Ecology and Evolutionary Biology Commons^™

Population Ecology Of The Diamondback Terrapin At Their Northern Range Limit, Patricia M. Levasseur

Doctoral Dissertations

This dissertation research focuses on the population ecology of the northern diamondback terrapin (Malaclemys terrapin terrapin) in Wellfleet Bay, MA. The northern diamondback terrapin is a Massachusetts-threatened turtle species restricted to estuarine environments. With a range from Cape Hatteras, North Carolina to Massachusetts, Cape Cod Bay is the northernmost part of the subspecies range. Mass Audubon’s Wellfleet Bay Wildlife Sanctuary has been using capture-mark-recapture (CMR) methods since 1980 marking over 3,000 individuals; however, low detection rates and variable search effort have resulted in unreliable population estimates not suitable for informing conservation practices within the bay. Low sample sizes, …

Applications Of Statistical Physics To Ecology: Ising Models And Two-Cycle Coupled Oscillators, Vahini Reddy Nareddy

Doctoral Dissertations

Many ecological systems exhibit noisy period-2 oscillations and, when they are spatially extended, they undergo phase transition from synchrony to incoherence in the Ising universality class. Period-2 cycles have two possible phases of oscillations and can be represented as two states in the bistable systems. Understanding the dynamics of ecological systems by representing their oscillations as bistable states and developing dynamical models using the tools from statistical physics to predict their future states is the focus of this thesis. As the ecological oscillators with two-cycle behavior undergo phase transitions in the Ising universality class, many features of synchrony and equilibrium …

The Influence Of Climate Change On The Ecology Of The Arctic Ground Squirrel In Denali National Park, Ak., Nigel A. Golden

Doctoral Dissertations

This dissertation research focuses on the ecology of the Arctic ground squirrel (Urocitellus parryii) in Denali National Park and Preserve, AK. The Arctic ground squirrels is a species of interest for monitoring efforts under the National Park Services’ Vital Signs Monitoring Program under the Vital Signs Monitoring program. The focus of this program is to monitor what is considered to be the most significant indicators of ecological conditions of the specific park resources that are of the greatest concern. The CAKN designated the Arctic ground squirrel (Urocitellus parryii) as one indicator species of park ecosystems. Despite being easy to observe …

Statistical Improvements For Ecological Learning About Spatial Processes, Gaetan L. Dupont

Masters Theses

Ecological inquiry is rooted fundamentally in understanding population abundance, both to develop theory and improve conservation outcomes. Despite this importance, estimating abundance is difficult due to the imperfect detection of individuals in a sample population. Further, accounting for space can provide more biologically realistic inference, shifting the focus from abundance to density and encouraging the exploration of spatial processes. To address these challenges, Spatial Capture-Recapture (“SCR”) has emerged as the most prominent method for estimating density reliably. The SCR model is conceptually straightforward: it combines a spatial model of detection with a point process model of the spatial distribution of …

Environmental Drivers Of Jaguar Distribution, Activity, And Abundance In Santa Rosa National Park, Costa Rica, Victor Montalvo

Doctoral Dissertations

Jaguars (Panthera onca) are a landscape species persisting in less than 54% of their historical distribution range; thus, the understanding of abiotic and biotic environmental factors affecting ecological interactions of this top predator in seasonal ecosystems such the dry forest is crucial for their conservation. In addition to factors affecting species ecology, some methodological constraints also could affect jaguar study outcomes leading to wrong decision-making. Data gathered from available jaguar peer-reviewed literature showed that there are large number of variables and techniques used to model jaguar distribution that did not contribute substantially to descriptions of jaguar distribution. Using …

Evaluation Of Environmental Factors Influencing American Marten Distribution And Density In New Hampshire, Donovan Drummey

Masters Theses

Though the American marten (Martes americana) is widely distributed across northern North America, habitat use and population abundance vary widely across the range. Due to its status as a furbearer, the species has been extensively researched, resulting in a large body of knowledge about the species’ ecology, distribution, and abundance, as well as drivers of population structure and dynamics. More recently, marten research has shifted focus to genetics, habitat associations, and estimation of population state variables. The rapid increase in estimation of states such as occupancy, abundance, and density has likely been driven by the increasing accessibility of …

