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Full-Text Articles in Research Methods in Life Sciences

An Automatic System To Evaluate Bait Station Visitation By Brown Treesnakes And Mongooses, Robert T. Sugihara, William C. Pitt, Are R. Berentsen, Francis L. Benevides Jr. Jan 2023

An Automatic System To Evaluate Bait Station Visitation By Brown Treesnakes And Mongooses, Robert T. Sugihara, William C. Pitt, Are R. Berentsen, Francis L. Benevides Jr.

Human–Wildlife Interactions

Understanding the temporal, spatial, and behavioral patterns of the free-ranging target species in response to candidate baits and baiting strategies is important to ensure control success. This information can also assist in the development and deployment of feeding stations and can exclude non-target species while constituting effective bait delivery and control strategies for certain invasive animals, especially at environmentally sensitive sites. We used passive integrated transponder (PIT) tags in conjunction with very-high frequency radio-telemetry to remotely record bait station visitations and evaluate bait attractiveness in separate field research studies of brown treesnakes (Boiga irregularis) on Andersen Air Force …


Genetic Evaluation Of The Current Distribution And Possible Diffrentations Between Lasiurus Borealis And Lasiurus Frantzii In Southwestern North America, Zeinab M. Haidar Jan 2023

Genetic Evaluation Of The Current Distribution And Possible Diffrentations Between Lasiurus Borealis And Lasiurus Frantzii In Southwestern North America, Zeinab M. Haidar

Cal Poly Humboldt theses and projects

Several recent accounts of overlap and historic misidentifications regarding two species of the genus Lasiurus, Western red bat (Lasiurus frantzii) and Eastern red bat (Lasiurus borealis), have cast doubt on our understanding of their distribution, assumed spatial allopatry, and interactions in the United States Southwest. With the use of morphometrics and genetic sequencing, utilizing tissue collected from specimens throughout California and adjoining states, we have reassessed the current distribution, best practices for field identification, and genetic differentiation between both species. Appropriate species classification by region was achieved utilizing mitochondrial DNA, targeting the cytochrome c oxidase …


Effects Of Social Context On Salivary Cortisol And Attention In Tufted Capuchins (Cebus [Sapajus] Apella), Andrew Desana Jan 2023

Effects Of Social Context On Salivary Cortisol And Attention In Tufted Capuchins (Cebus [Sapajus] Apella), Andrew Desana

Master’s Theses

Social context alters cognitive performance, but the mechanisms for this remain unclear. One possibility is that stressors associated with social contexts mediate changes in cognitive performance by influencing attention. We conducted two experiments to investigate how social context affects performance on an attention task in capuchin monkeys (Cebus [Sapajus] apella). We additionally validated and measured physiological stress through salivary cortisol. In experiment one, capuchins were exposed to three conditions where they were either isolated or paired with an affiliative or agonistic social partner separated by a barrier. In experiment two, subjects received affiliative and agonistic conditions without barriers to allow …


A Critical Look At Wild Pig Elimination: Myths And Facts, Kim M. Pepin, Travis L. Guerrant, Jeremiah L. Psiropoulos, Jeanine T. Neskey, John M. Tomeček, Michael J. Bodenchuk, Janean L. Romines Jan 2023

A Critical Look At Wild Pig Elimination: Myths And Facts, Kim M. Pepin, Travis L. Guerrant, Jeremiah L. Psiropoulos, Jeanine T. Neskey, John M. Tomeček, Michael J. Bodenchuk, Janean L. Romines

Human–Wildlife Interactions

Wild pigs (Sus scrofa) are abundant and widely distributed in the United States. They damage crops and pastures, predate livestock and sensitive species, impact ecosystem functions, and damage personal property. To address these issues, some states in the United States are seeking complete elimination. A frequently asked question by stakeholders is: “What portion of the population needs to be removed annually to reach elimination?” The number 70% is widely touted as the answer. There is little scientific evidence to support that this percent annual removal would be needed to achieve elimination, yet 70% has now become a standard …


Effectiveness Of Citizen Engagement In A State Agency Egg-Oiling Program To Reduce Urban Canada Goose Populations And Conflicts, Charles H. Cope, Tom F. Bidrowski, Jon P. Beckmann Jan 2023

