in 1992 to determine the biological effects of papermill sludge ash and wood ash application to forest land in western Maine. Four treatment amounts of papermill sludge ash- 0, 3, 6, and 9 tons/acre CaCO3 equivalent, and four treatment amounts of wood ash- 0, 3, 6, and 9 tons/acre CaCO3 equivalent were each applied to 24 plots in a newly established red pine (Pinus resinosa Ait.) plantation. The red pine study trees were measured for total tree height and rot collar diameter at the time of application, one and two years after residues were applied. The amount of competing vegetation was measured by taking above ground biomass samples within two 1/4 milacre plots within each treatment plot, and element concentration status of the predominant vegetation, Rubus spp., was obtained.
Statistical analysis (P<0.05) revealed no significant growth differences of red pine in plots treated with wood ash from those treated with sludge ash. Red pine trees in plots treated with sludge ash showed a significantly greater difference (height and diameter) from those in control plots at the highest application rate. While trees in plots treated with wood ash also had a significantly greater height at higher application rates than those in control plots, they (red pines) did not have significantly different diameters. Red pine trees in non treated- non brush sawed plots had a significantly greater height and a significantly lower diameter than red pine trees in brush sawed control plots.
Raspberry, which is the major competition in the study site, had a higher above-ground biomass in treated plots than in control plots using sludge ash. Although there was an increase, it was not significantly different (P<0.05) than what was found in control plots. Plots amended with wood ash however, showed a statistically greater amount of raspberry biomass from control at all levels of application.
Analysis of raspberry foliage revealed no significant change in elemental status at any level of sludge ash application. Wood ash amended plots showed significantly lower levels of Mn and Al concentrations (P<0.05), and increased levels of B, K and P at higher application rates than control plots.
Advisory Committee
William D. Ostrofsky, Associate Research Professor, Advisor
Katherine K. Carter, Associate Professor of Forest Resources
Robert K. Shepard, Professor of Forest Resources
Ronald Frank Smith
Doctor of Philosophy--December 1995
Field and greenhouse trials were established to determine the effects of stem injections of gibberellins A4 and A7 (GA) on the numbers of and within-crown distribution of see- and pollen-cones in black spruce (Picea mariana (Mill.) B.S.P.). Injecting GA increased the proportions of buds above the injection-point that developed reproductively. Combining GA with root pruning (RP) produced a greater increase in reproductive bud production than either treatment alone, but the complementary effect was less during the warm, dry summer in 1991 than during the we summer in 1992. In the greenhouse, drought or root pruning were required for GA to induce cones.
A second objective of this study was to test the hypothesis that RP reduces cytokinin export from the roots, thereby decreasing rates of cell division within developing buds and increasing their receptivity to GA. Injecting cytokinin reduced the stimulatory effects of GA and RP, the degree of reduction varying with the amount and timing of cytokinin application. Effects of treatments on bud apex development varied with bud position along the shoot. Mitotic index (MI) of proximal, distal, and terminal apices were unaffected by treatments. Conversely, medial apices from RP-trees, those most likely to differentiate reproductively, were smaller but exhibited only subtle differences in histochemistry from those from the controls and other treatments. Although RP reduced MI of medial apices, the effect was not statistically significant. The MI of medial apices from fecund trees was significantly lower during the slow growth phase of shoot elongation and higher at the time of bud differentiation, than those from poor cone producers.
The third objective of this study was to determine the effects of cone-induction treatments on current-year needle morphology, photosynthetic capacity, and gas-exchange properties. Drought increased pre-dawn shoot water potential (PMS), during the period that irrigation was withheld, but had no persistent effect on current-year needle development or rates of gas exchange. Conversely, RP did not affect PMS but significantly reduced current-year needle growth, nitrogen and chlorophyll contents, and rates of gas exchange. The potential implications of these results for cone development are discussed.