Applying Ecological Theory To Amphibian Populations To Determine If Wood Frogs (Lithobates Sylvaticus) Are Ideal And Free When Selecting Breeding Habitat, Taylor M. Braunagel

Masters Theses

Amphibian populations are declining globally due to a litany of factors including pollution, disease, climate change, and most importantly, habitat destruction. As most amphibian life histories involve their populations being recruitment limited, focusing on the mechanism behind breeding habitat selection will reveal useful cues that managers may use to increase abundance and breeding success. Though there are many theoretical models that describe the distribution of animals in response to a resource, the ideal free distribution (IFD) theory has not yet been applied to amphibian settling decisions. Through this application of the IFD, I have found that a population of wood …

Trait Variation And Long-Term Population Dynamics Of The Invasive Alliaria Petiolata (Garlic Mustard) Across Three Microhabitats In Its Invaded Range, Laura Hancock

Masters Theses

Long-term population dynamics across heterogeneous environments can be a major factor in determining species’ ability to expand their ranges and persist in novel environments. Whether and how the relative performance of populations in different microsites over time impacts invasion into new microsites is poorly understood. Though largely restricted to disturbed semi-shaded microhabitats in its home range, the invasive herb Alliaria petiolata (garlic mustard) successfully invades intact forest understories – a novel microhabitat – in its introduced range, where it is known to impact above and below ground community composition. To test the hypothesis that source-sink metapopulation dynamics may be promoting …

Improving Understanding Of Forest Communities And Biodiversity With Multi-Dimensional Landscape Gradients, Ben J. Padilla

Doctoral Dissertations

This dissertation was motivated by a desire to understand the effects of habitat degradation and urbanization on a single species in a single study system in western Massachusetts, the red-backed salamander (Plethodon cinereus), but along the way unexpected conceptual and methodological hurdles caused the work to grow into a multi-species, multi-region, and multi-scale endeavor. As I designed my dissertation research and began considering approaches to quantifying heterogeneity and human influence in my study landscape, I recognized inconsistencies in methods used to define and quantify landscape metrics, particularly in urban systems. To investigate further, I conducted a critical review …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

Autonomous Recording Units As An Alternative Method For Monitoring Songbirds, Lindsay Clough

Masters Theses

There is an increasing interest in the use of autonomous recording units as an alternative survey method to point count surveys conducted by human observers; however, questions remain about whether or not these recording units perform similarly to point count surveys and produce valid, comparable results. The use of individual listeners to transcribe the acoustic data collected by autonomous recording units is a common method for the analysis of recorded acoustic data, but potential variability among transcribers raises questions about the standardization of listening protocols to decrease inconsistencies in transcription results.

Autonomous recording units have been used to monitor birds …

Improving Growth And Survival Of Cultured Yellow Lampmussel (Lampsilis Cariosa) For Restoring Populations, Virginia Martell

Masters Theses

In North America 72% of freshwater mussel species are endangered, threatened, or of special concern due to factors such as habitat loss and degradation, biological invasion, and land use change. Propagation of freshwater mussels has been considered a necessary conservation strategy for population restoration where threats have been mitigated but small population sizes limit population viability. Yellow lampmussel is a species of freshwater mussel that is endangered, threatened, or imperiled throughout its range; therefore, I evaluated laboratory techniques (probiotic supplements and secondary rearing designs) to improve culture of yellow lampmussel for population restoration. Several aquaculture facilities commonly use probiotics; thus, …

Impact Of Native Natural Enemies On Populations Of The Invasive Winter Moth (Operophtera Brumata L) In The Northeast United States, Hannah J. Broadley

