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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

EFFICACY OF DORMANT SEASON HERBICIDE APPLICATION ON CONTROL OF JAPANESE HONEYSUCKLE (<em>LONICERA JAPONICA</em>) FOR HABITAT RESTORATION IN KENTUCKY

Weese, Jason L. 01 January 2015 (has links)
Kentucky’s disappearing native grassland communities provide habitat for native flora and fauna. A study was conducted to compare the efficacy of herbicides in control of the invasive Japanese honeysuckle (Lonicera japonica) applied at times when most native species are dormant. Six herbicide mixtures (glyphosate, glyphosate + imazapyr, glyphosate + imazapic, imazapyr, triclopyr + difluphenzopyr, and metsulfuron + difluphenzopyr) were applied in three seasons to assess the effect of application timing of each mixture on honeysuckle control. Herbicides were applied with a CO2 pressurized sprayer at three sites in a randomized complete block design. Pretreatment sampling indicated that Japanese honeysuckle constituted over 70% of plant cover at the study sites. Post-treatment sampling was conducted 60 days, 180 days, 420 days, and 540 days after the final application. All mixtures decreased percent cover of honeysuckle with varying effectiveness. Results indicate that the glyphosate, imazapyr, and metsulfuron + difluphenzopyr mixtures are particularly effective at controlling Japanese honeysuckle when applied at any time between October and April with suitable temperatures. Many native grasses and broadleaf forbs not found during pretreatment sampling also emerged post-treatment, either benefiting from application timing or indicating herbicide tolerance.
22

Variation in reproductive characteristics of lodgepole pine (Pinus contorta var. latifolia) in British Columbia

Berland, Anne 09 January 2014 (has links)
Lodgepole pine (Pinus contorta var. latifolia) is the most wide-ranging pine in North America. Populations in British Columbia vary widely in phenotypic and genotypic characteristics. The effect of climate on variation in reproductive characteristics has never been examined, yet is vital to the production of seed necessary for reforestation. This study aims to determine the relationship between the climate in B.C and variation in female cone and seed characteristics. The study makes use of the Illingworth provenance trial, sixty common garden plots that are distributed throughout British Columbia. Female cones from six provenances were collected at 21 sites during the summer of 2012. The number of scales was counted and maximum length was measured for each cone. Seed was extracted and counted. Variables were pooled for each tree. The climate at each site was described using data from ClimateWNA. Principal components analysis was used to reduce the highly correlated data set to the first two principal components (PC1 and PC2), which together described 76.7% of the variation in the data. PC1 was most closely aligned with variables related to temperature, the number of frost-free days, and degree-days above 5°C or below 0°C. PC2 was most closely aligned with precipitation and moisture variables. The reproductive variables were moderately positively correlated with one another. Analysis of variance indicated that average cone length and the average number of seeds per cone were significantly affected by both site and provenance, however the average number of seeds per cone was not. Average values of each reproductive trait for each site were modelled against the first two principal components using multiple analysis of variance and univariate linear modelling. The best-fit model for the average number of scales per cone included PC1 and PC2, however the model only described 4.9% of the variation in the data. The best-fit model for the number of seeds included only PC1, and iv the model only explained 4.1% of the variation in the data. The model for average cone length had the strongest results, with a model that included PC2 and explained 18.7% of the data. The results of the study indicate that climate is not the most important factor in predicting reproductive characteristics such as cone length, and the number of scales and seed per cone. The significant effect of moisture on average cone length was the strongest relationship identified in the study. The reproductive traits were best described by their stability across the climates of the test sites. High genetic variation in lodgepole pine populations may be contributing to the stability of reproductive traits. Lodgepole pine female cone and seed traits were stable for mature trees over a wide range of provenances and climate regions. / Graduate / 0309 / 0478 / anne.berland@gmail.com
23

An Evaluation of Disturbance-Induced Nutrient Changes and Climate Responses of Loblolly Pine Xylem

