Mountain Scholar :: Browsing by Author "Ojima, Dennis, committee member"

Browsing by Author "Ojima, Dennis, committee member"

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Open Access
Challenges in the sustainability of Libyan agriculture: opportunities for the Libyan seed system
(Colorado State University. Libraries, 2015) Lariel, Neama, author; Graff, Gregory D., advisor; Davies, Stephen, advisor; Stanelle, James, committee member; Ojima, Dennis, committee member
Globally, agriculture has met the needs of a growing population remarkably well (Agriculture and Natural Resources Team of the UK DFID, 2004). However, this success has been at the expense of our natural resources. A sustainable approach must lead future agricultural decision-making processes. According to Tilman, Cassman, Matson, and Polasky (2002), the global population is expected to increase by 50% in 2050; this increase in production will affect the environment adversely. There are numerous global challenges associated with creating a sustainable agriculture model. As one of the most arid countries on Earth and one that is just emerging from decades of authoritarian rule, Libya faces several big challenges in order for its agriculture to meet demand in a sustainable manner. Specifically, improvements in Libya’s seed system may be needed to help close the yield gap, reduce negative externalities associated with agricultural production, and facilitate the adaptation of Libyan agriculture to climate change. While there are many factors that contribute to Libya’s apparent current yield gap in wheat and barley, one of its most important agricultural sectors, the lack of availability of appropriate genotypes for each environment serves as the primary factor focused on in this study. The objectives to this research are to understand what varieties farmers currently grow, why they grow those varieties, and how they access the seed for those varieties as well as understanding what constrains farmers’ adoption of new varieties in order to recommend mechanisms of improvement to the seed system in Libya. To achieve sustainability in agriculture, higher yields must be maintained while minimizing environmental impacts, making it increasingly important to understand the Libyan seed system and its users and their access. This research has two primary hypotheses in regards to closing the yield gap: One focuses on the demand side and why farmers are not adopting improved varieties. The other concerns the supply side and questions of who provides wheat and barley seed to farmers, under what arrangements, and where the genetic varieties originate. The preliminary assumption is that Libyan wheat and barley farmers are more likely to use imported seeds than domestic seeds due to the lack of availability of improved local varieties due to the lack of breeding programs in Libya.
Open Access
Health-livelihoods-environment interactions: health and culture in livelihood decision-making and consequences for the environment in Indonesia
(Colorado State University. Libraries, 2020) Clarke, Melinda M., author; Galvin, Kathleen, advisor; Boone, Randall, committee member; Ojima, Dennis, committee member; Vaske, Jerry, committee member
This research examines the role of perceived health status in the livelihood decision-making of rural households and associated impact on the environment. I drew on three social-ecological frameworks to conceptualize relationships between health, livelihoods, and environment. The primary hypothesis examined is that changes in health status result in livelihood strategies that depend on increased natural resource extraction. Qualitative and quantitative data were collected in twelve villages of the Dumoga Valley, North Sulawesi, Indonesia from 2015 to 2016. These data were used to develop an agent-based model that acts as an experimental context to examine health-livelihood-environment over a longer timeframe than was captured through field data collection. Illegal, artisanal gold mining is the primary resource extraction activity included in livelihood strategies. A surprising effect identified in qualitative data analysis was that different ethnic groups in the study site display different responses to health status change and have distinct livelihood strategies. Quantitative data analysis demonstrates a relationship between landlessness and engagement in illegal gold mining, but no relationship between mining and health. Dynamics in the agent-based model suggest that health does affect both the number of miners and amount of land cleared. In addition, the model suggests that natural resources play an important role in short-term livelihood strategies developed in times of ill health.
