<p> Seagrass ecosystems are some of the most productive in the world and provide a variety of ecosystem services but are facing global decline chiefly due to anthropogenic disturbance. Mechanical disturbances to seagrass meadows from anchoring, propeller scars, and mooring scars result in losses or damage to both shoots and the underlying rhizome. I conducted a literature synthesis on the extent of, recovery from, and ecological impacts of these mechanical disturbances to seagrass meadows. The literature suggests that anchoring damage tends to be worst in deeper water where larger vessels anchor and can cause large (>100m²) loss per anchoring and recovery may take decades to over a century. Propeller damage is of largest concern in shallow (&lt;2m) areas experiencing heavy boat traffic because propeller damage can only occur where the propeller can come close to the seagrass. Mooring damage is highly variable depending on the type of mooring used (&lt;10m² to >1000m² scoured per mooring). Seagrass patches experiencing these mechanical disturbances have, in some studies, been found to have lower seagrass percent cover and shoot density than reference areas. This indicates scars can have &lsquo;halos&rsquo; of impacted seagrass meadow. Some seagrass systems cannot recover within a century (e.g. <i>Posidonia oceanica</i> meadows at the extent of their depth tolerance) while others recover annually from some disturbances (e.g., anchor scars &lt;1m²). Systems face altered species composition when scars are preferentially recolonized by certain species and patterns of recovery are affected by altered biogeochemical conditions following disturbances. Additionally, mooring, anchoring, and propeller scarring frequently alter meadow density, cover, patch size, patch shape, patch isolation, edge area, and ratios of edge to interior meadow leading to changes in faunal community structure. Correlations between these disturbances and faunal abundances, densities, and richness in seagrass ecosystems are complex, vary temporally (sometimes on the scale of days), and may result in species showing positive, negative, or no responses to a wide range of disturbance regimes. </p><p> To explore the connections between mooring scarring, the surrounding seagrass meadow condition and epifaunal community, in the second part of this thesis I measured 30 mooring scars to determine average scar size. To explore any potential &lsquo;halo&rsquo; effect around mooring scars for seagrass or epifauna and to seek any difference in epifaunal community between mooring and reference sites I also sampled paired sites at eight locations in Nantucket Harbor, Massachusetts three times each in the summer of 2015. Each location consisted of a meadow site actively experiencing mooring scarring and a reference site without moorings. My conservative sampling methods of the 30 sampled mooring scars found scars to average 21.1m². Across my paired sites, seagrass was found to have lower cover and lower canopy height in mooring versus reference sites. Seagrass cover and canopy height were lower in the first few meters (typically 2-3m) surrounding each scar in comparison to paired reference quadrats indicating a &lsquo;halo&rsquo; effect of each scar. I did not detect a difference in epifaunal community composition or density per blade between mooring and reference sites; however, the relatively constant per blade concentration of epifauna combined with the differences in seagrass biomass between the mooring versus reference sites indicate an overall increase in the total amount of epifauna in areas with less disturbance. Epifaunal community composition was different and between locations and sampling dates indicating these factors are more important than proximity to mooring scarring in determining epifaunal abundance and richness. When considering scar area and the &lsquo;halo&rsquo; of each scar I estimate that at least 32ha (2%) of Nantucket Harbor was impacted by mooring scarring. Given that the estimates of seagrass do not include areas previously denuded of this plant and that my measurements were conservative, likely a larger portion of this harbor&rsquo;s potential seagrass habitat is impacted. Combined with the findings of loss due to these direct boat-related physical disturbances of seagrass meadows worldwide across regions, this halo effect is likely to also be found for moorings globally. I encourage management of the issue by employing and fine-tuning mooring methods (such as deploying moorings with anchor connections that do not drag on the sea floor) to minimize these unintentional but strong effects of mooring on the recipient habitat.</p><p>

