Open Access. Powered by Scholars. Published by Universities.®

Biodiversity Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 6 of 6

Full-Text Articles in Biodiversity

Diversification And Convergence Following The Transition From Saltwater To Freshwater In Stingrays., Autumn D. Magnuson May 2023

Diversification And Convergence Following The Transition From Saltwater To Freshwater In Stingrays., Autumn D. Magnuson

College of Arts & Sciences Senior Honors Theses

One of the most fundamental questions in biology is why some groups of organisms are more diverse than others. Classic hypotheses for explaining differences in diversity consider distinctions in time, place, resources, and competitors as the staging grounds for differential diversification. Freshwater and saltwater environments have similar levels of diversity despite significant differences in size, so studying transitions between the two systems can provide insights into evolutionary processes. Despite the challenges associated with this transition, stingrays have invaded freshwater habitats multiple times across different continents, making them useful for better understanding these systems. In this study, I evaluated the frequency …


Nitrogen Availability In Dune Systems And Its Effect On Root Fungal Endophyte Communities., Haley E. Sage May 2022

Nitrogen Availability In Dune Systems And Its Effect On Root Fungal Endophyte Communities., Haley E. Sage

College of Arts & Sciences Senior Honors Theses

As global change persists, changes in resource availability can influence plant-microbe interactions. To understand how resource availability can influence these interactions and species diversity, I focused this research on how varying nitrogen (N) levels affect root endophyte communities in the plant species Ammophila breviligulata, an ecosystem engineer in the dune system. I analyzed the relationship between nitrogen addition and microbial community composition across 60 plots treated with three nitrogen addition levels (control, low, and high) in a long-term experimental field site in the Lake Michigan dunes. I identified Ammophila breviligulata's root endophyte community after creating a culture collection and …


Community Structure And Dynamics Of Benthic Macroinvertebrates In A Recreated Headwater Stream System On A Valley Fill In A Retrofitted Watershed Located In The Appalachian Coalfields Of Southeastern Kentucky (U.S.A.), Steven W. Bailey Aug 2021

Community Structure And Dynamics Of Benthic Macroinvertebrates In A Recreated Headwater Stream System On A Valley Fill In A Retrofitted Watershed Located In The Appalachian Coalfields Of Southeastern Kentucky (U.S.A.), Steven W. Bailey

Electronic Theses and Dissertations

The extraction of coal from steep-gradient surface mining sites such as in the Appalachian Coalfields of the U.S. produces excess debris that is often placed in adjacent valleys resulting in the creation of valley fills. Not only are headwater streams buried in the process, but watershed functions are either destroyed outright, or become fragmented and disconnected from adjacent ecosystems resulting in adverse effects to downstream biological communities. In this dissertation, the dynamics of stream macroinvertebrate community structure, composition, diversity, and biotic integrity are assessed at a “proof of concept” stream system recreated on a retrofitted valley fill. For comparison, two …


Approaches To Arthropod Conservation : Landscape Genetics, Community Assessment, And Prediction Of Extinction Risk., Victoria Annette Prescott Dec 2016

Approaches To Arthropod Conservation : Landscape Genetics, Community Assessment, And Prediction Of Extinction Risk., Victoria Annette Prescott

Electronic Theses and Dissertations

Although urbanization is a leading cause of species extinction throughout the world, the impact of urban development on arthropods is little studied and, as a result, poorly understood. I used three distinct approaches to studying arthropod conservation in North America. First, I used landscape genetics techniques to study the impact of urbanization on gene flow among populations of Rabidosa rabida, the rabid wolf spider. While gene flow was not detrimentally reduced, urban development correlated with a reduction in migration rates among populations, and to my knowledge, this is the first study to document isolation by resistance in spiders. Next, …


Effects Of Invasive Shrub Honeysuckle (Lonicera Maackii) And Forest Composition On Bird Communities In Woodland Stands., Katie Rae Lynch Aug 2016

Effects Of Invasive Shrub Honeysuckle (Lonicera Maackii) And Forest Composition On Bird Communities In Woodland Stands., Katie Rae Lynch

Electronic Theses and Dissertations

Invasive species pose a threat to aquatic and terrestrial ecosystems by decreasing biodiversity (Didham et al. 2005). Amur bush honeysuckle (Lonicera maackii) has typically reduced native plant diversity and altered animal communities by influencing animal abundance and activity (Collier and Vankat 2002). This study was intended to determine whether honeysuckle density or other characteristics of forested stands influence avian diversity, whether impacts are seasonally dependent, and whether correlations exist between attributes of forested stands and honeysuckle density. In order to test the hypotheses, thirteen forest stands within the Louisville Metropolitan Area were selected. They had similar tree composition …


Earthworm, Microbial Biomass, And Leaf Litter Decay Responses After Invasive Honeysuckle Shrub Removal From Urban Woodlands., Robert Preston Pipal Dec 2014

Earthworm, Microbial Biomass, And Leaf Litter Decay Responses After Invasive Honeysuckle Shrub Removal From Urban Woodlands., Robert Preston Pipal

Electronic Theses and Dissertations

Invasive species are one of the leading causes of biodiversity loss and their presence can significantly impact the structure and function of native ecosystems. In this dissertation, the impacts of the invasive honeysuckle shrub, Lonicera maackii, on exotic earthworm populations, leaf litter decay responses, and inorganic and organic nutrient pools in an urban woodland park are assessed. Chapter 1 provides a brief review of honeysuckle's effects on forest ecosystems. Chapter 2 describes honeysuckle’s effects on exotic earthworm populations and the seasonal importance of macroinvertebrates to leaf litter decomposition in urban woodlands. This study revealed that L. maackii promoted higher exotic …