Open Access
Land tenure security and land-cover change: a case study from protected area buffer zone communities in Madagascar
(Colorado State University. Libraries, 2023) Chang, Stephen, author; Leisz, Stephen J., advisor; Galvin, Kathleen, committee member; Ojima, Dennis, committee member
Tenure and property rights define the relationship that people have with land and natural resources. Customary tenure systems are predominant in Madagascar, where locally administered rule systems have the flexibility to adapt to changing conditions, inherent conflict resolution mechanisms, and often, community buy-in. However, laws and regulations at different governmental levels throughout the country's history have often caused tenure systems to overlap in rural areas, which, in turn, often causes conflict and tenure insecurity. One important alteration to existing land and natural resource tenure systems is the creation of protected areas, which are commonly created to preserve the endemic biodiversity of the country. Many investigations have attempted to link land tenure to land-cover change using earth observing satellite imagery, but the study reported here is the first of the kind for Madagascar. This study addresses the following questions: if and how a land tenure system and its relative security influence land-cover change within a community and if and how land tenure outside of a protected area influences change within. Land cover classifications created from the Landsat TM and ETM+ images achieved high accuracies despite low image availability due to the period during which the study took place and the significant cloud cover found over the study sites. Findings of the study show that protected areas are relatively unaffected by surrounding land-use and land tenure security in the villages near the protected areas, and that the protected areas are effective at conserving the forests within their boundaries. Within each community, however, conflict and tenure insecurity are associated with elevated conversion of forest areas to other land-covers, regardless of tenure. These results highlight the need to prioritize land tenure security to both ensure local communities access to land and natural resources and meet widespread goals related to conserving biodiversity held by the international conservation community through the support of customary tenure systems and the promotion of socially responsible agricultural transitions.
Open Access
Pathways of soil organic matter formation in agroecosystems as influenced by litter chemistry, root depth and aggregation
(Colorado State University. Libraries, 2024) Fulton-Smith, Sarah E., author; Cotrufo, M. Francesca, advisor; Paustian, Keith, committee member; Ojima, Dennis, committee member; Fonte, Steven, committee member
Soils contain more carbon (C) than any other terrestrial reservoir, and the increase of these C stocks has been targeted as a potential climate solution globally. Agroecosystems play a critical role in our ability to provide these climate solutions through increasing soil organic matter (SOM). There is significant potential for SOM accrual in agroecosystems due to the degradation of SOM typically observed in these systems. One promising approach to increasing soil C sequestration is through the selection of deep-rooted crops, such as Sorghum bicolor. However, significant questions remain about root inputs' ability to contribute to SOM in order to balance the greenhouse gas (GHG) lifecycle of a bioenergy feedstock. My dissertation aims to answer some of these questions as well as to propose a framework to integrate the study of SOM formation from crop inputs with soil aggregate structure. Bioenergy has the potential to emit fewer GHGs than other fuel sources, such as fossil fuels, yet there are some emissions during the transportation production of bioenergy feedstocks and fuels that could be offset by soil C sequestration. However, in annual bioenergy systems, aboveground biomass is typically removed from the system, meaning roots are the primary source of OM available to return to the soil. However, roots and shoots may differ significantly in their ability to contribute to SOM due to differences in litter chemistry. In Chapter 2, I conducted a field incubation to understand how sorghum root versus leaf litter, as influenced by their contrasting chemistry, affect the formation and stabilization of SOM. Using unique soil-biomass microcosms to incubate root or leaf litter in topsoil (0-30 cm) for 19 months in the field, I traced the fate of litter decomposition products by combining stable 13C and 15N isotope labeling with extensive separation of physical soil fractions, free or within different aggregate structures. I found that roots, which were lower quality than leaves, decomposed more slowly but contributed more efficiently to total SOM formation than leaves. However, leaves contributed more to the stable SOM pool (i.e. associated to minerals) while roots contributed more to less stable fractions (i.e. light particulate organic matter). Additionally, sorghum is known to produce roots to a depth of 2 meters. There is limited understanding of how roots deeper in the soil (e.g., below 30 cm) lead to SOM formation and stabilization. In Chapter 3, I used the same microcosm approach as in Chapter 2, with roots that were incubated up to a 90 cm depth to better understand how depth influences the ability of roots to contribute to the formation of SOM and what role aggregates play in this process. Results of this study showed that differences in root decomposition dynamics with depth resulted in greater accrual of root litter C in more stable mineral associated SOM pools in the surface depth while there was slower decomposition and greater accrual in the less stable particulate organic matter fractions in the deep soil. Interestingly, most of the stable fraction was recovered within soil aggregates, particularly microaggregates. The results of these experiments emphasized the important role of microaggregates in modulating SOM dynamics. In Chapter 4, I used the information gleaned from Chapters 2 and 3 as well as advances in the SOM research community to speculate on the role of aggregation, specifically microaggregates, in moderating SOM formation by presenting a conceptual framework that integrates aggregates within our current understanding of particulate and mineral associate SOM dynamics. Overall, my dissertation addresses fundamental questions about our ability to increase SOM levels and resulting soil C accrual through the production of a deep-rooted crop through a field incubation. At the same time, I have connected these relevant results to the broader SOM research community by presenting a novel conceptual model that advances our current SOM framework. My hope is that this will be a valuable contribution to the field and spark discussion and future research.