Recent trends indicate that firms are spending more money and resources on environmental protection and are seeking proactive ways to reduce the environment impact of their business actions. This dissertation discusses the impact of environmental issues on strategy formulation and proposes underlying themes of corporate environmentalism based on inclusion of the biophysical environment in strategy, formulation, and organization wide recognition of and response to environmental issues. Corporate environmentalism is proposed to consist of two constructs: an overall corporate environmental orientation wherein environmentalism is internalized as a corporate value, and an environmental strategic focus involving the integration of environmental issues into the strategic planning process. The construct of corporate environmentalism is operationalized and the relationship with its antecedents is empirically tested. Using theoretical perspectives from ecology, marketing, and strategic management, this study builds an integrated model of corporate environmentalism including its antecedents and consequences. Public concern, threat of legislation, top management commitment, long term focus, and the need for competitive advantage are some antecedents that were gleaned from the literature. A two-stage methodology was used: the first stage involved in-depth interviews with managers of 6 firms. Based on these interviews three models of corporate environmentalism were constructed. The second stage involved empirical testing of these models. A survey instrument was designed and mailed to 1012 firms. Exploratory and confirmatory factor analysis of the constructs of corporate environmentalism was done to examine the dimensionality of the constructs. The models were tested using path analysis. Top management commitment and the need for competitive advantage emerged as the two key variables that explained corporate environmentalism. Public concern and the threat of legislation indirectly influenced corporate environmentalism through top management commitment. Strategic implications of corporate environmentalism for firms are discussed and a framework for future research on environmental issues facing business is proposed.

Interest in corporate environmentalism has exploded in recent years from a minor concern to a serious endeavor. Most firms today devote an average of 1-2% of revenues to environmental matters. Recent research has shown that an upstream, proactive approach to environmental strategy can lead to win-win outcomes and improved environmental and financial performance. Much has been learned about how top managers develop and promote proactive ecostrategies, and the details of employee contributions are also becoming clear. However, middle managers' contributions to realized ecostrategy are largely unexplored, as are multilevel aspects of environmental strategy making. Drawing from literatures of strategic processes, organizational behavior, and environmentalism, the dissertation hypothesized that attitudes, behaviors, communication style, and identity orientation of middle managers is associated with the promotion of environmental initiatives by subordinates. A quantitative case study tested the hypotheses. Three companies in the retail grocery business participated in the study, and survey data was collected from 584 managers at three organizational levels. The final sample consisted of 406 managers, and hierarchical linear regression was used to analyze the data. Results show that middle managers' activities and attitudes are indeed related significantly to emergent environmental initiatives in the organizations studied. Thus, middle managers are critical, central players in achieving environmental performance improvements. In addition, specific patterns of middle manager involvement varied significantly by company, and there were indications that these patterns were related to organizational culture. Other results include the development and validation of an expanded measure of environmental initiative development that, for the first time, delineates a multiphasic process and proves useful in understanding the nuanced nature of proactive ecostrategy making. Similarly, the dissertation combined and retested previous findings from organizational behavior, strategic, and relational models of organizational environmentalism, thereby permitting comparison of the relative influence of different factors for the first time. Finally, this study represents the first use of multilevel quantitative analysis, specifically multilevel regression and hierarchical linear modeling, in the study of environmentalism in organizations. These results reinforce the value of mesolevel studies of environmentalism by providing depth and nuance that is inaccessible in organization-level quantitative studies or qualitative case studies.

<p> Estimating the water budget of three mid-latitude extratropical cyclones is attempted from the perspective of the precipitation efficiency (PE), using a method proposed for the study of convective columns. Using a lagrangian, system-relative volume centered on the surface low pressure, each cyclone was followed for most of its lifetime within a pre-defined volume (7 degrees latitude x 9 degrees longitude, or approximately 700 x 700 km). A comparison is then made of total atmospheric water vapor ingested to total moisture eliminated (as precipitation). We hypothesize that the PE increases with the intensity of the cyclone. This small sample confirms that idea, and thus encourages further study with this approach.</p><p>

