Master of Science in Chemistry, Youngstown State University, 2000, Department of Chemistry

Acute myeloblastic leukemia is known as an insidious, often times fatal, disease; however, its etiology has not been fully elucidated. This work was conducted so as to explore the potential environmental influences that may converge and precipitate a myelodsplastic event or even a leukemic disease state. Environmental chemicals were the primary focus of this investigation, including: the fertility drug clomiphene citrate, (Clomid); and a combination of pesticides commonly applied to produce.

Committee: Daryl Mincey (Advisor) Subjects: Biology, Ecology

Master of Science (MS), Wright State University, 2007, Biological Sciences

Baumer, Marilyn Cabrini. M.S., Department of Biological Sciences, Wright State University, 2007. Tree Seedling Establishment Under the Native Shrub, Asimina Triloba. Species that form forest understory layers affect canopy tree seedling establishment worldwide. In the Eastern United States, shrub understories like Rhododendrom maximum, a native evergreen species, and Lonicera maackii, an exotic, invasive species, diminish tree seedling survival. I compared the density and survival of canopy tree seedlings under and outside patches of the native shrub, Asimina triloba (L.) Dunal (Annonaceae) (pawpaw). I also conducted a manipulative experiment to determine whether above ground or below ground competition was more important in seedling growth and survival. Above ground competition was manipulated by tying back the leaves of the pawpaw and below ground competition was manipulated by trenching the perimeter of the study plots. Tree seedling density was approximately three times greater outside pawpaw patches than under pawpaw over the range of sites. Seedlings under pawpaw were both younger and shorter than those outside of pawpaw. Survival varied by species. Acer saccharum seedlings were about one and a half times more likely to survive outside pawpaw than under pawpaw. Prunus serotina seedlings were about three times more likely to survive outside pawpaw than under pawpaw. In contrast, pawpaw did not affect the survival of Fraxinus spp. seedlings. Differing survival rates may reflect characteristics related to the species shade tolerance. Light (measured by canopy densiometer) was greater outside pawpaw than under pawpaw. No significant differences in moisture levels were detected; however, at three of the four sites, moisture was greater under pawpaw than outside of pawpaw. The combination of above ground and below ground factors was more important in the survival and growth (measured by biomass) of planted A. saccharum seedlings under pawpaw than either above ground (open full item for complete abstract)

Committee: James Runkle (Advisor) Subjects: Biology, Ecology

Master of Science (MS), Wright State University, 2002, Biological Sciences

Zimmerman, Christopher Lee. M.S., Department of Biological Sciences, Wright State University, 2002. Using Ecological Land Units in a Gap Analysis for Conservation Planning in a Southwestern Ohio Watershed. Gap analysis is a method to identify insufficiency in biodiversity protection. In degraded agricultural landscapes, it requires information on the past, present, and the potential natural distribution of forest vegetation to construct a comprehensive nature reserve network. Using Geographic Information Systems (GIS), I conducted a biodiversity gap analysis to assess the representation of ecological land units (ELUs) supporting forest vegetation both within and external to the current reserve network in the Lower Twin Creek Watershed (LTCW), southwestern Ohio. I used this analysis to make conservation planning recommendations to the local park district. ELUs are based on relatively stable associations of soils, physiography, and potential natural vegetation. In heavily deforested landscapes, such as the LTCW, ELUs model a more intact functioning landscape by predicting the distribution of potential natural forest vegetation. ELUs were classified using multivariate and cluster analyses on forest canopy tree species and seven physiographic and soil variables derived from digital elevation models and a soil series map in GIS. A cluster analysis of the five most significant variables (landform, drainage, hillshade, curvature, and percent slope) influencing vegetation distribution resulted in nine discrete ELUs. They included uplands dominated by Fagus grandifolia – Acer saccharum, dry slopes dominated by Quercus spp. - Carya ovata, mesic slopes dominated by a mixed mesophytic community, and wet floodplains dominated by Platanus occidentalis – Populus deltoides. A reference ecosystem map was constructed using ArcView GIS Spatial Analyst with the five environmental variables identified in the multivariate analysis. To determine the area of forest cover in each ELU within (open full item for complete abstract)