Stratton, Rebecca Lynne 01 December 2011 (has links)
Dendrochronological techniques are currently limited to the identification of visible fire scars. However, through the development of new dendrochemical techniques, the potential exists to provide insight into a broader array of pyric ecosystems. In addition, the ability to identify historic climate-growth responses provides a better understanding of the conditions under which historic fire regimes occurred. This study provides the groundwork for the identification of a dendrochemical nutrient fire signature in xylem and identifies the climate-radial growth responses of loblolly pine (Pinus taeda L.) on five sites in the Piedmont of South Carolina. Changes in N, P, K, Ca, Mg, Zn, Cu, Mn, Fe, S, and Na concentrations in xylem as a result of a single fire were examined. The influences of monthly mean temperature, monthly total precipitation, Palmer Drought Severity Index (PDSI), Palmer Hydrological Drought Index (PHDI), and selected ocean-atmospheric oscillations such as El Nino-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Southern Oscillation Index (SOI) on radial growth using univariate and multivariate techniques were also assessed. Soil and duff analyses indicated sites were similar, but nutrient poor. Xylem mobile and immobile nutrient concentration analyses differed significantly through time for N, P, K, Ca, Mg, Zn, Cu, Mn, and S. No interactions were significant, thus identification of a nutrient fire signature was unsuccessful. The lack of significant interactions is attributed to the methodology used to collect the xylem nutrient samples; however, immobile nutrients indicate the most potential for future research. Climate-tree growth analyses indicate climate plays a role in the growth of mature loblolly pine in the South Carolina Piedmont. Temperature, precipitation, PDSI, positive phase NAO, and positive phase PDO are the primary drivers of loblolly pine radial growth. Temporal consistency results suggest drought sensitivity increases with tree age. Unlike the climate variables, the relationships between ocean-atmospheric oscillations and radial growth appear to be more cyclical in nature and only influence growth in positive phases.
24

A biosystematic survey of Sierra Lodgepole pine (Pinus contorta var. murrayana [Critchfield]) populations in the transverse and peninsular ranges of Southern California

Everett, Richard Gobin 01 January 1997 (has links)
No description available.
25

Understory Plant Community Structure in Forests Invaded by Garlic Mustard (Alliaria petiolata)

Aylward, Jason 13 July 2016 (has links)
ABSTRACT UNDERSTORY PLANT COMMUNITY STRUCTURE IN FORESTS INVADED BY GARLIC MUSTARD (ALLIARIA PETIOLATA) MAY 2016 JASON ALLEN AYLWARD, B.S., PAUL SMITH’S COLLEGE M.S. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Kristina Stinson Plant invasions represent a significant threat to the structure and function of natural ecosystems. Garlic mustard (Alliaria petiolata) has been identified as a threat to native communities mostly through small-scale studies and focused experiments. In this in situ observational study I examined the effects of garlic mustard invasion on species composition across multiple sites by comparing plant diversity and composition in invaded and adjacent non-invaded communities. Mean Shannon diversity was higher in invaded compared to non-invaded plots and invasion was associated with greater densities of invasive species such as burning bush (Euonymus alatus), and greater celandine (Chelidonium majus). In ordination space, the sites grouped more closely by geographic region than by invasion status, suggesting that regional environmental variation is important for community structure. My findings indicate that garlic mustard invasion is associated with other invasive plants, and that the understory plant community varies considerably across the region regardless of invasion status. Overall we show that community structure in garlic mustard invaded forest understories is not consistent across the landscape.
26

Evaluation of Red Alder Mortality in the Little Creek Watershed Following the 2009 Lockheed Fire

Theobald, Dylan Robert 01 March 2014 (has links)
Five hundred eighty red alder along a 2.16 km portion of the Little Creek riparian zone were assessed for mortality following the 2009 Lockheed Fire near Davenport, California. The study area was divided into burn severity zones and every red alder within the riparian zone was observed and assessed for mortality. Height, diameter at breast height (DBH), and age were collected on selected trees. An estimation of red alder large woody debris (LWD) input to Little Creek since a 2010 LWD survey (Smith, 2010) was calculated using average red alder tree dimensions applied to Smalian’s formula (MLNRO, 2011). The mean proportion of dead red alder in the non-burn zone and burn-zone was .11 and .45 respectively. Volume of red alder LWD in Little Creek is estimated to have increased approximately 245% since the fire. Given other factors may have played a role in red alder mortality in Little Creek, the analysis reported here supports fire also contributed to accelerated mortality of red alder established following the catastrophic debris torrent in 1955 in Little Creek. This study provides useful information regarding fire and red alder and establishes baseline conditions of the Little Creek riparian zone following the 2009 Lockheed Fire.
27