Doctoral Dissertations

Invasive insects increasingly affect forested landscapes and have important ecological and economic impacts. My dissertation focuses on population dynamics of winter moth (Operophtera brumata L.), an invasive pest in the northeastern United States. Native to Europe, this is the species’ fourth accidental introduction to North America. The Elkinton lab established the biological control agent Cyzenis albicans across the range of winter moth in the northeastern U.S. Prior research indicates that C. albicans’ ability to control winter moth likely depends on additional mortality from native natural enemies. My dissertation research evaluates the identity and role of natural enemies already …

Gynodioecy And Biotic Interactions: Plant Traits, Insect Preferences, And Population-Level Consequences, Laura A. D. Doubleday

Doctoral Dissertations

In species with distinct sexes, differences between the sexes often affect interspecific interactions. In gynodioecious flowering plants, where individuals are female or hermaphrodite, both pollinators and herbivores tend to prefer hermaphrodites. Because pollinators and herbivores affect plant fitness, their preferences have consequences for plant mating patterns, natural selection on mating-related traits, and plant breeding system evolution. Being sessile, the spatial arrangement of females and hermaphrodites in gynodioecious plant populations alters conspecific density and sex ratio locally, which can also have important fitness effects. My dissertation combines observational studies in natural Silene vulgaris populations and simulation modeling to address questions about …

Using Stable Isotopes To Examine Carry-Over Effects During The Full Annual Cycle Of A Migratory Bird, The Prairie Warbler, Michael E. Akresh

Doctoral Dissertations

To better conserve threatened species, conservationists need to understand the processes that affect species during their entire life cycle, including ‘carry-over effects’ which can occur if individuals’ previous experience influences their current or future performance. We studied prairie warblers (Setophaga discolor) to examine carry-over effects in a Nearctic-Neotropical migratory bird. Using carbon isotopes in birds’ blood as a measure of habitat moisture, we first assessed the effects of rainfall and habitat on the condition of prairie warblers wintering in The Bahamas. Annual variation in rainfall and spatial moisture interacted to influence birds’ condition: during a winter with less …

All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang

Doctoral Dissertations

Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O.sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Using population genetics analyses of South Asian and US weedy rice, my research reveals multiple independent evolution events giving rise to weed groups in the two geographic areas. Weeds in South Asia have highly heterogenous genetic backgrounds, with contributions from both cultivated varieties (aus and indica) …

Biology, Molecular Systematics, Population Dynamics And Control Of A Stem Gall Wasp, Zapatella Davisae (Hymenoptera: Cynipidae), Monica Davis

Doctoral Dissertations

Gall wasps are phytophagous insects that often go unnoticed, however, when they are released from their natural enemies, they have the capacity to outbreak and cause extensive foliar damage. One such outbreaking pest, Zapatella davisae, causes significant damage and mortality to black oak, Quercus velutina. In recent years, black oak decline has been documented in Long Island, New York and coastal New England. Little is known about the lifecycle, distribution or population dynamics of Zapatella davisae and the taxonomy of the species is still unclear. My first study described the biology and distribution of Z. davisae. Zapatella …

Improving Conservation Efforts Through A Better Understanding Of Forest Elephant Ecology, The Impacts Of Threats On Elephants And Freshwater Fisheries In Northern Congo, Roger Patrick Boundja

Doctoral Dissertations

IMPROVING CONSERVATION EFFORTS THROUGH A BETTER UNDERSTANDING OF FOREST ELEPHANT ECOLOGY, THE IMPACTS OF THREATS ON ELEPHANTS AND FRESHWATER FISHERIES IN NORTHERN SEPTEMBER 2016 ROGER PATRICK BOUNDJA, B.Sc. FORESTRY, MARIEN NGOUABI UNIVERSITY, BRAZZAVILLE MSc. UNIVERSITY OF CAPE TOWN PhD. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Curtice R. Griffin Catch data, including fish numbers, length-weight were collected during a multi-mesh Gillnet fisheries-independent survey in 2007-2008, and fisheries-dependent mixed gear surveys in 2009-2010 and 2015 across 400km stretch of the Sangha River located in the Sangha Tri-National. Overall, very high species richness (Chao 2 mean=250, SD=16.15) and diversity index (Simpson Inverse …

