Life Sciences Commons^™

Divergent Responses Of Cryptic Invasive Watermilfoil To Treatment With Auxinic Herbicides In A Large Michigan Lake, Syndell R. Parks

Masters Theses

Invasive plants are a major concern for environmental managers. Cryptic invasive taxa present additional challenges because of their potential to respond differently to management efforts. Invasive Eurasian watermilfoil (Myriophyllum spicatum) and hybrid watermilfoil (Myriophyllum spicatum x Myriophyllum sibiricum) cannot be reliably distinguished based on morphological characters and are therefore cryptic taxa. Laboratory studies show that on average, hybrid watermilfoil grows faster, branches more, and is less responsive to standard control measures developed for Eurasian watermilfoil. These laboratory results predict less effective control of hybrid watermilfoil in mixed populations treated uniformly with one of these control measures. However, to date there …

Adult Rainbow Trout Habitat Selection In The Henry’S Fork Of The Snake River, Idaho, Zachary Kuzniar

Masters Theses

Determining habitat selection for an organism across a geographic distribution is a primary challenge in modern behavioral ecology. Quantifying habitat use becomes increasingly difficult for species that exhibit complex life histories and complementary habitat requirements. Rainbow trout are an archetypal example due to their tendency to form local populations across a diversity of environments. The Henry’s Fork of the Snake River provides an opportunity to utilize microhabitat selection models to quantify stream features that may drive adult rainbow trout behavior at the local scale. In particular, within an 8.5 km, low gradient, groundwater-dominated reach that exhibits a general lack of …

Evaluating Accuracy And Bias In Genetic Monitoring Under Scenarios Of Population Decline, Susan K. Munster

Masters Theses

Accurate and unbiased estimates of current effective population size are of primary importance in making informed decisions for conservation purposes. One species of concern, the eastern red bat (Lasiurus borealis), is experiencing ongoing population losses due to wind turbine collisions. The proportion of the population being affected is currently unknown, although recent estimates of total fatalities at wind turbines over the time from 2000-2011 are in the hundreds of thousands for this species alone. The roosting habits of eastern red bats make it difficult to monitor their census population size (Nc); thus, genetic estimates of effective population size (Ne) may …

Microcystin Accumulation In Fish Muscle Tissue: Exploring The Safety Of Fish Consumption In Several Michigan Water Bodies, Heather Snyder

Masters Theses

A variety of anthropogenic factors, including global climate change and eutrophication, are causing increases in cyanobacterial abundance. Increased prevalence of cyanobacteria can be detrimental, as some genera of cyanobacteria have the ability to produce toxic secondary metabolites known as cyanotoxins. The cyanotoxin microcystin- a hepatotoxin, is the most ubiquitous and toxic cyanotoxin in freshwater ecosystems, and has been quantified in a number of aquatic organisms. Microcystin was quantified in 8 fish species from St. Mary’s River in June, Saginaw Bay in September, and from Stony Creek Lake in October in 2014 by the Michigan Department of Environmental Quality and the …

Toxin Production And Population Dynamics Of Gloeotrichia Echinulata With Considerations Of Global Climate Change, Sarah Stamann

Masters Theses

Global climate change has been identified as a driver for increasing cyanobacteria blooms world-wide. Blooms of the cyanobacterium, Gloeotrichia echinulata, (hereafter, G. echinulata) have been observed in Silver Lake (Oceana County, MI), often forming dense surface scums. This organism is known to produce the hepatotoxin, microcystin- LR, and its growth is linked to phosphorus accumulation from sediment and temperature.

A series of experiments at ambient and elevated temperatures (+2° and +6°above ambient) with sediment from four locations in Silver Lake with varying phosphorus concentrations were conducted to examine the effect of these variables on G. echinulata growth. These …

Photophysiological Studies Of Cyanobacterial Mats In Submerged Sinkholes Of Lake Huron, Michael Snider

Masters Theses

No abstract provided.

Evolution Of Invasive Species In Response To Management: Potential For Herbicide Resistance In Watermilfoil, Lindsey-Ann Louise Schulte

Masters Theses

Herbicides are commonly used to control invasive plants. While agricultural weed scientists have focused on herbicide resistance, little is known about its importance in nonagricultural settings. Hybrid Eurasian watermilfoil (Myriophyllum spicatum x M. sibiricum) is an invasive aquatic plant that is frequently managed with herbicides throughout the United States. In this thesis, I consider the potential for natural populations of this taxon evolving resistance to 2,4-dichlorophenoxyacetic acid (2,4-D), the most commonly used systemic herbicide. Evolutionary change in a trait between generations as a result of selection requires both genetically based variation of the trait within a generation (heritable …

Computational Modeling Of Β5-Β6 Carbapenemase Loop In Wild Type And Selected Mutants Of Oxa-24 Class D Β-Lactamase, James Roland Lafleur

Masters Theses

Bacterial resistance to antibiotic therapies, especially to β-lactams, is an increasing problem. β-lactamases are the main source of clinical resistance to these antibiotics, and the class D β-lactamases are one of the most rapidly expanding classes of these enzymes. The emergence of class D enzymes with the ability to hydrolyze the newest family of β-lactams - the carbapenems - is a serious concern for the healthcare system as carbapenems are last resort antibiotics: ideal for severe infections after other therapies have failed. Class D β-lactamases are very diverse in terms of sequence and substrate profile, and it remains unclear what …

Documenting Annual Differences In Vegetation Cover, Height And Diversity Near Barrow, Alaska, Timothy Frederick Botting

Masters Theses

Vegetation in the Arctic has been shown to respond to climate change. Documented changes have the potential to result in numerous ecosystem consequences. Therefore, understanding vegetation change is of great importance. This study documents changes in tundra vegetation with a focus on understanding the influence of annual differences in weather. Vegetation was sampled using a point frame method on 98 1-m² plots in 2010 and 2013 near Barrow, Alaska. A subset of 30 of these plots was also sampled in 2012 and 2014. Plant encounters were identified to species and grouped into one of the following functional groups: bryophytes, …

Assessment Of Northern Bobwhite Survival And Fitness At Felsenthal National Wildlife Refuge, Arkansas, Jacob W. Doggett

Masters Theses

In the West Gulf Coastal Plains (WGCP) northern bobwhite (Colinus virginianus) numbers are declining faster than range-wide averages and such declines have been linked to the consequences of land management within the region. Management for the endangered red-cockaded woodpecker (Picoides borealis) has benefitted northern bobwhite by restoring mature pine-grassland ecosystems in some areas of the region; however, at Felsenthal National Wildlife Refuge, Crossett, Arkansas, USA, the bobwhite population was not increasing despite the availability of seemingly suitable habitat from management for the endangered species. To understand factors that may be affecting bobwhite survival on Felsenthal National …

Bridging In Vi Tro & In S Il Ico Techniques: Uncovering The Structural Characteristics And Light-Dependent Modifications Of The Light-Response Btb Proteins In Arabidopsis Thaliana, Nicholas Reitz

Masters Theses

The conjugation of the NEDD8 protein has been found to cause a wide range of changes to the overall function of a protein. The addition of NEDD8 to a conserved lysine on Cul proteins has been found to provide Cul with increased flexibility, while the transcription factor protein p53 was prevented from binding to DNA after NEDD8 conjugation. Using Arabidopsis thaliana, we investigated the potential conjugation of NEDD8 to the AtLRB1 and AtLRB2 proteins, which are both members of Cul3-RING E3 Ubiquitin Ligase complexes, using both in vitro and in silico techniques. The AtLRBs are negative regulators of the red …