<p>This dissertation examines issues concerning sap flux scaled estimates of the canopy-averaged transpiration rate of trees per unit leaf area (E_L) and stomatal conductance (G_S), as well as their implications in the water and carbon balance of individuals and stands, with the final goal of an integrated assessment of 11 years of such data from two species (<italic>Pinus taeda</italic> and <italic>Liquidambar styraciflua</italic>) at the Duke Free Air Carbon dioxide Enrichment (Duke FACE) facility. These issues include (1) the effects of allometric relationships and xylem characteristics on the gas phase transport of water from leaves and the hydraulic supply of it, (2) consideration of the hydraulic capacitance in the inference of stomatal behavior from sap flux data and (3) the dynamic modeling of stomatal conductance to environmental drivers using Bayesian techniques. It is shown that a) for resolution of sap flux in conifers at the scale of minutes under dynamic conditions, time constants for both stomatal responses and hydraulic capacitance of sapwood must be considered, (b) nighttime conductance can lead to large errors in rates of sap flux measured under some conditions, (c) variation in allometry between <italic>P. taeda</italic> individuals can lead to different rates of transpiration and carbon assimilation per unit leaf area and that (d) hydraulic time constants for the stems of mature <italic>P. taeda</italic> at Duke FACE trees varied by the stem length considered and were on the order of 30-45 minutes for a 10-m segment. An analysis incorporating all these elements leads to the conclusions that (e) both elevated CO₂ (eCO₂) and fertilization (FR) resulted in proportionally larger reductions in the E_L and G_S of P. taeda as soil moisture decreased with (f) eCO₂ having little to no effect in months of high soil moisture and (g) FR leading to ~14% reduction of GS under high soil moisture in absence of eCO₂, while (h) both eCO₂ and FR led to reduced E_L and G_S of <italic>L. styraciflua</italic> across soil moisture conditions.</p> / Dissertation

Background: Food nourishes us, sustains us, and has the potential to both heal us and make us sick. Among many Indigenous cultures, traditional activities, ceremonies, events and practices often involve or use food, grounding Indigenous peoples within the context of their local, natural surroundings. This suggests that food is important not only for physical health, but also emotional, mental and spiritual health. The relationships that Indigenous peoples have with food can help us to understand the health of individuals, and the communities in which they live. Purpose: The following qualitative study explores how three generations of adults who live in one Labrador Inuit-Metis community experience and understand their relationships to food in a context of global change. Theoretical Orientation: The research is guided by Two-Eyed Seeing. Two-Eyed Seeing acknowledges that there are many different ways of seeing and understanding the world, some of which can be encompassed through a ‘Western eye’ and some through an ‘Indigenous eye.’ If we learn to see through both eyes, we can gain a perspective that looks very different than if we only view the world through a single lens. Methods: For the study, twenty-four people from the south-eastern Labrador community of St. Lewis participated in individual and joint story-telling sessions. A group story-telling session also took place where community members could share their stories with one another. During many of the story-telling sessions, participants shared photographs, which helped to illustrate their relationships to food. Findings/Discussion: Historically, the people of St. Lewis relied almost entirely upon their own wherewithal for food, with few, if any, government services available and very little assistance from the market economy. This fostered and upheld an Inuit-Metis culture that promoted sharing, reciprocity and respect for the natural world. Currently, greater access to government services and the market economy has led to the creation of certain policies and programs that undermine or ignore established social and cultural norms in the community. Conclusions: Existing Inuit-Metis knowledge should work alongside non-Indigenous approaches to policy and program development. This would serve to protect and promote the health of both individuals and communities.

