6,867 research outputs found
Improving the Efficiency of Wildlife Management: An Application to Waterfowl Production in the Prairie Pothole Region
Wildlife management agencies increasingly use economic analyses to improve the efficiency of their management policies. Few economic studies consider supply-side analyses for wildlife management, due, in part, to a lack of biological response data that capture the full range of management strategies and the influence of landscape characteristics. This paper uses a simulation model to generate biological response functions, which are then embedded within an economic model to determine least cost management strategies. The procedure is applied to waterfowl management in the Prairie Pothole Region of the northern Great Plains. Results highlight management inefficiencies that result from oversimplified response functions that do not account for non-linear relationships or spatial heterogeneity. Results also indicate that intensive management activities, which are generally compatible with agricultural land use, are a cost effective means of achieving waterfowl population objectives. This has important implications for the tradeoff between agricultural and waterfowl production in the Prairie Pothole Region.Resource /Energy Economics and Policy,
Spatial Data Science: Closing the human-spatial computing-environment loop
Over the last decade, the term spatial computing has grown to have two
different, though not entirely unrelated, definitions. The first definition of
spatial computing stems from industry, where it refers primarily to new kinds
of augmented, virtual, mixed-reality, and natural user interface technologies.
A second definition coming out of academia takes a broader perspective that
includes active research in geographic information science as well as the
aforementioned novel UI technologies. Both senses reflect an ongoing shift
toward increased interaction with computing interfaces and sensors embedded in
the environment and how the use of these technologies influence how we behave
and make sense of and even change the world we live in. Regardless of the
definition, research in spatial computing is humming along nicely without the
need to identify new research agendas or new labels for communities of
researchers. However, as a field of research, it could be helpful to view
spatial data science as the glue that coheres spatial computing with
problem-solving and learning in the real world into a more holistic discipline.Comment: 2 pages, Spatial Data Science Symposiu
Connectivity Explains Local Ant Community Structure in A Neotropical Forest Canopy: A Large‐Scale Experimental Approach
Understanding how habitat structure and resource availability affect local species distributions is a key goal of community ecology. Where habitats occur as a mosaic, variation in connectivity among patches influences both local species richness and composition, and connectivity is a key conservation concern in fragmented landscapes. Similarly, availability of limiting resources frequently determines species coexistence or exclusion. For primarily cursorial arthropods like ants, gaps between neighboring trees are a significant barrier to movement through the forest canopy. Competition for limited resources such as nest sites also promotes antagonistic interactions. Lianas (woody vines) connect normally isolated neighboring tree crowns and often have hollow stems inhabited by ants. We used two large‐scale liana‐removal experiments to determine how connectivity and nest site availability provided by lianas affect arboreal ant species richness, species composition, and β‐diversity in a lowland tropical forest in Panama. Removing lianas from a tree crown reduced ant species richness up to 35%, and disproportionately affected species that require large foraging areas. Adding artificial connectivity to trees mitigated the effects of liana removal. Ant colonization of artificial nests was higher (73% occupied) in trees without lianas vs. trees with lianas (28% occupied). However, artificial nests typically were colonized by existing polydomous, resident ant species. As a result, nest addition did not affect ant community structure. Collectively, these results indicate that lianas are important to the maintenance of arboreal ant diversity specifically by providing connectivity among neighboring tree crowns. Anticipated increases in liana abundance in this forest could increase the local (tree‐level) species richness of arboreal ants, with a compositional bias toward elevating the density of broad‐ranging specialist predators
Evaluation of Physical Fitness Tests and the Usefulness of an Internal Crew Questionnaire to Predict Job Readiness in Hotshots