Committee: James Runkle (Advisor) Subjects: Biology, Ecology

MS, University of Cincinnati, 2006, Arts and Sciences : Biological Sciences

The species Drosophila bipectinata Duda was used in a series of projects aimed at appending empirical support to vital aspects of sexual selection theory, including mechanisms of selection and ‘good genes' models. The first chapter reports no evidence to support that male vigor, as measured by latency and duration of copulation, can explain the mating success of males larger in body and comb size found in a previous field study. Also, no evidence of female cryptic choice was found in this system. The second chapter reports a genetic association between two condition dependent secondary sexual traits; the finding of a positive association between two traits that differ in kind (sex combs vs. courtship song), and thus presumably have different developmental pathways, provides evidence of the presence of ‘good genes' in this system. Future directions include testing for evidence of female choice for male D. bipectinata song and/or comb size.

Committee: Dr. Michal Polak (Advisor) Subjects: Biology, Ecology

PhD, University of Cincinnati, 2006, Arts and Sciences : Biological Sciences

A major goal of ecological research is to determine causes for patterns of biodiversity. Establishing a connection between environmental variables and patterns of species richness provides a foundation for modeling species-habitat relationships. In general, a more heterogeneous environment provides more ecological opportunities for more species than a less heterogeneous environment. The relationship between environmental heterogeneity and species richness is dependent on the spatial scale at which analyses are conducted and on the taxonomic group studied. Often, researchers use indicator groups or species when assessing biodiversity. However, a single taxonomic group (e.g., mammals) or a cluster of species (e.g., small mammals) may respond to environmental variables differently from groups excluded from the analysis, and may not be a good indicator of overall biodiversity. Furthermore, much of the research has been conducted at small- or large- spatial scales, and relatively few studies have been conducted at meso-scales. This study investigated the role of environmental heterogeneity in determining patterns of biodiversity of different terrestrial vertebrate groups, and examined the consistency of the results across three commonly used spatial meso-scales of analysis. Relationships between environmental heterogeneity and species richness were analyzed using multiple regression. All measured categories of environmental heterogeneity were important predictors to model patterns of species richness, explaining 40% to > 99% of the variation in species richness. However, the relationship between the different types of heterogeneity and patterns of species richness varied with the grouping of species and the spatial scale. In general, at all three meso-scales, the variables selected to represent environmental heterogeneity were not as good at explaining the variation in species richness for reptiles as they were for other taxonomic groups. In addition, mammal species rich (open full item for complete abstract)

Committee: Dr. Guy Cameron (Advisor) Subjects: Biology, Ecology

MS, University of Cincinnati, 2004, Arts and Sciences : Biological Sciences

Invasive species oftentimes reduce the diversity of native biota. The invasive house gecko Hemidactylus frenatus is displacing an asexual resident, H. garnotii, on a global scale. We quantified behavioral interactions and resource consumption in dyads and triads composed of different combinations of sexes and species. Resource consumption by H. garnotii was not impacted by H. frenatus. H. frenatus males were aggressive toward conspecific males, but not toward conspecific or heterospecific females. Males courted females in dyads and triads, and by some measures showed a preference for H. garnotii. Results support the hypothesis that interspecific sexual interference is the mechanism of displacement. Males may cause displacement by interfering with asexual reproduction. These results lend empirical support for a theoretical disadvantage of asexuality that is predicted to lead to rapid displacement. This study demonstrates the importance of quantifying interactions among populations, such as invasions and displacements, at the level of individual behavior.

Committee: Dr. Kenneth Petren (Advisor) Subjects: Biology, Ecology

Master of Science, University of Toledo, 2007, Biology (Ecology)

Soil efflux (SEF) is an important component in the global carbon cycle. The combination of root and microbial respiration, SEF is often used as a measure of biological productivity in the soil. Although SEF has been widely studied, some areas have been neglected, including the effect of timber harvest management on SEF and SEF in different soil horizons. Timber harvesting compacts the soil, removes standing vegetation, increases debris, alters the microclimate, etc., all of which could potentially alter SEF. The Missouri Ozark Forest Ecosystem Project (MOFEP) is a long-term study in which the Missouri Department of Conservation installed experiments of singletree uneven-age (UAM), clear-cut even-age (EAM), and control no-cut (NHM) timber harvests to seek ecosystem-management alternatives. I found SEF to be the highest in the deepest portion of the soil pit for EAM and UAM, double that of NHM at the same depth and surface efflux of all three treatments.