This research project is based upon the assumption that humanity is passing through a period of great transition, or “Great Turning,” in which we have a critical opportunity to pass from a destructive “industrial growth society” to a “life-sustaining society” (Macy and Brown, 1998). I argue that the current scale of social, political, environmental, economic, psychological, and spiritual challenges reflects an underlying “disconnect disorder” (Arabena, 2006), and that these combined external and internal crises present an opportunity for widespread transformative learning and a collective shift. My core hypothesis is that this transition depends on humanity’s ability to engage in a dual process of individual and collective transformation through remembering our connections with ourselves, with one another, with the natural world, and with a sense of purposeful engagement in the world. I investigate this hypothesis through an in-depth, relational study of the Ecology of Leadership program (EOL) at the Regenerative Design Institute (RDI) in Bolinas, California, an organization that aims to “serve as catalyst for a revolution in the way humans relate to the natural world.” The Ecology of Leadership represents a unique model of transformative adult education that incorporates the principles of “inner permaculture” and regenerative design to support participants in cultivating personal and collective transformation. I introduce a “relational” theory and methodological approach, which centralizes Indigenous and ecological principles of relationship, respect, reciprocity, and regeneration. Using interviews (p=20), surveys (p=409), arts-based data (p=12), sharing circles (p=8), and participatory research, I integrate personal and participant narratives together with images, graphics, poems, and practices to bring this case study of the Ecology of Leadership to life. I also advocate for a new model of “regenerative research,” in which the research itself is life-giving and contributes to the healing, transformation, and regeneration of the researcher, the community of research, and the whole system. Based upon my interactions, observations, and interviews in the EOL program and my reflections and supportive research, I conclude by articulating the “Ecology of Transformation,” a holistic model for transformation that incorporates inner and outer change with practices for reconnection to oneself, the natural world, and the village.

abstract: Investments in climate science come with an expectation of social benefit. Science policy--decision processes through which individuals and organizations support, manage, and evaluate research--plays an important role in determining those outcomes. Yet the details of how climate science policy actually works have received very little attention amid academic and policy-focused discussions of climate science. This dissertation examines climate science policy with particular attention to how it supports "public values" that justify research investments. It is widely recognized funding for climate science in the US has advanced knowledge considerably in recent decades but failed to produce useful information for decision makers. In Chapter 2, I use a methodological approach known as Public Value Mapping (PVM) to investigate this failure of the science policy system. My results show that science funding institutions have been ineffective at guiding climate science toward desired outcomes because of problematic, but common assumptions about the links between science and societal benefit. The remaining chapters look more closely at the implications of these tacit assumptions, which are held by individuals, and embedded in the organizations that implement climate science policy. Chapter 3 examines the notion that prediction is essential to climate science. Wide acceptance of the "prediction imperative" limits the scope of climate science policy. Chapter 4 examines the interplay of values and assumptions in two recently established organizations in Australia, each supporting research on climate change adaptation. In Chapter 5 I document a widespread assumption in the climate science literature that agreement among multiple models should bolster confidence in their results. This can only be correct if the models are independent of one another. Climate scientists have not demonstrated this to be true, nor have they offered a plausible framework for doing so. This dissertation adds an important dimension to our understanding of how climate science knowledge is produced, while offering constructive and practical recommendations to science policy decision makers working in government programs that fund climate science. Insight from these chapters suggests that an explicit and reflexive focus on values in science policy can be helpful to organizations pursuing science policy innovation. / Dissertation/Thesis / Ph.D. Science and Technology Policy 2010

Traditionally, hypoxia has been defined as the situation where DO levels have fallen below 2.0 mg O2 L-1, but increasing evidence suggests that this low level of DO is inadequate to describe the onset of hypoxia impacts for many organisms. Consequently, there is a need for a greater understanding of how ‘moderate’ alterations in DO levels will affect ecosystem processes and functionality, specifically through behavioural and physiological alterations at the organism and community level. This thesis reports on mesocosm experiments which were conducted to examine the effects of moderate ( > 3.0 mg O2 L-1) hypoxia on firstly, a key ecosystem engineer, the brittlestar Amphiura filiformis, and secondly, on the Station L4 infaunal macrobenthic community. Station L4 is a longstanding marine biodiversity and MSFD reference site and forms part of the Western Channel Observatory. At the organism level, short-term (14 d) exposure to moderate hypoxia significantly reduced oxygen uptake rates, oocyte diameter and oocyte development in A. filiformis. However, these physiological affects occurred irrespective of brittlestar population density. Additionally, moderate hypoxia reduced brittlestar activity, in terms of bioturbation behaviour, consequentially having an effect on ammonium and silicate fluxes. These observations were only detected when brittlestar population density was high. It was concluded that denser populations of A. filiformis may therefore exhibit the greatest changes in behaviour and shifts in ecosystem function as competition for resources and oxygen heightens. The benthic community at Station L4, displayed considerable tolerance to medium-term (6 wk.) exposure to moderate hypoxia, in terms of structure, diversity and bioturbatory behaviour, but these results may be different if exposure was longer or more severe. Alterations in nutrient fluxes were detected, but there was little evidence to suggest these changes were due to macrofaunal behavioural alterations. Additionally, results from this study revealed that bringing complex natural communities into the mesocosm caused a substantial loss of individuals and species, mainly due to translocation and disturbance effects. This important insight into the effects of bringing community assemblages into the mesocosm confirms that even with a loss of diversity, the L4 community maintained functionality and was resilient to alterations in DO. This suggests that the L4 benthic community does not depend on any one specific species for the provision of important ecosystem processes, resulting in considerable functional resilience within the L4 system. However, vulnerability to benthic systems may increase if functionality is dominated by species such as A. filiformis. Consequently, moderate hypoxia may not immediately affect benthic communities in terms of structure and diversity, but the physiological effects on individuals, especially to reproductive development, may cause alterations in the quality and quantity of planktonic propagules supplied by benthic species to the pelagic environment. This could affect benthic community diversity and functionality in the long term if repeated hypoxic events occur.

