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Synthesizing Phylogeography and Community Ecology to Understand Patterns of Community DiversityWilliams, Trevor J. 29 July 2021 (has links)
Community ecology is the study of the patterns and processes governing species abundance, distribution, and diversity within and between communities. Likewise, phylogeography is the study of the historic processes controlling genetic diversity across space. Both fields investigate diversity, albeit at different temporal, spatial and taxonomic scales and therefore have varying assumptions. Community ecology typically focuses on contemporary mechanisms whereas phylogeography studies historic ones. However, new research has discovered that both genetic and community diversity can be influenced by contemporary and historic processes in tandem. As such, a growing number of researchers have called for greater integration of phylogeography and ecology to better understand the mechanisms structuring diversity. In this dissertation I attempt to add to this integration by investigating ways that phylogeography and population genetics can enhance studies on community ecology. First, I review traditional studies on freshwater fish community assembly using null model analyses of species co-occurrence, which shows that fish are largely structured by deterministic processes, though the importance of different mechanisms varies across climates, habitats, and spatial scales. Next, I show how phylogeographic data can greatly enhance inferences of community assembly in freshwater fish communities in Costa Rica and Utah respectively. My Costa Rican analyses indicate that historic eustatic sea-level change can be better at predicting community structure within a biogeographic province than contemporary processes. In comparison, my Utah analyses show that historic dispersal between isolated basins in conjunction with contemporary habitat filtering, dispersal limitation, and extinction dynamics both influence community assembly through time. Finally, I adapt a forward-time population genetics stochastic simulation model to work in a metacommunity context and integrate it with Approximate Bayesian Computation to infer the processes that govern observed community composition patterns. Overall, I show that community ecology can be greatly enhanced by including information and methods from different but related fields and encourage future ecologists to further this research to gain a greater understanding of biological diversity.
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INFLUENCE ON BIODIVERSITY ON CANOPY PROCESS IN A HARDWOOD PLANTATION FOREST ECOSYSTEMTaylor M Nelson (10716447) 28 April 2021 (has links)
Increased biodiversity
generally enhances terrestrial ecosystem productivity. While niche-use
efficiency is thought to drive the biodiversity-productivity relationship, the
mechanisms within niche-use efficiency are not well understood. A potential
mechanism for niche-use efficiency is nutrient-use efficiency. To measure
nutrient-use efficiency, we calculated nitrogen-resorption efficiencies (NRE) because
nitrogen is an important growth limiting nutrient for forest productivity. We
used a plantation
implemented as a full factorial design that included two levels of competition,
implemented as different planting densities (one- and two-meter planting
densities), and three diversity levels (monocultures, two-, and three-species
plantings) that included three hardwood tree species (northern red oak (<i>Quercus
rubra</i>), black cherry (<i>Prunus serotin</i><i>a</i>), and American chestnut (<i>Castanea dentata</i>). For our
nitrogen-resorption efficiency data, we found that NRE increased as diversity
and planting density decreased, but the magnitude of the response varied among
species. This outcome suggests that while increased diversity likely provides a
release from intra-specific competition, different combinations of species will
play a critical role in shaping biodiversity-productivity relationships. Forest
nutrient cycling can also be influenced by herbivory. To address the effects of
forest diversity on herbivory rates, we monitored rates of foliar damage along
with foliar nitrogen content. To
measure foliar nitrogen content, we collected spectral data from early,
midseason, and late season foliar samples. To assess foliar damage, we
collected and imaged leaves from two canopy positions in order to measure late
season foliar area and estimate pre damaged foliar area. We found that
diversity and foliar nitrogen content have a positive relationship, and
diversity does influence canopy damage but the effects vary among species and
density. Upon further analysis, we found that foliar nitrogen content and
canopy damage are correlated. Meaning individual trees showed a release from
intraspecific competition, which lead to an increase in available nutrients and
higher canopy quality, showing that stands with higher canopy quality
experienced higher levels of damage.<br>
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PREDICTING SITE SUITABILITY FOR KUDZU (PUERARIA MONTANA) IN THE GREAT LAKES BASIN AND SURROUNDING REGIONAshley M Kovach-Hammons (12462825) 26 April 2022 (has links)
<p> Kudzu (Pueraria montana) is an invasive woody vine widespread throughout the southeastern United States, with recent studies predicting that its habitat will expand northward. New occurrences and recent studies using climatic parameters suggest that the Midwestern region of the United States is at the greatest risk of kudzu invasion. As there have already been 25 reports of kudzu within the Great Lakes basin, and no previous landscape models exist for the basin, I developed probability models from existing spatial data (land cover, hydrology, geology, annual precipitation, elevation, aspect, and known kudzu locations) using generalized additive, bioclimate envelope, and maximum entropy methods. I further expanded each model to include the basin and a 2.25-degree buffer in order to include 193 reported kudzu sites. For each predictive model, I determined the area under the curve (AUC) for a receiver operating characteristic curve (ROC) comparing false positive and false negative rates. I performed field surveys at eight known sites of kudzu presence in Michigan, Indiana, and Ohio. Each presence site was