Open Access
Projecting end-of-century human exposure to eastern Colorado tornadoes and hailstorms: meteorological and societal perspectives
(Colorado State University. Libraries, 2020) Childs, Samuel J., author; Schumacher, Russ, advisor; Demuth, Julie, committee member; Ojima, Dennis, committee member; Rasmussen, Kristen, committee member; Rutledge, Steven, committee member
The eastern half of Colorado is one of the most active areas for hailstorms and tornadoes in the U.S. An average of 39 tornadoes and 387 severe hail reports are tallied each year over this domain, and a number of damaging events, particularly hailstorms, have occurred in recent years. In an era of climate change, it is of worth to project how the frequency, geography, and severity of tornadoes and hailstorms may change over time, and doing so on a localized scale can shed light on the small-scale complexities that broader analyses miss. It is important to consider both meteorological and non-meteorological effects when projecting the changing human risk and exposure to these hazards in the future, as human factors such as population growth means that more people may potentially be exposed to tornadoes and hailstorms regardless of how climate change may influence storm characteristics. As such, this doctoral study employs a multidisciplinary, multi-perspective approach to investigate how the tornado and severe hail footprint may change across eastern Colorado by the end of the 21st century, and in turn how the impacts on those who live and work in this area may be exacerbated. A baseline climatology of tornadoes and hailstorms across eastern Colorado is established using Storm Prediction Center data records. Both hazards show increasing frequency since the 1950s, but when the temporal range is limited to 1997–2017, tornado reports and days show decreasing trends while severe hail reports and days continue to show upward trends. Population bias is inherent in the data records of both hazards and manifests itself as a clustering of reports near urban centers and along major roadways where people live and travel. However, the increasing number of severe hail days and proportion of hail reported at larger sizes is less likely to be influenced by population growth and thus may have a meteorological origin. Convective parameters output from high-resolution dynamical downscaling simulations of control and future climate scenarios using the Weather and Forecasting model are used as proxies to create and compare synthetic tornado and hail reports between the two simulations. Up to three more severe hail days and one more tornado day per year on average by the period 2071–2100 is found, maximized in the north-central part of the domain. This result is combined with population projections from the Shared Socioeconomic Pathways in Tornado and Hail Monte Carlo models to simulate changes in the number of people living underneath tornado tracks and hail swaths by the year 2100. Human exposure evolution is sensitive to the overlap of population and hazard spatial footprints, but the model predicts worst-case scenarios of a 178% increase in exposure to severe hail and a 173% increase in exposure to tornadoes by the end of the 21st century. In addition, population effects outweigh meteorological effects when simulated independently. Some simulations yield a decreasing human exposure to severe hail due to the greatest projected increases in hailstorms over rural, agricultural land. This finding provides motivation for an interview study of eastern Colorado farmers and ranchers to measure perceptions of exposure and sensitivity to severe hail. Most interviewees view hailstorms as a common nuisance throughout eastern Colorado and are most concerned with small hail that falls in large volumes or is driven by a strong wind since these scenarios cause the most damage to crops. Respondents express anxiety and dejection toward hailstorms, as they can significantly affect crop yields and in turn impact their livelihoods and local economy. Understanding this agricultural perspective validates ongoing research into hail surface characteristics and can promote stronger partnerships between the forecasting and farming communities. The synthesis of results from this dissertation, with its unique localized look at the human and meteorological factors contributing to a changing exposure, can be of great worth to forecasters, urban planners, emergency managers, insurance agents, and other local decision-makers. Moreover, this work will help to educate the local public about the past, present, and future of tornadoes and severe hailstorms within eastern Colorado, with the aim of protecting lives and property from their negative impacts.
