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Assessing Biological Condition Of Restored Streams In An Agriculturally Impaired Chesapeake Bay Sub-Watershed, Julia M. Portmann, Bruce Wiggins

Department of Biology - Faculty Scholarship

Intensive agricultural practices can be detrimental to aquatic biological conditions; however, restoration such as removing livestock and creating in-stream habitat can strengthen biotic communities. Smith Creek, a sub-watershed of the Chesa- peake Bay, was designated a showcase watershed in 2010 by the United States Department of Agriculture to demonstrate the efficacy of widespread restoration. Our study sought to follow up on these efforts by assessing the individual and combined impacts of restoration, habitat, and land cover on aquatic macroinvertebrate communities in Smith Creek. We predicted that longer-restored sites, sites with less surrounding pasture, and streams with larger substrate size would …

Pasturelands As Natural Climate Solutions: A Socioecological Study Of Tree Carbon And Beef Production Trade-Offs, Bela Starinchak

Masters Theses, 2020-current

Forest restoration is the most effective natural climate solution, with the potential to sequester 37% of the carbon dioxide (CO₂) needed to reach the Paris climate mitigation goal. Cattle pastures offer an underutilized opportunity to increase global forest restoration efforts, improve biodiversity, and maximize carbon storage through the adoption of management strategies that prioritize the incorporation of trees into pasturelands. However, remote estimations of tree carbon storage in pastoral systems have never been field-verified and their accuracy is unclear. Furthermore, the effect of increased trees on cattle production is understudied across biomes. Lastly, the restoration potential of these …

Locomotion And Life History In A Leaping Primate: Mechanics And Energetics Of Movement Throughout The Propithecus Lifespan, Nicholas Heslep

Masters Theses, 2020-current

Arboreal primates are typically altricial, exhibit long juvenile periods, and use dynamic locomotor behaviors that can be challenging and risky. Sifaka (Propithecus verreauxi) have particularly slow life histories for their size, with long juvenile periods, protracted reproductive careers, and long life spans. Slow somatic growth poses potential mechanical challenges for juvenile sifaka who use thigh-powered vertical clinging and leaping to follow group members during travel. I examined mechanical and energetic costs of movement in developing sifaka. I instrumented 8 wild sifaka (3 yearlings, 3 subadults, 2 adults) in 4 social groups with inertial sensors measuring tri-axial acceleration for …

Understanding Context Dependent Responses To Climate Change In Arizona Tiger Salamanders (Ambystoma Mavortium Nebulosum), Kentrell Richardson

Masters Theses, 2020-current

Future emissions scenarios project climate change to increase average global temperatures by at least two ℃ in the next 50 years resulting in changes in local climate and causing increased variability within microclimates. Ectotherms are especially sensitive to climate change due to their dependence on environmental temperatures to regulate physiological functions. Changes in temperature are likely to impact thermally cued processes within amphibians and result in changes in variable magnitudes and directions within local populations.

Salamanders were placed in cups and partially submerged in a water bath and heated at a rate of ~0.27℃/ minute. Once salamanders were unable to …

The Response Of Microcystis And The Microbiome To Exogenous Hydrogen Peroxide, Bryan A. Puma

Masters Theses, 2020-current

Microcystis spp. produce prolific annual blooms in freshwater systems worldwide. The success of these blooms depends heavily on the Microcystis spp. overcoming environmental factors such as oxidative stress caused by reactive oxygen species (ROS) like hydrogen peroxide. Most Microcystis genomes do not contain many genes for responding to oxidative stress, including those that encode the enzyme catalase. Other cyanobacteria such as Prochlorococcus that also lack hydrogen peroxide degrading enzymes have been shown to benefit from partnerships with heterotrophic bacteria. Microcystis spp. may also receive similar benefits from heterotrophic bacteria in the phycosphere. To test this hypothesis, we examined the …

Pilfering Passerines? Inter-Class Competition: A New Direction In Foraging Ecology, Shannon Gillen

Masters Theses, 2020-current

Life in the epigeal layer below leaf litterfall often goes unexplored. Shrews (Soricidae, 1910) have foraged in this microhabitat for millions of years, carving out an existence in harsh habitats around the world, ranging from the tropics to subarctic boreal tundra. Two shrew species that inhabit the Shenandoah Valley of Virginia, the least shrew (Cryptotis parva) and northern short-tailed shrew (Blarina brevicauda), were the focus of this study. Shrews make epigeal foraging trails while they continually forage for food, and caching is a way to save this food for times of low and sporadic food availability. …