Effectiveness Of Citizen Engagement In A State Agency Egg-Oiling Program To Reduce Urban Canada Goose Populations And Conflicts, Charles H. Cope, Tom F. Bidrowski, Jon P. Beckmann

Human–Wildlife Interactions

In many cases, urban environments create high-quality habitat for wildlife that may allow species to form commensal relationships with humans. Positive impacts of urban environments (e.g., high-quality nesting habitat) may enhance survival and/or increased fecundity. One species that has shown the ability to form commensal relationships with humans in urban environments is Canada geese (Branta canadensis). Canada goose populations have continued to rebound in Kansas, USA, and across the Great Plains, such that the estimated resident population in Wichita, Kansas, grew from 0 to >5,000 resident geese and the over-winter population increased from 1,600 in 1997 to >18,000 …


Importance Of The Microhabitat And Microclimate Conditions In The Northern Gray-Cheeked Salamander (Plethodon Montanus) Across An Elevation Gradient, Trevor Chapman Dec 2022

Importance Of The Microhabitat And Microclimate Conditions In The Northern Gray-Cheeked Salamander (Plethodon Montanus) Across An Elevation Gradient, Trevor Chapman

Electronic Theses and Dissertations

The southern Appalachian Mountains have among the highest salamander diversity in the world, largely due to local speciation in the family Plethodontidae. Plethodontid salamanders (i.e., lungless salamanders) are particularly sensitive to habitat climate conditions due to their reliance on cutaneous respiration, and their immediate environmental conditions (microhabitat) likely influence their dispersion and activity more than the large-scale atmospheric conditions. The Northern Gray-cheeked salamander (Plethodon montanus) is restricted to high elevations in the Appalachian Mountains. Our goal was to investigate the relationship between P. montanus and its microhabitat by examining behavioral preference for climatic conditions, characterizing the microclimate with …


Internal Vertebral Morphology Of Bony Fishes Matches The Mechanical Demands Of Different Environments, Dana Baxter, Karly E. Cohen, Cassandra M. Donatelli, Eric D. Tytell Nov 2022

Internal Vertebral Morphology Of Bony Fishes Matches The Mechanical Demands Of Different Environments, Dana Baxter, Karly E. Cohen, Cassandra M. Donatelli, Eric D. Tytell

Engineering Faculty Articles and Research

Fishes have repeatedly evolved characteristic body shapes depending on how close they live to the substrate. Pelagic fishes live in open water and typically have narrow, streamlined body shapes; benthic and demersal fishes live close to the substrate; and demersal fishes often have deeper bodies. These shape differences are often associated with behavioral differences: pelagic fishes swim nearly constantly, demersal fishes tend to maneuver near the substrate, and benthic fishes often lie in wait on the substrate. We hypothesized that these morphological and behavioral differences would be reflected in the mechanical properties of the body, and specifically in vertebral column …


Orb-Weaver Diversity And Niche Partitioning In Ecuador’S Amazonian Foothills: What Spiders Can Reveal About Tree Fall Gaps, Streams, And Cultivated Areas, Riley Endries Oct 2022

Orb-Weaver Diversity And Niche Partitioning In Ecuador’S Amazonian Foothills: What Spiders Can Reveal About Tree Fall Gaps, Streams, And Cultivated Areas, Riley Endries

Independent Study Project (ISP) Collection

As abundant predators at the top of arthropod food chains, spiders are excellent bioindicators. Araneae is a megadiverse and extremely understudied order, especially in the tropics. This study aims to investigate the diversity of orb-weaver spiders across a disturbance gradient and variety of habitat types as well as their microhabitat preferences and potential niche partitioning. Spider collection was performed on spiders of the families Araneidae, Tetragnathidae, and Theridiosomatidae in Sumak Kawsay in Situ biological reserve in the lower elevation cloud forest of Ecuador’s Andean foothills. Spiders and webs were observed and analyzed from primary and secondary forest tree fall gaps, …


Arthropod Assemblages At The Intersection Of Epiphyte And Soil Habitats: An Assessment Of Understory Level Nonvascular Epiphyte Communities And Their Connectivity Within A Tropical Montane Rainforest, David “Max” Jones Oct 2022

Arthropod Assemblages At The Intersection Of Epiphyte And Soil Habitats: An Assessment Of Understory Level Nonvascular Epiphyte Communities And Their Connectivity Within A Tropical Montane Rainforest, David “Max” Jones

