Colorado College Logo

  DigitalCC

Use AND (in capitals) to search multiple keywords.
Example: harmonica AND cobos

2016-2017

10 hits

  • Thumbnail for A Spatial Analysis of Microclimates and Seedling Growth at an Abrupt Treeline on Pike's Peak
    A Spatial Analysis of Microclimates and Seedling Growth at an Abrupt Treeline on Pike's Peak by Chang, Lani C

    Treelines are climatically constrained ecotones existing worldwide. With global warming and climate change, treelines are expected to advance in elevation on a global scale. Previous research has shown that abrupt treeline shapes are advancing at far slower rates than diffuse treeline structures, indicating that temperature increases are not the only factor. Smaller-scale, endogenous factors may be at play including microclimates, tree-to-tree interactions and feedbacks. Our study at an abrupt treeline on Pike’s Peak aims to understand the effects of temperature and smaller-scale factors on seedling growth, in the effort to try and understand the feedbacks involved in treeline movement and formation. Results indicate that this specific abrupt treeline is creating a microclimate that facilitates seedling growth above the historical treeline. Once this new growth of seedlings matures, another abrupt treeline will form and perpetuate the process.

  • Thumbnail for Examining the Impact of the Northward Migration of Yellow Cedar on Ecosystem Biogeochemistry and the Net Carbon Equilibrium
    Examining the Impact of the Northward Migration of Yellow Cedar on Ecosystem Biogeochemistry and the Net Carbon Equilibrium by Jurney, Patrick

    Abstract: Yellow Cedar is an ecologically, culturally, and commercially important tree species; its habitat extends 20° in latitude from Southeast Alaska to the Northern California. It is experiencing extensive decline in areas of low elevation, latitude, and drainage capacity. This decline is due largely to climate change decreasing the snowpack, resulting in root-freezing injuries. Future climate change will place even the northernmost reaches of its range in conditions conducive to mortality by the end of the 21st century, putting Yellow Cedar on a path towards extinction. As vast areas of Yellow Cedar forest experience mortality, the species is also slowly migrating north to newly suitable habitat. Its northward migration is hampered by meager dispersal capability and its niche traits which limit its competitiveness to marginal soils. The effects of Yellow Cedar’s northward migration needs to be better understood to properly implement conservation strategies that can protect the longevity of the species. In particular, how does Yellow Cedar colonization alter soil conditions and forest ecosystem function? Soil biogeochemical analyses in pioneer stands indicate that the presence of Yellow Cedar improves the suitability of soils to many forest species; soils have higher N content and are less acidic. The results also illuminate a decrease in the bioavailability of soil carbon with the presence of Yellow Cedar, which suggests that the species increases carbon storage capacity of soils in temperate rainforests. This suggests an increase in soil respiration in areas of decline, a positive feedback cycle from global warming. Yellow Cedar is an important case study of the global impacts of climate change on our biosphere and a harbinger for many species as climate change intensifies.

  • Thumbnail for How does culture or development construct the way people think about and act towards the environment?
    How does culture or development construct the way people think about and act towards the environment? by Wei, Siqi

    This study examines the similarities and differences in environmental values and attitudes between Chinese and US college students, and predicts their correlation with one’s intention to take environmental actions. Quantitative findings suggest that the majority of participants in both groups share a similar level of environmental knowledge and converged environmental attitudes, except for their perception of nature. Qualitative findings, however, reveal that the perception of environmental problems and the structure of environmental attitudes differ greatly between these two groups of participants insofar as their similar levels of environmental concerns. Contextual factors between these two cultures are also explored to evaluate their enabling or constraining effects on environmental behaviors. This study represents a substantial step in building a better understanding of the interplay between cultural practices and environmental attitudes. It also has great implication for promoting the efficiency of the practice of environmental education at an international level.

  • Thumbnail for How does culture or development construct the way people think about and act towards the environment?
    How does culture or development construct the way people think about and act towards the environment? by ,

    This study examines the similarities and differences in environmental values and attitudes between Chinese and US college students and predicts their correlation with one’s intention to take environmental actions. Quantitative findings suggest that the majority of participants in both groups share a similar level of environmental knowledge and converged environmental attitudes except for their perception of nature. Qualitative findings, however, reveal that the perception of environmental problems and structure environmental attitudes differ greatly between these two groups of participants insofar their similar levels of environmental concerns. Contextual factors between these two cultures are also explored to evaluate their enabling or constraining effects on environmental behaviors. This study represents a substantial step in building a better understanding of the interplay between social and cultural practices and environmental attitudes. It also has great implication for promoting the efficiency of the practice of environmental education at an international level.