Committee: Jiquan Chen (Advisor) Subjects: Biology, Ecology

Master of Science, University of Toledo, 2007, College of Arts and Sciences

Prescribed burning is a major management technique used to restore oak woodlands to previous oak savanna conditions. Burning alters biotic and biophysical variables by combusting the litter layer and heating the soil; however, the net effects of these cool fires on ecosystem processes like soil respiration (SR) are not well understood. This study examined immediate and seasonal responses of biotic variables, biophysical variables, and SR to prescribed burning in Northwest Ohio successional oak woodlands. A chronosequence of treatments (0, 1, 3, and 5 years after burning) was compared with unburned woodland to estimate the duration of fire effects. A paired design limiting landscape variability was incorporated by maintaining a burn exclusion area within the freshly burned treatment (0yr). The relationship between SR and its biotic and biophysical predictors, and the temperature sensitivity of SR (Q10) were also examined across treatments. Measurements were taken weekly between March 2005 and January 2006. Data were primarily analyzed with repeated measures analysis of variance. This study suggested that repeated fires had persistent impacts on forest structure and species composition, and transitory impacts on litter biomass, soil temperature, soil moisture, soil nutrients, SR, and Q10. Generally, changes caused by fire were not significantly different across the chronology; instead, fire effects were only visible within the first year after burning, and were most evident by comparing the paired sites. Fire effects changed by season so that spring SR at the freshly burned site was 18% higher than the paired site, summer SR was 36% lower, and fall SR recovered to unburned rates. Relationships between SR and its predictors changed slightly after burning, but soil temperature remained the dominant predictor across all treatments and seasons. Therefore, the effects of a single fire on successional woodland SR were seen to be weak and short-lived.

Committee: Jiquan Chen (Advisor) Subjects: Biology, Ecology

Master of Arts, University of Toledo, 2004, College of Arts and Sciences

The burning of fossil fuel since 1845 has increased the amount of greenhouse gasses within the atmosphere resulting in global climate change (Townsend et al. 1996). An increased carbon dioxide level from pre-industrial period to the present is thought to contribute 60% of the observed global warming (Grace 2004). Therefore understanding how and where carbon is sequestered is essential for predicting future climatic change and CO2 concentration modeling. Current carbon models do not take area of edge influence (AEI) into consideration which can account for a significant portion of a forested landscape (Mlandenoff et al. 1994). Failing to take the AEI into consideration could cause substantial error at the landscape scale. In this study it was determined that aboveground tree carbon (AGTc) had a depth of edge influence (DEI) of 12 m in both the recent and old inner edge and 5 m for the old outer edge. In addition, down woody debris carbon (DWDc) had a DEI of 22 m for recent and old inner edge and 5 m for the old outer edge. Snag carbon (snagc) had no DEI in any edge; recent inner, old inner, recent outer or old outer. Litter carbon (litterc) had a DEI only in the old inner edge and it extended for 5 m. This study alludes to the possibility of a photosynthetic gradient through the differences in leaf mass per area (LMA) values across an edge to interior gradient. The differences in DWD and the possible photosynthetic gradient could cause substantial error in current landscape level carbon estimates. Understanding how edges effect carbon allocations will improve our ability to predict landscape level carbon storage for developing future management plans.

Committee: Jiquan Chen (Advisor) Subjects: Biology, Ecology

Master of Science, University of Toledo, 2004, Biology (Ecology)

Assessing leaf level processes in the context of other hierarchical levels (e.g., whole-plant, canopy, species, and landscape) is a current focus of ecophysiologists, and a discipline requiring additional research. The primary study objective was to examine foliar responses to light gradients (i.e., photosynthetically active radiation, PAR) across different species, age classes, and vertical positions in two landscapes: the northern deciduous forests of Wisconsin (CNF) and the Ozark highlands of southeastern Missouri (Ozarks). We measured the photosynthetic response of several light curve characteristics (e.g., maximum photosynthetic rate (Amax), stomatal conductance at Amax (gsmax), apparent quantum yield (f), and compensation point (G), and dark respiration rate (RD)) changes in microclimate (e.g., vapor pressure deficit (VPD), temperature, and fraction of PAR intercepted (fPAR)), leaf (e.g., SPAD chlorophyll concentration, (SCL)), and canopy characteristics (e.g., canopy openness) of ten tree species in two climatically different landscapes. Species include bigtooth aspen, paper birch, red oak, red maple and sugar maple (CNF) and shortleaf pine, hickory, scarlet, black, and white oaks (Ozarks). Three stand age classes (i.e., young, intermediate, and mature) were measured for all species in CNF. Stand age (CNF), species, and canopy position significantly affected a majority of the photosynthetic characteristics (a = 0.10). Furthermore, photosynthetic characteristics of shade intolerant species were typically greater than shade tolerant (p < 0.0001 to 0.0999). In CNF, there were no significant effects of age on gsmax and Amax, but there were significant two-way interactions of species and age (p <0.0001). This result indicates within CNF gsmax and Amax of species react differently to stand maturation. For example, paper birch gsmax and Amax decrease with age, while increasing with age in the bigtooth aspen. In the Ozarks only species and canopy positions were compa (open full item for complete abstract)