Open Access
The nature of choice: unraveling individual decision-making for climate-adaptation, science-participation, and environmental stewardship in Mexico
(Colorado State University. Libraries, 2019) Shinbrot, Xoco A., author; Jones, Kelly W., advisor; Newman, Greg, committee member; Ojima, Dennis, committee member; Solomon, Jennifer, committee member
Broadly, this dissertation research assesses the determinants of individual decision making that constrain or enable livelihoods, for science-policy outcomes and environmental behaviors. This research draws on traditional frameworks for behavior change but integrates novel concepts that have been established in other fields as influencing choice. Though the sustainability field has relied on traditional frameworks for over the past 50 years, the conceptualization of internal cognitive factors like climate perceptions and motivations as well as environmental, socio-economic, and demographics factors remains siloed in their respective disciplines of social psychology and environmental psychology. This dissertation addresses these deficiencies through conceptual, methodological, and empirical contributions to the field of behavior change research. Conceptually, this dissertation tests the influence of four major frameworks on choice: (1) the theory of planned behavior, which refers to the knowledge, attitudes, and social norms that contribute to behavioral intentions; (2) the volunteer motivations framework, which conceptualizes participation in volunteer programs as due to dispersed motivations to participate; (3) the credibility-relevance-legitimacy framework, which refers to the three components needed for decision-makers to use science for action; and (4) the sustainable livelihoods approach framework that conceptualizes livelihood outcomes as a product of the household assets they control while influenced by their external institutional and environmental vulnerability context. In Chapter 2, I modify the sustainable livelihoods framework by integrating climate perceptions into the livelihood assets that households use to make livelihood decisions, with implications for uptake of adaptation strategies for climate change. In Chapter 3 I integrate the volunteer motivation framework into the credibility-relevance-legitimacy framework, suggesting that both are needed for explaining participation in public participation in science, i.e. citizen science. Finally, in Chapter 4 I integrate the theory of planned behavior with the credibility-relevance-legitimacy framework, to show that both are necessary for understanding changes to conservation knowledge, attitudes, and stewardship behaviors over time. Methodologically, this dissertation also contributes novel techniques for encouraging behavior changes for citizen scientists in Chapters 3 and 4. Specifically, conservation decision-makers were included within the traditional citizen science, water-monitoring training to amplify perceptions of project relevance for conservation programs, to improve participation in citizen science as well as to improve social outcomes of knowledge, attitudes, and stewardship behaviors. In an experimental design, half the citizen scientists received the traditional training, while the other half received the intervention training which included an hour and a half presentation from conservation decision makers. We found that while short term perceptions of the relevance of the program was improved, there was a need to enhance legitimacy of program design (i.e., with the voices of citizen scientists), as many volunteers were more interested in studying water quality than water flow. However, the training did positively influence some measures of conservation knowledge and attitudes, and was able to influence frequency of talking to others about conservation. These findings suggest that program managers in citizen science need to know about citizen scientists' motivations to frame recruitment and retention strategies. Additionally, in Chapter 2 this dissertation empirically tests the role of climate vulnerability and adaptation policy making through an in depth examination of coffee farmer adaptation strategies in the state of Chiapas, Mexico, and what determines adoption of adaptation strategies. These results show that the vulnerability context (including market distance, community location, and experience of disasters) the household assets (including natural, social, and physical capitals), and climate perceptions as an additional asset, play an important role in facilitating adaptation to climate change. This research calls attention to the need for stronger policy making that provides financial encouragement for underutilized adaptation strategies such as crop diversification while simultaneously developing climate workshops to strengthen climate perceptions and encouraging participation in agricultural organizations that facilitate information exchange about climate adaptation strategies. Overall, this dissertation calls attention to the social and ecological impacts that citizen science and sustainable development policies have, and the influence that internal cognitive and socio-economic factors play, as well as external environmental factors, for influencing choice to engage in these activities. Because many of these factors are immutable in the short term – such as environmental or socioeconomic factors – this dissertation broadly suggests that to influence choice, decision makers need to recognize cognitive factors like perceptions of climate change, motivations to participate, and perception of project relevancy. Only when we can understand these cognitive factors can informational interventions be appropriately designed for social and ecological outcomes.