Urban Habitats Impact The Song And Reproductive Success Of A Migratory Bird, The Gray Catbird (Dumetella Carolinensis), Sasha Ewing

Masters Theses, 2020-current

Urban environments are relatively recent on an evolutionary timescale, and, as such, they create novel selection pressures that may influence fitness and mate choice. Many ecologically significant factors change with increasing levels of urbanization, such as increasing anthropogenic noise, increasing impervious surface, and decreasing forest cover. There is growing empirical evidence that anthropogenic noise affects features of birdsong and, separately, that avian nesting success varies across an urban gradient, but rarely do studies examine both – a necessary step to elucidate the evolutionary potential of these novel pressures. I investigated song features, body morphometrics, and reproductive success in male gray …

Assessing Red Spruce (Picea Rubens) Restoration Potential Under Current And Future Predicted Climate Change In Virginia, Christian Brown

Masters Theses, 2020-current

Global climate change threatens many species across the planet. High-elevation species, such as red spruce (Picea rubens), face significant and immediate threats from climate change. Red spruce has faced anthropogenic disturbances for over a century and is only recently beginning to regenerate across its range, making it an ideal restoration candidate. Ecological niche modeling has become a common method of identifying the suitable habitat of a species, providing vital information to land managers carrying out restoration efforts. In this study ecological niche models were used in a novel way, predicting distribution and habitat suitability separately to determine the …

Urbanization Drives Changes In Avian Communities, Which Are Reflected In The Song Of A Vocal Mimic, Jaclyn Tolchin

Masters Theses, 2020-current

Urban landscapes present problems for wildlife including highly modified habitat, anthropogenic noise pollution, and competition for suitable habitat. These novel selection pressures can filter species present in urban habitats or result in changes to behavior. Recent studies show that some bird species sing differently (louder, higher pitch, faster) in noisier, urban areas compared to quieter, more rural areas, and that anthropogenic noise alone can exclude species. I investigated how the level of urbanization affects 1) bird species composition, and 2) the assemblage of species that a songbird mimics from the local bird community. I studied gray catbirds, Dumetella carolinensis, across …

Identifying Key Stream Restoration Variables In An Agriculturally Impaired Chesapeake Bay Watershed, Julia Portmann

Masters Theses, 2020-current

The Chesapeake Bay watershed spans several states, supports diverse ecosystems, and is crucial to local economies. However, agricultural practices in this region impair water quality. The Smith Creek watershed, within the Shenandoah Valley, was designated a showcase watershed in 2010 by the United States Department of Agriculture to demonstrate the efficacy of implementing restoration projects. We sampled fifteen farms ranging from unrestored to thirty-six years since restoration. At each site, we conducted a kick-net survey for macroinvertebrates, measured canopy cover, algal density, substrate size, and bank height and angle. We identified macroinvertebrates to family and calculated the Chesapeake Basin-wide Index …

Is Immediate Flexibility Present In A Vocal Mimic, The Gray Catbird (Dumetella Carolinensis), Across An Urban Gradient?, Shannon K. Eppert

Masters Theses, 2020-current

Increasing urbanization has increased anthropogenic noise levels near developed areas. Urban noise is high amplitude and low-frequency, and these frequencies can overlap with the signals animals use to communicate, including bird songs. Many urban birds sing higher minimum frequencies in urban areas, which avoids some masking by noise, but the mechanism behind this difference is not well understood. Immediate flexibility is the ability to alter song in real-time in the presence of sudden noise, allowing for avoidance of masking and better signal transmission. I investigated if male catbirds increased signal transmission in the presence of anthropogenic versus high-frequency noise playback …

Population Study Of Native And Invasive Turtles In Harrisonburg, Virginia, David R. Weisenbeck

Senior Honors Projects, 2020-current

The Red-eared Slider, Trachemys scripta is an invasive species responsible for declines in turtle species across the world. Trachemys scripta is native to two parts of southern Virginia but the species has been introduced throughout the rest of the state, often related to the release of pet trade animals. This study aimed to identify the extent of Trachemys scripta’s establishment and impact on native species in Harrisonburg, Virginia. Turtles were trapped in a mark-recapture study during the springs and summers of 2018, 2019, and 2020 in four local ponds in Harrisonburg, Virginia. Cormack-Jolly-Seber population models were constructed using data …