Advisory Committee
Michael S. Greenwood, Ruth Hutchins Professor of Tree Physiology, Advisor
Katherine K. Carter, Associate Professor of Forest Resources
Ian R. Davison, Associate Professor of Plant Biology
Ivan J. Fernandez, Associate Professor of Forest Soils
Graham R. Powell, Professor of Tree Biology, University of New Brunswick
Sayeed R. Mehmood
Master of Science--December 1995
Forest resources play a crucial role in Maine's economy. Maine is the most heavily forested state in the U.S. It is also one of the two top paper producing states. Industries in an economic system are linked through inter-industry transactions. A "shock" in any of the industries thus affects the whole economic system. Due to its importance in the Maine economy, changes in the forestry sector results in effects felt throughout the system. One of the few unique natures of forestry investment is that the returns come well into the future. This makes forest policy analysis an extremely complex issue. Simulation programs provide an efficient means of analyzing the impacts of policy decisions.
This study attempts to adopt the Interactive Policy Analysis Simulation System (IPASS) model for Maine. As most of the simulation models based on the input-output theory, this study also required the collection of extensive secondary data from different state and federal agencies. Analysis of the data revealed that the forestry sector provides 5 percent of the total state employment, 10 percent of the employee earnings and about 30 percent of the state's total exports. A database was then built for the Maine IPASS model. From the baseline analysis, IPASS was found to be inappropriate for long-term forecasts. Impacts of five scenarios prescribing varying levels of timber harvesting for a six-year period were then investigated. The analysis showed that changes in the forestry sector would have substantial effects on industries like manufacturing, wholesale trade, finance, services, and education. IPASS provided specific impacts in terms of losses or gains in employment and earnings in major Maine sectors.
Advisory Committee
David B. Field
Thomas J. Corcoran
Robert W. Rice
Gary L. Hunt
Laurence Mott
Doctor of Philosophy--August 1995
The macromechanical properties of single wood pulp fibers are well documented. Traditional microscopic observation of fiber tensile tests have established relationships between the morphology of the secondary cell wall and fiber ultimate tensile stress, modulus and strength. The contribution of defects to morphology property relationships is less well understood. While it has been established that fibers of identical S2 layer microfibril angle are subject to mechanical variability due to the presence of cell wall defects, the impact of defect types is not documented and fundamental data regarding damage tolerance and fracture mechanisms of the fiber cell wall is severely lacking.
Mechanical models often treat collapsed single fibers as orthotropic laminates. Stress and strain distributions throughout the fiber structure are handled accordingly in this simplified manner because of the technical difficulties associated with measuring single fiber geometries and the micromechanical properties of the cell wall itself. In order to better understand the impacts of fiber processing and associated induced defects, it is necessary to be able to quantify stress and strain distributions in single fibers. In this fashion the contribution of fiber geometry and defects to single fiber macromechanical properties may be better understood.
This study empirically quantified microstrain distributions in highly localized regions of the fiber structure for the first time. Mature black spruce (picea mariana) latewood fibers from a single growth ring were kraft pulped and then individually prepared for a tensile testing technique that employed a free fiber alignment mechanism. The tensile testing assembly was used to quantify both macromechanical properties (load, elongation and slope) and micromechanical strain distributions. Microstrains were measured by observing fiber tensile tests using an environmental scanning electron microscope (ESEM). Successive images of the straining fiber at approximately 2500x magnification were captured digitally and subject to a digital image correlation technique employing a Powell maximization routine. Fiber surface displacements were measurable to within 0.008 µm (0.1 pixel). Full-field displacement measurements were then converted to strain distribution maps. By this method it was possible to quantify strain distributions surrounding bordered pits, cell wall creases and microcompressions in visibly defect-free cell wall.
