Ecology and Evolutionary Biology Commons^™

Microsite Requirements For Successful Regeneration In Lowland Northern White-Cedar (Thuja Occidentalis) Forests, Jeanette Allogio

Electronic Theses and Dissertations

Declines in stands of northern white-cedar (Thuja occidentalis L., hereafter cedar) have been observed as both shifts in species composition and reductions in cedar densities, particularly those stands in lowland sites (Curtis 1946, Boulfroy 2012). While several factors inhibiting cedar regeneration have been identified, a thorough understanding of the conditions that best promote regeneration is lacking. Our objectives for the first chapter were to characterize the site conditions associated with successful regeneration in lowland cedar stands and to describe how spatial patterns of various cedar size classes relate to site preference and to regeneration dynamics. These objectives were achieved …

Monarch Butterfly (Danaus Plexippus) Roost Site-Selection And Viability East Of The Appalachian Mountains, Brandon Boxler

Electronic Theses and Dissertations

The Monarch butterfly is a flagship species and pollinator whose populations have declined by approximately 85% in the last two decades. Their largest population overwinters in Mexico, then disperses across the eastern United States and Canada during April to August. Between September-December, the butterflies return south using two migratory flyways, one spanning the central United States and another following the Atlantic coast. They fly during the day and at night roost in large groups. Roosting habitat is essential to the continuation of the Monarchs’ migration, however, threats such as anthropogenic habitat disturbance and climate change potentially endanger sustainability of these …

American Eel Behavior And Survival In An Impounded River System, Matthew A. Mensinger

Electronic Theses and Dissertations

After beginning life in the Sargasso Sea, American eel enter river systems as juveniles and swim upstream in pursuit of freshwater habitat. Many encounter dams during this migration which act as barriers to upstream movement and limit eel establishment in headwater systems. Some dams have been retrofitted with fishways to improve watershed connectivity, but the individual selection imposed by these structures remains uncharacterized. We considered whether individual differences in behavior (i.e., personality) may be used to predict the propensity of juveniles to use a passage structure, suggesting that eel personality may predict access to habitat upstream of dams. Migrating, juvenile …

Chytridiomycota In Tree Bark, Paige Strasko

Honors College

Chytridiomycota is a phylum of microscopic aquatic fungi that form motile spores that typically have a single posterior flagellum, thus they require water to disperse (James et al., 2000). Chytridiomycota, collectively called chytrids, have round shapes with structures called rhizoids that absorb nutrients and anchor them to their substrate (Mueller et al., 2004). Chytrids are typically found in aquatic environments and soils since zoospores require water to germinate (James et al., 2000), but they also have been found in a number of unexpected environments. Chytrids are difficult to find because they are microscopic and have time-sensitive life cycles (Mueller et …

Responses Of Juvenile Atlantic Salmon To Competition And Environmental Change: Implications For Performance In Maine Streams, Nicole C. Ramberg-Pihl

Electronic Theses and Dissertations

New England’s climate is changing faster than that of any other region in the continental United States. Over the last century, Maine has experienced an increase in annual temperature of approximately 1.48^oC along with a 15 percent increase in annual precipitation. Temperature and precipitation play vital roles in shaping the ecology of freshwater environments. Therefore, changes in regional climate could undermine the structure and stability of Maine’s freshwater systems as they currently exist.

Maine currently harbors the last wild populations of Atlantic salmon (Salmo salar) in the United States. Atlantic salmon were once abundant in Maine …

Assessing Predator Risk To Diadromous Fish Conservation In The Penobscot River Estuary, Lauri Leach

Electronic Theses and Dissertations

Successful conservation of pinnipeds in the northwest Atlantic has led to increasing populations of harbor (Phoca vitulina) and gray seals (Halichoerus grypus) in the Gulf of Maine. Seals are often perceived as predators and competitors for fish, and as a result, come into conflict with fisheries and fish conservation. Increasing numbers of seals have become a recent concern in the Penobscot River Estuary in Maine, as habitat restoration and diadromous fish conservation have been top priorities in this region for the past decade.