<p> Russian olive is an exotic actinorhizal tree intentionally introduced to the U.S. in the early 1900&rsquo;s. It has become a dominant component of riparian ecosystems throughout the western U.S. Unlike most other riparian trees in the semi-arid west, Russian olive germinates and grows both in the open and in the understory of mature cottonwood stands. As an actinorhizal species, it forms an endosymbiosis with soil actinobacteria in the genus <i>Frankia</i> that allows for atmospheric N₂-fixation. This leads to higher soil N concentrations and mineralization rates underneath the tree&rsquo;s canopy than outside. Russian olive&rsquo;s high abundance and impact on soil N suggest it may alter plant communities, but these impacts have not been previously demonstrated. I investigated the impacts of Russian olive on shading, soil N availability, and plant communities and documented how those impacts varied across a semi-arid riparian ecosystem along the South Fork of the Republican River in eastern Colorado. Of the suite of environmental variables I measured, presence or absence of cottonwood canopy had the largest effect on Russian olive impacts. Russian olive increased shading, soil N availability, and proportion exotic plant and forb cover more in the open than underneath a cottonwood overstory.</p><p> Actinorhizal endosymbioses provides an important N source in terrestrial ecosystems, but N₂-fixation rates decrease due to high exogenous N and low photosynthetically active radiation (PAR). The amount that these environmental variables reduce N₂-fixation in host-<i>Frankia </i> symbiosis types dictates the strength and duration of those symbioses&rsquo; impacts on ecosystems. To understand how the two main types of endosymbioses (<i>Alnus-</i> and <i>Elaeagnus-Frankia</i>) differ in their response to environmental variability, I conducted a greenhouse experiment comparing growth and nodulation between two genera of actinorhizal species, <i> Elaeagnus</i> and <i>Alnus,</i> across exogenous N and PAR levels. Overall, <i>Elaeagnus</i> species had higher nodulation rates and tissue % N than <i>Alnus</i> species. Nodulation rate and growth response to nodulation were both lower at low PAR than high PAR for both genera. The reduction in the growth response to nodulation at high exogenous N was lower in <i>Elaeagnus-Frankia</i> symbiosis than <i> Alnus-Frankia</i> symbiosis. These results suggest that <i>Elaeagnus </i> species are more likely to cause a greater and longer-lasting increase in soil N than <i>Alnus</i> species.</p><p> A main objective of exotic species management is to increase native plant cover. However, few studies monitor plant community response to exotic species management, and the few that have suggest secondary invasion is likely, particularly when effects of the target invasive persists and management efforts cause disturbance. To measure the role of these two factors in plant community response to Russian olive removal, I monitored soil N availability and plant communities along the South Fork of the Republican River two years before and three years after the tree&rsquo;s removal. Russian olive&rsquo;s impact on soil N availability persisted, with levels staying high around removed Russian olive stems three years after removal. The plant community around removed Russian olive also had no increase in native plant cover but a dramatic increase in kochia (<i> Bassia scoparia</i>) cover following removal. My research demonstrates that Russian olive increases exotic plant cover in areas it invades and simply removing the tree does not promote native species recovery.</p><p>

<p> Groundwater is an essential input to agriculture world-wide, but it is clear that current rates of groundwater use are unsustainable in the long term. This dissertation assesses both current use of groundwater for country- to global-scale agriculture, and looks at the future of groundwater. The focus is on 1) quantifying food directly produced as a result of groundwater use across spatially-varying agricultural systems, 2) projecting future groundwater demands with consideration of climate change and human decision-making, and 3) understanding the system dynamics of groundwater re-use through surface water systems. All three are addressed using a process-based model designed to simulate both natural and human-impacted water systems. </p><p> Irrigation can significantly increase crop production. Chapter 1 combines a hydrology model (WBM) with a crop model to quantify current crop production that is directly attributed to groundwater irrigation in China. Unsustainably-sourced groundwater &mdash; defined as groundwater extracted in excess of recharge &mdash; accounted for a quarter of China&rsquo;s crop production, and had significant spatial variability. Climate variability and groundwater demand magnified one another in hot and dry years, causing increased irrigation demand at the same time as limited surface water supplies. </p><p> Human decisions about water resource management can impact both the demand and sustainability of groundwater use. Chapter 2 takes an interdisciplinary approach to projecting India&rsquo;s future (to 2050) groundwater demands, combining hydrology and econometric modeling. The econometric model projects how humans make decisions to expand or contract the irrigated land area of crops in response to climate change. Even in areas with precipitation increases, human decisions to expand irrigated areas led to increasing demands for groundwater. We additionally assessed the potential impact of a large water infrastructure project to alleviate groundwater demands in India, and found that maximum alleviation (up to 16%) was dependent upon the storage volume and location of new reservoirs. </p><p> One proposed method for reducing the world&rsquo;s demand for groundwater is to increase the efficiency of agricultural water use. However, these same inefficiencies cause a portion of extracted groundwater to enter surface water systems; it can then be reused, creating a complex system in which groundwater demand does not linearly decline with increased water use efficiency. Chapter 3 quantifies the amount of groundwater that enters surface water systems, the number of times this water is reused for agriculture, and the minimum amount of groundwater required by current agricultural systems in the hypothetical scenario of perfect irrigation efficiency.</p>