Advisory Committee
Stephen M. Shaler
Leslie H. Groom
Robert W. Rice
Pierre F Lepoutre
Barry S. Goodell
Ridzuan Ramli
Master of Science--August 1995
MDF from Empty Fruit Bunches (EFB) of Elaies guenensis were produced experimentally and the effect of pretreatment (hot water and 2% sodium hydroxide) and resin content (4% and 6%) on the quality of boards were investigated. Thermo-mechanical pulp (TMP) from the EFB was produced on a single disk refiner from which panels were pressed under a constant temperature and pressure. Samples from each panel were tested for modulus of rupture (MOR), modulus of elasticity (MOE), tensile strength perpendicular to surface (internal bond), linear expansion (LE), water absorption (WA) and thickness swelling (TS) at 2 and 24 hours, according to ASTM D-1037-89. Hot water extraction of the fibers resulted in panels with significantly (5% significance level) better properties. All properties were significantly improved at the higher resin levels.
Commercial and laboratory produced MDF were analyzed for the ratio of interfiber void within the panels using image analysis techniques. The interfiber void was determined using microtome sections and a light microscope interfaced with an image analysis system. Based on sequentially acquired 2-D images, 3-D models of the panel microstructure were constructed. The ratio of void area between layers (top and middle) parallel to the surface of panels was significantly different. The effect of layer orientation (sections perpendicular to the surfaces) on void ratio was not significantly different between the edges of the panels. The ratio of void area within the panels was negatively related to density.
Advisory Committee Stephen M. Shaler
Robert W. Rice
Richard Jagels
Yanrou Han
Doctor of Philosophy--August 1995
The study had two major objectives. One objective was to assess soil drainage class, individual tree, and position within tree effects on physical and mechanical properties. The other objective was to examine the relationships of specific gravity, MOR and MOE to age and how the relationships were affected by soil drainage class, individual tree and position within tree. The emphasis was on red maple (Acer rubrum L.), but sugar maple (Acer saccharum Marsh.) was also included in the study.
In the first objective, 15 dominant red maple were selected from a red maple-sugar maple stand that extends across a range of drainage classes. Eight trees were taken from a well-drained site and seven from a poorly drained site. Bolts were taken at three bole positions (lower, middle, upper) from each tree. In addition, seven dominant sugar maple were selected from the well-drained site. However, a bolt was taken only from the lower portion of each bole. Specimens from each bolt were cut and tested according to ASTM Standard D143-83 and data were collected on the following properties: specific gravity, radial shrinkage, tangential shrinkage, compression parallel to the grain, shear, side hardness and end hardness. Bending specimens, 1x1x16 in., were cut from the lower bolt of red maple trees from the well-drained site. The data were analyzed using a general linear model and regression procedures.
In the second objective, microbending specimens, extending from pith to bark along two opposite radii, were cut from each bolt. Part B included six additional trees from the well-drained site, making a total of 14 trees for that site. Specific gravity, MOR and MOE were determined for each specimen. Segmented regression was used to estimate the transition age from juvenile wood to mature wood for each property. A general linear model was used to test for effects of site, tree, position within tree and age.
Site, tree, position, the interaction of site and position, and the interaction of tree and position had significant (P < 0.05) effects on the physical and mechanical properties of red maple, except for the position and the site-position interaction effects on the tangential shrinkage. All the physical and mechanical properties of red maple on the wet site were larger than those on the dry site, except for the tangential shrinkage. As compared with the book values, the results of the physical and mechanical properties of red maple on both sites are larger than those values published in ASTM 2555 and Wood Handbook. The physical and mechanical properties of sugar maple statistically larger than those of red maple.
Age, site, tree, position, and site and position interaction, and the position and tree interaction significantly affected specific gravity, MOE and MOR in the juvenile zone. Age did not significantly affect specific gravity, MOE and MOR in the mature zone, but the effects of site, tree, and interaction of tree and position, and the interaction of position and tree were significant. Red maple has an increase in specific gravity, MOE and MOR from the pith outward, followed by a leveling off. In the mature zone, specific gravity, MOE and MOR of red maple on the wet site were larger than on the dry site. There were variations among and within trees. The average percentage increase for MOE and MOR of red maple from juvenile wood to mature wood was from 11 to 40. Specific gravity of red maple on both sites increased relatively less than MOR and MOE. Trends of microbending properties of specific gravity, MOE and MOR for sugar maple at the bottom bole position were less pronounced than those of red maple. Sugar maple had higher specific gravity, MOE and MOR than red maple.
