Exploitation of a single-cohort fishery under risk: A simulation-optimization approach

A numerical approach involving dynamic programming and computer simulation is used to examine the socially optimal exploitation of a single-cohort fishery under risk, with specific reference to the Exmouth Gulf Prawn Fishery in Western Australia. Best management strategies for given investment levels are sought before optimizing investment. The results for this industry show that time of year is much more important then level of biomass in determining best fishing policies, and that the timing of the catch is sensitive to natural fluctuations in some biological variables. Employing a “closed season” policy for part of the year appears an attractive way of reconciling private and social objectives under commonality. Under or overcapitalization does not reduce benefits markedly.     

Isozyme Variation in Echinocereus engelmannii var. munzii (Cacteceae)

Assessing the degree of evolutionary differentiation between a rare taxon and its relatives is critical from a biological perspective. Because funding and time are limited, conservation biologists need to set maintainance of truly unique pieces of biodiversity as a higher priority than maintenance of interesting populations of widespread species. Although many factors go into setting priorities, thorough assessment of evolutionary distinctiveness based on multiple lines of evidence is the most basic. We used isozyme characters to assess the distinctiveness of a purportedly rare taxon, Echinocereus engelmannii var. munzii (Munz's hedgehog cactus), from other common varieties of the same species. We sampled at least 15 individuals from one population in each of the three mountain ranges where E. e. var. munzii is present within the United States plus three corresponding desert populations of a more common variety. To test for clinal variation between mountain and desert populations, we sampled three elevationally intermediate populations in the San Bernardino Mountains. We recognized a total of 104 band patterns for nine enzyme systems. All nine enzyme systems yielded polymorphic zymograms. Although we found substantial intrapopulation variability, no significant isozymic differentiation was apparent among any of the sampled populations. Lack of such differentiation implies that the effects of selection or drift have not been felt or detected in these populations. In terms of these enzyme systems Echinocereus engelmannii var. munzii is not distinct from other members of the species. Although there is no evidence of isozymic distinction, morphological evidence should be included in any decisions to submerge this taxon.     

Importance of Crop Yield in Calibrating Watershed Water Quality Simulation Tools1

Surendran Nair, Sujithkumar, Kevin W. King, Jonathan D. Witter, Brent L. Sohngen, and Norman R. Fausey, 2011. Importance of Crop Yield in Calibrating Watershed Water Quality Simulation Tools. Journal of the American Water Resources Association (JAWRA) 47(6):1285–1297. DOI: 10.1111/j.1752‐1688.2011.00570.x Abstract: Watershed‐scale water‐quality simulation tools provide a convenient and economical means to evaluate the environmental impacts of conservation practices. However, confidence in the simulation tool’s ability to accurately represent and capture the inherent variability of a watershed is dependent upon high quality input data and subsequent calibration. A four‐stage iterative and rigorous calibration procedure is outlined and demonstrated for Soil Water Analysis Tool (SWAT) using data from Upper Big Walnut Creek (UBWC) watershed in central Ohio, USA. The four stages and the sequence of their application were: (1) parameter selection, (2) hydrology calibration, (3) crop yield calibration, and (4) nutrient loading calibration. Following the calibration, validation was completed on a 10 year period. Nash‐Sutcliffe efficiencies for streamflow over the validation period were 0.5 for daily, 0.86 for monthly, and 0.87 for annual. Prediction efficiencies for crop yields during the validation period were 0.69 for corn, 0.54 for soybeans, and 0.61 for wheat. Nitrogen loading prediction efficiency was 0.66. Compared to traditional calibration approaches (no crop yield calibration), the four‐stage approach (with crop yield calibration) produced improved prediction efficiencies, especially for nutrient balances.     

Modeling eelgrass spatial response to nutrient abatement measures in a changing climate

For many coastal areas including the Baltic Sea, ambitious nutrient abatement goals have been set to curb eutrophication, but benefits of such measures were normally not studied in light of anticipated climate change. To project the likely responses of nutrient abatement on eelgrass (Zostera marina), we coupled a species distribution model with a biogeochemical model, obtaining future water turbidity, and a wave model for predicting the future hydrodynamics in the coastal area. Using this, eelgrass distribution was modeled for different combinations of nutrient scenarios and future wind fields. We are the first to demonstrate that while under a business as usual scenario overall eelgrass area will not recover, nutrient reductions that fulfill the Helsinki Commission’s Baltic Sea Action Plan (BSAP) are likely to lead to a substantial areal expansion of eelgrass coverage, primarily at the current distribution’s lower depth limits, thereby overcompensating losses in shallow areas caused by a stormier climate.     

