James J. Jacobs

Estimating the Economic Value of Improved Trout Fishing on Wyoming Streams

Abstract Economic information that can be used to determine which management alternatives best meet public demands within limited budgets is important to resource management agencies. The objective of this study was to generate estimates of economic benefits of improvements on Wyoming trout fishing streams that could be used to evaluate different improvement projects. A mail survey was conducted to determine characteristics and preferences of anglers fishing Wyoming streams, and the contingent valuation method (CVM) was used to estimate economic benefits associated with fishing under improved conditions. Questions were associated with fishing for any or all trout species an angler might encounter on Wyoming streams. Benefits of improvement were based on CVM questions involving a hypothetical doubling of the chance of catching a large trout and a hypothetical increase in trout populations. Tourist and resident fishing license subgroups also were analyzed. Anglers in the tourist license group traveled long ...

How much sagebrush is too much: an economic threshold analysis.

Much research concerning sagebrush control methods and forage response after control has been conducted due to the importance of sagebrush-grass dominated rangelands for livestock and wildlife in the western United States. Very little research has addressed the economic feasibility of sagebrush control at various levels of abundance. This study estimates the economic thmhold abundance of sagebrush based on forage response data from a sagebrush control experiment in Carbon County, Wyo. Forage response data are based on the difference in herbage between treated and untreated experimental units from sites ranging in initial sagebrush canopy cover from 4 to 40%. Breakeven returns per AUM were estimated for each sagebrush canopy cover level assuming 2,4-D (2,4-dichlorophenoxyacetic acid) or burning (for 28 to 40% canopy cover) as a control method with lives of control at 1S, 20, and 25 years. These breakeven returns were compared to a net lease rate of S6.13/AUM. Results indicate the economic threshold abundance of sagebrush is 12% assuming, 2,4-D as the control method and a control longevity of 25 years, but the feasible sagebrush abundance increases as longevity of control decreases. If the longevity of the control only lasts 20 years, the sagebrush abundance must be at least 20% before treating sagebrush becomes economically feasible. If the longevity of control is only 15 years, sagebrush abundance must be at least 24% canopy cover before treatment is economically viable. Given estimates of the cost of burning are almost half that of spraying with 2,4-D, all the scenarios which had enough biomass to sustain a burn (28% to 40%) indicated sagebrush controJ by fire was economically viable.

The Relationship between Cognitive Mode and Right Hemisphere Test Performance

This study investigated the relationship between cognitive mode and right hemisphere test performance. Seventy-six randomly selected elementary students were administered the Adapted Childrens Form of Your Style of Learning and Thinking (SOLAT) to obtain their left, right, and integrated hemisphere cognitive mode scores. The same students were also administered the Judgment of Line Orientation test, Bender-Gestalt test, Torque Task, and the Word Production test. Subjects determined to have a predominant right hemisphere cognitive mode (N = 38) scored significantly higher on the Judgment of Line Orientation test, Torque Task, and Word Production test, and significantly lower on the Bender-Gestalt test than subjects with a predominantly left hemisphere cognitive mode (N = 25) and/or integrated hemisphere cognitive mode (N = 13). Right hemisphere cognitive mode scores correlated positively and significantly with Judgment of Line Orientation scores, and negatively and significantly with Bender-Gestalt scores.

Sagebrush Control: At What Canopy Cover Is It Economically Justified?

Abstract We determine the economic threshold level for big sagebrush control based on 18 yr of forage-response data from an experiment conducted in Carbon County, Wyoming. We analyze the impacts of climatic variables and treatment site characteristics, such as sagebrush abundance levels, precipitation, and understory composition, on forage response and threshold level. We find that sagebrush canopy cover levels, April precipitation, May soil moisture, and understory composition are statistically significant factors in explaining forage response to sagebrush treatment. Forage yield across treated and untreated plots for 10 canopy cover levels, ranging from 4% to 40%, are analyzed via panel data regression techniques. We further investigate the impact of variability in precipitation and understory characteristics on economic outcomes of sagebrush control by analyzing three scenarios. Scenario 1 uses actual forage response data that include all variability from precipitation and understory composition. Scenario 2 uses regression-predicted yields across plots assuming average precipitation and soil moisture conditions. Scenario 3 uses regression-predicted yields assuming average precipitation, soil moisture, and understory characteristics across plots. Net present values based on value of grazing (for estimated yield differences between treated and untreated plots assuming 50% forage utilization) compared to treatment cost across sagebrush cover levels are estimated across these three scenarios. Results indicate that the economic threshold level of sagebrush infestation for the study period was between 8% and 24% for the analyzed scenarios. This indicates variability in precipitation and understory composition impact forage response and the resulting economics of sagebrush control. We conclude that range managers should consider potential control site characteristics and long-range weather forecasts when contemplating sagebrush control. Resumen Determinamos el nivel del umbral económico para el control de la artemisa basados en 18 años de datos sobre la respuesta del forraje en un experimento realizado en Carbon County, Wyoming. Analizamos el impacto de variables climáticas y características del sitio tales como niveles de abundancia de artemisa, precipitación y la composición abajo del dosel en la respuesta del forraje y el nivel de umbral. Encontramos que los niveles de cobertura aérea de la artemisa, la precipitación de abril, la humedad del suelo de mayo y la composición son factores estadísticamente significantes para explicar la respuesta del forraje en el tratamiento de la artemisa. El rendimiento de forraje a lo largo de las parcelas tratadas y no tratadas para diez niveles de cubierta aérea fluctuaron del 4% al 40% son analizados por medio de técnicas de regresión de datos panel. Además investigamos el impacto de la variabilidad en precipitación y características debajo del dosel en los resultados económicos del control de la artemisa analizando tres escenarios. En el escenario uno, se usaron los datos de la respuesta actual del forraje la cual incluye toda la variabilidad de la precipitación y composición de abajo del dosel. El escenario dos, usa rendimientos predichos de regresión a lo largo de las parcelas asumiendo precipitación promedio y condiciones de humedad del suelo. El escenario tres usa rendimientos predichos de regresión asumiendo precipitación promedio, humedad del suelo y características de abajo del dosel a través de las parcelas. Valores presentes netos basados en el valor del pastoreo (estimados de las diferencias entre los rendimientos de las parcelas tratadas y no tratadas asumiendo un 50% de utilización del forraje) comparado con el costo del tratamiento a través de los niveles de cobertura de la artemisa son estimados a través de estos tres escenarios. Los resultados indican que el nivel del umbral económico de infestación de artemisa para el periodo de estudio fue entre 8% y 24% de los escenarios analizados. Esto indica que la variabilidad en precipitación y composición abajo del dosel impacta la respuesta del forraje resultando en el control económico de la artemisa. Concluimos que manejadores de pastizales deben considerar las características potenciales de control en el sitio y rangos amplios de pronósticos de tiempo cuando consideren el control de la artemisa.