Advisory Committee
Robert K. Shepard
Robert W. Rice
Stephen M. Shaler
Christopher W. Murdoch
William D. Ostrofsky
M. Kristina McLean
Master of Science/ARE (Resource Utilization)--May 1995
The Caribou-Speckled Mountain Wilderness (CSMW), is the only official wilderness in Maine managed by the U.S. Forest Service. It was designated as official wilderness by congress in September 1990. Following this designation, The U.S. Forest Service commissioned a project with the University of Maine to study the use and users of this newly-designated wilderness.
The goals of this thesis are to describe the current users and typical uses of the CSMW, their expectations, perception, and attitudes, and compare them to the users of other wilderness areas.
The physical characteristics of the CSMW are reflected in its use and user characteristics. Most trips to the CSMW lasted for less than five hours and included several encounters with other visiting groups, unlike the typical visit described at most other wilderness areas. Although experiencing high encounter levels for a typical wilderness visit, the visitors did not allow this characteristic of the CSMW affect their quality rating of the wilderness. Respondents were also highly educated and earned higher than average incomes, which is characteristic of wilderness users. General comparisons could be made between the CSMW and other wildernesses, but statistical analysis could not be accomplished. Preferences and expectations of the users of the CSMW were not necessarily consistent with wilderness management ideals as established in the Wilderness Act.
Advisory Committee
Stephen D. Reiling, (Chair) Professor, Resource Economics & Policy
Joanne Tynon, Assistant Professor, Forest Resources
Hsiang-tai Cheng, Associate Professor, Resource Economics & Policy
Holly L. James
Master of Science/ARE--August 1995
Cultural eutrophication diminishes the recreational and aesthetic benefits of lakes. To protect and improve the quality of Maine's lakes, the Maine Department of Environmental Protection sets lake-protection policies and undertakes lake-reclamation projects, but without economic information. Information about the economic effects of lake water quality protection would be useful to lake managers in evaluating policies and developing public education programs. The first thesis objective is to use a hedonic property value model to determine if lake water clarity significantly influences property values and drive implicit prices for changes in water clarity. The second thesis objective is to explore the effect of different measures of water clarity on estimated implicit prices.
The study includes 34 Maine lakes, selected in six separate market groups, exhibiting varying levels of water clarity. Property sales occurring between 1990 and 1994 were used in the hedonic model. Consumers perceptions of water clarity were ascertained through a telephone survey of property purchasers. Results show that water clarity significantly impacts lake-front property values, with a one meter improvement in water clarity producing improved property values ranging from $17 to $66 per foot frontage, depending on the market group. Results from the telephone survey and hedonic estimation indicate that lake-front property purchases consider both the current and the historical trend in water clarity when making their purchase decision. Therefore, both of these variables need to be included in the equation to produce unbiased estimates of the coefficient on current water clarity, the policy variable.
Advisory Committee
Kevin J. Boyle, (Chair), Associate Professor, of Resource Economics & Policy, Chair
Hsiang-tai Cheng, Associate Professor, Resource Economics & Policy
Stephen D. Reiling, Professor, Resource Economics & Policy
Craig F. Thomas
Master of Science/ARE--May 1995
Small specialty food processors (SFPs) in Maine/New England find their growth constrained. Inability to penetrate markets is a major problem in this industry. small food processors are also unable to enjoy the economies of scale that larger competitors enjoy. Simply speaking, small specialty food processors lack the capital to expand their capabilities. Compounding this, they lack the distribution channels to expand their customer base and revenue. Barring aid from state government, how do small specialty food processors break out of their confining niche?
