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Context-dependent niche variation and fitness consequences in California sea lions

Description

Niche variation among sexes and life stages within a population has been documented in many species, yet few studies have investigated niche variation within demographic groups or across ecological contexts. We examined the extent to which pregnant California sea lions (Zalophus californianus) at each of three breeding colonies target alternative…

Niche variation among sexes and life stages within a population has been documented in many species, yet few studies have investigated niche variation within demographic groups or across ecological contexts. We examined the extent to which pregnant California sea lions (Zalophus californianus) at each of three breeding colonies target alternative prey resources and habitats. The three colonies are distributed across distinct regions of the Gulf of California, Mexico and have divergent population dynamics. We compared the nature of niche variation among colonies and investigated the fitness consequences of different foraging strategies within each colony. We analyzed the δ13C and δ15N values from fur collected from 206 suckling pups to characterize relative maternal foraging locations (δ13C) and trophic levels (δ15N) during the metabolically demanding late stages of gestation and lactation that occur simultaneously in California sea lions. The δ13C and δ15N values were regressed against pup body condition index values to compare the relative individual-level fitness benefits of different maternal foraging strategies. We found that the nature and extent of niche variation differed among colonies. Niche variation was most pronounced at the two largest colonies that appear to experience the highest levels of intraspecific competition and the variation was consistent with habitat features. One colony (Granito) displayed two distinct foraging groups with indistinguishable median pup body condition values, whereas the second (San Jorge) exhibited continuous niche variation and pup body condition varied in relation to maternal foraging location and trophic level, suggesting disparities among alternative foraging strategies. For the smallest colony (Los Islotes), females occupy similar niches with a few outliers. Body condition values of pups at this colony were most variable, but did not vary with maternal foraging strategy. Our results provide evidence for intrapopulation niche variation among demographically similar individuals during a period of high metabolic stress and reproductive importance. This work suggests possible fitness benefits conferred by alternative foraging strategies, and calls into question the common assumption that members of a population are ecologically equivalent. Future research aimed at understanding animal foraging strategies should consider the nature and extent of niche variation in the context of local ecological conditions.

ContributorsCrawford, Tara Gancos (Author) / Gerber, Leah R. (Thesis advisor) / Ogle, Kiona (Committee member) / Kurle, Carolyn M (Committee member) / Arizona State University (Publisher)

Created2013

Food security and financial success in Central Arizona farmers' markets: presences, absences, lived experience, and governance

Description

Farmers' markets are a growing trend both in Arizona and the broader U.S., as many recognize them as desirable alternatives to the conventional food system. As icons of sustainability, farmers' markets are touted as providing many environmental, social, and economic benefits, but evidence is mounting that local food systems primarily…

Farmers' markets are a growing trend both in Arizona and the broader U.S., as many recognize them as desirable alternatives to the conventional food system. As icons of sustainability, farmers' markets are touted as providing many environmental, social, and economic benefits, but evidence is mounting that local food systems primarily serve the urban elite, with relatively few low-income or minority customers. However, the economic needs of the market and its vendors often conflict with those of consumers. While consumers require affordable food, farmers need to make a profit. How farmers' markets are designed and governed can significantly influence the extent to which they can meet these needs. However, very little research explores farmers' market design and governance, much less its capacity to influence financial success and participation for underprivileged consumers. The present study examined this research gap by addressing the following research question: How can farmers' markets be institutionally designed to increase the participation of underprivileged consumers while maintaining a financially viable market for local farmers? Through a comparative case study of six markets, this research explored the extent to which farmers' markets in Central Arizona currently serve the needs of farmer-vendors and underprivileged consumers. The findings suggest that while the markets serve as a substantial source of income for some vendors, participation by low-income and minority consumers remains low, and that much of this appears to be due to cultural barriers to access. Management structures, site characteristics, market layout, community programs, and staffing policies are key institutional design features, and the study explores how these can be leveraged to better meet the needs of the diverse participants while improving the markets' financial success.

ContributorsTaylor, Carissa (Author) / Aggarwal, Rimjhim (Thesis advisor) / York, Abigail (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)

Created2013

Coupled hydrology and biogeochemistry in social-ecological watersheds

Description

Hydrology and biogeochemistry are coupled in all systems. However, human decision-making regarding hydrology and biogeochemistry are often separate, even though decisions about hydrologic systems may have substantial impacts on biogeochemical patterns and processes. The overarching question of this dissertation was: How does hydrologic engineering interact with the effects of nutrient…