Distribution And Population Dynamics Of Ungulates In The Mongolian Gobi, Buuveibaatar Bayarbaatar

Doctoral Dissertations

The Mongolian Gobi is one of the most spectacular and important regions in Central Asia, comprising the largest area of intact grassland in the world. In recent years, a growing human population, expanding exploitation of natural resources, and the development of infrastructure in the region place increasing pressure on these species and their habitats. This dissertation has focused on three species of ungulates such as Mongolian saiga (Saiga tatarica mongolica) in western Mongolia, and Asiatic wild ass (Equus hemionus), and goitered gazelle (Gazella subgutturosa) in Southern Gobi. The study on endangered saiga antelope in …

Evaluating Resistance Surfaces For Modeling Wildlife Movement And Connectivity, Katherine Zeller

Doctoral Dissertations

The continued growth of human populations and associated development in many areas of the world is causing persistent fragmentation of natural habitats. In response, wildlife corridors are often promoted as essential for the conservation of wildlife species. Wildlife corridors allow for the movement of individuals between habitat patches and confer many benefits including the maintenance of metapopulations and metapopulation dynamics, the maintenance of seasonal migratory routes, genetic exchange, and the potential for individuals and populations to shift their ranges in response to climate change. Wildlife corridors are modeled across a resistance-to-movement surface where resistance represents the willingness of an organism …

Ecological Consequences Of Lost Anadromous Forage Fish In Freshwater Ecosystems, Steven R. Mattocks

Masters Theses

Beginning in the early 1600s, dam construction in New England obstructed anadromous fish access to spawning grounds during migration. As a result, anadromous forage fish populations have declined, which has impacted freshwater, marine, and terrestrial ecosystems. To determine the impacts of dams on anadromous forage fish and freshwater ecosystems, I used historical and current data to estimate population changes in alewives (Alosa pseudoharengus) from 1600-1900. A significant reduction in spawning habitat occurred in New England as a result of 1,642 dams constructed between 1600 and 1900, resulting in 14.8% and 16.6% lake and stream habitat remaining by 1900, …

Variations In The Invertebrate Communities Of Wild Cape Cod Cranberry Bogs, Barbara Wagner

Masters Theses

As a species domesticated only in the last century, agricultural cranberry plants (Vaccinium macrocarpon) remain little removed from their wild relatives. Thus, it is a potential model species for studies of the earliest stages of domestication; however, there is little available quantitative information on its wild population biology and ecology. As such information is vital to studies of the ecological changes occurring during domestication, the purpose of this study was to consolidate the relevant knowledge available and conduct a preliminary search for patterns in the invertebrate communities of wild bogs. The alpha diversity was found to be greater …

Population Genetic Analysis Of Atlantic Horseshoe Crabs (Limulus Polyphemus) In Coastal Massachusetts., Katherine T. Johnson

Masters Theses

Atlantic horseshoe crabs (Limulus polyphemus) have endured decades of intense harvest pressure. Genetics studies have shown evidence of distinct sub-groups spanning the coast, although few fine-scale studies have been done to delineate these groups on a local level. Massachusetts lies directly between two of these sub-groups. With documented differences in prosomal widths of horseshoe crabs from either side of Cape Cod, it is possible that Cape Cod is a barrier to gene flow and that there are two distinct genetic groups within Massachusetts. Regulations currently consider all horseshoe crabs to be of one stock. I examined 6 microsatellite …

Density-Dependent Survival In The Larval Stage Of An Invasive Insect: Dispersal Vs. Predation, Adam A. Pepi

Masters Theses

1. The success of invasive species is often thought to be due to release from natural enemies. This hypothesis relies on the assumption that species are regulated by top-down forces in their native range and implies that species are likely to be regulated by bottom-up forces in the invasive range. Neither of these assumptions has been consistently supported with insects, a group which include many highly destructive invasive pest species.