<p> The coastal zone of Louisiana is changing due to multiple pressures associated with sea-level rise, subsidence, and the inability of sediment or organic accretion to keep pace. The expected increases in sea level and salinity may affect the distribution of the existing plant communities. In addition, these changes in the environment could lead to shifts in plant community composition. During the summer of 2014, I researched how changes in salinity and water levels may change the establishment of vegetation in Louisiana marshes. Randomly selected Coastwide Reference Monitoring System (CRMS) sites were used to collect vegetation data and soil samples. The collected soil samples from fresh, intermediate, brackish, and saline marsh sites were used in a seed bank study. The seed bank study evaluated the effects of different levels of salinity and flooding on seed germination and species richness. Seed germination was highest in soil samples collected from fresh and intermediate sites when these samples were exposed to low salinity (0.0 ppt) and non-flooded conditions. My study only found 43 seedlings in the 10 ppt treatment of 336 total seed germinations, and only 2 seedlings were found in the 20 ppt salinity treatment. Salinity was the dominant factor governing seed germinations and species richness. I also determined that the parent plants for the species found in my seed bank study were more likely to be found within the study site. However, the species data showed at least one species or genus was not present in either the historical or the field collected data. Therefore, the dispersal distance of some seeds from their parental seed provider could have been several hundred meters.</p>

<p>Ecological risk assessment (ERA) is a framework for monitoring risks of exposure and adverse effects of environmental stressors to populations or communities of interest. One tool of ERA is the biomarker, which is a characteristic of an organism that reliably indicates exposure to or effects of a stressor like chemical pollution. Traditional biomarkers which rely on characteristics at the tissue level and higher often detect only acute exposures to stressors. Sensitive molecular biomarkers may detect lower stressor levels than traditional biomarkers, which helps inform risk mitigation and restoration efforts before populations and communities are irreversibly affected. In this study I developed gene expression-based molecular biomarkers of exposure to metals and insecticides in the model toxicological freshwater amphipod Hyalella azteca. My goals were to not only create sensitive molecular biomarkers for these chemicals, but also to show the utility and versatility of H. azteca in molecular studies for toxicology and risk assessment. I sequenced and assembled the H. azteca transcriptome to identify reference and stress-response gene transcripts suitable for expression monitoring. I exposed H. azteca to sub-lethal concentrations of metals (cadmium and copper) and insecticides (DDT, permethrin, and imidacloprid). Reference genes used to create normalization factors were determined for each exposure using the programs BestKeeper, GeNorm, and NormFinder. Both metals increased expression of a nuclear transcription factor (Cnc), an ABC transporter (Mrp4), and a heat shock protein (Hsp90), giving evidence of general metal exposure signature. Cadmium uniquely increased expression of a DNA repair protein (Rad51) and increased Mrp4 expression more than copper (7-fold increase compared to 2-fold increase). Together these may be unique biomarkers distinguishing cadmium and copper exposures. DDT increased expression of Hsp90, Mrp4, and the immune response gene Lgbp. Permethrin increased expression of a cytochrome P450 (Cyp2j2) and decreased expression of the immune response gene Lectin-1. Imidacloprid did not affect gene expression. Unique biomarkers were seen for DDT and permethrin, but the genes studied were not sensitive enough to detect imidacloprid at the levels used here. I demonstrated that gene expression in H. azteca detects specific chemical exposures at sub-lethal concentrations, making expression monitoring using this amphipod a useful and sensitive biomarker for risk assessment of chemical exposure.