To understand how pinnipeds are responding to these efforts, as well as the risks they pose to …

From Phocine Distemper To Avian Influenza: A Study Of Immunogenetic Diversity In Two Sympatric Pinniped Species, Alayna K. Gigliotti

Electronic Theses and Dissertations

Gray (Halichoerus grypus) and harbor (Phoca vitulina) seals are sympatric species that inhabit the North Atlantic and have been subject to mortality events from disease outbreaks, particularly phocine distemper and avian influenza virus. Across mortality events, gray seals tend to exhibit a higher survival rate, which could be explained by various ecological factors impacting rates or direction of selection in parts of the genome related to the immune system. These factors could include haul-out site density, habitat, and degree of inter/intraspecies interaction. This research aims to compare genetic diversity within the Major Histocompatibility Complex (MHC) class …

Distributions And Abundances Of The Red Tide Dinoflagellate Alexandrium Catenella In The Eastern Gulf Of Maine And Bay Of Fundy In Relation To Diatoms In June, July And August Of 2019, Kimberly Lina D'Adamo

Electronic Theses and Dissertations

A series of three oceanographic survey cruises were conducted in June, July, and August of 2019 in the northeastern Gulf of Maine and Bay of Fundy. Surface water samples were collected and analyzed for enumerations of cell densities of the dinoflagellate Alexandrium catenella in relation to cell densities of diatoms. Hydrographic profiles of temperature, salinity, and nutrients (silicate and nitrate) were also made at each station. Data were analyzed to determine if there was any statistically significant evidence of allelopathic interference imparted by diatoms that impede A. catenella. A. catenella cells were most abundant in June, reaching 6,195 cells per …

Movement And Survival Of Atlantic Salmon Smolts In The Penobscot River, Maine, Alejandro Molina Moctezuma

Electronic Theses and Dissertations

The Penobscot River system hosts the largest population of endangered Atlantic salmon Salmo salar in the United States. However, total adult returns in this river remain low. Historically low numbers led to listing of the distinct population segment (DPS) in 2000, and the Penobscot River population was included in the DPS in 2009. Reducing mortality in all life stages is crucial for the recovery of Atlantic salmon populations. One of the life stages associated to high mortality is the juvenile stage (smolts), in which individuals migrate downstream towards the estuary. During this migration smolts face a series of new conditions …

Developing A Long-Term Perspective On The Sensitivity Of Lake Trophic State Changes In Maine, Simona Lukasik

Electronic Theses and Dissertations

Even with similar external drivers, lakes can respond differently because of key ecosystem features that determine lake sensitivity. Identifying factors that determine lake sensitivity are important for successful lake management. The purpose of this research was to determine patterns of algal community change over the past 400 years in lakes with watersheds that vary in surficial geology, specifically the glacio-marine clay layer in Maine known as the Presumpscot formation. Responses to two external drivers, major land use changes and climate change, were assessed. Four lakes were chosen based on their surficial geology and land use history: Unity Pond, Webber Pond, …

Predicting And Managing Risk To Bats At Commercial Wind Farms Using Acoustics, Trevor Peterson

Electronic Theses and Dissertations

Bat populations in North America face novel threats from white-nose syndrome and widespread turbine-related mortality related to the rapidly expanding wind power industry in addition to long-standing pressures from habitat loss and degradation. Bats, unlike most small mammals, are long-lived and slow to reproduce, highlighting the importance of understanding and managing anthropogenic sources of mortality. My dissertation research used acoustic bat detectors to measure bat activity at commercial wind projects, predict patterns in risk, and design strategic measures to reduce fatality rates by curtailing turbine operation during periods when bats are most active. Bats collide with wind turbines only when …

Sourcing And Evaluating The Use Of Detritus As A Supplementary Diet For Bivalve Aquaculture Using Stable Isotopes And Fatty Acid Biomarkers, Adrianus C. Both

