Life Sciences Commons^™

Functional Diversity Enhances Detection Of Ecosystem Stability And Resolution Of Predator-Prey Interactions Within A Multitrophic Community, Ashley Lorraine Kissick

Open Access Dissertations

Habitat fragmentation and loss are principal factors that contribute to the decline of biodiversity which in turn has a negative impact on ecosystem function. There has been growing interest in understanding diversity’s role in the mechanisms behind ecosystem resilience with much attention focusing on how functional diversity, or the range of species’ ecological roles in a community, impacts ecosystem function. Under the functional insurance hypothesis, stability in ecosystems is maintained by species that perform similar functions but have asynchronous responses to disturbance. There are three proposed stability mechanisms that operate through species’ asynchronous responses: cross-scale resilience, response diversity, and density …

Quantifying Terrestrial Ecosystem Carbon Dynamics With Mechanistically-Based Biogeochemistry Models And In Situ And Remotely Sensed Data, Shaoqing Liu

Open Access Dissertations

Terrestrial ecosystem plays a critical role in the global carbon cycle and climate system. Therefore, it is important to accurately quantify the carbon dynamics of terrestrial ecosystem under future climatic change condition. This dissertation evaluates the regional carbon dynamics by using upscaling approach, mechanistically-based biogeochemistry models and in situ and remotely sensed data.

The upscaling studies based on FLUXNET network has provided us the spatial and temporal pattern of the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important physiological role in carbon assimilation. In the second chapter, we consider the effect of atmospheric CO2 …

The Role Of Seed Attributes In Eastern Gray Squirrel Foraging, Mekala Sundaram

Open Access Dissertations

Seed attributes are important predictors of rodent foraging behaviors. I examined the role of seed attributes in eastern gray squirrel (Sciurus carolinensis) foraging behavior from an evolutionary, economic, ecological and biochemical perspective. From an evolutionary perspective (chapter 2), I found that squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and evolutionarily labile seed traits, which supports a diffuse coevolutionary relationship between hardwood trees and squirrels and provides indirect evidence supporting the Janzen-Connell and handling time hypotheses. From an economic perspective (chapter 3), I found that eastern gray squirrels are homogenous with respect to their preferences for seed …

Lower Food Web Dynamics In Lakes Michigan And Huron: Spatial And Temporal Responses To Recent Oligotrophication, Margaret Hutton Stadig

Open Access Theses

Nutrient abatement programs, originally enacted to counter eutrophication have successfully suppressed nutrient loads and relative primary production in marine and freshwater systems. Recently, the additive impacts of invasive filter feeders have further reduced offshore primary production in several aquatic systems throughout the world. It has been hypothesized that the biological activity of these invasive species may sequester nutrients within the nearshore benthic environment, creating steep gradients in primary production between nearshore and offshore habitats. In the Laurentian Great Lakes, past studies of oligotrophication have primarily focused on food web responses in offshore habitats. Organisms at higher trophic levels have been …

Evolutionary Potential Of A Dispersal-Restricted Species In Response To Climate Change, Lorena Torres Martinez

Open Access Dissertations

Habitat replacement and fragmentation associated with projected climate change pose a critical threat to global biodiversity. Edaphically limited plant species with restricted dispersal abilities will be especially handicapped to track their optimal climate spatially. Instead, the persistence of these species will depend on their capacity to adapt in situ to novel climate regimes. Here I evaluated the evolutionary potential of Lasthenia fremontii, an annual plant species restricted to ephemeral wetlands called vernal pools in California to adapt to the projected patterns of climate change. Across L. fremontii distribution there is a latitudinal gradient in precipitation which, combined with reduced …

The Biology And Management Of Waterhemp In Indiana, Joseph M. Heneghan

Open Access Theses

Waterhemp is a dioecious weed species indigenous to the Midwestern United states yet it has only recently become problematic in agronomic crop production in Indiana. Waterhemp is a small-seeded broadleaf which has increased in prevalence in conjunction with an increase in conservation tillage practices. Waterhemp germinates and emerges from the top 3 cm of soil and is known to exhibit extended periods of continual emergence, longer than most other summer annual weed species that are typically present in agronomic production settings. As a C4 species, waterhemp then grows rapidly and is capable of producing thousands of seeds, while effectively competing …