Committee: Jiquan Chen (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2007, Evolution, Ecology, and Organismal Biology

Nitrogen (N) is the nutrient most limiting to plant growth (NPP) in temperate forests. In N-limited temperate forests, most of the N required for NPP is recycled between soil and plant N pools by the microbial process of N-mineralization (Nmin). However, human activities have increased atmospheric N deposition (Ndep) to forests in the last 50-100 years, and this surplus N may increase NPP. But, forest responses to Ndep are not satisfactorily understood, and depend on how atmospheric N inputs are partitioned between soils and plants. From my field data collection at a mature forest site, I estimated that NPP required 51 kg N ha-1 yr-1, most of which was used for fine root and leaf production (62% and 31%, respectively). Each year, Nmin supplied 87% of Nreq, and Ndep contributed an additional 13%, 4% of which was due to canopy retention of Ndep (Ncr). Data from my mesocosm 15N-labelling experiment suggested that very little (<10%) of Ncr observed in the field was actually taken up by trees, and the majority of Ndep (>85%) was assimilated into soil pools. These results suggest that Ndep could not have significantly increased forest NPP at UMBS over the time scale of my studies. My greenhouse experiment corroborated this conclusion, with tree seedlings showing no significant increase in photosynthesis or growth in response to Ndep at ambient rates. However, Ndep to forest ecosystems has been occurring for decades in industrialized regions, and most of the N inputs have been incorporated into soil organic matter (SOM). Research across temperate forests has suggested that forests exposed to large N inputs over time exhibit decreased soil C/N ratios, which are associated with faster Nmin rates. Using meta-analysis, I verified this pattern in the literature, and discovered novel relationships between forest soil properties and their responses to N inputs. My results demonstrated a long-term, quantitative relationship between Ndep and Nmin, and suggest that NPP may increase (open full item for complete abstract)

Committee: Peter Curtis (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2007, Mathematics

We study the evolution of conditional dispersal using a Lotka-Volterra reaction-diffusion-advection model for two competing species in a nonhomogeneous, temporally constant environment. We assume that the two species are identical except for their dispersal strategies. Both species employ random diffusion combined with advection upward along resource gradients. We use a perturbation argument to understand the evolution of these rates. When the advection rates are small relative to the diffusion rates, we find that stronger advection is preferred. However, when the advection rates are large relative to the diffusion rates, we find that weaker advection is preferred. We also studied the case where the two species have differing strategies, one with a very strong biased movement relative to diffusion, and the other with a more balanced approach. If the advection rate of the latter is small, the two species can coexist. But if its advection rate increases sufficiently, the second species drives the first to extinction. So we see in these results a preference against overly strong advection and in favor of a more balanced strategy, suggesting the existence of an optimal intermediate rate.