Estimates of employment levels in Maine's food processing industry in 1995 is 5,900 people (Irland Group 1988). The SFP's are a subset of this group. This number is alarmingly small when compared to employment levels in past years. In the last 45 years, Maine has averaged losses of 302 food processing jobs a year (Irland Group 1988). Most of these job losses occurred during the decline of the poultry industry between 1972 and 1985 (Irland Group 1988:21). Despite heavy job losses, all may not be lost for Maine's SFP sector. Over a quarter of the food processing firms still in existence are small family businesses (SFP's). "There is potential for this microbusiness sector to stabilize part-time and seasonal employment patterns, which are characteristic of parts of the food processing sector in Maine" (Irland Group 1988:22). If in fact Maine has lost its competitive advantage among the nation's larger food processors, perhaps Maine's small processors can still build and maintain competitive advantages in the high-quality specialty foods market. Niche processing may compliment Maine's high-quality, high-value specialty crops such as wild blueberries, seafood, potatoes, and dairy.
This research examines the applicability of strategic alliances, or "networks", among specialty food processors and other compatible firms. These alliances, with large or small firms, could allow SFPs to improve their competitiveness without large, risky capital outlays.
Advisory Committee
Dennis Watkins, (Chair), Professor of Community Development
Alan S. Kezis, Professor, Resource Economics & Policy
James A. Wilson, Professor, Resource Economics & Policy
Kellee G. Livingston
Master of Science/ARE--August 1995
After World War II agricultural production shifted to farming methods based on advancing agricultural technologies. These technologies included increasing use of chemical fertilizers and pesticides to increase agricultural yields. While these technologies increased yields, they also had externality effects such as soil erosion, air, and water pollution. As farmers become aware of problems with conventional farming methods, interest in alternative farming methods has grown. Sustainable farming methods such as biological and organic farming offer alternatives to conventional farming methods by reducing the amount of chemical inputs used in agricultural production.
The issue of farming methods is of particular importance to the Maine potato industry. Over the last forty years Maine potato farmers have seen declines in potato production and decreasing profits. Production declines coupled with increased interest in sustainable farming methods present a challenge to the Maine potato industry. Maine potato farmers are faced with the challenge of finding sustainable methods of farming that reduce chemical inputs and externalities, and therefore the costs of production, while maintaining the high yields associated with conventional farming methods.
This research develops production functions for three methods of potato production in Maine: conventional, reduced inputs and biological pest control. These functions are helpful in identifying inefficiencies in the production of Maine potatoes that may be contributing to the decline in potato production. They can be used by economists, scientists, and policy makers to aid the Maine potato farmer. The results suggest that conventional farming over uses chemical inputs. If farmers reduce conventional inputs, farmers can reduce costs while maintaining yields comparable with conventional methods. Further research should be conducted on sustainable farming methods with use of field rather than experimental station data.
Advisory Committee
George K. Criner, (Chair), Associate Professor, Resource Economics & Policy
Michelle Marra, Associate Professor, Resource Economics and Policy
Hsiang-tai Cheng, Associate Professor, Resource Economics & Policy
Alan S. Kezis, Professor, Resource Economics & Policy
Emy E. Suwarni
Master of Science in Wildlife Ecology--May 1995
There are three conservation management systems in Indonesia, Strict Nature Reserves, Wildlife Sanctuaries, and National Parks. I examined the management practices, administrative structures, approaches, and objectives at a representative site for each management system and assessed the obstacles to meeting the objectives. I then evaluated the relative effect these obstacles have on management for each area.
Obstacles to meeting the management objectives in Strict Nature Reserves are: a) little public support because local people do not receive direct benefits from protected areas, b) the Rangers are bored because they are given no direction for management related work, c) funds are limited for inventory and monitoring activities, d) little attention is given to planning, and e) limited transportation support for the Rangers.
In wildlife sanctuaries the high floral and faunal diversity creates conflict between recreation and conservation objectives. Further, lack of local government involvement results in conflict between the sanctuary manager carrying out management objectives and local interests. In national parks obstacles include the different perceptions of the purpose of the park (local government wants to develop recreation activities, whereas the Park Services restricts human activities), and inadequate skills and knowledge of the Rangers required to adequately do their job.