Embargo
Tropical forest root characteristics and responses to drying across environmental gradients
(Colorado State University. Libraries, 2024) Longhi Cordeiro, Amanda, author; Cusack, Daniela F., advisor; Ojima, Dennis, committee member; Cotrufo, M. Francesca, committee member; Conant, Richard, committee member
Fine roots represent the interface between plants and soils, and as such regulate all major biogeochemical cycles in terrestrial ecosystems, including tropical forests. Tropical forests play a crucial role in global carbon (C) cycling, largely due to their extensive root biomass and significant soil C stocks. However, these ecosystems have been experiencing more frequent severe droughts across some regions and are predicted to continue experiencing these extreme drought events in the future. This dissertation seeks to contribute to the understanding and synthesis of tropical root responses to drying in varying environmental conditions. In chapter 1, I gave an introduction about the importance of fine roots to ecosystem function and the impacts of drying in tropical forests. In chapter 2, I characterized root biomass, morphology, nutrient content, colonization to 1.2 meters depth as well as and arbuscular mycorrhizal fungal (AMF) to 20 cm depth in 32 plots across four distinct lowland Panamanian forests which are representative of the vast variation in soil fertility and mean annual precipitation (MAP) found across tropical forests. Root characteristics measurements, such as morphology and chemistry, at soil layers deeper than 30 cm have been rarely documented and to the best of knowledge this is the first study in tropical forests. I observed that that some root traits changed with soil depth similarly across sites while others had site-specific variation. I also observed larger variation at the soil surface and that morphological traits, in addition to root biomass can affect soil C stocks. In chapter 3, the effects of experimental and seasonal drying on fine root dynamics were explored using a partial throughfall reduction experiment across the same 32 plots as in chapter 2. I found that chronic drying impacted root biomass, productivity, morphology and arbuscular mycorrhizal fungi (AMF) colonization. Root biomass and characteristics also changed across seasons with different dynamics across depths. Chapter 4 focused on the effects of drought on tropical seedling development in a controlled chamber environment. I observed that drying decreased seedling growth, but high soil fertility and AMF inoculation mitigated these effects. I also observed changes in root morphology, leached C, new C allocation patterns, and aboveground traits in response to drought, but with usually interacting effects with fertility and AMF inoculation. Chapter 5 contributes a tropical root database (TropiRoot 1.0 database) with root data extracted from scientific papers across different countries and continents. Overall, this dissertation provides novel results and insights into the variation in root characteristics among tropical forests and their responses to climatic drying with interacting effects of fertility, symbionts and soil depth effects. It brings novel measurements that have never been published in tropical forest studies. In chapter 2, I found novel results about how different tropical forests had similar patterns of root variation with depth. It indicated differences in resources acquisition at the soil surface (likely for nutrients) and at deeper soil layers (likely for water) that are usually less investigated. I also showed a large variation of roots at surface soil across different forests that may influence forest responses to global change factors. In chapter 3, I supported some results across the literature such as drying decreasing root growth at the soil surface. However, I added new results such as drying decreasing root productivity at deeper soil layers, and changing root morphology and associations with symbionts probably to compensate the lower root growth. All together I observed that drying promoted changes in acquisition strategies and also that fertile forests may respond differently to drying. In chapter 4, I showed some clear tradeoffs in plant traits providing evidence that they are constantly changing in response to the environment. Also, I provided some novel results on the mechanisms, such as nutrient retention, on how mycorrhizal and fertility mitigated some negative effects of drying on plant growth. This aligns with the field study showing some possible resilience in the fertile forests to drying. The findings highlight the complex interactions between root traits and environmental conditions, offering important implications for predicting tropical forest responses to changing moisture and nutrient availability. All these chapters together provided a good understanding on how different forests respond to environmental changes. These impacts on soil C storage, links with root function and possible larger vulnerability of some forests are great topics for future studies.
Open Access
Vulnerability to drought in the La Paz, Mexico watershed
(Colorado State University. Libraries, 2015) Haeffner, Melissa, author; Galvin, Kathleen, advisor; Betsill, Michele, committee member; Leisz, Stephen, committee member; Ojima, Dennis, committee member
This study explores the relationship between drought vulnerability and migration in the ranchero community in the Sierras of the La Paz watershed in Baja California Sur, Mexico. Using household survey data, I examine how the various dimensions of vulnerability are related to migration as an adaptation strategy to drought. Contrary to what is predicted by environmental migration and climate vulnerability theory, drought exposed rancheros who had high sensitivity and low adaptive capacity did not use migration as an adaptation strategy in the last severe drought (2006-2012), despite migration being a central part of their traditional culture. This dissertation shows how rural upstream households are constrained in traditional adaptation options (including migration options) while new options have become available (including sedentary options) - because of other social changes in the same watershed, specifically, the expansion of urban services. Taking a closer look at watershed dynamics, I find that urban services have both positive and negative impacts on ranchero drought vulnerability. On the one hand, urban services diversify ranchero water sources in normal seasons; on the other hand, access to urban services does not remain consistent in severe drought. I conclude with a new conceptualization of drought responses with a discussion of the implications of these findings for future research and public policy that includes a need for broader stakeholder inclusion.

Browsing by Author "Ojima, Dennis, committee member"

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