Independent Study Project (ISP) Collection

Canopy arthropods communities represent a disproportionate amount of global species richness (Stuntz 2001). Understanding arthropod composition and connectivity of lower epiphyte communities is important in understanding how canopy arthropods communities are formed and will respond to change (Floren and Linsenmair 1998). As such this study examined arthropod assemblages living within nonvascular epiphyte communities (epiphyte mats) living directly upon lower trunk regions of 24 trees in a tropical montane rain forest within the Santa Lucia Nature Reserve in Pichincha, Ecuador. Trees were assessed for size, epiphyte diversity, and epiphyte coverage before arthropod sampling within the epiphyte mats. Soil assessments were taken …


The Nesting Behavior Of Russet-Backed Oropendola On Sumak Allpa, Ecuador: An Analysis Of Nest Construction And Interactions With Competing Species, Claire Molina Oct 2022

The Nesting Behavior Of Russet-Backed Oropendola On Sumak Allpa, Ecuador: An Analysis Of Nest Construction And Interactions With Competing Species, Claire Molina

Independent Study Project (ISP) Collection

Nests are the literal place of birth of bird species; they are incredibly important in the survival and reproduction of populations. Therefore, nesting behavior is a gateway into the lives and success of the animals. With the degradation of natural landscapes due to human activity, there is more of a need to monitor these nests to ensure healthy inhabitants. The Russet-backed Oropendola (Psarocolius angustifrons) creates unique, pendulous nests that are subject to piracy, parasitism, and predation; as well as weather phenomenon’s such as wind and rainstorms. This study describes the nest construction behavior, nest materials and nest architecture by collecting …


Afforestation And Biodiversity: Bryophyte Richness Changes Between Icelandic Forest Types, Kian Mcdonough Oct 2022

Afforestation And Biodiversity: Bryophyte Richness Changes Between Icelandic Forest Types, Kian Mcdonough

Independent Study Project (ISP) Collection

Forest-dwelling bryophytes (mosses, liverworts, hornworts) greatly contribute to biodiversity and ecosystem function but are largely under-studied in comparison to vascular plants. With Iceland’s large-scale afforestation efforts there is a need to understand how different afforestation species are affecting biodiversity, including bryophyte diversity. This study looked at differences in ground-floor bryophyte richness across Sitka spruce, lodgepole pine, and downy birch forests and found that bryophyte richness was highest in the Sitka spruce forests and lowest in downy birch forests. While this suggests a negative correlation between bryophyte richness and light availability, since the conifer species have the densest copy cover, other …


Observational Study Of Woolly Monkey Behavior And Vocalizations: Behavioral Time Allotment And Vocalization Habits Of A Small Population Of Poeppig’S Woolly Monkey (Lagothrix Lagotricha Poeppigii) In The Ecuadorian Amazon, Marina Smith-Hanke Oct 2022

Observational Study Of Woolly Monkey Behavior And Vocalizations: Behavioral Time Allotment And Vocalization Habits Of A Small Population Of Poeppig’S Woolly Monkey (Lagothrix Lagotricha Poeppigii) In The Ecuadorian Amazon, Marina Smith-Hanke

Independent Study Project (ISP) Collection

Poeppig’s woolly monkey (Lagothrix lagotricha poeppigii), a species of primate native to the Amazonian regions of western Brazil, eastern Ecuador, and northeastern Peru, is classified as endangered by the IUCN. These large, frugivorous primates are threatened by habitat loss and climate change as a result of human interference. Deforestation, hunting, petroleum mining, and illegal trafficking are all huge threats to this species. As a result of these pressures, their populations have decreased by at least 30% over the past three generations. However, as keystone seed dispersers, they are essential for Amazonian ecosystem health; without their seed dispersal services, a loss …


Maternal Responses In The Face Of Infection Risk, Patricia C. Lopes, Brenna M. G. Gormally, Aubrey Emmi, Delilah Schuerman, Chathuni Liyanage, Ursula K. Beattie, L. Michael Romero Jun 2022

Maternal Responses In The Face Of Infection Risk, Patricia C. Lopes, Brenna M. G. Gormally, Aubrey Emmi, Delilah Schuerman, Chathuni Liyanage, Ursula K. Beattie, L. Michael Romero