Overcoming some obstacles in meeting the management objectives of all three protected areas can be achieved by similar methods such as improving the socio-economics of local communities by assisting in the establishment of home industries, or constructing irrigation systems for agriculture and fishery, maintaining good communication between protected area officials and local government, and improving the skills and capabilities of the Rangers.
Overall, this study indicates there are three priorities that ought to be considered and implemented to achieve better management of protected areas: 1) local community understanding, communication, and involvement, 2) baseline natural resources inventories, and 3) strengthening of protected area personnel capacities.
Advisory Committee James A. Sherburne, Director, Office of International
Programs and Professor of Wildlife Ecology, Chairperson
Daniel J. Harrison, Associate Professor of Wildlife
Joanne F. Tynon, Assistant Professor of Forest Resources
Theodore D. Chapin
Master of Science in Wildlife Ecology--August 1995
American marten (Martes americana) are generally considered an associate of mature forests and their populations are susceptible to over-harvesting and habitat loss. Despite the potential for clearcutting to fragment habitat of area-sensitive, forest-dependent species such as marten, few studies have evaluated the influence of landscape pattern on use of habitat and spatial distribution of marten in areas with extensive timber harvesting. Thus, I examined relationships among measures of landscape pattern and spatial use of habitat by 33 (17 male and 16 female) resident and 32 (17 male and 15 female) non-resident adult (>1 year) marten in an extensively logged landscape.
Area of forest stands (>6 m in height) used by resident marten (median = 27 ha, n = 12) was greater (P < 0.003) than stands that contained no locations (median = 1.5 ha, n = 128); no stands <2.7 ha (n = 88) contained locations (n = 1,188) of residents. Further, stands used by residents were closer to the nearest stand larger than 2.7 ha (i.e., the smallest stand that contained locations; P = 0.057) and to a large (637 km2) forest preserve (P = 0.075) than stands that contained no locations. However, there was no difference in distance to nearest stand of any size (P = 0.219) between stands used by residents and stands containing no locations. I also examined the potential influence of landscape pattern on spatial use of habitat by marten at 4 spatial scales ranging from 10 to 250 ha. At all 4 spatial scales, grid cells that contained locations of resident marten had a higher percent forest >6 m in height (P < 0.008) and intersected stands of greater area (P < 0.006) than cells containing no locations. At cell sizes of 125 ha and 250 ha, used cells intersected fewer residual stands (P < 0.024). Analyses for non-residents revealed similar effects of stand area and isolation, despite that non-residents exhibited greater variability of stand use. Home ranges (n = 27) of all resident adult marten were composed of >60% forest cover >6 m in height. Shape indices were not different (P > 0.490) between used cells and cells containing no locations. Marten used forest types within their home ranges irrespective of forest edges. Although distance between marten locations and forest edge were significantly different (P = 0.049) from expected, expected distances exceeded observed distances by only 10 m. The median size of the largest forest stand in marten home ranges was 1.5 km2 for females and 2.5 km2 for males; thus, contiguous forest patches of 1.5-2.5 km2 may be necessary to maintain resident marten in logged landscapes. My results concur with companion studies that concluded marten select habitat at a landscape scale, and indicate that landscapes characterized by few, large residual forest stands close in proximity received greater occupancy by resident marten than areas with small isolated stands. Thus, forest planning aimed at reducing fragmentation via retaining large residual stands may help to maintain resident adult marten in extensively logged landscapes.
Although marten have been consistently associated with mature conifer-dominated forests, evidence exists that suggests complex vertical and horizontal woody structure are important habitat components. Further, because of the combined effects of trapping and timber harvesting on marten populations, information about marten habitat associations in an untrapped, unlogged landscape is needed as a baseline for comparisons with trapped, timber-harvested landscapes. Therefore, I investigated seasonal habitat selection of 38 (20 male and 18 female) marten in the absence of trapping and timber harvesting, in Baxter State Park, Maine.