paired with a control (known kudzu absence site). I collected environmental data including canopy cover, volumetric soil moisture, soil pH, litter depth, midstory species diversity and diameter at breast height (DBH), and overstory basal area. Each environmental measure was compared between kudzu presence and control survey sites as well as between in-basin and out?of-basin survey sites using a two-way ANOVA. Maximum entropy models produced the highest AUC in both the basin and buffer models during model development. These models showed that urban and disturbed habitats resulted in the greatest probability of potential habitat for kudzu. I found no statistically significant differences in environmental characteristics between kudzu absent and presence sites or between in- and out-of-basin sites, suggesting kudzu might be dispersal-limited rather than limited by environmental characteristics. Continuing existing management and further monitoring of kudzu spread is likely necessary to limit further introduction and to mitigate spread of kudzu within the Great Lakes region. </p>
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Phylogenetic Community Structure Of Aquatic Beetle Assemblages In A Multi-wetland ExperimentKelly, Sandor Lawrence 01 January 2012 (has links)
Phylogenetic Community Structure (PCS) metrics are becoming more common in community ecology. PCS metrics estimate the phylogenetic relatedness among members of an ecological community or assemblage. If ecological traits are conserved, then phylogenetic clustering (i.e., taxa are more closely related than expected by chance) indicates habitat filtering as the key process in community assembly. On the other hand, a pattern of phylogenetic overdispersion (i.e., taxa are more distantly related than expected by chance) suggests competition is dominant. Most studies to date have used PCS of unmanipulated ecosystems, but the value of PCS metrics will be best revealed in experiments. This project used PCS for aquatic beetle (Coleoptera) assemblages in experimentally manipulated seasonal wetlands on a cattle ranch in south-central Florida, and compared PCS metrics to standard ecological metrics. Wetlands were experimentally treated with all combinations of pasture management, fencing to exclude cattle, and controlled burning during 2006-2009. Beetle assemblages in fenced wetlands were significantly more overdispersed compared to non-fenced wetlands, suggesting that this treatment decreases habitat filtering, causing competition to become the dominant process in community formation. There was also a significant pasture x fence x burn interaction effect, with assemblages in wetlands differing in PCS depending on what combination of the three treatments were applied. Phylogenetic Diversity (PD – a measure of branch length of a community or assemblage on a phylogenetic tree) was highly correlated with genera richness (number of genera), and these metrics along with the expected number of genera (D – an ecological diversity index) found significant differences among burn treatments and a pasture x iii burn interaction. The results of this study indicate that PCS metrics complement classical ecological methods and should be widely applied.
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<strong>FOREST RESPONSE FOLLOWING THE LOSS OF ASH</strong>Madison Elizabeth Beckstedt (16624320) 20 July 2023 (has links)
<p>This study is part of an ongoing project established in 2007 as an emerald ash borer (<em>Agrilus planipennis</em>) trapping study. The primary objective of this thesis was to assess how forests have changed following the loss of ash over a 15-year period, from 2007 to 2022. The study aimed to answer three key questions: 1) How has the loss of ash affected the regeneration and recruitment patterns of ash and other tree species? 2) Which specific species are driving forest regeneration and recruitment in the absence of ash? 3) Can the data be used to predict future changes in forest composition following the loss of ash? To achieve these objectives, I conducted analyses of 44 forests representing 19 different forest types in Indiana, Michigan, and Ohio. Forest composition was examined at the overstory, midstory and understory levels to capture the overall impact of ash loss on forest regeneration and succession. Despite the decline or total loss in overstory ash, ash regeneration continued at most sites from 2017 to 2022. However, ash regeneration was not observed at 15 sites, and competition from established shade-tolerant species, such as red maple and American elm, was identified as a primary factor hindering ash recruitment. The loss of ash did not lead to significant changes in forest types. Forest types at all sites remained stable, with only minor shifts in dominant species. Tree species that were already present in the overstory filled the space left by the lost ash, thereby maintaining the existing forest types. In terms of driving species, my findings demonstrated a rapid increase in red maple dominance across all sites, particularly in the absence of ash. Red maple exhibited vigorous growth, suggesting it plays a crucial role in shaping future forest composition following ash loss. Other species, including black cherry, American elm, and American basswood, also contributed to forest regeneration, with some sites showing a shift toward a higher abundance of these species. Although the loss of ash has led to changes in forest composition, existing species have shown resilience and adaptability in filling the niche left by the lost genus. The long-term effects of emerald ash borer infestation on forest ecosystems are complex and multifaceted. This study provides insights into the regeneration and recruitment patterns of ash and other tree species following ash loss. The data suggest that while forests have experienced loss of ash, the remaining understory and midstory individuals of this species may contribute to future overstory recruitment. Furthermore, the dominance of red maple highlights its potential as a key driver of forest composition in the wake of ash loss. </p>
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Effects of Agricultural Land-use on Forest Development, Herb Community Composition and Spatial DynamicsHolmes, Marion Andrews January 2017 (has links)
No description available.