  • Thumbnail for Ozone trends from 2005 to 2016 at the Manitou Springs Station: attainment of the lowered ozone NAAQS in Colorado Springs
    Ozone trends from 2005 to 2016 at the Manitou Springs Station: attainment of the lowered ozone NAAQS in Colorado Springs by Li, Yingxuan

    Hourly averaged ozone (O3) measurements from 2005-2016 collected at the Manitou Springs station, Colorado, were analyzed to determine long-term trends and assess the ability for the Colorado Springs metropolitan area to be in attainment of the O3 National Ambient Air Quality Standards (NAAQS). The EPA recently lowered the NAAQS for O3 from 75 ppbv to 70 ppbv, posing attainment challenges for high elevation regions of the western United States, including Colorado Springs, due to the impacts of baseline O3. Baseline O3 is defined as O3 that is transported to a location from upwind sources. This study aims to identify possible causes of different O3 trends in Colorado Springs. The annual 99th percentile O3 concentration showed a significant decrease of -0.71 ppbv yr-1 (-0.96% ppbv yr-1), and the annual 5th percentile significantly increased by 0.81 ppbv yr-1 (5.8% ppbv yr-1), while the annual 50th and 95th percentiles did not show significant trends. The decreasing trends generally appeared to occur at the 95th and 99th percentiles, attributing to the effectiveness of both local and nationwide O3 precursor emission controls. The increasing trend in the 5th percentile indicates possible increased baseline ozone. Seasonal variability of O3 concentrations was present with 50th percentile O3 values in spring (45 ppbv) and summer (46 ppbv) being significantly higher than fall (36 ppbv) and winter (35 ppbv), in part due to the seasonal patterns of photolysis conditions and temperature. Although multiple studies have observed increasing trends in springtime O3 in the western U.S., no such spring trends were observed this analysis. The lack of significant trends may be due to the particular location and topography of the monitoring site, which is east of the Continental Divide and in the foothills of the Pikes Peak region, as well as the influence from the nearby urban emissions. We also performed cluster analysis of 10-day HYSPLIT back-trajectories generated for spring (April-May) and summer (June-August) and looked at O3 trends within each cluster. For spring, most of the clusters did not indicate significant linear trends; the only significant positive trend was associated with low-altitude transport over the Pacific (Cluster 2). For summer, a significant positive trend was found in the 95th percentile of Cluster 6, representing the low-altitude transport from the southeast. The wintertime 5th and 50th percentiles indicated significant increases, with slopes of 1.13 ppbv yr-1 (17.2% ppbv yr-1) and 0.3 ppbv yr-1 (0.93% ppbv yr-1). Rapid development of oil and natural gas industry around the area may contribute to these positive trends, and this is an area for future research.

  • Thumbnail for Projected distributional changes in Arctic-breeding passerines as a factor of land cover change in Northern Alaska
    Projected distributional changes in Arctic-breeding passerines as a factor of land cover change in Northern Alaska by Burk, Erin

    In North American bird species, breeding distributions are shifting north toward the poles with climate change (Hitch and Leberg 2007). Habitat type could act as a better predictor of shifts in the breeding distributions of territorial birds than elevation or temperature gradients alone, as both an individual’s breeding performance and adult survival depend on habitat suitability (Reif et al. 2010). Using models that predict how the vegetative structure will change in a tundra landscape, we can predict how territorial bird distributions might change alongside a warming climate as a factor of habitat type. This study makes population and bird species richness projections for tundra-breeding birds based on their habitat preference at the Primus Creek study site in the Noatak National Preserve, Alaska.