Electronic Theses and Dissertations

Detritus is a ubiquitous component of ecosystems and an important fuel for secondary production. Due to the extractive nature of bivalve aquaculture, detritus is often incorporated into carrying capacity and growth models for cultured bivalves. However, despite the complexity and difficulty in obtaining direct measurements, detritus is often treated as a homogeneous food source in models. Further understanding the role detritus plays in the diet of cultured bivalves could lead to more comprehensive and accurate models as well as more informed site selection for growers. The purpose of this study was to assess the abundance, bioavailability, and contribution of detritus …

Characterizing The Range Shifts Of Two Peromyscus Species In Maine, Molly Bennett

Honors College

In a changing climate, two species of mice in Maine (Peromyscus maniculatus and Peromyscus leucopus) are currently undergoing range shifts. The objective of my thesis is to determine the historical and current range of each species within the state of Maine. I used two approaches. I assembled ear biopsies collected this summer in Acadia National Park and throughout the state by the Gardner and Levesque labs to genotype the mice as either P. maniculatus or P. leucopus. Additionally, I summarized research that denotes where the two species were historically present around the state. These species are functionally impossible to tell …

Seed Dispersal Effectiveness In The Penobscot Experimental Forest, Gabrielle Link

Honors College

Previous studies have shown that scatter-hoarding small mammals increase seed germination success through the process of collecting and caching seeds throughout the forest. This study seeks to explore this further by examining how specific cache microsite preferences among these small mammals impacts the germination and growth of northern red oak (Quercus rubra). Seeds were planted in six different microsites across three forest treatments. Germination, seedling height, and herbivory were then monitored over time. We found that microsite did not have a significant effect on germination or height, however microsite did impact herbivory probability, and open microsites made seedlings more vulnerable …

Confirmed Presence Of Parahepatospora Carcini In Carcinus Maenas Population Of Maine, Brittany Torchia

Honors College

Carcinus maenas (European green crab) is an invasive species that made its way to North American waters in the 1800s on European trading ships. As an invasive species they cause problems by competing with native species for the resources within their shared ecosystem. They can also introduce pathogens that can infect and wreak havoc on native populations. In Nova Scotia, Bojko et al. (2017) found the pathogen Parahepatospora carcini, a clade IV microsporidian parasite found in the hepatopancreas of aquatic arthropods, in C. maenas. Because this case was located within close range of Maine waters, the objective of this study …

Assessing Lipid Content In Migrating Alewife, Anthony Zenga

Honors College

Alewife are a commercially, economically, and ecologically important fish, that expend large amounts of energy during their long migrations to spawning habitat. This energy demand can influence an individual’s chances of surviving and reproducing successfully. To understand how energy use may affect fitness, we captured alewife from the Souadabscook Stream over the course of their spawning migration. Fifty fish were sampled each week from May 12th to June 10th 2019. The lipid content of each individual was measured by using i) a Distell Fatmeter and ii) gravimetric analysis by measuring muscle moisture as an indirect method to assess lipid content. …

College Of Natural Sciences, Forestry, And Agriculture_Wle 220 Ecological Statistics Description, Stephen M. Coghlan, Jr.

College of Natural Sciences, Forestry, and Agriculture

Email from Stephen M. Coghlan, Jr., Associate Professor of Freshwater Fisheries, Ecology Department of Wildlife, Fisheries, and Conservation Biology, University of Maine to the Provost Office describing how he incorporated the COVID-19 pandemic into his class WLE 220 Ecological Statistics in the Spring 2020 Semester

Browntail Moth Research At The University Of Maine: A Report Of Activities And Findings 2016-2020, Eleanor Grodon, Karla Boyd, Hye Weon Hwang, Barbra Cole, Angela Mech

General University of Maine Publications

The browntail moth has become a very serious problem for many communities in southern, midcoast and central Maine over the past several years as this insect has reached populations levels that we have not seen in 80 to 100 years. Researchers at the University of Maine have teamed up with entomologists in the Maine State Department of Agriculture, Conservation, and Forestry Maine Forest Service (MDACF) to track the spread and investigate the causes of the outbreak and evaluate management strategies for this daunting pest.

The report was prepared by Prepared by: Dr. Eleanor Groden, Professor of Entomology, Emerita, School of …