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

When animals are sick, their physiology and behavior change in ways that can impact their offspring. Research is emerging showing that infection risk alone can also modify the physiology and behavior of healthy animals. If physiological responses to environments with high infection risk take place during reproduction, it is possible that they lead to maternal effects. Understanding whether and how high infection risk triggers maternal effects is important to elucidate how the impacts of infectious agents extend beyond infected individuals and how, in this way, they are even stronger evolutionary forces than already considered. Here, to evaluate the effects of …


Developing A Novel Place Preference Assay To Compare Drosophila Species Over Time, Martha M. Brinson May 2022

Developing A Novel Place Preference Assay To Compare Drosophila Species Over Time, Martha M. Brinson

Honors Theses

Across phylogeny, integration of external factors, memory, and internal states of the organism dictate organismal behavior and mechanisms. The underlying genetic components can affect these behaviors such as in genomic changes arising from speciation. In this thesis, a new place preference assay was evaluated in the analysis and investigation of two species of Drosophila flies (D. melanogaster and D. simulans) to measure similarities and differences and their attraction to two different food substrates. Sleep and circadian measurements were also recorded during experimentation. The Drosophila Activity Monitor 5M (DAM5M) System and Sleep Circadian Analysis MATLAB Program (SCAMP) analysis were …


Signaling Strategies And Competition In Male Tungara Frogs, Alison S. Kim Apr 2022

Signaling Strategies And Competition In Male Tungara Frogs, Alison S. Kim

Pacific Undergraduate Research and Creativity Conference (PURCC)

No abstract provided.


The Relationship Between Substrate Composition, Community Structure And Feeding Preferences Of Parrot Fishes (Scaridae) In Anmardub, Guna Yala Coastal Reefs, Caitlin Amman Apr 2022

The Relationship Between Substrate Composition, Community Structure And Feeding Preferences Of Parrot Fishes (Scaridae) In Anmardub, Guna Yala Coastal Reefs, Caitlin Amman

Independent Study Project (ISP) Collection

Coral reefs are important marine ecosystems, as they support biodiversity and generate buffer zones, yet their abundance is incredibly limited globally. One of the main threats that coral reefs face is excessive macroalgal coverage, which limits sunlight from reaching corals, and thus, limits the energy that can reach them. Parrot fish (Scaridae) are keystone herbivores, as they consume macroalgae growing on corals, which aids in reef survivability. While there is previous research on the abundances, sizes, and feeding habits of Scaridae species in the Caribbean, there is no published research on how community structure and feeding preferences of parrot fishes …


Behavioral And Physiological Effects Of Heavy Metals On Fish: A Review And Preliminary Results, Diana V. Morales Mar 2022

Behavioral And Physiological Effects Of Heavy Metals On Fish: A Review And Preliminary Results, Diana V. Morales

Theses and Dissertations

Pollution, specifically heavy metal pollution, in various bodies of water has been a significant issue for decades. Research has been conducted on heavy metals and their effects on the environment, larger fish species, and humans since the 1970s (Skidmore, 1964; Adeniyi et al., 2007; Adeosun et al., 2015; Bawuro et al., 2018). It is known that zinc is a neurotoxin in some species and causes harm to the environment. It is also known that it causes harm to people if it is ingested or if they are exposed to it for long periods of time (Mahurpawar, 2015; Mizuno and Kawahara, …


Cold Shock Induces A Terminal Investment Reproductive Response In C. Elegans, Leah Gulyas, Jennifer R. Powell Jan 2022

Cold Shock Induces A Terminal Investment Reproductive Response In C. Elegans, Leah Gulyas, Jennifer R. Powell

Biology Faculty Publications

Challenges from environmental stressors have a profound impact on many life-history traits of an organism, including reproductive strategy. Examples across multiple taxa have demonstrated that maternal reproductive investment resulting from stress can improve offspring survival; a form of matricidal provisioning when death appears imminent is known as terminal investment. Here we report a reproductive response in the nematode Caenorhabditis elegans upon exposure to acute cold shock at 2 °C, whereby vitellogenic lipid movement from the soma to the germline appears to be massively upregulated at the expense of parental survival. This response is dependent on functional TAX-2; TAX-4 cGMP-gated channels …