Influence Of Testosterone On Male-Male Competition In The Red-Sided Garter Snake, Thamnophis Sirtalis Parietalis, Isabella M. G. Bukovich

Senior Honors Projects, 2020-current

Female mimicry in the red-sided garter snake, Thamnophis sirtalis parietalis, is described in several well-studied evolutionary advantages, but an aspect that remains elusive is how reproductive traits are linked to the 3-fold higher circulating androgens in males with this phenotype. In this study, we implanted male garter snakes (n=15 per group) with either a blank implant (SHAM; control) or a T implant, the latter simulating the female mimic phenotype. Following simulated low-temperature dormancy, males were scored for courtship intensity over three days of behavioral trials with females housed in the same facility. Males were sacrificed, and sperm were collected …

Population Status, Threats, And Conservation Of Preuss's Red Colobus (Piliocolobus Preussi) And Other Diurnal Primates In The Ndokbou Forest, Littoral Region, Cameroon, Ruth Bowers-Sword

Masters Theses, 2020-current

The Ebo-Makombe-Ndokbou forest block in southwest Cameroon lies within the Gulf of Guinea biodiversity hotspot, characterized by extremely high levels of species richness and endemism, including those of primates. These forests may contain one of the last populations of the Critically Endangered Preuss’s red colobus monkey (Piliocolobus preussi; PRC), which is found only in southeastern Nigeria and western Cameroon. Gun hunting for bushmeat and habitat loss and degradation from logging and agriculture are the main threats to PRC. The conservation status of PRC and other primates in the Ndokbou forest are largely unknown, with most regional research efforts occurring in …

Novel Method To Determine Paleodiet Of Extinct Equid Merychippus Sp. Using Dental Calculus, Ranjit Z. S. Virk

Senior Honors Projects, 2020-current

Within the Miocene Epoch, the emergence of grasslands within North America coincided with the incidence of higher-crowned teeth (hypsodonty) within the proto-horse Merychippus that allowed for the inclusion of these expanding grasslands as a food source. As herbivorous paleofauna consume plant matter, microscopic remains become incorporated within dental calculus and, due to their diagnostic morphology, can be used to identify dietary components. In Merychippus, the recovery of plant microfossils holds the potential to provide greater clarity on the paleodiet of these equids. In the present study, the purpose was to quantify and compare Merychippus paleodiet constituents among sample groups. …

Habitat Utilization And Impact Of Flooding On James Spinymussel (Parvaspina Collina) Populations In Virginia Streams, Christine A. Verdream

Masters Theses, 2020-current

The James spinymussel (Parvaspina collina) is Critically Endangered and endemic to Virginia’s James River basin. P. collina was listed as Endangered in 1988 and more than 90% of the species has been lost over the last 30 years (USFWS 1990). Despite the development of a recovery plan in 1990, there has not been a comprehensive reassessment of P. collina in over 30 years. This study explored the relationship between flooding and P. collina population dynamics in a flood prone stream and further explained habitat occupancy. Study sites included Swift Run and Little Oregon Creek, both of which still …

Modeling Species Distribution And Habitat Suitability Of American Ginseng (Panax Quinquefolius) In Virginia, Jacob D. J. Peters

Masters Theses, 2020-current

American ginseng (Panax quinquefolius) is a well-known and sought-after medicinal plant native to North America that is facing increased threat of extinction due to overharvesting, herbivory, and habitat loss. Species distribution and habitat suitability models may be valuable to landowners interested in sustainable harvest or to institutions interested in the conservation and restoration of the species. With unequal sampling efforts across a region of interest, it is likely that some locations with appropriate habitat may be misrepresented in model predictions. This study refined a state-derived species distribution model for ginseng through increased sampling effort across the Cumberland Plateau …

Determining The Impacts Of Urbanization On Song Structure And Its Function In Territorial Defense For Gray Catbirds (Dumetella Carolinensis), Morgan L. Rhodes

Masters Theses, 2020-current

In urbanized habitats, animals are faced with novel selection pressures such as differences in community structure and increased urban noise. Urban noise pollution can negatively impact songbirds as low-frequency noise often masks portions of birds’ mating signal and reduces signal transmission. Previous research has demonstrated that songs of birds in more urban habitats have structural differences that enhance signal transmission when noise is present. These studies have focused on species that deliver short, stereotyped songs with limited repertoires. Gray catbirds (Dumetella carolinensis, family: Mimidae) sing long bouts containing imitated, improvised, and invented song elements, and therefore may have …