Hotshots are elite wildland firefighters that are used in all capacities from first attack to the most hazardous duties during wildland firefighting. The unpredictable nature of the wildfire creates a dangerous and physically challenging environment for those attempting to stop its advance. Hotshot wildland firefighters must be conditioned to perform the tasks associated with their job and to avoid injury. Purpose: The purpose of the current study was to evaluate possible assessment tests in an effort to predict job readiness for interagency hotshot crew members. Methodology: Thirty-six male and female type 1 hotshot crew members completed 4 physical fitness tests in addition to completing the Wildland Firefighter Tasks and Abilities (WFTA) questionnaire. Crewmembers completed a pre-screening questionnaire (PARQ) and the WFTA questionnaire that assessed their attitude and belief about wildfire job tasks, their ability to complete the tasks, and the ability of their colleagues on the crew to complete job tasks associated with wildland firefighting. Results: The 6 mile hike with 65lb pack (p\u3c0.01) and the push-up test were significantly (p\u3c0.05) correlated with the Eleven predictor variables and the three Calculated variables (sum overall ability, upper body, lower body) (table 2). Furthermore, the 4 mile run test was significantly (p\u3c0.05) correlated with all predictor variables and the three Calculated variables, except laying hose (p=-0.21), pump work (p=-0.21), and mop-up (p=-0.28) (table 2). Secondly, the 6 mile hike with 65lbs and the 4 mile run contributed significantly to predicting the overall ability, sum overall ability, upper body, and lower body variables suggesting that they are good indicators for job readiness
Oil-Mediated Mortality and Induced Behavioral Modifications of Coastal Insects
The Deepwater Horizon oil spill affected over one thousand kilometers of the southeastern United States’ coast in the Gulf of Mexico especially Louisiana’s salt marshes. These marshes are a vital part of the state’s economy and coastal ecology; however, the insects residing in this area remain largely unstudied. The goal of my project was to answer specific questions arising from two ongoing investigations of the insects in the oiled marshes. I sampled insects using sweep nets and insect vacuums to determine the most efficient technique to use in the marsh, compared insects collected in oiled and non-oiled marshes, and completed a taxonomic list of all of the insects collected in the marsh. I determined the effect of weathered oil on the mortality and foraging behavior of the ant Crematogaster pilosa. I used the house cricket, Acheta domesticus, to test the effect of direct and indirect oil exposure on insect mortality. I also used colonies of A. domesticus to determine if any sub-lethal effects occurred as a result of exposure to oil vapors. Sweep-net sampling collected four times more insects than vacuuming and collected significantly more insect taxa (p = 0.0005). Oiled marshes had increased insect populations compared with non-oiled areas (p = 0.0495). Over 108 insect morphospecies were collected in the marsh. C. pilosa’s foraging behavior was drastically reduced by oil presence (p \u3c 0.0001) though oil did not usually increase mortality. The time for 50% and 100% mortality to occur in A. domesticus was significantly less when exposed to direct contact with oil (p \u3c 0.0001 for both 50% and 100%) and indirect contact with oil (p = 0.0053, p = 0.0005 for 50% and 100%, respectively). House crickets exposed to oil vapors showed reduced adult life spans, longer time to maturation, and changes in resistance to parasites when compared with controls. All these data indicate oil exposure can change insect populations, rates of mortality, and behavior
HYDRAULIC RESPONSE TO EMULSIFIED VEGETABLE OIL BIOSTIMULATION: IN-SITU TEST IN A HIGHLY HETEROGENOUS URANIUM CONTAMINATED AQUIFER
The purpose of this study was to determine if the injection of emulsified vegetable oil (EVO) to remediate a uranium-contaminated aquifer can result in a reduction in hydraulic conductivity. The secondary purpose was to determine if there was evidence of a “memory effect,” a phenomenon where the second time an electron donor is injected, the environment responds to it faster. This has been observed at many remediation sites. A previously treated (2009) uranium contaminated aquifer at Y-12 National Security Complex located in Oak Ridge, Tennessee, was injected with EVO to determine whether hydraulic conductivity changes and to assess the effectiveness of EVO treatment for reducing dissolved uranium. Acetate was monitored in downgradient wells as an indicator of biodegradation. On December 13, 2017, a 20% EVO and groundwater mixture was injected within the Y-12 FRC Area 2 site. Periodic measurements of hydraulic conductivity and dissolved uranium concentration were taken from a control wells, three injection wells, and four down-gradient wells for 134 days. During the experiment, hydraulic conductivity in the injection wells decreased by up to two orders of magnitude but only up to one order of magnitude in half of the down-gradient monitoring wells located 2.5 to 11 m away. Dissolved uranium concentrations significantly decreased in the injection wells, but not in the monitoring well directly down-gradient of injection because dissolved uranium concentrations increased by day 78 and surpassed pre-injection concentrations due to oxidation of reduced uranium in those wells. Acetate concentrations indicated an accelerated response to EVO compared to the 2009 study results. However, this was the only evidence of “memory response.” The results of this study show that injecting EVO can have unintended consequences related to hydraulic conductivity, which can reduce EVO effectiveness or even cause bioremediation using EVO to fail. The effects of EVO interacting with aquifer media and injection well spacing should be carefully considered to minimize changes in preferential flow, limit oxidation of reduced uranium, and maximize the effectiveness of the treatment
The effects of habitat and connectivity on tropical ant ecology and behavior.