Ephemeroptera Culturing Methods: An Analysis On Rearing And Toxcity Testing On Sensitive Early Life Stages Of Native Mayfly Taxa, Geneve Rainette Edwards Jan 2022

Ephemeroptera Culturing Methods: An Analysis On Rearing And Toxcity Testing On Sensitive Early Life Stages Of Native Mayfly Taxa, Geneve Rainette Edwards

Theses, Dissertations and Capstones

Standard toxicity testing organisms are utilized for regulatory purposes and often ecological risk assessments. Ephemeroptera taxa have been reported to be more sensitive to aquatic contaminants than the standard toxicity testing organisms currently used in determining effects on aquatic ecosystems. Establishing methods for culturing native Ephemeroptera taxa will provide a more sensitive test organism to determine the toxicity of contaminants and will be more representative of the responses of native taxa. Additionally, it will provide a test organism at the most sensitive life stages. The objective of this research is to develop methods for culturing and testing of native Ephemeroptera …


Fish And Invertebrate Use Of Restored Vs. Natural Oyster Reefs In A Shallow Temperate Latitude Estuary, Jonathan H. Grabowski, Christopher J. Baillie, Adam Baukus, Rachael Carlyle, F. Joel Fodrie, Rachel K. Gittman, A. Randall Hughes, David L. Kimbro, Juhyung Lee, Hunter S. Lenihan, Sean P. Powers, Kevin Sullivan Jan 2022

Fish And Invertebrate Use Of Restored Vs. Natural Oyster Reefs In A Shallow Temperate Latitude Estuary, Jonathan H. Grabowski, Christopher J. Baillie, Adam Baukus, Rachael Carlyle, F. Joel Fodrie, Rachel K. Gittman, A. Randall Hughes, David L. Kimbro, Juhyung Lee, Hunter S. Lenihan, Sean P. Powers, Kevin Sullivan

University Faculty and Staff Publications

Coastal marine habitats continue to be degraded, thereby compelling largescale restoration in many parts of the world. Whether restored habitats function similarly to natural habitats and fully recover lost ecosystem services is unclear. In estuaries, oyster reefs have been degraded by multiple anthropogenic activities including destructive fishing practices and reduced water quality, motivating restoration to maintain oyster fisheries and other ecosystem services, often at relatively high cost. We compared fish and invertebrate communities on recently restored (0–1 year post-restoration), older restored (3–4 years post-restoration), and natural oyster reefs to determine if and when restored reefs support functionally similar faunal communities. …


Population Dynamics, Relative Abundance, And Habitat Suitability Of Adult Red Drum (Sciaenops Ocellatus) In Nearshore Waters Of The North-Central Gulf Of Mexico, Crystal Hightower, J. Marcus Drymon, Amanda E. Jefferson, Matthew B. Jargowsky, Emily A. Seubert, Simon Dedman, John Mareska, Sean P. Powers Jan 2022

Population Dynamics, Relative Abundance, And Habitat Suitability Of Adult Red Drum (Sciaenops Ocellatus) In Nearshore Waters Of The North-Central Gulf Of Mexico, Crystal Hightower, J. Marcus Drymon, Amanda E. Jefferson, Matthew B. Jargowsky, Emily A. Seubert, Simon Dedman, John Mareska, Sean P. Powers

University Faculty and Staff Publications

In the Gulf of Mexico, the red drum (Sciaenops ocellatus) is an immensely popular sportfish, yet the Gulf of Mexico stock is currently managed as data-limited in federal waters. The results of the federal stock assessment conducted in 2016 for Gulf of Mexico red drum were not recommended for providing management advice. Consequently, we sought to address data gaps highlighted in the assessment by producing up-to- date overall and sex-specific growth models, standardized indices of relative abundance, and predictions of habitat suitability and by updating estimates of natural mortality. Using a time series for the period of 2006–2018, we assigned …


Ephemeroptera Culturing Methods: Development Of Culturing And Rearing Methodology And High Sulfate Simulated Mine Effluent Toxicity Test Using Field Collected Water, Daniel Edward Brady Jan 2022

Ephemeroptera Culturing Methods: Development Of Culturing And Rearing Methodology And High Sulfate Simulated Mine Effluent Toxicity Test Using Field Collected Water, Daniel Edward Brady

