Forest Biology Commons^™

Dam It All: A Multi-Scalar Investigation Into The Ecological Role And Function Of Beaver Dams, Kenneth Larsen

Dissertations, Master's Theses and Master's Reports

The central theme of this dissertation is ecological scaling, which examines how small, localized features, such as beaver ponds, contribute to large-scale watershed processes and how different modeling approaches at various scales reveal distinct insights. Through a combination of probabilistic modeling and high-resolution empirical research, this work demonstrates that small ponded systems, particularly those created by beavers (Castor canadensis), serve as critical biogeochemical control points, whose contributions to sediment and nutrient dynamics have been historically underestimated.

In Chapter 1, I contextualize this research within the broader fields of freshwater ecology, watershed modeling, and ecological restoration. I introduce the …

Fine Root And Ectomycorrhizal Functional Traits Of Quercus Rubra Populations From Across A Latitudinal Gradient, Emma L. Shedd

Dissertations, Master's Theses and Master's Reports

Forests are increasingly considered for their carbon sequestration value, but their ability to store carbon is dependent on a close balance between carbon fluxes into and out of ecosystems. Nutrient uptake of roots and associated symbiotic communities results in respiratory carbon release, which is projected to increase with warming and represents a substantial uncertainty in earth system modeling. Traits that are functionally related to nutrient uptake can be used to estimate carbon fluxes, but our understanding of the trade-offs that govern root, and especially fungal, traits is limited. Fine roots in surface soils are responsible for the bulk of plant …

Sugar Maple (Acer Saccharum Marsh.) Tree-Ring Growth And Carbon Stable Isotope Responses To Nitrogen And Climate, Libbie Ring

Dissertations, Master's Theses and Master's Reports

This dendrochronological and stable carbon isotope study used tree rings from sugar maple (Acer Saccharum Marsh.) collected at long-term nitrogen (N) amended sites throughout Michigan to understand N amendment and deposition, climate, and growth relationships. Climate responses varied by site, however, we found importance in grouping sites by “productivity” which is related to inherent N and soil nutrients. Our results did not detect an overall effect of N amendments on growth during the treatment period. However, data shows N amendments benefiting larger diameter trees, while smaller diameter trees responded more positively without amendments, especially on more productive sites. Results …

Small Mammal Diet As An Indicator Of Lyme Disease And The Road To Endemicity In Michigan’S Upper Peninsula, Jacqueline E. Suits

Dissertations, Master's Theses and Master's Reports

Lyme disease is expanding in the Upper Midwest due to climate change, forest degradation, and shifting wildlife communities. Small mammals are key reservoir hosts, and their foraging behavior offers insight into environmental conditions that sustain pathogen transmission. We used DNA metabarcoding to investigate small mammal diets across seasonal, spatial, and infection gradients in Michigan’s Upper Peninsula. We identified dominant dietary plant and arthropod taxa, seasonal shifts, and slight variation by species, site, and Lyme infection status. Taxa associated with Lyme-positive individuals were primarily linked to moist, edge, and disturbed habitats, areas that also support ticks and disease spread. These results …

Rotten Through The Cores: What Decomposition Can Tell Us About Carbon Cycling, Eileen C. Reeves

Dissertations, Master's Theses and Master's Reports

Sequestration of carbon (C) in forests means that the C is stored in the ecosystem and not emitted to the atmosphere, thus slowing the accumulation of greenhouse gases and mitigating the acceleration of manmade climate change. Quantifying the pools and fluxes of C in forests is therefore of considerable interest to landowners, policy makers, and scientists.

Decomposition is an ecological process central to the movement of C through ecosystems. This dissertation uses several techniques to help determine the factors influencing the speed of decomposition and long-term fate of decomposed plant material. In Chapter Two, phospholipid fatty acid analysis was used …

The Effects Of Experimental Warming On Root Respiration And The Fungal Community Of Tropical Forest Soil, Malik A. Sankofa

Dissertations, Master's Theses and Master's Reports

Climate induced changes in tropical forests fungal communities could impact diversity and abundance, forest health, and carbon release/sequestration. Under warmer soil temperatures and over time, we hypothesized that arbuscular mycorrhizal, pathogen, saprotroph diversity and abundance would increase, that ectomycorrhizal and overall fungal diversity and abundance would decrease, and that root respiration would be unaffected. Experimental warming (+2-3 ℃) was conducted on root ingrowth cores at the Tropical Responses to Altered Climate Experiment (TRACE) in Puerto Rico. ITS2 metabarcoding was used to analyze fungal diversity and abundance in control or warmed root/soil samples. We found that warming decreased arbuscular mycorrhizal diversity, …