Committee: Yuan Lou (Advisor) Subjects: Biology, Ecology; Mathematics

Doctor of Philosophy, The Ohio State University, 2007, Natural Resources

Southeastern floodplain forests are species-rich ecosystems that respond to dynamic interactions between disturbance and hydrologic regimes. In this dissertation, I examined how the composition and structure of floodplain forest ecosystems are regulated by these disturbances, with a particular emphasis on understanding how large woody vines interact with natural and anthropogenic disturbances in floodplain forests. The long-term studies of forest dynamics in the Congaree National Park and the Savannah River Site in South Carolina provide ideal settings to study the interactions of hydrologic and disturbance regimes in species-rich forests with a significant large woody vine component. During the twelve years following Hurricane Hugo devastated portions of the old-growth floodplain forest of the Congaree National Park, liana communities have responded to the changes in forest structure. In heavily damaged bottomland hardwood forests, liana densities initially decreased when the host trees were severely damaged but exceeded pre-hurricane densities within twelve years. In both low and high damaged bottomland hardwood forests, vine communities have experienced increasing diameter growth rates and decreasing mortality rates. Long-term trends in the density and distribution of lianas may indicate shifts in the composition of plant functional types in these forests. Radial increment data from lianas can provide insight into long-term trends in diameter growth, response to disturbance, and longevity. Ring width data suggest that liana species respond differently to the extent of canopy disturbance. Campsis consistently grew faster than Toxicodendron, with one exception being the five years following Hurricane Hugo in areas that suffered severe damage. Toxicodendron diameter growth rates increased through time starting in the 1970's. Existing definitions for old-growth red river floodplain forests are either so broad so as to include almost any mature floodplain forest or so (open full item for complete abstract)

Committee: P. Goebel (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2007, Evolution, Ecology, and Organismal Biology

Herein, I describe research that quantifies how native and non-native (henceforth exotic) benthic organisms influence community and ecosystem processes. As aquatic ecosystems are recovering from years of excessive inputs of nutrients and industrial pollution, the influence of benthic food webs on the overall ecosystem likely will increase. By conducting a series of laboratory and outdoor experiments, observational studies, and field assessments in small reservoirs, I quantified how benthic organisms transfer material to higher trophic levels. For the native omnivore, gizzard shad Dorosoma cepedianum, growth and survival depended on the quality of sediment detritus, suggesting that detritus quality ultimately can regulate community and ecosystem productivity, mediated by its influence on gizzard shad biomass available for trophic transfer to piscivorous fish (Chapter 2). The addition of an exotic, benthic fish, round goby Neogobius melanostomusto the Lake Erie ecosystem, by being preferentially consumed over native prey by smallmouth bass Micropterus dolomieuappears to transfer benthic energy and contaminants to the pelagic food web (Chapter 3). A field study and historical data in Lake Erie revealed biomagnification of PCBs by an exotic species component (comprising round goby and dreissenid mussels Dreissenaspp.) to native terminal predators, smallmouth bass and largemouth bass Micropterus salmoides(Chapter 4). Recovering benthic macroinvertebrate communities in Lake Erie appear influenced by dreissenid mussels and dreissenid mussel interactions with PCBs and organic content of sediments (Chapter 5). As nutrient and contaminant inputs continue to decline and exotic species continue to proliferate, I predict an increase in the relative importance of such benthic transfer pathways in influencing variability in transfer of energy and contaminants from to the pelagic food web.

Committee: Roy Stein (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2005, Natural Resources

Large wood jam (LWJ) abundance and structure reflect hierarchical processes. Understanding relationships between LWJ and stream-corridor geomorphology is important for ecological restoration of streams. I identified four geomorphic settings of approximately 1 km channel length in an old-growth landscape of Northern Michigan, based on stream gradient and valley constraint. Redundancy analysis indicated greater similarity of LWJ at reach scales (300 m) within geomorphic study sections than among geomorphic sections. The size of pieces of wood in LWJ, the number of pieces in LWJ, and the volume of loose pieces of large wood (LW) appeared to be greater in stream reaches of old-growth than second-growth forest. LWJ and LW piece size appeared to correspond similarly with environmental factors, but LWJ abundance related inversely with LW abundance. Linear K-function analysis revealed random spatial distribution of LWJ at all scales (from 5 m to several km) within most geomorphic study sections, contrary to predictions. Aggregated patterns occurred, however, in each case when LWJ distribution was considered in contiguous geomorphic sections because LWJ clustered in low or mid-gradient sections. Uniform spacing was also apparent in two of four cases (at scales of 5 m and more than 1 km) when LWJ spanning more than 50% of the channel were evaluated in contiguous geomorphic sections. LWJ abundance, the number of LWJ spanning the entire channel, and the number of smallest LWJ (2-5 pieces) corresponded significantly with geomorphic setting, with most geomorphically-defined variance related to stream width, sinuosity, and the presence of rock-plane bedding. Patchy stream-corridor geomorphology corresponded with patchy LWJ characteristics, supporting stream restoration practices that fit amounts and types of LWJ to stream-corridor setting. The functional effect of LWJ on fish assemblages in geomorphic patches remains, however, equivocal. Variability was high in the abundance of fi (open full item for complete abstract)