Development of a Laboratory Protocol for the Micropropagation of Monterey Pines (<i>Pinus Radiata</i>), Año Nuevo Stand

Wells, Karen E 01 May 2009 (has links)
Monterey pine (Pinus radiata), a native tree to California and two Mexican islands, is important both ecologically and economically. Outside native stands, Monterey pines are grown for landscaping in California and on plantations around the world. Pitch canker, a disease caused by the fungus Gibberella circinata Nirenberg & O’Donnell (Fusarium circinatum Nirenberg and O'Donnell) is threatening the survival of Monterey pines. The disease currently affects Monterey pines in many parts of the world including the native stands. No effective chemical or biological control is available but some Monterey pines show resistance to the disease. The purpose of this project was to develop a working protocol for producing genetic clones of the resistant pines through micropropagation. These genetic clones will be used for outplanting in places outside the native stands for ornamental and plantation purposes. This project analyzes the results of ten trials with varied parameters and bases the final protocol on the parameters used in the trial that induces the growth of new shoots. The final protocol developed in this project describes, step-by-step, the media preparation for the initiation, plant material collection, surface sterilization of plant material, plating in media and initiation of shoots on explants. The protocol calls for collecting shoot tips with hardened buds that have not yet elongated, then washing the shoot tips in sterile water with Tween 20 for 15 minutes. The shoots tips are then surface sterilized in a 50% bleach solution for 20 minutes. The explants are broken into disks (to minimize damage to the cells) by inserting the tip of a scalpel and tilting it slightly. The initiation media shown to induce growth consists of ½ strength LePoivre basal salt mixture, 5mg/L benzylaminopurine, 3% sucrose and 0.8% agar and is adjusted to a pH of 5.7, then autoclaved for 20 minutes. The explants are inserted into solidified media and incubated in a growth chamber programmed for 16 hours of light and 8 hours of dark with temperatures of 27ºC and 22ºC and light irradiance of 80µEm-2s-1. After 1 month the protocol calls for transferring the growing shoots to elongation media with full LP basal salts and transferring every month. When the number of desired shoots has been reached the forthcoming protocol for rooting can be followed.
28

Livestock Mortality at Beef Farms with Chronic Wolf (Canis lupus) Depredation in the Western Great Lakes Region (WGLR)

Vandergon, Arion 01 December 2008 (has links)
Gray wolf (Canis lupus) depredation on beef calves has been studied extensively in recent years. As wolf populations increase throughout the United States there is a corresponding increase in wolf/livestock interactions. Most research concentrates on summaries of reported depredations and surveys of producers affected by depredations. The objective of this study was to present data on the fate of beef calves on 3 farms in Minnesota and Wisconsin over a 2-year period. Predator presence/absence was studied as an indicator of potential depredations. Also, data are presented comparing 2 techniques that may aid researchers and livestock producers with monitoring livestock. Radio telemetry collars and ear tags were applied to beef calves on 3 farms in northern Minnesota and Wisconsin during the spring and summer of 2006 and 2007. During this time, 4 calves were killed by wolves on the study farms. Wolves did not appear to be selecting the youngest calves and most depredations occurred from April through July. Although not statistically significant, wolf sign appeared at slightly higher rates on study farms than on land adjacent to these farms. Predator sign, including coyote (Canis latrans) and black bear (Ursus americanus), appeared more often in the heavily forested areas of the farms. Radio collars and radio ear tags were helpful for monitoring beef calves during this study. Radio collars had much longer transmitting distances than ear tags (2.3 ± 0.8 miles and 0.4 ± 0.2 miles, respectively). Radio ear tags had a potential for causing beef calves' ears to droop or were ripped out, possibly lowering their market value. Currently, cost is prohibitive for the widespread use of radio transmitters for monitoring livestock but as the price of new technologies decreases, transmitters may become an integral part of livestock production on farms with chronic wolf depredation.
29