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Biodiversity of ants and associated mites in constructed grasslands at multiple spatial scalesCampbell, Kaitlin Uppstrom 24 July 2015 (has links)
No description available.
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Reconstructing the Great Ordovician Biodiversification Event through brachiopods of OklahomaTrubovitz, Sarah, 23 September 2016 (has links)
No description available.
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Individual and Community-Level Drivers of Antimicrobial Resistance in Midwestern Beef and Dairy Cattle CommunitiesOvercast, Macon Z. 09 August 2022 (has links)
No description available.
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Investigating Reproductive Phenology and Alloparental Care in Leuciscid Fishes using Niche Theory ApproachesHultin, Emma Ann 26 May 2022 (has links)
Mutualism is an understudied phenomenon across taxa, but is important to the persistence and structure of communities. The role of positive interactions in supporting threatened species is critically important given that freshwater fish are extremely vulnerable due to the combined effects of climate change and habitat degradation. To disentangle complex positive multi-species interactions, I applied both Eltonian and Hutchinsonian niche approaches to the reproductive mutualism of leuciscids known as nest association, a form of alloparental care characterized by an adult of one species guarding the offspring of another. I conducted this study with the leuciscid community of Toms Creek in which Bluehead Chub Nocomis leptocephalus is the primary nest builder and nest associate species include Rosyside Dace Clinostomus funduloides, Rosefin Shiner Lythrurus ardens, Mountain Redbelly Dace Chrosomus oreas, Crescent Shiner Luxilus cerasinus, White Shiner Luxilus albeolus, Central Stoneroller Campostoma anomalum, Creek Chub Semotilus atromaculatus, and Blacknose Dace Rhinycthys atratulus. I applied Hutchinsonian niche theory with respect to hydrology and water temperature to define the reproductive phenology of each species involved in the reproductive mutualism, then used Eltonian niche theory to define the role of each species in parental and alloparental care. My dual niche theory approach elucidates the reproductive requirements of each species and quantifies the contribution of nest associates to alloparental care, which historically have not been included in definitions of nest association. My results show that Blacknose Dace Rhinichthys atratulus and Creek Chub Semotilus atromaculatus are not true nest associates of Bluehead Chub Nocomis leptocephalus based on their reproductive phenology and observed nesting behaviors. In contrast to previous work on nest association, most associate species did contribute to parental care through nest defense and vigilance behaviors, and their specific behaviors were influenced by morphology. By clearly defining the reproductive niches of these species, this study lays the groundwork for future investigation of how various climate scenarios may impact multi-species reproductive mutualisms. / Master of Science / Positive interactions are understudied throughout ecology, but are important to the persistence and structure of communities. The role of positive interactions in supporting threatened species is critically important given that freshwater fish are at high risk of extinction due to the combined effects of climate change and habitat degradation. To understand the complex positive interactions in freshwater fish, I applied both niche theory approaches to a mutualistic reproductive interaction known as nest association, where an adult of one species builds a nest on which it guards the offspring of other species (formally: a type of alloparental care). I conducted this study with the leuciscid (commonly known as minnow) community of Toms Creek in which Bluehead Chub Nocomis leptocephalus is the primary nest builder and nest associate species include Rosyside Dace Clinostomus funduloides, Rosefin Shiner Lythrurus ardens, Mountain Redbelly Dace Chrosomus oreas, Crescent Shiner Luxilus cerasinus, White Shiner Luxilus albeolus, Central Stoneroller Campostoma anomalum, Creek Chub Semotilus atromaculatus, and Blacknose Dace Rhinycthys atratulus. For each species involved in the reproductive mutualism, I defined the seasonal timing of reproduction with respect to hydrology and water temperature, then defined their role in parental and alloparental care. My approach clarifies the reproductive requirements of each species and establishes the contributions of associate species to alloparental care, which historically have not been included in definitions of nest association. My results show that Blacknose Dace Rhinichthys atratulus and Creek Chub Semotilus atromaculatus are not true nest associates of Bluehead Chub Nocomis leptocephalus based on their reproductive requirements and observed nesting behaviors. In contrast to historic descriptions of nest association, most associate species did contribute to parental care through nest defense and vigilance behaviors, and their specific behaviors were influenced by their size and physical adaptations. By clearly defining the reproductive needs and roles of these species, this study lays the groundwork for future investigation of how various climate scenarios may impact positive relationships among species.
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