L'objectif de cette thèse a été de comprendre le fonctionnement économique des pêcheries et de proposer des politiques de gestion des ressources halieutiques. L'attention a été portée essentiellement sur la pêcherie crevettière guyanaise. Une première analyse a été effectuée à partir d'une base de données historique. Les premiers constats ont été que cette pêcherie a été marquée par une forte diminution de son stock, de son effort, de sa production, ce qui a conduit à la fermeture de certaines entreprises. Les premiers résultats ont permis de comprendre que la production de cette pêcherie est fortement dépendante du stock et que la forte diminution de ce dernier n'est pas liée à la surpêche. En effet, malgré une baisse considérable de l'effort de pêche et du prélèvement, le stock a continué de s'effondrer, suggérant ainsi que d'autres facteurs peuvent être mis en cause. En particulier, la zone de pêche est caractérisée par un environnement amazonien avec une mangrove importante et de nombreux cours d'eau. L'intégration de la mangrove dans l'analyse, qui a pourtant connu une diminution de sa surface dans les années 90, n'a pas permis d'expliquer l'effondrement du stock observé. Cependant l'intégration d'autres facteurs comme le débit des fleuves et la température de surface de l'océan ont permis de mieux comprendre la chute du stock dans cette filière. La pêcherie crevettière guyanaise semble en effet fortement impactée par le changement global, notamment l'augmentation de la température des eaux dans les zones de prélèvement. De surcroît, le dernier chapitre suggère que certains phénomènes endogènes à la pêcherie, comme les effets de congestion entre les navires de pêche, rendent l'ensemble de la pêcherie plus sensible à des chocs exogènes technologiques, économiques ou biologiques, en amplifiant l'impact de ces derniers sur les décisions optimales des entreprises concernant l'effort de pêche. Afin de préserver la pêcherie crevettière en Guyane française, il apparaît donc essentiel d'essayer de limiter, dans la mesure du possible, les sources du changement climatique, au lieu de modifier profondément les pratiques économiques du secteur. / The objective of this thesis was to understand the economic behavior of fisheries and to propose resource management policies. The focus was mainly on the French Guiana shrimp fishery. First an initial analysis will be performed on a historical data basis. Initial findings have showed that this fishery was characterized by a strong decrease in its stock, its effort, its production and lead to the closure of some companies. The results have helped also to understand that the production in this fishery is highly dependent on stock and the decrease of the stock is not related to overfishing. Indeed, despite a considerable decline in fishing effort and production, the stock continued to slump suggesting that other factors may be involved. In particular the fishing zone is characterized by an Amazonian environment with significant mangrove and many rivers. The integration of mangrove in the analysis, which shows a decrease in its surface in the 90s did not explain the collapse of the stock. However, the integration of other factors such as rivers and sea surface temperatures have increased understanding of stock depletion in this sector. The French Guiana shrimp fishery is highly influenced by global change, notably increasing in temperature. Moreover, the last chapter suggests that some endogenous phenomena in the fishery, like the congestion effects between fishing vessels, make the whole fishery more sensitive to technology, exogenous economic or biological shocks, amplifying their impact on the optimal business decisions regarding fishing effort. In order to save the French Guiana shrimp fishery, it appears therefore crucial to try to limit the sources of climate change instead of deeply modifying economic practices in this sector, which may lead to misunderstandings by fishermen and local political conflicts.