Near-Surface Soil Nitrogen And Vegetation Response To Invasive Emerald Ash Borer In Forested Black Ash Wetlands Of The Western Upper Peninsula, Michigan, Usa, Daniel A. Beyer

Dissertations, Master's Theses and Master's Reports

Invasive emerald ash borer (EAB) (Agrilus planipennis Fairmaire) poses an imminent threat to the structure and function of North American hardwood forests, particularly black ash (Fraxinus nigra Marshall), and alters the hydrologic and ecological services of their wetlands. Black ash trees regularly grow in seasonally saturated soils and are responsible for hydrologic regulation and nutrient cycling. In this study, a gradient of black ash wetlands impacted by EAB were monitored to assess vegetation changes and near-surface soil nitrogen availability. Vegetation community changes were intertwined with nitrogen cycle disturbances following EAB infestation. As black ash died and fell to …

Fine Root Respiration In Quercus Rubra Is Influenced By Multidimensional Trade-Offs In Root Trait Space, Emma L. Shedd

Dissertations, Master's Theses and Master's Reports

Economic theory is often applied to plant strategies, arguing that trade-offs exist between maximizing quick returns on investment within short lifespans or producing longer-lived tissues with slower returns. While these trade-offs are well-studied aboveground, their influence on belowground traits, including root respiration, remains unclear. Resource heterogeneity and symbioses with mycorrhizal fungi may complicate root trade-off axes beyond those predicted by economics theory alone. Investigating fine root trade-offs in Quercus rubra populations along a latitudinal gradient in the Midwest, USA, we identified two distinct axes of variation in root traits: one related to a potential “fungal symbiosis” trade-off and another representing …

Sequencing Antisense Transcriptome Of Populus Through Antisense/Sense Transcript Pair Enrichment, Emma V. Burke

Dissertations, Master's Theses and Master's Reports

Past transcriptome research on plants focused primarily on protein coding genes, and only recently researchers began looking into the non-protein coding regions that may play significant roles in gene regulation. Antisense RNA transcripts that are found naturally in the cell share complementary sequence with sense transcripts and have been shown to regulate expression of their sense counterparts. Since antisense RNA has been largely under-studied and difficult to sequence because of their low relative abundance, new methods are needed to target antisense RNA for efficient genome-wide profiling. To address this gap in methods to efficiently and cost effectively enrich antisense RNA …

Impacts Of Introduced Earthworms On Sugar Maple Sap Chemistry And The Discourse Of Invasion Ecology, Shelby Nicole Lane-Clark

Dissertations, Master's Theses and Master's Reports

To delve into further understanding of the relationships between introduced earthworms, forest ecosystems, and the human systems they impact, two approaches were taken. In the first approach, we seek to explore ways we can shift the discourse within and regarding the field of invasion ecology by re-framing how we approach discussion, management, and education regarding introduced species. Language issues surrounding introduced species through the example of earthworms in North America are described and potential solutions are provided, including a repositioned perspective that may facilitate better relationships with the natural world. The goal is to shift the language to be more …

Common Garden Study Reveals Frost-Tolerant, Generalist Northern Seed Sources Are Best Suited To Expand Range Of Quercus Rubra, Emily Lindback

Dissertations, Master's Theses and Master's Reports

Climate change is shifting the potential suitable range of northern red oak (Quercus rubra L.) faster than it can migrate, creating an adaptation lag. Quercus rubra is prominent in eastern North American forests and important for its carbon sequestration, ecological roles, and economic significance. Our study addresses which populations of Q. rubra are best suited for climatic conditions at the northern and central range limits. Our findings can inform forestry management policies such as assisted migration, where species are transferred within their native range to mitigate the effects of climate change. We planted over 800 Q. rubra seedlings …

Spatiotemporal Variability In Winter Severity: Consequences For White-Tailed Deer Populations And Habitat Sustainability, Grace Parikh

