The evolution of jaws in cichlid fishes of the East African Great Lakes is a textbook example of adaptive radiation in vertebrates. Karl Liem postulated that this adaptive radiation has been possible due to the functional decoupling of two cichlid functional units – the pharyngeal jaw (PJ) and the oral jaw (OJ). This functional decoupling of the jaws has enabled the OJ to be relieved of its dual role of prey capturing and processing and has allowed the PJ to take on the role of prey processing. As a result, African cichlids have adapted the morphology of their functional units (i.e., oral jaws) to specialize in a feeding mechanism best suited for their habitat. However, global morphological changes (across the OJ and PJ) are understudied, especially, at the genetic level. In this study, two rock dwelling species of African Cichlids from Lake Malawi were used - Labeotropheus fuelleborni (LF) and Tropheops “red cheek” (TRC). Both species have distinct craniofacial morphologies for specialized benthic feeding (LF) and for generalized feeding (TRC). This morphological variation allowed us to investigate the functional decoupling of the jaws by studying differences in bone shape and muscle volumes in an F5 hybrid population. Strong phenotypic correlations were observed between and within the tissues of the OJ and PJ. Further, to identify phenotype to genotype associations, a Quantitative Locus (QTL) analysis and a fine mapping analysis was conducted. The results show some evidence of overlapping genetic control (i.e., pleiotropy) suggesting some genetic coupling between the two jaws.

ABSTRACT Classifying and Mapping Diversity in a Species-Poor System: the mangrove meta-community of Laguna Chacahua National Park, Oaxaca, Mexico by Elizabeth Kay Weisgerber Both field transects and imagery grid plots were analyzed with the goal of creating a community classification map for the mangrove forest of Parque Nacional Lagunas de Chacahua. In total, data was collected in 49 sites throughout the park, recording measures such as DBH, basal area, estimated dominance, frequency, cover and relative dominance. Field locations were marked and georeferenced with a GPS and grid plots overlaid on satellite imagery of the park were generated via a random number table. Species' attributes delineating the identifiable features for each dominant species within Chacahua were noted and used to recognize patterns in species assemblages. Fourteen distinct ‘sub-communities’ within the mangrove meta-community were recognized using this data and verified with 165 field photos. Relative dominance values were compared between field and grid data. These data revealed a similar pattern with Rhizophora mangle being most dominant under each method. Avicennia germinans was second in relative dominance, Laguncularia racemosa a close third while Conocarpus erectus was rarely found, most likely due to over-harvesting. Rapid degradation of mangrove forests is occurring on a global scale. Understanding the complex dynamics that occur within the mangrove meta-community is essential to its conservation. Vegetation maps are essential tool in monitoring changes throughout the mangrove but are rarely of sufficient detail for everyday use. Generating highly detailed vegetation maps in a cost-effective and timely manner is an important step for their conservation, particularly in developing countries. This study demonstrates methods and techniques for producing a vegetation map that portrays the level of complexity that exists within the species-poor mangrove environment. This map will be donated to the management team of Parque Nacional Lagunas de Chacahua to better aid in management.

It is widely accepted that allelopathy is not only significant, but more or less singular, in the inhibition of understory vegetation in California Eucalyptus globulus (blue gum) plantations. However, there is no published documentation of allelopathy by blue gums against California native species. Here, we present evidence that germination and early seedling growth of five California native species are not inhibited by chemical extracts of blue gum foliage, either at naturally-occurring or artificially concentrated levels. In the greenhouse, seeds were germinated in field-collected soil from mature blue gum plantations and the adjacent native, coastal scrub communities. In petri plates, seeds of native species were germinated in the presence of concentrated volatile and water-soluble compounds from fresh foliage of blue gum, coast live oak (Quercus agrifolia) as a negative control, or white sage (Salvia apiana) as a positive control, or in a water control. In the greenhouse, blue gum soil supported germination and early seedling growth of native species equal to or better than coastal scrub soil. In the lab, germination of native species was not inhibited when grown in the presence of volatile compounds from blue gum foliage, compared to the native control (coast live oak) or the neutral water control. Germination of three out of five native species tested was not inhibited in the presence of water-soluble compounds from blue gum foliage, compared to coast live oak or the water control. Our results contradict the long-standing paradigm that blue gums are toxic to California natives, which may have significant implications for management and restoration of land historically occupied by blue gum plantations.