Examining The Effect Of Interstitial Space On Eastern Oysters (Crassostrea Virginica): Applications Of Photogrammetry And Three-Dimensional Modeling, Bailie Lavan

Masters Theses, 2010-2019

Global oyster populations have decreased by as much as 99% in the past century. Oysters are known ecosystem engineers, providing benthic habitat for macrofauna, linking benthic and pelagic food webs, improving water quality, and mitigating shoreline erosion. Restoration efforts are critical in re-establishing native oyster populations. In the Chesapeake Bay, where oyster loss is primarily due to severe over harvest, artificial substrates with geometric shapes are widely used in restoration efforts. However, natural oyster reefs form emergent shapes with a high degree of aggregation and many interstitial spaces (three-dimensional volumetric spaces between oysters within a reef). The lack of interstitial …

Anti-Crispr Vs. Crispr: The Evolutionary Arms Race Between Microorganisms, Rachael M. St. Jacques

Masters Theses, 2010-2019

CRISPR arrays are a defense mechanism employed by bacteria against viral invaders. Cas proteins do the work in detecting, capturing, and integrating the viral DNA into the CRISPR array (Barrangou et al., 2007). Anti-CRISPR proteins are produced by phages, viruses that infect bacteria, to stop the bacterial host’s CRISPR-Cas complex from interrupting the phage life cycle (Bondy-Denomy, et al., 2015).

SEA-PHAGES is a course-based bacteriophage research network composed of 120 colleges and known at James Madison University as Viral Discovery. JMU uses the unsequenced Streptomyces griseus ATCC10137 as a host for bacteriophage discovery and propagation, and in this study we …

Reproductive Character Displacement In Calopteryx Aequabilis And C. Maculata: Improving Species Recognition Through The Divergence Of Male Mating Preferences, Melissa Encinias

Masters Theses, 2010-2019

An ongoing evolutionary question is how co-occurring species maintain reproductive barriers when they are morphologically, behaviorally, and ecologically similar. Without geographic isolation, traits involved in species recognition may be under selection to enhance reproductive barriers. Exaggerated trait differences between species in sympatric populations may reflect selection to reduce misdirected mating between species, or reproductive character displacement. While this phenomenon is widely recognized as an important stage in the speciation process, there is little direct evidence of this process in nature. In two North American damselfly species, Calopteryx aequabilis and C. maculata, wing pigmentation is sexually dimorphic and also shows …

Assessing Populations Of Eastern Brook Trout (Salvelinus Fontinalis) Above And Below Waterfalls In Mountain Streams Of Virginia, Hannah Eisemann Macmillan

Masters Theses, 2010-2019

Anthropogenically driven factors, such as increasing temperature and sediment in valley streams, acidification of mountain streams, and the introduction of non-native trout, are restricting habitat suitable for healthy populations of eastern brook trout (Salvelinus fontinalis) throughout their native Appalachian range. Brook trout are important as predators of insects in mountain streams and as a favorite of anglers. It is crucial that remaining populations in sustainable habitats be identified and preserved. Waterfalls are geologic knickpoints preventing base-level lowering that create unique, stable landscapes above them, which may alleviate the temperature-productivity/acidity “habitat squeeze” for populations of brook trout and could …

Herpetological Assemblages In Tropical Dry Forests Of The Azuero Peninsula, Panama: An Evaluation Of Reforestation, Tyler Kovacs

Masters Theses, 2010-2019

Tropical dry forests are considered one of the most endangered tropical ecosystems making reforestation increasingly necessary to restore Panama’s unique ecoregion. The isolated dry ecoregion surrounding the Bay of Parita in Panama has a long history of deforestation and cattle grazing. Successful reforestation of this land is important to restore ecosystem health and biodiversity. In Panama, reforestation ranges from monocultures of exotic teak (Tectona grandis) to passive regeneration. Faunal recovery within these reforestation systems may vary due to different habitat characteristics. In this study, amphibian and reptile communities were compared in two types of reforestation systems and protected riparian forests …

Urban Stream Restoration: An Evaluation Of Material Processing And Conveyance Channels, Madeline Berg

Masters Theses, 2010-2019

Stream restoration is gaining popularity in the Mid - Atlantic region to offset impacts from urbanization. Increased levels of impervious surfaces, decreased vegetation along banks, and changes in water flow patterns make urban stream ecosystems flashy and result in high erosion rates, increasing the amount of nutrients entering the Chesapeake Bay. Different restoration practices can play a large role in the amount of nutrients and organic matter leaving a stream and the amount of habitat that is present in-stream.

