Browsing by Author "Berven, Keith"

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    Effects of Forest Tree Species Composition on Vernal Pond Water Chemistry, Decomposition, Primary Productivity and Amphibian Larval Fitness Traits
    Mrowca, Morgan; Berven, Keith
    Human activities have dramatically changed the composition of tree species in North American forests. These changes have altered the composition of leaf litter in woodland ponds, which has been linked to the decline of amphibian populations. Leaves from different species of trees that accumulate in ponds each fall differ in their chemical composition and produce species-specific effects on water chemistry, nutrient availability and rates of decomposition that ultimately affect the fitness (growth, development and survival) of amphibian larvae that develop in these ponds. These findings have been based on artificial pond research. This project aimed to show that the composition of trees (species, size, and number of individual trees) surrounding temporary woodland ponds directly affected the chemical characteristics (pH, dissolved oxygen, conductivity, and phenolic concentration) and rates of decomposition of the aquatic pond environment. Documenting this relationship in natural pond communities will provide an impetus for developing forest management practices that benefit amphibians and other organisms that live in these aquatic environments. We found that high levels of red maple had a positive correlation with polyphenol levels, as well as a negative correlation with pH and conductivity levels. Elms showed to have a relationship with the decomposition rates of ponds. These each could be associated with the variation in juvenile tadpole mass at metamorphosis.
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    GHPI Biodiversity Subcommittee Report, 2022
    (2022-05) Banes-Berceli, Amy; Berven, Keith; Carlson, Matthew; Diesing, Eric; Hartson, Mary; Jamieson, Mary; Jamison, Megan; LaLone, Douglas; Raffel, Thomas
    Assessment of biodiversity and wildlife habitats on campus; recommendations
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    The New Zealand Mud Snail (Potamopyrgus Antipodarum) Ecology And Management Of A Global Invader
    (2022-07-28) Gist, Jeremy A.; Tiegs, Scott; Berven, Keith; Luttenton, Mark; Strayer, David
    The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is among the most globally widespread aquatic invaders, colonizing at least 40 countries across 6 continents. NZMS have recently colonized rivers of the Laurentian Great Lakes region. where little is known about their impacts on the native communities of the ecosystems they invade. In chapter one, I present the results of a systematic review of 245 articles, and outline NZMS impacts, distribution, population dynamics, vectors of spread, and management. The invasion success of NZMS stems from their opportunistic traits allowing them to tolerate broad ranges of environmental conditions. However, optimal conditions for successful establishment are evident. NZMS can become exceptionally abundant and impact multiple facets of aquatic ecosystems, though populations can fluctuate seasonally and over longer time scales, likely due to environmental constraints. In chapter two, I tested the efficacy of three different chemical reagents for NZMS decontamination on recreational fishing gear and combined these results with results of a self-administered public survey gauging the level of willingness individuals have to participate in a given NZMS decontamination technique. The greatest mortality of NZMS was caused by Formula 409, and participants of the survey revealed Formula 409 to be the chemical they'd be most willing to use. Chapter three outlines an investigation of the effects of NZMS on the diets and condition of fish in a recently invaded stream, the Au Sable River (Michigan, USA). Trout consumed NZMS throughout the duration of the study, while sculpin minimally consumed NZMS. Of the 83 trout collected, 60% contained NZMS in their stomachs. Age 2 trout that consumed NZMS exhibited reduced condition relative to those that contained fewer NZMS. Lastly, chapter four consists of a study to characterize NZMS population dynamics and their effects on native benthic invertebrates in the Au Sable River. NZMS populations exhibited pronounced seasonality with peak densities typically occurring during the Summer and Autumn of each year. NZMS numerically dominated the benthic community and were associated with differences in the overall benthic community composition. The results of these studies highlight how NZMS can affect native communities and higher consumers in rivers of the Great Lakes region and contribute to a more robust understanding of the global NZMS invasion, such that undesired impacts can be minimized or averted.
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    Underwater behavior of gentoo (Pygoscelis papua) penguins
    Lechnar, Amanda; Berven, Keith
    Penguin underwater behavior has been difficult to observe and assess both in the wild and under human care. A study of ten gentoo (Pygoscelis papua) penguins located at the Detroit Zoo investigated underwater behavior from September 2016 to February 2017. In 2016, the Detroit Zoo opened the new Polk Penguin Conservation Center, a habitat with a 25-foot-deep, 326,000 gallon pool designed to improve well-being and promote species-typical behaviors. The gentoo penguins were monitored underwater using both live observation with focal animal sampling and automated temperature-depth recorders. Information was gathered from 90 hours of observation to better understand how the design of the habitat impacted the welfare of the penguins, as measured by use of space, and how often behaviors such as play and aggression occur. Key factors such as location and depth in the water, time of day, proximity to other penguins, and behavior of each penguin were recorded. The results included activity budgets that describe the most common underwater behaviors; conditions of play behaviors and feedings; and interactions with humans; and the amount of time each penguin spent in the water. These factors show how some gentoo penguins in the care of humans utilize their water space, socialize with other penguins, and how the conditions of the Polk Penguin Conservation Center promote good penguin welfare.