Changes in climate result in wide-ranging economic impacts, especially for businesses that rely on consistent weather patterns. The North Carolina ski resorts (Beech Mountain Ski Resort, Appalachian Ski Resort, Sugar Mountain Ski Resort, Wolf Ridge Ski Resort, Cataloochee Ski Area, and Sapphire Valley Ski Area) are the southernmost resorts on the east coast in the US. They are able to stay in business because of the diverse terrain and elevation of the Appalachian Mountains where they can see low record temperatures of -34°F. Observable increases in temperature and less snowfall accumulations generate concern for these businesses that rely not only on snow but temperatures low enough to produce their own snow. To understand what may happen in the future, it is pertinent to examine past and ongoing trends. Yearly snowfall data from fall 2010 to spring 2018 were obtained from the Community Collaborative Rain, Hail & Snow Network (CoCoRaHS) and interpolated using ordinary kriging. Teleconnections (Arctic Oscillation, El Niño Southern Oscillation, and North Atlantic Oscillation) were examined to help compare similar years to observe possible relationships. The stations that had data for all of the years observed were spatially analyzed through regression kriging (RK) to determine how climate change will affect those areas. A kernel density map was then created from active CoCoRaHS stations to observe which areas need more stations to generate better interpolation data for future years. The results are impactful for the ski resorts, helping them to make effective business decisions based on climate trends and to promote the use of citizen science to improve research efforts.

Freshwater reservoirs store, process, and emit to the atmosphere large quantities of carbon (C). Despite the important role of reservoirs in the global carbon cycle, it remains unknown how human activities are altering their carbon cycling. Climate change and land use are resulting in lower dissolved oxygen (DO) concentrations in freshwater ecosystems, yet more frequent, powerful storms are occurring that temporarily increase DO availability. The net effect of these opposing forces results in anoxia (DO < 0.5 mg L-1) punctuated by short-term increases in DO. The availability of DO controls alternate redox reactions in freshwaters, thereby determining the rate and end products of organic C mineralization, which include two greenhouse gases, carbon dioxide (CO2) and methane (CH4). I performed ecosystem-level DO manipulations and evaluated how changing DO conditions affected redox reactions and the production and emission of CO2 and CH4. I also explored how the magnitude and drivers of CH4 emissions changed spatio-temporarily in a eutrophic reservoir using time series models. Finally, I used a coupled data-modeling approach to forecast future emissions of CH4 from the same reservoir. I found that the depletion of DO results in the rapid onset of alternate redox reactions in freshwater reservoirs for organic C mineralization and greater production of CH4. When the anoxia occurred in the water column (vs. at the sediments), diffusive CO2 and CH4 efflux phenology was affected, and resulted in degassing occurring during storms before fall turnover. I observed that the magnitude of CH4 emissions varied along a longitudinal gradient of a small reservoir and that the environmental drivers of ebullition and diffusion can change substantially both over space (within one hundred meters) and time (within a few weeks). Finally, I developed a forecasting workflow that successfully predicted future CH4 ebullition rates during one summer season. My research provides insight to how changing DO conditions will alter redox reactions in the water column and greenhouse gas emissions, as well as provides a new technique for improving future predictions of CH4 emissions from freshwater reservoirs. Althogether, this work improves our understanding of how freshwater lake and reservoir carbon cycling will change in the future. / Doctor of Philosophy / Freshwater reservoirs store a lot of carbon in their sediments and emit a lot of carbon as greenhouse gases (carbon dioxide and methane) to the atmosphere. However, climate change, land use, and water quality management can change the chemical reactions that are responsible for the production of carbon dioxide and methane, which could have substantial effects on the global carbon budget. Here, I manipulated the oxygen conditions of a freshwater reservoir and monitored the chemistry and greenhouse gas emissions in the experimental reservoir relative to an upstream reference reservoir. I then estimated the methane emissions from the reservoir to understand how the chemistry and greenhouse gas emissions in freshwater reservoirs may change in the future. I found that reservoir oxygen availability controls the magnitude and timing of the chemical reactions that produce carbon dioxide and methane, which in turn alters greenhouse gas emissions. Additionally, I developed models that showed how the magnitude and drivers of methane emissions changed within a small reservoir over time. Finally, I was able to predict the timing and magnitude of methane bubbling from the sediments. Altogether, this work provides evidence how climate change, land use change, and water quality management will affect future water chemistry and greenhouse gas emissions from reservoirs.