Planktonic larvae of marine organisms are increasingly being exposed and required to respond to a changing physical environment. Adult sea urchins occupy both intertidal and subtidal waters and broadcast spawn gametes into the water column to contend with variable physical conditions. To answer how populations of invertebrates residing at different depths adequately prepare their offspring to cope with different levels of ultraviolet radiation (UVR), we collected adult purple sea urchins, Strongylocentrotus purpuratus, from four sites (two intertidal and two subtidal (~15 m deep)) on the central coast of CA to compare UV tolerance in offspring. Our measurements of UVA (321–400 nm) and UVB (280–320 nm) irradiance at all collection sites showed UVA and UVB were low or absent in subtidal sites compared to intertidal sites. Our study found that offspring from intertidal populations experience a less severe developmental delay when exposed to environmentally relevant levels of UVR (using artificial lighting) than offspring from subtidal populations. The mean percent cleavage delay for UV-treated embryos relative to the controls was 16% (± 2.3 SE) for intertidal sites and 21.1% (± 2.7 SE) for subtidal sites. This suggests that environmental UV cues or additional environmental cues experienced by intertidal mothers may prepare offspring to resist effects of UV exposure during early development. To further understand differences in biochemistry of the eggs released from mothers of different populations (i.e. differences in maternal investment), we assessed differences in protein abundance among batches of eggs from intertidal and subtidal populations. We identify a range of candidate proteins involved in various cellular processes such as cell cycle regulation, signaling and transport, oxidative stress and metabolism that may help developing embryos cope with UVR stress. These candidate proteins may also help us understand adaptations important for survival of developing marine organisms in changing ocean conditions.

Over the 21st century, climate change and wetland habitat loss will pose major threats to the Eastern Massasauga (Sistrurus catenatus), a federally threatened and Great Lakes region endemic rattlesnake. I collected capture-recapture data from sites across the range and modeled the effect of climatic variables on growth rate and asymptotic size. I found that high snow residence time was associated with larger asymptotic sizes but slower growth, while high spring precipitation increased growth rate. I then projected future growth and size under different carbon emission scenarios. Given the threat posed by successional encroachment of woody vegetation, I used spatially explicit capture-recapture models to examine the effects of landscape characteristics and phenology on the spatial distribution of density for a population in Michigan. I found highest density in areas close to a stream and with low vegetation intensity, which can inform prescribed burn programs and give additional insights into life history.

Knowledge of the impacts of white-tailed deer (Odocoileus virginianus; hereafter deer) as dominant herbivores throughout the Southeastern United States of America is lacking. To address this, three paired experimental units of exclosures and controls were constructed in 2000 on three Wildlife Management Areas across Mississippi within the ecoregions of the Upper Coastal Plain, Lower Coastal Plain, and the Mississippi Alluvial Valley. Vegetation was sampled in the summers of 2000, 2005, and 2021 including vegetation structure, canopy coverage, basal area, and species composition. Additionally, in 2005 and 2021, biomass was sampled to determine potential impacts on nutritional carrying capacity. Among the three study sites, vegetation metrics followed successional trends and were not influenced by herbivory or lack thereof. Additionally, regional differences in nutritional carrying capacity seemed to be of greater importance than herbivory. This research illustrates the difference in effects of deer by region and forest type.

Ruminant animals comprise the greatest proportion of herbivores around the world, provide essential ecosystem services and human consumable protein by consuming grass and human inedible dietary fiber. Herbivory pressure alters plant communities and species diversity, effectively making grazing animals ecosystem engineers in dynamic ecosystems. Development of advanced computer processing power coupled with biometric and ecosystem sensors may be employed in the internet of things framework to create an integrated information system designed to inform understanding of grazing system function and animal energy balance. Towards this end, I utilized Bos indicus / Bos taurus crossbred steers (n = 20) across two study sites each in consecutive calendar years and fitted them with GPS and accelerometer collar systems. Steers were grazed in improved grass pastures containing Tall Fescue (Festuca arundinacea) and Bermudagrass (Cyanodon dactylon). Forage samples were collected in a 20-m grid pattern at 35-day intervals to test nutritional composition, and NDVI maps were created using remotely sensed data collected using a UAV mounted camera system. In the first chapter, I utilize the movement ecology framework to investigate metabolic theory and animal behavior on energy budgets, then explore available technology to utilize in an integrative information system. In Chapter 2, I tested preprocessing and behavior collection methods used to train a machine learning randomforest classification model to predict animal behavior using triaxial accelerometers. Landscape functional scale and optimal sampling density is the primary focus of Chapter 3, where I explored the complex relationship between sampling regime, interpolation strategy, and landscape complexity, demonstrating that sampling density is a product of desired accuracy and landscape complexity. Finally, I focused on animal growth in Chapter 4, demonstrating the functionality of a walk-over-weigh system, and identified robust regression as the most accurate smoothing method to identify and remove spurious animal weights.