Hydrology and biogeochemistry are coupled in all systems. However, human decision-making regarding hydrology and biogeochemistry are often separate, even though decisions about hydrologic systems may have substantial impacts on biogeochemical patterns and processes. The overarching question of this dissertation was: How does hydrologic engineering interact with the effects of nutrient loading and climate to drive watershed nutrient yields? I conducted research in two study systems with contrasting spatial and temporal scales. Using a combination of data-mining and modeling approaches, I reconstructed nitrogen and phosphorus budgets for the northeastern US over the 20th century, including anthropogenic nutrient inputs and riverine fluxes, for ~200 watersheds at 5 year time intervals. Infrastructure systems, such as sewers, wastewater treatment plants, and reservoirs, strongly affected the spatial and temporal patterns of nutrient fluxes from northeastern watersheds. At a smaller scale, I investigated the effects of urban stormwater drainage infrastructure on water and nutrient delivery from urban watersheds in Phoenix, AZ. Using a combination of field monitoring and statistical modeling, I tested hypotheses about the importance of hydrologic and biogeochemical control of nutrient delivery. My research suggests that hydrology is the major driver of differences in nutrient fluxes from urban watersheds at the event scale, and that consideration of altered hydrologic networks is critical for understanding anthropogenic impacts on biogeochemical cycles. Overall, I found that human activities affect nutrient transport via multiple pathways. Anthropogenic nutrient additions increase the supply of nutrients available for transport, whereas hydrologic infrastructure controls the delivery of nutrients from watersheds. Incorporating the effects of hydrologic infrastructure is critical for understanding anthropogenic effects on biogeochemical fluxes across spatial and temporal scales.

ContributorsHale, Rebecca Leslie (Author) / Grimm, Nancy (Thesis advisor) / Childers, Daniel (Committee member) / Vivoni, Enrique (Committee member) / York, Abigail (Committee member) / Wu, Jianguo (Committee member) / Arizona State University (Publisher)

Created2013

Institutional analysis of water management for agriculture in the Chancay-Lambayeque basin, Peru

Description

This research presents an analysis of the main institutions and economic incentives that drive farmers behaviors on water use in the Chancay-Lambayeque basin, located in Lambayeque (Peru), a semi arid area of great agricultural importance. I focus my research on identifying the underlying causes of non-collaborative behaviors in regard to…

This research presents an analysis of the main institutions and economic incentives that drive farmers behaviors on water use in the Chancay-Lambayeque basin, located in Lambayeque (Peru), a semi arid area of great agricultural importance. I focus my research on identifying the underlying causes of non-collaborative behaviors in regard to water appropriation and infrastructure provisioning decision that generates violent conflicts between users. Since there is not an agreed and concrete criteria to assess "sustainability" I used economic efficiency as my evaluative criteria because, even though this is not a sufficient condition to achieve sustainability it is a necessary one, and thus achieving economic efficiency is moving towards sustainable outcomes. Water management in the basin is far from being economic efficient which means that there is some room for improving social welfare. Previous studies of the region have successfully described the symptoms of this problem; however, they did not focus their study on identifying the causes of the problem. In this study, I describe and analyze how different rules and norms (institutions) define farmers behaviors related to water use. For this, I use the Institutional Analysis and Development framework and a dynamic game theory model to analyze how biophysical attributes, community attributes and rules of the system combined with other factors, can affect farmers actions in regard to water use and affect the sustainability of water resources. Results show that water rights are the factor that is fundamental to the problem. Then, I present an outline for policy recommendation, which includes a revision of water rights and related rules and policies that could increase the social benefits with the use of compensation mechanisms to reach economic efficiency. Results also show that commonly proposed solutions, as switch to less water intensive and more added value crops, improvement in the agronomic and entrepreneurial knowledge, or increases in water tariffs, can mitigate or exacerbate the loss of benefits that come from the poor incentives in the system; but they do not change the nature of the outcome.

ContributorsRubinos, Cathy (Author) / Eakin, Hallie (Committee member) / Abbot, Joshua K (Committee member) / York, Abigail (Committee member) / Arizona State University (Publisher)

Created2013

Developing behavioral indices of population viability: a case study of California sea lions in the Gulf of California, Mexico

Description

Despite years of effort, the field of conservation biology still struggles to incorporate theories of animal behavior. I introduce in Chapter I the issues surrounding the disconnect between behavioral ecology and conservation biology, and propose the use of behavioral knowledge in population viability analysis. In Chapter II, I develop a…