The Ergonomic Program Implementation Continuum (EPIC): Integration of health and safety - A process evaluation in the healthcare sector

IntroductionThis article presents a health and safety intervention model and the use of process evaluation to assess a participatory ergonomic intervention.MethodThe effectiveness of the Ergonomic Program Implementation Continuum (EPIC) was assessed at six healthcare pilot sites in Ontario, Canada. The model provided a framework to demonstrate evaluation findings.ResultsParticipants reported that EPIC was thorough and identified improvements related to its use. Participants believed the program contributed to advancing an organizational culture of safety (COS). Main barriers to program uptake included resistance to change and need for adequate funding and resources. The dedication of organizational leaders and consultant coaches was identified as essential to the program's success.Impact on IndustryIn terms of impact on industry, findings contribute to the evidence-based knowledge of health and safety interventions and support use of the framework for creating a robust infrastructure to advance organizational COS and link staff safety and wellness with patient safety in healthcare.     

DISTRIBUTED RUNOFF FORMULATION DESIGNED FOR A PRECISION AGRICULTURAL LANDSCAPE MODELING SYSTEM1

A precision scale landscape model designed for agricultural applications is described in this paper. The Precision Agricultural Landscape Modeling System (PALMS) is a combination of two process‐based models: a diffusive wave runoff model with ponding (described in detail) and a biosphere model with a crops module (briefly reviewed). Several innovations, including numerical formulations for the hydrologic properties of the soil surface with crusting, slope/tillage angle interactions, and change of roughness and detention storage with cumulative precipitation have been included. The model is compared to observations on one 1.8 ha field planted with maize and soybeans during four growing seasons, and one 24 ha field planted with maize during one growing season. Daily average soil moisture is simulated well (within 5 percent volumetric), except in extended runoff/ponding episodes. Physical processes not simulated in the model suggest possible explanations for model errors. Planned improvements for PALMS are also presented.     

Forest planning in an Oregon case study: Defining the problem and attempting to meet goals with a spatial-analysis technique

Five major management goals were identified for the upper Grande Ronde River Basin on the Wallowa-Whitman National Forest in northeastern Oregon: to produce high-quality fish habitat, to maintain elk habitat, to restore and maintain forest conditions within the natural range of viability, and to contribute to community economic stability. From the broad goals, specific goals for stream temperature, habitat effectiveness index (HEI), habitat corridors, maintenance of land in late or old seral stages, and a nondeclining even flow of timber were selected. A case study was undertaken in a small watershed that is under typical societal constraints to determine whether one decisionsupport tool, SNAP II+, could evaluate the selected goals in a single planning exercise. Three riparian management strategies and two forest road scenarios were used. The exclusion of harvest and road-building from riparian zones in order to increase habitat protection decreased harvest levels and net present value but maintained preactivity stream temperatures. Other resources were generally maintained within prescribed management levels. Although the technique has limitations (e.g., it does not account for riparian zones in calculations of forage and cover for HEI, and it can use the maximum but not minimum acreage goal for some resources), it shows promise for evaluating management tradeoffs in watershed analysis.This is Paper 3069 of the Forest Research Laboratory, Oregon State University, Corvallis, Oregon.     

CONTROLLING NONPOINT EXTERNALITIES WITH INPUT RESTRICTIONS IN AN IRRIGATED RIVER BASIN1

ABSTRACT: Irrigated agriculture is a major nonpoint source of surface water quality degradation. Nonpoint source discharges can be controlled by either output taxes or restrictions, or input taxes or restrictions. The economic theory of externality control with taxes or restrictions on input use is developed. The effectiveness of alternative input control policies in improving surface water quality is demonstrated with a mathematical model of the agriculture and water quality in Washington State's Yakima River Basin. Water quality parameters considered were river nitrogen concentration, water temperature, and cropland soil losses. Producer and social abatement costs were the most important measures of policy effectiveness.