Understanding family forest owners’ (FFOs’) attitudes and behaviors towards climate change will allow for more sustainable forest management practices to be implemented, helping to combat climate change and its impacts. The goals for this research are (1) to begin measuring U.S. FFO attitudes toward climate change, (2) to determine what factors impact these attitudes, and (3) to determine how they influence the FFO’s management practices using the Responsible Environmental Behavior (REB) framework (Hines et al. 1987). Chapter 1 explores the different facets of my thesis project focusing on forests and forests’ ecosystem services, forest ownership in the United States, and exploration of the REB model and serves as a more in-depth introduction section of Chapter 2. I explored past research of climate change attitude and beliefs and found age, political affiliation, education level and income of U.S. forest owners and foresters were significant factors in comparison to their climate change belief or attitude. Chapter 2 follows my research project, in which I measure the climate change attitudes of FFOs in Alabama, Oregon, and Wisconsin and their employment of climate centered forest management practices as well as the factors that influence these practices using mailed surveys. Based on the categories developed by Maibahc et al. (Maibach et al. 2009) to describe the general public’s attitudes towards climate change, I found about 16% of the FFOs in the study area were in the Alarmed segment, 16% in the Concerned, 37% in the Cautious, 2% in the Disengaged, 10% in the Doubtful, and 20% in the Dismissive. FFOs in Oregon and Wisconsin were more likely to be in a higher climate change attitude segment than those in Alabama. FFOs who had a college degree were more likely to be in a higher climate change attitude segment than those and a college degree. Climate change attitude was not a significant factor in determining if the FFO would carry out a climate centered management practice within the REB framework but rather the FFOs who indicated financial objectives were an important reason for owning their forest\land were more likely to carry out the listed management practices. These results indicate climate change belief is not necessary for an FFO to manage their land to mitigate or adapt to future climate impacts, but rather the individual objectives and values determine which management practices are utilized.

Artificial light at night (ALAN), or ecological light pollution, is increasingly prevalent worldwide. Exposure to ALAN tends to negatively impact animals—particularly, nocturnal animals—but life-history strategies may mitigate these costs. Animals in many regions are also increasingly exposed to climate-related stressors, such as heat and drought. Yet, interactions among ALAN, life-history strategy, and stress tolerance are unknown. Therefore, I determined if developmental ALAN exposure (1) affects development, (2) affects adult phenotype, including heat and desiccation tolerance, and (3) affects and/or interacts with life-history strategy. To address my aims, I used the variable field cricket (Gryllus lineaticeps) because its geographic range is increasingly exposed to ALAN, heat, and drought conditions; it exhibits different life-history strategies (flight-capability vs. flight-incapability); and it is mainly nocturnal. Although developmental duration and success were not impacted by ALAN exposure, ALAN affected adult phenotype, with a positive effect on body mass, body size, and reproductive investment, and a negative effect on heat tolerance. Life-history strategy also affected stress tolerance—flight-incapable females had greater heat tolerance, and their desiccation tolerance was improved by ALAN exposure. Thus, key features of environmental change (i.e., exposure to ALAN, heat, and drought) may favor some life-history strategies over others.

<p>Plants often grow in communities closely surrounded by neighbouring plants. Plants can actively and intensely compete for resources and also anticipate competition by sensing environmental cues from the presence and identity of neighbours. Moreover, it’s been proposed that the evolution of both increased and decreased competitive ability may serve as a mechanism for invasiveness. However, still little is known about how plants integrate competitive responses when sensing multiples cues of competition and which individual competitive traits respond to the identity of competitors. In addition, whether and why the evolution of competitive traits may contribute to the ability of introduced species to become invasive is also poorly understood.</p> <p>Here I present a body of work that examined the competitive responses of a native and an invasive plant species to cues of competition and the identity of neighbours. I also examined how experimental manipulation of pot volume, to control belowground resources, affects plant growth and allocation. In one study I tested the competitive responses of the North American native, <em>Impatiens pallida</em>, to cues signalling the presence of neighbours above and belowground simultaneously in competitive environments composed of either siblings or strangers. I demonstrate that<em> I. pallida</em> can recognize siblings and shows more aggressive competitive behaviours towards strangers than kin.</p> <p>In two other studies, I compared the competitive responses of the invasive and native ecotypes of <em>Alliaria petiolata</em> to changes in density, as well as to the presence and identity of neighbours. I found that invasive ecotypes produced less competitive phenotypes especially under high density. Moreover, I found that invasive ecotypes performed better when sharing rooting space with neighbours that were siblings.</p> <p>Taken together, these results demonstrate the ability of these plant species to respond to the identity of neighbours and provide strong evidence in support of the evolution of reduced competitive ability hypothesis in invasive plant species potentially mediated by the action of kin selection in invasive ecotypes.</p> / Doctor of Philosophy (PhD)