Theses, Dissertations and Capstones

Ephemeroptera taxa are not frequently used in toxicity testing; however, some mayfly taxa may be more sensitive to aquatic pollutants than standard test organisms used to determine anthropogenic effects on aquatic ecosystems. Additionally, some standard test organisms are not native to the Appalachian region and may not be truly reflective of the effects on native organisms. With mayflies not being the typical test organism, there is not a great deal of literature on culturing methods for this organism. For a standard acute toxicity test, there must be 80% survival within the control organisms for the test to be considered viable. …


Evaluating Relative Abundance, Fish Length, And Marine Protected Area Effectiveness For Four Key Rocky Reef Species Along The Northern Californian Coast, Leon Davis Jan 2022

Evaluating Relative Abundance, Fish Length, And Marine Protected Area Effectiveness For Four Key Rocky Reef Species Along The Northern Californian Coast, Leon Davis

Cal Poly Humboldt theses and projects

Marine protected areas (MPAs) were created with the purpose of helping conserve and restore diminished populations of marine organisms. Measuring the effectiveness of MPAs requires long-term monitoring, investigating the abundance and size distributions of the species that utilize the conservation areas, and comparing the results to neighboring reference sites that are not currently protected. In this study, observations from long-term MPA monitoring in northern California (2010-2019) were modeled with substrate, oceanographic, spatial, temporal, and body size variables to describe the variability in abundance and size of three fish groups: Black rockfish (Sebastes melanops), the Blue rockfish group (comprised …


Modernizing Fish Surveys: Evaluating How Reliable Environmental Dna Sampling Is In Monitoring Fish Populations, Alicia Cozza Jan 2022

Modernizing Fish Surveys: Evaluating How Reliable Environmental Dna Sampling Is In Monitoring Fish Populations, Alicia Cozza

EWU Masters Thesis Collection

No abstract provided.


Investigating The Genetic Diversity Of Immune Genes In Non-Native Populations Of American Bullfrogs (Rana Catesbeiana), Luisa Nereyda Segovia Jan 2022

Investigating The Genetic Diversity Of Immune Genes In Non-Native Populations Of American Bullfrogs (Rana Catesbeiana), Luisa Nereyda Segovia

Cal Poly Humboldt theses and projects

The American Bullfrog (Rana catesbeiana) is a highly invasive species that has successfully colonized habitats around the world. The genetic variability of immune genes within invasive populations, like that of bullfrogs, may contribute to how resistant a population is to pathogens. The objective of this project was to characterize the genetic diversity of an immune gene in invasive bullfrog populations in California to better understand how persistent these populations might be over time. To characterize immune gene variability, I isolated exon 2 of the Major Histocompatibility Complex (MHC) Class II Beta chain gene and a neutral mitochondrial marker, …


Pushing It To The Limit: Determining Asian Elephant (Elephas Maximus) Olfactory Sensitivity And Discrimination Through A Behavioral Choice Task, Matthew S. Rudolph Dec 2021

Pushing It To The Limit: Determining Asian Elephant (Elephas Maximus) Olfactory Sensitivity And Discrimination Through A Behavioral Choice Task, Matthew S. Rudolph

Theses and Dissertations

Elephants have shown remarkable olfactory capabilities. Their sense of smell impacts their foraging choices, behavior, and ultimately, survival. Being able to detect a target odor can allow elephants to locate specific resources, identify threats, and find receptive conspecifics. Previous studies have shown that elephants can consistently detect target odors, but have not identified the limits of this detection. Thus, to investigate the extent of elephants’ odor detection capabilities, we tested Asian elephants in a two-step odor discrimination task. First, we investigated whether elephants could detect odors at varying levels of dilution after a training procedure, and then whether they could …


American Bullfrog (Lithobates Catesbeianus) Diet In Uruguay Compared With Other Invasive Populations In Southern South America, Gabriel Laufer, Noelia Gobel, Mauro Berazategui, Matías Zarucki, Sofía Cortizas, Alvaro Soutullo, Claudio Martinez Debat, Rafael O. De Sá Dec 2021

American Bullfrog (Lithobates Catesbeianus) Diet In Uruguay Compared With Other Invasive Populations In Southern South America, Gabriel Laufer, Noelia Gobel, Mauro Berazategui, Matías Zarucki, Sofía Cortizas, Alvaro Soutullo, Claudio Martinez Debat, Rafael O. De Sá