2. Winter moth (Operophtera brumata) is an invasive defoliator in North America that appears to be regulated by mortality in the larval stage in its invasive range. To …

The Effectiveness And Applicability Of Amphibians As Indicator Species For Long-Term Monitoring Of Ecological Changes In New England Forests, Ahmed Siddig

Doctoral Dissertations

The objective of this study is to assess the potential of two amphibians species, Eastern Red-backed Salamander (Plethodon cinereus (Green)) and Eastern Red-spotted Newt (Notopthalmus viridescens viridescens Rafinesque), as indicator species of forest disturbances at Harvard Forest, located in Petersham, Massachusetts, United States. Specifically, I 1) assess the impacts of these focal species to decline of hemlock forests in Harvard Forest; 2) calibrate abundance indices of P. cinereus based on artificial and natural objects surveys with a population size estimator based on depletion sampling; and 3) assess the potential of these salamanders as indicator species by developing an …

Experimental Test Of Genetic Rescue In Isolated Populations Of Brook Trout, Zachary L. Robinson

Masters Theses

Translocations are an important aspect of the management of natural populations in an increasingly fragmented landscape. Maintaining connectivity and gene flow is beneficial for both contemporary fitness and adaptive potential in the face of environmental change. Genetic rescue (GR) can alleviate inbreeding depression, genetic load, and increase adaptive potential of populations. Here, I have translocated 10 (5 of each sex) brook trout (Salvelinus fontinalis) to four geographically proximate and environmentally similar fragmented stream-dwelling populations of brook trout in Virginia to test for genetic rescue. The translocated brook trout contributed to more families than would be expected under neutral …

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented …

Regional Comparison Of Overwintering Mortality, Fecundity, And Virulence In The Hemlock Woolly Adelgid, Artemis Demas Roehrig

Masters Theses 1911 - February 2014

Throughout the eastern United States, the spread of the hemlock woolly adelgid, Adelges tsugae Annand, has caused high mortality of eastern hemlocks Tsuga canadensis (L.). We recorded overwintering survival and fecundity of A. tsugae, and tree new growth at sites in the northeastern and southeastern United States and in a common garden experiment in Massachusetts.

Overwintering mortality of A. tsugae was much higher in the north (87%) than the south (37%) in 2009, and showed significantly positive density-dependence in the north only. In 2010, overwintering mortality decreased in both regions but remained higher in the north (54%) than the …

Habitat Heterogeneity Concentrates Predators In The Seascape: Linking Intermediate-Scale Estuarine Habitat To Striped Bass Distribution, Cristina Kennedy

Masters Theses 1911 - February 2014

Predators are key components of aquatic ecosystems and innovative approaches to understanding their spatial distribution are imperative for research, effective management, and conservation. Discontinuities, created by abrupt changes between two unlike entities, are irregularly-distributed, intermediate-scale features that can have a disproportionate effect on organismal distribution within the seascape. Here I use the discontinuity concept to relate the distribution of a predator, striped bass (Morone saxatilis), to physical features within Plum Island Estuary (PIE), MA. I mapped the distribution of 50 acoustically-tagged striped bass during four monthly surveys at 40 sites to evaluate if heterogeneity in physical features concentrated …

Interactions Between Pieris Oleracea And Pieris Rapae (Lepidoptera: Pieridae) Butterflies, And The Biological Control Agents Cotesia Glomerata And Cotesia Rubecula (Hymenoptera: Braconidae)., Megan V. Herlihy

Masters Theses 1911 - February 2014

Pieris oleracea, formerly Pieries napi, was once a widespread pierid butterfly in New England until the introduction of a biological control agent, Cotesia glomerata. It has been suggested that C. glomerata is responsible for the range reduction of P. oleracea. There are been several introductions of a second more specialized biological control agent, Cotesia rubecula, to the United States since the 1960’s. My first goal was to determine the current distribution and status of P. rapae parasitoids and the effectiveness of C. rubecula as a biological control agent since its release. The findings of a survey …