Committee: P. Goebel (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2005, Evolution, Ecology, and Organismal Biology

Stochastic dynamic programming (SDP) models have been used to examine the trade-off dynamics of survival- and reproduction-promoting behaviors in birds during the non-breeding season. The models assume that dawn and dusk choruses are components of adaptive daily routines of singing and foraging under unpredictable environmental conditions. I examined predictions from SDP models using white-breasted nuthatches (Sitta carolinensis). First, I performed an observational study where I observed nuthatch pairs isolated in small woodlots (isolated pairs) or in large woodlots where several pairs resided (social pairs). I was interested in whether nuthatch vocalizations followed patterns predicted by SDP models, and whether there were differences between vocal and other behaviors of social and isolated nuthatch pairs. I found that while nuthatch vocalizations were as predicted by the models, especially song which peaked at dawn and dusk, foraging did not occur as predicted. Social environment of the birds appeared to influence behaviors, as isolated pairs called and sang less than social pairs, and isolated females foraged more than social females. In the second component of my dissertation, I performed a mate-removal experiment to investigate hypotheses from SDP models. I found a trade-off between singing and foraging, and this trade-off changed over the winter. Upon removal of a mate, males increased the frequency of two song types. My results did not support predictions regarding patterns of singing and foraging, as male song peaked at dawn and showed a decline throughout the day, while foraging peaked at dusk. In the third component, I investigated how nutritional state influences mate-attraction and foraging behaviors of white-breasted nuthatches. I removed the female of nuthatch pairs to induce males to sing at dawn. Then each male was caught and subjected in captivity to two feeding regimes, ad libitum food or food-deprivation for two hours prior to dusk. Upon release (open full item for complete abstract)

Committee: Thomas Grubb (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2004, Evolution, Ecology, and Organismal Biology

In this study, we explore large-scale movements in ruffed grouse (Bonasa umbellus) in Ohio by characterizing juvenile and adult dispersal, investigating the effect of landscape characteristics on movement behavior and examining the relationship between movement and the risk of predation. Our first objective was to investigate the natal and adult dispersal characteristics of ruffed grouse throughout the entire annual breeding cycle, using a behavioral definition of dispersal. Once dispersal movements could be accurately identified, we explored whether landscape variables measured at coarse-grained scales could help explain general movement characteristics. We used Akaike Information Criterion (AIC) techniques for model selection to explore the relationship between metrics of both landscape composition and configuration and the decision to disperse by adults and juveniles, their net dispersal distances and rates of movement, and their home range sizes. Ecologists often assume that dispersing individuals experience an increase in predation risk due to increased exposure to predators while moving. We tested the hypothesis that predation risk is a function of rate of movement and site familiarity using a Cox's proportional hazards model. Overall, we documented a surprisingly high proportion of adults undertaking seasonal dispersal movements and juveniles undergoing dispersal in the spring, particularly compared to grouse studies conducted in the northern portion of its range (Chapter 1). We also found that coarse-grained landscape characteristics affect movement behavior, but effects varied considerably among specific behaviors and across spatial scales. While large-scale landscape composition (i.e. % forest) and edge density significantly affected dispersal behavior little evidence was found for landscape configuration per se affecting movements (Chapter 2). Finally, we found evidence indicating that increased movement rates may increase the risk of predation for adult (open full item for complete abstract)

Committee: Elizabeth Marschall (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2004, Evolution, Ecology, and Organismal Biology