  • Thumbnail for The Environmental and Spiritual Significance of Chi’chil Bildagoteel, an Apache Sacred Site
    The Environmental and Spiritual Significance of Chi’chil Bildagoteel, an Apache Sacred Site by Lucas, Emily

    The combination of environmental and spiritual threats posed by mining on sacred geographies is exemplified in the struggle for Chi’chil Bildagoteel , or Oak Flat, a site in southeastern Arizona sacred to the San Carlos Apache Tribe that is currently threatened by an impending copper mine.

  • Thumbnail for The Implementation of a Methodology to Measure and Analyze the Effects of Inquiry Teaching on Student Development of Inquiry Skills
    The Implementation of a Methodology to Measure and Analyze the Effects of Inquiry Teaching on Student Development of Inquiry Skills by Cadow, Charlotte

    Current science education standards mandate the inclusion of inquiry within curricula. However, existing research fails to address the correlation between the teaching of inquiry and the learning of inquiry skills. A unique opportunity presents itself at the Catamount Center where undergraduate students work with small groups of 5th grade students to facilitate a 4-week “Inquiry Unit.” This paper adapts and applies an existing theory by Ruiz-Primo (2010) to introduce a methodology that assesses the presence and quality of conclusion components in 5th grade inquiry papers. As a result of this research, several hypotheses have been generated regarding the successful implementation of the Inquiry Unit at the Catamount Center.

  • Thumbnail for The Roots of Impasse: How Neoliberalism has Shaped Recovery Planning for Endangered Fish in the Columbia River Basin
    The Roots of Impasse: How Neoliberalism has Shaped Recovery Planning for Endangered Fish in the Columbia River Basin by Linse, Lea Michelle

    Management of the Columbia River has come to an impasse: after decades of litigation and controversy, there is a growing sense among stakeholders that there may be no good solution to the conflict between endangered salmon and the region’s expansive hydroelectric generation system. Dams and reservoirs pose severe challenges to the survival and migration of salmon and have been blamed for significant population declines over the past century. Addressing this issue, however, is complicated by the fact that river management strategies to benefit the fish often require operational changes that reduce the productivity of hydroelectric power generators, and thus they are strongly opposed by hydroelectric interests and dam operators. Still, the National Marine Fisheries Service, the agency charged with ensuring that other federal agencies’ actions (including actions of federal dam operators) do not jeopardize listed species, is constantly pressured by Native American tribes, environmental groups, and other stakeholders to implement just that sort of management plan. Caught between the two sides, the NMFS, instead of being decisive, has tended to avoid upsetting the status quo and has been often criticized for it. This report seeks to explain why the NMFS has been so reluctant to regulate the hydroelectric system. It shows that, despite the authority of the NMFS the Endangered Species Act, they must operate within the confines of what is politically feasible. Political feasibility is constrained in part by the legacy of a trend toward neoliberalism that gained influence in U.S. politics during the 1980s and 1990s. Specifically, neoliberal policies aimed at limiting federal involvement in economic activities and private land under the ESA have become impediments to federal action in the Columbia that would give endangered fish priority over development activities that threaten their survival. Two such policies are analyzed in this report, the “no surprises” policy, which was originally designed for private landowners but is now used between regulating and regulated agencies, and the “best available science” mandate for federal action under the ESA.

  • Thumbnail for Treeline Micrometeorology and How It Is Affected by Airflow on Pikes Peak
    Treeline Micrometeorology and How It Is Affected by Airflow on Pikes Peak by Cofsky, Caleb James

    We aimed to find what kinds of microclimates were created by an abrupt treeline and relate those microclimates to the spatial structure of the treeline itself. We specifically wanted to understand how airflow is directly related to air temperature upslope of treeline. To do this, we took data from an abrupt treeline on Pike’s Peak in the Front Range of the Colorado Rocky Mountain Range. Our data was taken in September of 2016, which is representative of the tail-end of the growing season for trees. The wind speed and direction appeared to have a strong relationship with the air temperature, as the daytime uphill anabatic airflow created eddy zones of slow-moving air that were able to warm up from sensible heat dissipated at the ground surface., The nighttime downhill katabatic winds accumulated pockets of slow-moving cold air. This study helped us understand that sheltering with respect to treelines is not the result of single and independent trees, but rather the result of the entire treeline as complete three-dimensional structure. This is important because the effects of sheltering at treeline will vary from location to location based on the shape of the entire spatial structure of the ecotone.