University of Wyoming Open Journals
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Characterization of the W-weighted Drazin inverse over the quaternion skew field with applications
No full textA characterization of the W-weighted Drazin inverse as well as some determinantal representations of the W-weighted Drazin inverse over the quaternion skew filed are derived. Moreover, a Cramer's rule for finding the unique solution of a class of restricted quaternion matrix equations is obtained
The combinatorial inverse eigenvalue problems: complete graphs and small graphs with strict inequality
No full textIdentifying Avian Community Response to Sagebrush Vegetation Restoration in Grand Teton National Park
No full textApproximately 50-60% of native sagebrush steppe has been lost to non-native grasses, which has contributed to population decreases for sagebrush-associated songbirds. Removal of non-native grasses and restoration treatments may return structure and function of sagebrush steppe and ultimately benefit songbirds, but their responses must be evaluated. To determine breeding songbird community responses to sagebrush restoration treatments, in 2013 we conducted bird surveys at restored plots at the Kelly Hayfields restoration area in Grand Teton National Park, Wyoming. We compared bird communities and vegetation characteristics in restored plots to plots that were unrestored and to areas of native sagebrush steppe as starting and endpoints for restoration, respectively. Unrestored plots were dominated by non-native grasses; restored plots were dominated by forbs and bare ground and had very little shrub cover (< 0.1%). Native sagebrush plots were dominated by shrubs and native bunchgrasses. Bird community composition was distinct among the three types of plots. Abundance of grassland birds was highest in unrestored plots, and was positively related to cover of non-native grass and litter depth. Abundance of shrubland birds was highest in native sagebrush, and was positively associated with shrub cover. There were very few detections of birds in restored plots, and most species were negatively associated with the high levels of bare ground that characterized these plots. Restored areas may initially (â¤5 yrs) provide little breeding bird habitat, which should be accounted for when determining schedules of restoration treatments at Kelly Hayfields
Identifying Rare Montane Meadow Parnassian Butterfly Populations Across Grand Teton National Park, Wyoming
No full textThe pristine, protected ecosystem of Grand Teton National Park (GRTE) is the ideal location to study the relationships between butterfly populations and the habitats on which these insects depend. Two montane meadow butterfly species, Parnassius clodius and Parnassius smintheus, were investigated in this study to identify patterns of habitat occupancy relating to variables across GRTE and into the surrounding territory of BridgerâTeton National Forest (BTNF). Population dynamics of P. clodius have been intensively studied by our research group over several consecutive years in one isolated population in Grand Teton National Park. However, little has been investigated regarding the Parnassian butterfliesâ population range across the GRTE ecosystem. For this study, presence-absence butterfly surveys were conducted across 45 meadow sites in preferred habitat during the Parnassius flight season (June â July 2013). We found that P. clodius occupied 80% of the meadows surveyed, which was far greater than was originally predicted. P. smintheus, the more rare Parnassian butterfly in the GRTE ecosystem, was only found at 9% of the meadows surveyed. Understanding population ranges and habitat limits of these butterfly populations will be useful for managers and scientists within GRTE, and will assist conservation efforts for other related Parnassian species that are threatened or endangered worldwide due to habitat loss and climate change
Nutrient Limitation and Uptake Rates in Streams and Rivers of the Greater Yellowstone Ecosystem
No full textNutrient pollution of aquatic ecosystems is a growing concern as the influence of human activities continues to increase on the landscape. Headwater streams have long been shown to process nutrients via the biofilm community growing on the bottom of streams. The growth and activity of these biofilms is often limited by the availability of nitrogen (N), phosphorus (P), or co-limited by both N and P. Although small stream nutrient dynamics are relatively well understood, comparatively little is known about larger, non-wadeable rivers. Biofilms on the river bottom are likely still nutrient limited, but there becomes an increased potential for light limitation as rivers increase in depth. In addition to biofilms on the bottom of rivers, free-living microbial communities suspended in the water column also occur in rivers and process nutrients - a component of nutrient processing largely ignored in streams. In summer 2013 we worked in streams and rivers of the Greater Yellowstone Area (GYA) to establish the nutrient limitation status of minimally-impacted rivers, as well as the role of the water column in processing nutrients as streams increase in size. For both the nutrient limitation and water column uptake studies, we are using the GYA sites in addition to systems from other regions of the US to establish what controls the various aspects of nutrient dynamics in rivers. Our results from the GYA, in addition to Midwest and Southwest US rivers, will provide water quality managers with new strategies for improving water quality downstream, and clarify mechanisms controlling nutrient retention in rivers
NASA-NPS Landscape Climate Change Vulnerability Project (LCCVP) Team Meeting at AMK Ranch
No full textA NASA-funded research team met May 19-22 at the AMK Ranch for a semi-annual team workshop. Participants included: Montana State University â Andy Hansen, Tony Chang, Regan Nelson, Nate Piekielek Woods Hole Research Center â Patrick Jantz, Scott Zolkos NPS Inventory & Monitoring Program â John Gross, Bill Monahan Great Northern LCC â Tom Olliff NASA Ames â Forrest Melton, Jun Xiong Guest â Steve Running (University of Montana) Chef â Jodi Stevens The goal of the project is to demonstrate the four steps of climate adaptation planning in two US Department of Interior Landscape Conservation Cooperatives (LCCs) using NASA and other data and models. Objectives are: 1. Hindcast and forecast future climate and land use scenarios. 2. Assess the vulnerability of ecological processes and key habitat types. 3. Evaluate management options. 4. Design and implement management adaptation strategies. 5. Facilitate decision support