During summer (1 May-31 October), marten used forest types disproportionate to availability within their home ranges (P = 0.030). Stands with substantial spruce-budworm (Choristoneura fumiferana) mortality (<50% overstory canopy closure) had the highest selection index during summer, which was significantly higher (P = 0.003, pairwise rejection level = 0.008) than the mature (>12 m in height), well-stocked (>50% canopy closure) mixed forest type. No significant differences in selection index were detected among mature well-stocked coniferous, deciduous, or mixed forest types. During winter (1 November-30 April), marten used forest types proportionate to availability within home ranges (n = 7 males, 1 female). My results suggest that marten do not require dense or coniferous canopy cover and are consistent with the hypothesis that vertical and horizontal structural complexity may be a more important habitat component than species composition of the forest overstory. Thus, post-harvest techniques, such as on-site delimbing and slash management, may enhance the quality of regenerating forest stands for marten habitat. Further research examining the separate effects of trapping and timber harvesting would provide valuable information about marten habitat requirements and assist in managing the species in trapped, timber-harvested landscapes.
Advisory Committee
D. J. Harrison, Associate Professor of Wildlife Ecology, Chairperson
William B. Krohn, Leader, Maine Cooperative Fish and Wildlife Research Unit and Professor,
Wildlife Ecology and Zoology
Steven A. Sader, Professor of Forest Resources and Forest Engineering
Kenneth D. Elowe, Director, Wildlife Division, Maine Department of Inland Fisheries and
Wildlife
Robert A. Long
Master of Science in Wildlife Ecology--August 1995
White-tailed deer (Odocoileus virginianus) lack intrinsic mechanisms to maintain populations below K-carrying capacity. Thus, deer populations on a large island where most predators have been extirpated and hunting is prohibited should be limited by food resources. This is not the case on Mount Desert Island (MDI), Maine, where the deer population is stable or declining and is below forage carrying capacity. Studies elsewhere have suggested that low recruitment, associated with high mortality rates of fawns, may contribute to declines in deer populations. Thus, we monitored cause-specific mortality of fawns (n = 29) from birth to 1 year of age during 1991-95.
Annual rate of fawn survival was 0.26. Rate of predator-caused mortality was 0.52, with coyote (Canis latrans) predation (n = 8) accounting for at least 47% of mortalities from all causes (n = 17). Mortality rate from drowning was 0.24 (n = 3), and mortality rate associated with deaths from vehicles was 0.14 (n = 3). An index to home-range (MINDIST) was not different between a sample of fawns that died prior to 60 days of age (n = 6) and fawns that survived (n = 12). Of fawns radio-collared as neonates, 10 of 14 mortalities occurred during the first 2 months of life. Survival rate from 6 months to 1 year was 0.65; 4 mortalities (2 predation, 2 drowning) were observed during this interval. A subgroup of fawns (n = 11) captured near the Sand Beach area had a higher rate of survival to 1 year of age (S = 0.67) than did fawns from all other areas (n = 18, S = 0.00). Recruitment to 1 year of age was lower than has been observed in other northeastern deer populations. Low recruitment associated with multiple causes of fawn mortality may be limiting deer populations in some areas on MDI; however, differential rates of fawn survival throughout MDI may explain an apparent patchy distribution of deer.
The relative consumption of deer and alternate prey species by coyotes may relate to their social organization on MDI. Coyotes across North America exhibit a wide range of group sizes, from a single pair, to extended family groups (packs). The tendency for coyotes to form packs has been linked to the proportion of large prey (typically ungulates) in their diet; however, it is not known whether prey size influences group size, or whether other ecological factors (e.g., lack of exploitation, saturation of territories) cause formation of social groups that subsequently consume larger prey. Coyotes on MDI exhibit pack behavior and consume more deer, and fewer snowshoe hare (Lepus americanus), than was reported for a population on the adjacent mainland, where coyotes did not form packs. Therefore, I compared the relative density of snowshoe hare between MDI and the mainland using an index to hare abundance. Lower densities of hare on MDI would suggest that coyotes on MDI forage opportunistically (i.e., they consume relatively more deer because hare densities are low), and would support the hypothesis that coyotes form packs to increase their foraging efficiency on large prey. In contrast, higher hare densities on MDI would suggest that coyotes do not necessarily need to consume deer, and may be forming packs for reasons other than increasing foraging efficiency on deer.