We use a variety of methods to study population connectivity. In Chapter 1, we use stable isotope ratios in feathers to make Bayesian inferences about the migratory connectivity between breeding and wintering grounds of Henslow's sparrows. We use hydrogen and carbon stable isotope ratios (deltaH and deltaC). We compare the deltaH and deltaC of feathers from wintering sparrows to five breeding region deltaH and deltaC to estimate the probability that each individual wintering sparrow originated from each of the five regions. Breeding bird abundances are used as prior probabilities of breeding region origin. We conclude that there are no clear linkages between specific breeding regions and wintering sites. In Chapter 2, we use three methods to estimate dispersal in Henslow's sparrows. 1)deltaH in feathers are used to determine whether an individual breeding bird has a deltaH signature characteristic of the breeding site. 2) Song structure is used as the signature of an individual's previous breeding-ground origin. 3) Genetic markers are used to evaluate population structure. Genetic structure is evaluated using three estimates. Fst estimates and private alleles are used to calculate the number of migrants per generation (Nm) between sites. Private alleles are evaluated to determine if they are truly private. A Bayesian clustering method is used to infer the number of populations. All methods revealed high rates of dispersal. In Chapter 3, three methods for estimating dispersal are compared: deltaH in feathers, genetic population structure, and spatial autocorrelation (SAC). We compare the dispersal estimates of five migratory species. With the SAC analysis, we find no clear evidence for dispersal as a major synchronizing agent. However, new statistical methods may allow for the parsing out the effect of dispersal. One species had historically high dispersal (limited genetic structure) but currently low dispersal (high deltaH correlations). Another species had a deltaH (open full item for complete abstract)

Committee: Thomas Waite (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2004, Evolution, Ecology, and Organismal Biology

Success of wetland restoration/creation efforts in adequately replacing impacted wetlands is dependent in part on identifying and quantifying key habitat features that are important in structuring the composition of wetland-dependent faunal communities. My Ph.D. project focused on advancing our understanding of the local and landscape-level factors that structure faunal diversity in wetlands. The first chapter examines how certain wetland-design characteristics affect the structure of amphibian communities in constructed replacement wetlands. I find strong evidence that predatory fish and the absence of a shallow littoral zone in constructed wetlands have a negative impact on amphibian diversity, while wetland size is not an important factor. The second chapter presents habitat-suitability models for seven pond-breeding amphibian species using variables describing the surrounding landscape composition (at 200m and 1km scales) and within-wetland factors such as wetland size and presence of predatory fish. Landscape composition is a good predictor of amphibian diversity at natural wetlands within the agricultural landscape of Ohio. The amount of forest cover within 200m, cumulative length of paved roads within 1km, presence of predatory fish, and distance to other wetlands are variables that explain most of the variability. Chapter three examines the association between wetland bird species diversity (breeders, non-breeders and spring migrants) and the amount of emergent vegetation cover in the wetland as well as the size of the wetland complex within which a wetland was constructed. Breeding bird diversity and density is highest in wetlands with high vegetation cover (60-80%), and the size of the wetland complex is positively associated with both overall diversity and density of several individual species. In the fourth chapter, I compare amphibian communities in existing constructed replacement wetlands to communities in natural forested and emergent wetlands within (open full item for complete abstract)

Committee: Thomas Hetherington (Advisor) Subjects: Biology, Ecology

Doctor of Philosophy, The Ohio State University, 2003, Evolution, Ecology, and Organismal Biology

I examined three aspects of forest fragmentation to determine how they impact resident and migrant bird species. The first aspect was the relationship between habitat patch area and species presence and richness. I performed an observational study along riparian woodlands to determine the abundance and distribution of bird species and avian guilds. Woodland area better predicted bird species presence than woodland width. In addition, the probability of detection was positively correlated with woodland area for 11 bird species and negatively correlated with woodland area for eight species. A management simulation of woodland riparian corridor width indicated that current management suggestions were inadequate to provide habitat for a variety of Neotropical woodland migrant bird species. In the second aspect of my research, I examined the ability of two species of birds to supplement their habitat requirements by incorporating disjunct habitat patches on either side of a watercourse into a single territory. I found the probability of eastern wood-pewees (Contopus virens) crossing water gaps to reach simulated singing conspecific to be negatively associated with vegetation gap width. Red-eyed vireos (Vireo olivaceus) demonstrated no significant trend. However, the strength of red-eyed vireo vocal responses after crossing was inversely proportional to the width of waterway. These results suggest that species may differ in their response to simulated conspecific vocalization, and that water gaps less than 30 m wide may not hinder all avian species from crossing to reach playbacks, but may still curtail territorial responses. The third aspect of my work was to determine the ability of a species to colonize empty habitat patches. I simulated patch extinction events by removing Carolina chickadees (Poecile carolinensis) from woodland fragments. I found that chickadees arrived sooner in woodlots connected to other woodland by habitat corridors. I also found that individual c (open full item for complete abstract)

Committee: Thomas Grubb (Advisor) Subjects: Biology, Ecology