The Interactive Effects Of Pesticide Exposure And Infectious Disease On Amphibian Hosts, Katherine M. Pochini

Open Access Theses

Natural systems are home to a multitude of natural and anthropogenic stressors, which draw an array of effects on ecological communities. While these effects have been investigated individually, it is important, given the routine co-occurrence of these stressors, to understand their interactive effects. Pesticide exposure and infectious disease are two common, co-occurring stressors that each have documented detrimental effects on species and, as evidence suggests, may have interactive effects. Moreover, existing research suggests that these interactive effects are highly context dependent, eliciting different results based on species, disease agent, toxin, and environment. Given the variability with which species may experience …

Reflexivity: A First Demonstration, Melissa Jane Swisher

Open Access Dissertations

Currently, the emergent relation of reflexivity after training a set of baseline relations has not been demonstrated with any animal—human or nonhuman. True reflexivity can only be demonstrated if no identity (i.e., physically matching stimulus) relations are trained. In six experiments, the emergence of reflexivity and its opposite, anti-reflexivity, were explored. Pigeons received concurrent successive matching training on two or three arbitrary tasks: AB hue-form and BC form-hue (and AC hue-hue) matching. Once they had acquired these tasks, they were tested for BB (form-form) reflexivity or BB’ (form-form) anti-reflexivity matching. Most (10 of 13) pigeons that received three arbitrary tasks …

Nestmate Recognition In Odorous House Ants (Tapinoma Sessile): Effects Of Social Plasticity, Urbanization, And Laboratory Maintenance, Timothy J. Luttermoser

Open Access Theses

Odorous house ants (Tapinoma sessile) are a widespread North American ant species and common nuisance pest. In addition to their pest status, odorous house ants are of interest as a model system for understanding the factors that lead to variable queen number and nesting strategy across ants, as well as possible insight into common traits of exotic invasive (or “tramp”) ant species. While T. sessile is native to North America, in urban environments it forms large supercolonies with many queens and nest sites connected by trails, similar to a variety of exotic invasive ants, most of which are …

Investigating Physiological Collaborations Between A Lower Termite And Its Symbionts, Brittany F. Peterson

Open Access Dissertations

This project was completed in an effort to better understand the contributions of symbiotic microbes to the biology of Reticulitermes flavipes, the eastern subterranean termite. Lower-termites, like R. flavipes, house symbionts from all three domains of life within their hindgut paunch. This intimate association is reflected in nearly every aspect of termite biology. Here, I investigate these physiological collaborations as they relate to digestion and immunity. My efforts focused on 1) quantifying the role of bacteria in wood digestion within the termite gut, 2) evaluating the role of symbionts in protection against pathogens, and 3) identifying gene products that bacterial …

Using Individual-Based Modeling To Explore How Environmental And Anthropogenic Factors Impact Piping Plover Breeding Success, Alexander J. Cohen

Open Access Theses

The Piping Plover (Charadrius melodus) is an intensively managed shorebird species which breeds in part along the Atlantic Coast. Major threats to Piping Plovers include habitat loss and degradation, predation, human disturbance, and vulnerability to the elements. Common management techniques include predator exclosures and symbolic fencing around nests to deter humans from entering nesting areas. However, Piping Plover productivity is highly variable even with management. Many site- and season-specific factors affect plovers and their interactions with other inhabitants of the beach environment. Variability in magnitude and patterns of human disturbance, plover behavioral tolerance of disturbance, and a variety of beach …

The Decline Of Cisco Coregonus Artedi At Its Southern Range Extent: Stock Biology And Management Implications, Andrew E. Honsey

Open Access Theses

The cisco Coregonus artedi is distributed throughout northern North America and is relegated to coldwater, oligotrophic systems. Populations of cisco located at the species' southern range extent, including northern Indiana and southern Michigan, have drastically declined over the past century, seemingly due to a combination of climate warming and exacerbation of hypolimnetic hypoxic conditions via intensive land-use and resulting increases in nutrient loading. Apart from their decline, information on southern ciscoes is lacking, including basic stock demography and genetic variability. Such information may shed light on the likely sustainability (or lack thereof) of remaining populations. The first portion of this …

Suitability Of Blue Ash (Fraxinus Quadrangulata) And Green Ash (F. Pennsylvanica) To Emerald Ash Borer (Agrilus Planipennis) And Its Larval Parasitoid Tetrastichus Planipennisi., Donnie "L. " Peterson