FACTORS INFLUENCING IMPACT OF BIOLOGICAL CONTROL AGENTS OF THE EMERALD ASH BORER

Murphy, Theresa 24 March 2017 (has links)
Agrilus planipennis, the emerald ash borer (EAB), is a destructive invasive forest pest decimating North American ash trees. Population-wide management of EAB focuses on biological control, with the introduction of four parasitic wasps; one egg parasitoid, Oobius agrili and three larval parasitoids- Spathius galinae, Spathius agrili and Tetrastichus planipennisi. This thesis examines some of the factors influencing the establishment of these larval biocontrol agents. Chapter 1 examines the relationship between woodpeckers and the parasitoids S. agrili and T. planipennisi. Both woodpeckers and these parasitoids attack the larval stage of EAB, which means their impacts overlap and potentially interact. To examine this relationship, I established parasitized larvae on ash trees and then used screening to exclude woodpeckers from some sections of the tree. Results show that while there is no evidence of discriminatory feeding for or against parasitized larvae, the presence of parasitized larvae changes woodpecker feeding behavior at a stand-level. I hypothesize that this change is due to these larval parasitoids being a low-food reward and that parasitism contributes to a change and decrease in patch quality, causing woodpeckers to quit foraging sooner than usual. My second chapter focuses on Spathius galinae, which was recently approved for release in the north central and northeastern US in 2015, to provide additional population control. Spathius galinae’s long ovipositor (4-5.3mm) is theoretically expected to help target EAB in ash with larger diameters and bark thicknesses. Using experimentally infested logs of varying thicknesses in the laboratory I tested the limits and preferences for oviposition of S. galinae, to understand its potential impact on EAB. My results demonstrated that although parasitism by S. galinae drops significantly when bark thickness reaches 8 mm, this prevents S. galinae only from reaching EAB larvae in my largest ash trees (S. galinae will play a vital role in providing additional control and in supporting ash regeneration in aftermath areas of EAB invasions.
30

Status, Movements, and Habitat Use of Moose in Massachusetts

Wattles, David W 01 January 2011 (has links) (PDF)
Moose (Alces alces) have been re-established in much of the historic range in the northeastern United States. Recently the southern edge of the species ranges has been extended southward into southern New England and northern New York from established populations in northern New England. The southern expansion raised questions as to the ability of this northern species to cope with higher temperatures, areas densely populated by humans, and different forest types further south. In light of these recent developments, we conducted a literature search on moose in the northeastern United States and distributed a questionnaire and conducted phone interviews with biologists responsible for moose management across the region to determine the status and management of moose in New England and New York. Furthermore, in 2006 we initiated a study on the home ranges, movements, and habitat use of moose in Massachusetts. We captured and collared moose with Global Positioning System (GPS) collars to track their movements in the Commonwealth. The surveys and interviews with the state biologists revealed that moose populations appeared to be stabilizing in southern New England. However, the moose population continued to grow in northern New York. Moose populations in northern New England were managed with an annual fall harvest, but moose hunting was not allowed in southern New England or New York. Throughout the region moose vehicle collisions were a major concern (>1,000 occur each year) including several that resulted in human fatalities. The collaring study has revealed the importance of maintaining a variety of forest cover types, age classes, and wetland habitats to meet the seasonal needs of moose, including early successional habitats created by logging that appear to be important for moose. Mean home range sizes were 64.9 km2 (SE = 12.9) and 73.3 km2 (SE = 9.4), respectively, for females and males in central Massachusetts, and 164.5 km2 (SE = 62.6) for males in western Massachusetts. Moose often interacted with roads and human development on the uplands, but used less developed areas of their home ranges. This demonstrates the importance of preserving the integrity and connectivity of the forested landscape of Massachusetts.

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