Due to the recent interest in stream restoration as a tool to help the health of the Chesapeake Bay, this study …

Forest Structure Of Long-Term Conserved Areas Utilizing Different Strategies On A Continental, Glacial Moraine Formed Island, Christopher Coggin

Masters Theses, 2010-2019

Understanding patterns of forest succession can help advise management plans within New England nature preserves. This study took place on Block Island, 13 miles off the coast of Rhode Island. The island has greater than 200+ years of farming practices. After 1960, conservation groups began reforesting the island using different strategies, such as actively planting with native and exotic tree species, mowing, and preventing further development. In 2018, woody vegetation was inventoried along transects within four reforested sites. Sites were characterized as the following: actively planted with exotic and native tree species and mowed (AP-M), actively planted with exotic and …

Microplastics In Full View: Birds As Bioindicators Of Malta's Coastal Ecosystem Health, Dalton Brauer

Masters Theses, 2010-2019

Plastic pollution has recently become a widely studied topic, yet research on microplastics has remained lacking for specific geographic regions. Microplastics are small plastics resulting from degradation or the dumping of raw material and can lead to deleterious impacts on the coastal marine environment and its organisms. To assess Malta’s coastal environmental health, water birds (inshore, offshore and pelagic species) were used as bioindicators by assessing the presence and abundance of plastic within their stomach contents. The project hoped to fill some of the current gaps in knowledge on microplastics within Malta by creating a working baseline, as well as …

Geospatial Analysis Of Eastern Oyster Habitat And Disease In The Chesapeake Bay, Hannah Bradley

Senior Honors Projects, 2010-2019

Crassostrea virginica, common name eastern oyster, in the Chesapeake Bay is currently at 1% of its peak annual landings in 1884 (600,000 metric tons). This decline is in spite of being considered a resilient species. Causes of the decline include overharvesting, disease, and habitat loss. While efforts have been made to combat each cause, the key element to recovering the population is coordinated habitat restoration. This study aims to develop a GIS-based habitat model for the eastern oyster in the Chesapeake Bay. The first goal of this study was to determine the water quality parameters necessary for successful oyster …

Potential Benefits Of Restored Riparian Zones In An Agricultural Matrix For Bat Communities, Matthew T. Harris

Masters Theses, 2010-2019

Riparian buffers planted within agricultural matrices for wildlife conservation are expected to support numerous taxa, but a lack of empirical testing has limited evaluation of these practices. It is imperative that biologists and land managers understand how current conservation practices impact bats so that the ecosystem services provided by bats are maintained as farming practices continue to intensify in regions dominated by agriculture. This study evaluates the effects of planted riparian buffers along streams in an agricultural matrix by comparing acoustic bat activity along streams in active cattle pasture with activity at streams where riparian buffers have been planted. Forest …

The Combined Effects Of Soil Fertility And Soil Amendments On The Growth And Mycorrhizal Associations Of American Ginseng (Panax Quinquefolius), Emily Ann Murray

Masters Theses, 2010-2019

Arbuscular mycorrhizal fungi (AMF) are fungi that form symbiotic associations with 70-90% of plant families. They are known to allow for the extension of the root system as well as an increase in plant size by assisting with the uptake of nutrients such as nitrogen and phosphorus. The role that AMF play in plant health and success has led to the development of commercial inoculum, which is used in agricultural settings. However, soil fertility, and soil amendments are known to affect AMF and plant associations. This study intends to look at how cultivated American Ginseng seedlings are affected by commercial …

Competition And Predation: Interactions Between American Eels (Anguilla Rostrata) And Brook Trout (Salvelinus Fontinalis) In Virginia Mountain Streams, Jonathan Studio

Masters Theses, 2010-2019

Competition has played a large role in structuring natural communities, especially with regards to vulnerable organisms. Brook trout and American eel populations have declined in the Mid-Atlantic Region of the United States as a result of anthropogenic development around freshwater ecosystems, and thus, subsequent conservation efforts of both species have included habitat restoration. Conservation efforts have increased the co-occurrence of these predatory fish species that are known to require similar resources. The main objective of this research was to elucidate the potential for competition between brook trout and American eels through analysis of their preferred prey, diet overlap, and supplementary …