Despite years of effort, the field of conservation biology still struggles to incorporate theories of animal behavior. I introduce in Chapter I the issues surrounding the disconnect between behavioral ecology and conservation biology, and propose the use of behavioral knowledge in population viability analysis. In Chapter II, I develop a framework that uses three strategies for incorporating behavior into demographic models, outline the costs of each strategy through decision analysis, and build on previous work in behavioral ecology and demography. First, relevant behavioral mechanisms should be included in demographic models used for conservation decision-making. Second, I propose rapid behavioral assessment as a useful tool to approximate demographic rates through regression of demographic phenomena on observations of related behaviors. This technique provides behaviorally estimated parameters that may be applied to population viability analysis for use in management. Finally, behavioral indices can be used as warning signs of population decline. The proposed framework combines each strategy through decision analysis to provide quantitative rules that determine when incorporating aspects of conservation behavior may be beneficial to management. Chapter III applies this technique to estimate birthrate in a colony of California sea lions in the Gulf of California, Mexico. This study includes a cost analysis of the behavioral and traditional parameter estimation techniques. I then provide in Chapter IV practical recommendations for applying this framework to management programs along with general guidelines for the development of rapid behavioral assessment.

ContributorsWildermuth, Robert (Author) / Gerber, Leah R. (Thesis advisor) / Collins, James (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)

Created2012

Collaborative wildland fire restoration: innovative approaches in Arizona's Sky Islands

Description

Over the last few decades, the western United States has experienced more extreme wildland fire events, remarkable for their size and severity. The frequency, intensity, and size of wildfires is projected to only increase, with severe consequences for biodiversity, ecosystem services, human property, and more broadly, the sustainability of western…

Over the last few decades, the western United States has experienced more extreme wildland fire events, remarkable for their size and severity. The frequency, intensity, and size of wildfires is projected to only increase, with severe consequences for biodiversity, ecosystem services, human property, and more broadly, the sustainability of western forests. These trends are the result of a complex suite of factors including, past land-use policies, fire suppression, climate change, and human development. To protect fire-adapted ecosystems from further damage, fuel reduction and fire reintroduction are required over large landscapes, necessitating government agencies, landowners, and other interests to work together. In response, collaborative fire restoration efforts are forming to carry out this much needed work. This research takes a multi-level approach to understanding these new models for fire management and restoration. Collaborative, landscape-level approaches to fire reintroduction are a direct response to a failure in past policies and approaches, which necessitates a discussion of why these policies allowed fires to grow worse and why management failed to effectively prevent this from happening. Thus, a historical analysis of wildland fire policy and management constitutes one layer in this analysis. Collaborative frameworks to wildland fire reintroduction are few and far between, which obliges a discussion of how collaboration works and why it may be necessary. An in-depth case study of FireScape, a collaborative effort in southeastern Arizona to restore wildfire completes this analysis and provides a discussion of the challenges, benefits, and implications of these new approaches. The context for this case study is southeastern Arizona's Sky Islands. The Sky Islands region spans the U.S. Mexico borderlands and is a biodiversity hotspot, making it an ideal place to explore the interactions between humans and natural systems. The more recent emphasis on collaboration in wildfire management has yet to be fully explored in other academic circles. Collaboration is essential in fire restoration and provides one pathway to solve complex natural resource management issues.

ContributorsRaymondi, Ann Marie (Author) / Hirt, Paul W (Thesis advisor) / York, Abigail (Thesis advisor) / Pyne, Stephen J (Committee member) / Arizona State University (Publisher)

Created2012

Gender Differences in Perceptions of Water in Arizona: Insights from the Science of Water Art Project

Description

The Science of Water Art project is a collaborative work that brings together professionals, community members, college students and children to think about the role that water plays in each of our lives. Using a sample of 4th grade classrooms in Maricopa County, over 3000 drawings of children's perception of…

The Science of Water Art project is a collaborative work that brings together professionals, community members, college students and children to think about the role that water plays in each of our lives. Using a sample of 4th grade classrooms in Maricopa County, over 3000 drawings of children's perception of water today and in the future were collected. The 9-11 year olds were asked to draw pictures of 1) how they saw water being used in their neighborhood today (T1), and 2) how they imagined water would be used in their neighborhood 100 years from now (T2). The artwork was collected and coded for nine different themes, including: vegetation, scarcity, pollution, commercial sources of water, existing technology, technology innovation, recreational use, domestic use, and natural sources of water. Statistically significant differences were found between boys and girls for vegetation, technology and domestic use themes. This project allows for a look into how climate change and water insecurity is viewed by younger generations and gives a voice to children so that they may share their outlooks on this vital resource.