Background Dengue is a significant problem of international health concern. According to the World Health Organization in 2012, globally, dengue is “the most important mosquito borne viral disease” with incidence 30 higher than it had been 50 years ago. While most of the burden of disease associated with dengue is located in areas with a tropical and sub-tropical climate, increasing evidence suggests temperate areas are also at risk. Considering the recent introduction of relevant mosquito vectors into Southern Europe, and increasing numbers of imported dengue via travelers, Europe and other temperate areas may be increasingly at risk for dengue emergence, establishment and local transmission in the foreseeable future. Methods Recent dengue emergence in Madeira and reemergence in Tokyo underline the hypothesis that passenger air-travel can be an important conduit for the importation of vector-borne disease leading to emergence in naïve areas climatically suitable for dengue transmission, including parts of Europe. Combining information on travel with virus genetic similarity was useful in discerning likely pathways of for the importation of infections. Generalizing information learned from outbreaks in Tokyo and Madeira with global epidemic intelligence, global travel networks, and climate change projections, leads to more refined understanding of the magnitude of dengue infectious imported into temperate areas and these virus introduction events’ potential implications for seeding epidemics in the 21st century. Results While compared to total travel, imported dengue events and epidemics of dengue outside the tropics are rare, our combined evidence and modeled estimations suggest strongly that epidemic dengue emergence in temperate areas is possible and will continue to increase. We found that global change dynamics including warming temperatures in the much of the northern hemisphere and increasing passenger interconnectivity between areas endemic for dengue and dengue free areas are key mechanisms partly explaining these unprecedented epidemiological transitions. Conclusion While we calibrated our models on information known about dengue, many elements of the methods and conclusions may increase understanding of the potentially global implications for imported infections of other climate-sensitive infectious diseases’ that may have similar parameters. During 2016 and the years to come, techniques developed in this doctoral research will contribute to models used in risk analysis for vector-borne diseases of interest, including the increasing important potential for imported Chikungunya and Zika viruses into a variety of unexposed areas.

In the southwest United States, the current prolonged warm drought is similar to the predicted future climate change scenarios for the region. This study aimed to determine patterns in vegetation response to the early 21st century drought across multiple biomes. We hypothesized that different biomes (forests, shrublands, and grasslands) would have different relative sensitivities to both climate drivers (precipitation and temperature) and legacy effects (previous-year's productivity). We tested this hypothesis at eight Ameriflux sites in various Southwest biomes using NASA Moderate-resolution Imaging Spectroradiometer Enhanced Vegetation Index (EVI) from 2001 to 2013. All sites experienced prolonged dry conditions during the study period. The impact of combined precipitation and temperature on Southwest ecosystems at both annual and sub-annual timescales was tested using Standardized Precipitation Evapotranspiration Index (SPEI). All biomes studied had critical sub-annual climate periods during which precipitation and temperature influenced production. In forests, annual peak greenness (EVImax) was best predicted by 9-month SPEI calculated in July (i.e., January-July). In shrublands and grasslands, EVImax was best predicted by SPEI in July through September, with little effect of the previous year's EVImax. Daily gross ecosystem production (GEP) derived from flux tower data yielded further insights into the complex interplay between precipitation and temperature. In forests, GEP was driven by cool-season precipitation and constrained by warm-season maximum temperature. GEP in both shrublands and grasslands was driven by summer precipitation and constrained by high daily summer maximum temperatures. In grasslands, there was a negative relationship between temperature and GEP in July, but no relationship in August and September. Consideration of sub-annual climate conditions and the inclusion of the effect of temperature on the water balance allowed us to generalize the functional responses of vegetation to predicted future climate conditions. We conclude that across biomes, drought conditions during critical sub-annual climate periods could have a strong negative impact on vegetation production in the southwestern United States.