<p> Pinyon-juniper (<i>Pinus monophylla &ndash; Juniperus osteosperma</i>) woodlands have expanded and infilled over the last 150 years to cover more than 40 million ha in the Great Basin. Many land managers seek to remove Pinyon-juniper trees using a variety of treatments. This thesis looks at six different Pinyon-juniper removal projects in Central and Eastern Nevada. We established a total of 73 vegetation and soil monitoring plots (38 treated, 35 adjacent untreated) across six Pinyon-juniper removal projects in Central and Eastern Nevada to look at the effects of fire, hand thinning, and chaining. The four burns examined together in Chapter 1 had similar elevation, precipitation, and pre-treatment vegetation communities in the untreated areas, but the treated areas had significantly different responses to treatment. With nonmetric multidimensional scaling (NMS), we found a useful 3-axis ordination of the plots (stress=7.1, R²=.966). Within ordination space, the treated plots were well grouped by parent material. These results informed a Poisson generalized linear model that found parent material factorized explained 86.5% of the deviance in cheatgrass (<i>Bromus tectorum</i>) cover at the treated plots. The projects on soils derived from welded tuff had very little cheatgrass while soils derived from limestone or mixed limestone/volcanics were dominated by cheatgrass. Parent material should be considered an important factor when planning Pinyon-juniper removal treatments. Chapter 2 examined the effects of a hand thinning. The hand thinning significantly reduced tree cover [F(1,10) = 7.43, p = 0.027] to less than 2%. Perennial grasses on the site are slightly higher in the treated area. There was a significant increase in perennial grass cover from 2013 to 2014 [F(1,10) = 14.5, p = 0.003]. The hand thinning did not have significant effects on shrubs, annual grasses, annual forbs, perennial forbs, ground cover, stability, species richness, diversity, infiltration, or gap structure. Because hand thinning does not remove the shrubs or other perennials, site resistance can be maintained. With sufficient understory vegetation to maintain resistance post treatment (as in phase I or early phase II Pinyon-juniper woodlands), nonnative annual grasses are less likely to dominate after treatment. Chapter 3 examined the effects of a chaining. The effects of the 40-year old chaining are still significant even though Pinyon-juniper trees are reinvading and make up >5% of the cover in the treated area. The treated areas still have a much more productive understory than adjacent untreated areas. Perennial grass cover, frequency, and density was 2-5 times greater in the chained area. The treated area had fewer large gaps (>100 cm). However, interspace infiltration times were slower in the treatment (t(4)=-2.14, p=0.09). Surface and subsurface soil aggregate stability remained significantly lower in the treatment for vegetation-protected and unprotected samples (t(4)=3.53, p=0.024; t(4)=3.10, p=0.036). Chainings have long-term benefits for vegetation, but also long term impacts on soils and hydrologic ecosystem processes. When planning Pinyon-juniper removal treatments, land managers should consider the plant community, temperature and precipitation regime, and soils at the potential treatment location to better achieve desired outcomes.</p>

<p> Water quality perception is borne out of various factors, which include taste, risk perception, water chemical and microbial parameters, trust in supplier, among others. This study addressed some of the factors that influence drinking water quality perception in the SIUE community for tap and bottled water. This was done through a survey that was delivered to the students, faculty, administration, staff, and alumni members of the university; a link to the online survey was provided via the school email, and a total number of 779 respondents participated in the survey. Some of the variables used in this study are based on general concern for taste, cost, water-chemicals (such as lead), drinking water behavior as well as demographic variables such as age, knowledge level and ethnicity. This study is based on data received from the survey conducted of the SIUE population for undergraduates, graduates, faculty, staff, administration, and alumni. Data were analyzed using several statistical methods including Spearman rank correlation coefficient and Kruskal-Wallis test. The results indicated that age and ethnicity have a significant impact on water quality perception. Drinking water behavior, age, and knowledge are well correlated in this study; therefore, they were not able to be separated.</p><p>