ContributorsVins, Holly Elizabeth (Author) / Wutich, Amber (Thesis director) / Newland, Judy (Committee member) / Beresford, Melissa (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Social Transformation (Contributor) / School of Human Evolution and Social Change (Contributor)

Created2013-05

CALIXTLAHUACA: A COMPARATIVE ANALYSIS ON URBAN FEATURES AND POLITICS

Description

During the current excavations at Calixtlahuaca, many aspects of its urban landscape have been uncovered. By using these details, my objective is to determine the political environment of the site. However, in Mesoamerican archaeology, there has been little evaluation of the politics in smaller city-states as compared to larger ones…

During the current excavations at Calixtlahuaca, many aspects of its urban landscape have been uncovered. By using these details, my objective is to determine the political environment of the site. However, in Mesoamerican archaeology, there has been little evaluation of the politics in smaller city-states as compared to larger ones such as Tenochtitlan. In order to solve this dilemma, I compared Calixtlahuaca to two groups of Mesoamerican capital cities: (1) city-state centers such as Cholula, Tlaxcallan, various Aztec city-states; and (2) hillside sites similar to Calixtlahuaca in topographic placement. The importance of certain elements in these sites is more heavily considered than others and sites that have pre-existing knowledge about their political systems took precedence. By comparing urban aspects of these sites including location, population, density, urban layout, and urban architecture, I have created a model that relates urban form to political organization. I applied this model to infer the political organization of Calixtlahuaca. This model can later be applied throughout Mesoamerica and eventually to sites at other regions.

ContributorsSmigielski, Ryan Michael (Author) / Smith, Michael E. (Thesis director) / Nelson, Ben (Committee member) / York, Abigail (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)

Created2013-05

Community Collective Action: A Case Study Documentary on Phoenix's Sky Harbor Neighborhood Association

Description

This project aims to provide a contextualized history of the Sky Harbor Neighborhood Association‟s community collective action efforts. The Sky Harbor Neighborhood (SHN) of East Phoenix is bounded on the West by 24th St., on the East by 32nd St., on the North by Roosevelt St., and the South by…

This project aims to provide a contextualized history of the Sky Harbor Neighborhood Association‟s community collective action efforts. The Sky Harbor Neighborhood (SHN) of East Phoenix is bounded on the West by 24th St., on the East by 32nd St., on the North by Roosevelt St., and the South by Washington Street. SHN is a majority Latino, low-income, working class community (U.S. Census Bureau, 2010) that faces a variety of challenges including low walkability due to inadequate pedestrian infrastructure, low tree coverage, and crime. East Van Buren St., which has a reputation for being one of Phoenix‟s red-light districts, splits the neighborhood in two. In addition, the SHN lacks some key amenities such as grocery stores and is partly considered a food desert by the United States Department of Agriculture (USDA Economic Research Service, 2012).

ContributorsPearson, Kimberly (Author) / Golub, Aaron (Thesis director) / Wiek, Arnim (Committee member) / York, Abigail (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Sustainability (Contributor)

Created2012-12

Zoning and Community Health: A Case Study into Natural Gas Extraction in Pennsylvania

Description

Natural gas development in the Northern Appalachian region has skyrocketed dramatically over the past decade. Correspondingly to the unprecedented growth rate of the natural gas industry, population health risks have shifted dramatically in response to both aerial and water pollution. With energy as a key input in all sectors of…

Natural gas development in the Northern Appalachian region has skyrocketed dramatically over the past decade. Correspondingly to the unprecedented growth rate of the natural gas industry, population health risks have shifted dramatically in response to both aerial and water pollution. With energy as a key input in all sectors of Appalachian life, the Pennsylvania region serves as a fascinating case study where clusters of unconventional gas drilling wells intersect varying population densities and governing laws to create different levels of health risks. Studies have found that horizontal hydraulic fracking corresponds to an increased risk of upper respiratory symptoms (URS), low birth weights, premature births, and certain cancers (White et al., 2009). Also, zoning and local planning laws are policy tools local governments can use to directly influence community wellbeing (Diez-Roux, 2011). This study will focus on the spatial relationship between upper respiratory symptoms (URS), a key volatile health benchmark, and the zoning/planning laws that the Oil and Natural Gas Industry must adhere to. Our project seeks to provide a preliminary understanding of the interplay between different natural gas zoning laws and the resulting health implication risks that appear in the Marcellus shale region of Pennsylvania. This is necessary to appropriately regulate and monitor hydraulic fracking. To get a better understanding of this phenomenon, spatial autocorrelation and analysis of variance statistics are integrated to generate a surface-level understanding of areas impacted by natural gas development. To guide the creation of our models, we geographically process the unconventional well locations, upper respiratory symptom health utilization, and zoning law data to develop insights that policymakers can take into consideration. Regionally, natural gas has become an integrated part of the energy sector and a driver of local economic development. The patterns drawn from this assessment provide a novel way of understanding the population health risks posed by different zoning ordinance models.

ContributorsHernandez, Aidan (Author) / York, Abigail (Thesis director) / Schomburg, Madeline (Committee member) / School of Human Evolution & Social Change (Contributor, Contributor) / Thunderbird School of Global Management (Contributor) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)

Created2021-05