Open Access Theses

Emerald ash borer (EAB) (Agrilus planipennis ) is a primary pest that has killed tens of millions of North American ash (Fraxinus spp.) trees. The larval parasitoid Tetrastichus planipennisi was introduced from China as part of a classical biological control program for long-term EAB management. The high mortality rates of ash trees greatly reduce the number of EAB hosts and may make it difficult for parasitoids to persist. However, blue ash ( F. quadrangulata ) is relatively resistant and appears to be able to survive EAB infestation. If natural enemies can attack EAB in infested blue ash they …

Vegetation And Soil Characteristics Of Pine Plantations And Naturally Regenerated Hardwood Forests On The Hoosier National Forest, Patrick James Duffy

Open Access Theses

During the 1930s there was widespread erosion on farmland and subsequent land abandonment. As a result, Pinus strobus L. (white pine), P. resinosa Aiton (red pine), and P. echinata Mill. (shortleaf pine) were planted in the Midwest to prevent erosion and rehabilitate sites. These species were selected due to their wide availability at the time. Currently, it is the goal of the U.S. Forest Service to provide a more natural and sustainable landscape, in part by removing these non-native Pinus stands and by replacing them with native hardwood species. The ultimate success of hardwood restoration depends, in part, on the …

Naturalized Offspring From An 85-Year-Old Chinese Chestnut (Castanea Mollissima) Planting: Stand Dynamics And Genetic Relationships, Amy Christel Miller

Open Access Theses

Chestnuts, members of the genus Castanea , family Fagaceae, are valuable worldwide, and all species have noteworthy ecological, economic, and cultural importance in their native ranges. Historically, American chestnut (Castanea dentata (Marshall) Borkh.) was an abundant tree species in eastern North America until its decimation in the early 20 th century by chestnut blight, caused by the fungus Cryphonectria parasitica . To regain the benefits of this prized species in North America, efforts are ongoing to produce and introduce blight-resistant hybrids of C. dentata and the blight-resistant Chinese chestnut ( C. mollissima Blume). It is important that the C. …

Ecological Interactions Affecting American Chestnut Restoration And Allegheny Woodrat Conservation In Indiana, Rita Michelle Blythe

Open Access Theses

The Allegheny woodrat (Neotoma magister ) is a small rodent native to rocky habitats surrounded by deciduous forests in the eastern United States. Woodrats have recently experienced a severe range-wide decline and are a species of conservation concern throughout their range. In Indiana, the persistence of woodrat populations is threatened by a loss of genetic diversity, so captive propagation was initiated to ameliorate the immediate threat of inbreeding depression and improve local genetic diversity. However, achieving the objectives of captive propagation ultimately depends on the ability of captive-reared individuals to survive in the wild until they can contribute reproductively …

Effects Of Amur Honeysuckle (Lonicera Maackii [Rupr.] Herder) Invasion And Removal On Native Vegetation And White-Footed Mice (Peromyscus Leucopus) In Mixed-Hardwood Forests Of Indiana, Joshua Michael Shields

Open Access Dissertations

The threat of non-native invasive species continues to compromise the ecological and economic integrity of our natural resources. Numerous investigators have documented the negative effects of invasive species on native biota. However, much work is still needed with regard to how invasive species spread in space and time, factors contributing to impacts on native biota within invaded ecosystems, and resultant effects of removing invasive species. In terms of invasion patterns, few studies have documented local patterns and rates of woody plant invasions, and even less is known about changes in spatial patterning and factors influencing structural characteristics (diameter and height) …

Habitat Restoration Of A Constructed Ohio River Embayment, Caleb Michael Rennaker

Open Access Theses

Backwater habitats of large rivers provide habitat for aquatic biota and influence important predator-prey interactions in fishes and other aquatic organisms. However, these areas often exhibit turbid conditions and lack habitat complexity. Restoration of lentic habitats through direct habitat manipulations has shown success in prior efforts, but these methods have not been tested in backwater habitats of large rivers. I attempted to create habitat in an Ohio River embayment by establishing founder colonies of aquatic macrophytes coupled with the placement of underwater gravel beds. I also evaluated the effects of total suspended solids (TSS) on overwintering structures of American Pondweed …