Biology Faculty Publications

Between 2000-2020, more than ten new populations of the invasive American bullfrog (Lithobates catesbeianus) have been reported in the southern cone of South America. We studied the stomach contents of 126 bullfrogs from a population at an early invasion stage in Uruguay (Acegua, Cerro Largo Department). We observed a rich diet, with extensive prey volume range (1 mm3 to more than 7 000 mm(3)); the most frequent items were Hymenoptera (19.6%), Coleoptera (16.4%), Amphipoda (13.3%), Anura (8.9%) and Heteroptera (8.7%). Despite some overlap, differences were observed in volume (chi(2) = 54.6, p <0.001, d.f. = 2) and prey quantity (F = 8.1, p <0.001, d.f. = 79) between males, females, and juveniles. Juveniles showed significantly higher consumption of terrestrial prey by count (82% of their total ingestion) than adults (29% for males and 32% for females) (chi(2) = 28.5, p <0.001, d.f. = 2). Adults, especially females, showed a high frequency of cannibalism (33% of their total ingestion; chi(2) = 20.9, p <0.001, d.f. = 2). Comparing our data with other bullfrog regional studies, we found great plasticity in trophic habits and differences in the incidence of cannibalism (higher incidence in the populations of Acegua, Uruguay, and Buenos Aires, Argentina). These differences could be related to local biodiversity, but also could be affected by the invasion phase. Cannibalism frequency was higher in small bullfrog populations, where it could be favoring the establishment success. This shift in foraging strategies during the invasion process had been insufficiently evaluated in amphibians. Knowing the ecological determinants for the invasion by bullfrogs can be useful to the development of management strategies.


A Phenological Analysis Of Páramo Vegetation Along An Altitudinal Gradient: The Influence Of Camelids On Andean Flora In The Páramo Of Chimborazo, Ecuador, Tessa Seifried Oct 2021

A Phenological Analysis Of Páramo Vegetation Along An Altitudinal Gradient: The Influence Of Camelids On Andean Flora In The Páramo Of Chimborazo, Ecuador, Tessa Seifried

Independent Study Project (ISP) Collection

This study hopes to reveal the mechanisms behind camelid-plant interactions in the Chimborazo province of Ecuador, which is known for having a large population of domesticated alpacas (Vicugna pacos), along with wild vicuñas (Vicugna vicugna) that were reintroduced into the area 30 years ago. These camelid species, especially vicuñas, are understudied within Ecuador in regards to their effects on plant composition, diversity, and spatial phenology. To gain a better insight into this topic, three sites were chosen: a site inhabited by only vicuña, a site inhabited by only alpaca, and a site inhabited by both species. The vicuña site sat …


A Ladder Of Endemicity: A Pioneering Study Of Anuran Communities Along An Elevational Gradient In The Eastern Andean Cloud Forests, Ecuador, Ella Halbert Oct 2021

A Ladder Of Endemicity: A Pioneering Study Of Anuran Communities Along An Elevational Gradient In The Eastern Andean Cloud Forests, Ecuador, Ella Halbert

Independent Study Project (ISP) Collection

Per unit of area, Ecuador is home to the most herpetofauna of any region on Earth, yet many ecosystems are under researched. Positioned between the Eastern Andes and the Amazon rainforest, the Río Pastaza Basin of Ecuador has been the recent focus of anuran biodiversity surveys and is home to many endemic species. This study aimed to determine how the anuran community composition of a vertical transect in the Llanganates National Park varied between elevations. A 7-day expedition was conducted along a new trail up Abitagua Range spanning 1,050 m in elevation. Each night, visual encounter surveys were employed to …


Eradicating Zebra Mussels: What Works?, Elijah Davies Aug 2021

Eradicating Zebra Mussels: What Works?, Elijah Davies

Symposium of Student Scholars

The invasion of U.S lakes and rivers by the invasive species of zebra mussels called Dreissena polymorpha has caused catastrophic harm to the local ecosystem by reproducing and outcompeting native mussel species as well as harm to pipes leading into water sources by binding to surfaces and reproducing to the point that the mussels clog pipes. In addition, recreation areas must be closed due to the sharp shells making areas unusable. In the past, research has focused on individual molluscicides and their eradication of zebra mussels, as well as their effect on native flora and fauna. My research will contrast …