Dissertations, Master's Theses and Master's Reports

Winter in the northern Great Lakes presents a suite of challenging conditions for animals, in terms of limited food availability and increased energetic cost of locomotion and thermoregulation. Variable winter severity is liable to cause interannual fluctuations in habitat viability and use by animals, in addition to modulating physiological responses in animals to conserve energy. For example, white-tailed deer (Odocoileus virginianus) congregate at high densities under eastern hemlock (Tsuga canadensis) or northern white-cedar (Thuja occidentalis) stands, which provide forage, thermal cover, reduced snow depth, and enhanced vigilance. However, a suite of climatic, edaphic, and …

Plant Community Response To Novel Silvicultural Treatments In Great Lakes Northern Hardwoods, Stefan F. Hupperts

Dissertations, Master's Theses and Master's Reports

The objective of this dissertation is to assess plant community response across a range of silvicultural disturbances and test ecological hypotheses to better inform ecologists and forest managers. To provide context for the utility of revising silvicultural systems, I review natural disturbance regimes and historical practices that have shaped contemporary Great Lakes northern hardwood forests (Chapter 2). Further, I identify important ways to expand the silvicultural toolbox and better emulate natural disturbance regimes. Building on this theoretical underpinning, I investigate the initial regeneration and plant community response to two novel silvicultural experiments: the Northern Hardwood Experiment for Enhancing Diversity (NHSEED) …

Application Of Short Tandem Target Mimic (Sttm) Technique For Functional Analysis Of Micro-Rna396 In Transgenic Poplar Trees, Surattana Boonsai

Dissertations, Master's Theses and Master's Reports

Short Tandem Target Mimic (STTM) is a commonly technique used for functional studies of a number of genes in several plant model systems. However, very little is known about application of STTM technique in tree species. In this study, STTM was applied to knock down microRNA396 (miR396) in transgenic poplar trees for the first time. STTM396 expression resulted in dramatic decrease in miR396 expression levels leading to taller plants with larger leaves and larger leaf cell size. Additionally, an expression analysis of growth regulating factor genes (GRFs) that are members of miR396 target gene family showed up-regulation of GRF07 gene …

Above-Ground Biomass And Carbon Estimations And Recommendations For Forests In Turkey, Cuma Uykun

Dissertations, Master's Theses and Master's Reports

Climate change mitigation and biodiversity conservation are issues that are tightly related to the environment and the public’s awareness of forest conservation, which are currently major areas of global interest. Greenhouse gas emissions and removals are required to be reported regularly (5 year intervals) and in compliance with the United Nation’s Framework Convention on Climate Change (UNFCCC) of 1992, which was later extended by the Kyoto Protocol International Treaty. The UNFCCC`s policy has been accepted by more than 150 countries. Turkey`s forests are controlled and managed by the government and some major tree species still need to have their own …

Characterization Of Genic Microsatellite Markers (Est-Ssrs) In The Endangered Oak Species Quercus Georgiana M.A.Curtis, Priyanka Dipak Kadav

Dissertations, Master's Theses and Master's Reports

Quercus is important ecologically and economically because it provides food and habitat for wildlife, wood and paper products for humans. Oaks are endangered due to various factors like shifting climates, habitat loss, drought, pathogens and genetic swamping. Quercus georgiana (M.A. Curtis) is an endangered and restricted oak species which is remaining only in the southeastern part of the US. Efforts are required to conserve this endangered species from extinction. Conservation of this species can be done through these methods: ex-situ conservation (arboretum and botanical garden) and in-situ conservation strategies which protect the species in its natural habitat. For this conservation …

Arbuscular Mycorrhizal Fungi Of Northern White Cedar (Thuja Occidentalis L.): Habitat Effects On Fungal Communities And Inoculum Effects On Plant Growth On Acid Peat Soils, Guswarni Anwar

Dissertations, Master's Theses and Master's Reports

The relationship of arbuscular mycorrhizal (AM) fungi with northern white cedar (NWC) was examined from the perspective of both fundamental questions about habitat specificity in the root fungal community, as well as applied questions regarding AM fungal efficacy in NWC restoration in peat soils. I performed two experiments testing the effects of AM fungi on survival, growth, and nutrition of NWC seedlings; and one molecular study to determine the habitat effects on community composition of NWC root-associated fungi. First, a greenhouse AM inoculation experiment was conducted in factorial combination with fertilization and liming to examine conditional effectiveness of AM fungal …