This dissertation explores the role that physical connections among and within habitats play in determining the local diversity and behaviors of cursorial organisms. Understanding the processes that regulate local community assembly and that contribute to the maintenance of species diversity is a cornerstone of community ecology. Ants are a useful model for studies of local communities because they are abundant and fulfill a variety of ecological roles. Chapter one of the dissertation examines the how lianas (woody vines) function as connective structures among tree crowns and how these connections affect arboreal ant community structure within a tropical forest canopy. Trees without lianas act as islands and the number of ant species living in these isolated trees can be predicted by tree size alone. Chapter two describes an experimental approach to examining the relationship between arboreal ants and lianas. Cutting lianas out of trees and connecting trees with ropes revealed that connectivity is a key resource that lianas provide to arboreal ants. The removal of lianas decreased species richness and caused the development of a strong, positive species-area relationship between ant species richness and tree size. Connecting neighboring trees together with ropes completely mitigated the effects of liana removal. Chapter three explored how ants use physical pathways to move across the forest floor. Ants will readily use exposed roots or ropes as highways to move through the complex matrix of leaf litter on the forest floor. As a result, ants appeared in higher frequency on these structures compared to the nearby leaf litter. Increasing the number of paths in an area also increased the rate of discovery and recruitment to food resources by focal species. In combination, these observations and experimental manipulations highlight how connecting isolated habitats or providing bridges through complex environments can enhance local species diversity and promote a variety of interactions among organisms at small spatial scales
Comparison of lower extremity strength and strength symmetry among U.S. Ski Team sports
Most research in ski sports performance, injury, and sport physiological demands focuses on alpine ski racing. Very little research is available describing aerial and moguls ski competitors. Purpose: Compare lower extremity strength limb symmetry index (LSI) and relative strength (RS) among alpine, mogul, and aerials ski competitors. Methods: Archival data from 156 males and females from the U.S. Ski Team at Olympic, World Cup, and national levels were analyzed to compare RS and LSI among ski sports. Strength data consisted of maximal isometric bilateral squat strength values from each leg independently. A 3x2x2 factorial ANOVA was conducted to determine differences and interactions between sex, competitive level, and sport type on LSI. A second factorial ANOVA was conducted to compare RS among the same factors. Results: The main effects of sport type (p = 0.194), competitive level (p = 0.061), and sex (p = 0.260) were not significant for LSI. There were no significant interactions between independent variables for LSI. The main effects of sport type (p = 0.041) and sex (p \u3c 0.001) were significant for relative strength. Alpine racers were significantly stronger than moguls (p = 0.002) and aerials (p = 0.001) competitors. Males were significantly stronger than females (p \u3c 0.001) in all three disciplines. No other significant findings for main effects or interactions were found. Conclusion: The low presence and variation in LSI may indicate that a bilateral maximum strength test may not be ideal for identifying LSI. Strength differences among sports may exist due to exposure to forces associated with speed. Sex differences in relative strength may be due to anthropometric variations
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