Density of snowshoe hare, hare fecal pellet density, and understory stem density have been shown to be related in Maine. I counted understory stems on 46 transects on MDI and used the relationship between stem cover units [SCU = understory deciduous stems + (3 x understory coniferous stems)] and hare pellets, in addition to information on the distribution of SCU's throughout MDI, to estimate a median pellet density of 2076 pellets/ha/4 months on MDI. This value corresponded with an estimated hare density of 0.060 hare/ha. On the mainland study site median pellet density was estimated as 1103 pellets/ha/4 months, which corresponded with an estimated hare density of 0.032 hare/ha. Mean pellet density, and therefore hare density, was significantly higher on MDI (1.9 fold) than on the mainland. Coyotes, therefore, may be forming groups on MDI for reasons unrelated to snowshoe hare density or acquisition. This finding supports the hypothesis that coyotes on MDI may exhibit group formation because of territory saturation and reduced dispersal opportunities, but is not consistent with the hypothesis that group formation has developed because of a need to increase foraging efficiency on deer.
Advisory Committee
Daniel J. Harrison, Associate Professor of Wildlife Ecology, Co-Chairperson
Allan F. O'Connell, Jr., Faculty Associate in Wildlife Ecology, Co-Chairperson
James R. Gilbert, Professor of Wildlife Ecology
Alan S. White, Associate Professor of Forest Resources
Siti Kaniawati
Master of Science in Wildlife Ecology--August 1995
Great Smoky Mountains and Yosemite are two American national parks which have problems due to bear-human interactions. These parks report many human injuries and property damage due to these interactions. Thus, these parks have prepared bear management plans to minimize conflicts for human safety and to maintain natural environment for bears. Bear management in these parks is examined for application to reduce negative interactions between komodo dragons and humans in Komodo National Park, Indonesia.
Komodo dragon (Varanus komodoensis) is a prehistoric-like reptile which is surviving in Indonesia. It is endemic to Indonesia and becoming tourist attraction, especially for foreigners. To make it easier for visitors to observe komodo dragons, a feeding program was provided (Cohn 1994) but was terminated in 1994 (Marhadi 1994, pers. comm.) Mulyana and Ridwan (1992) believe that the feeding program was the most significant reason for the alteration of komodo dragon behavior. As a result, many komodo dragons became dependent on unnatural food. In addition, the presence of humans living within the park has also helped to alter komodo dragon behavior as they became accustomed to the presence of humans. On occasion, komodo dragon-human interactions have resulted in injuries even human deaths. To reduce these negative interactions, Komodo National Park management has prepared a komodo dragon management plan. Fencing of the area previously used as a feeding site, strict regulations for visitors and inholders, providing alternative nature-related recreation sites, and intensive extension and education programs, have been initiated by Komodo National Park management.
Komodo dragon management has to be a high priority in Komodo National Park. Continuing management efforts in Komodo National Park: maintaining alternative recreation sites, providing equipment to move the nuisance komodo dragons, strict regulation of garbage dumping and burning, are recommended to do to reduce interactions between humans and komodo dragons and to assure human safety in Komodo National Park. Further studies of komodo dragon ecology and visitor behavior are needed to support komodo dragon management and other natural resources in Komodo National Park. Meanwhile, extension and education programs must continue to increase human awareness on conservation and natural resource issues.
Advisory Committee
Allan F. O'Connell, Jr., Faculty Associate in Wildlife Ecology, Co-Chairperson
James R. Gilbert, Professor of Wildlife Ecology, Co-Chairperson
James A. Sherburne, Director, Office of International Programs and Professor of Wildlife
Ecology
Floyd L. Newby, Associate Professor of Forest Resources and Program Leader, Parks and
Recreation