Ecological impacts and management strategies for western larch in the face of climate-change

Approximately 185,000 forest inventory and ecological plots from both USA and Canada were used to predict the contemporary distribution of western larch (Larix occidentalis Nutt.) from climate variables. The random forests algorithm, using an 8-variable model, produced an overall error rate of about 2.9 %, nearly all of which consisted of predicting presence at locations where the species was absent. Genetic variation among 143 populations within western larch’s natural distribution was predicted from multiple regression models using variables describing the climate of the seed source as predictors and response data from two separate genetic tests: 1) 15-year height at a field site in British Columbia, Canada, and, 2) two principal components of 8 variables describing growth, disease tolerance, and phenology of 6-year-old trees in a test in Idaho, USA. Presence and absence of the species and genetic variation within the species were projected into future climates provided by three General Circulation Models and two scenarios. Although the projections described pronounced impacts on the species and its populations, concurrence among the six projections pinpointed areas where the probability would be high that the future climate would be suitable for western larch. Concurrence among projections also was used to locate those sources of seed that should be best attuned genetically to future climates. The procedures outline a logical approach for developing management strategies for accommodating climate-change while taking into account the variability imposed by the differences among climatic estimates.     

Novel methods for discriminating behavioral differences between stickleback individuals and populations in a laboratory shoaling assay

Threespine sticklebacks (Gasterosteus aculeatus) from different habitats have been observed to differ in shoaling behavior, both in the wild and in laboratory studies. In the present study, we surveyed the shoaling behavior of sticklebacks from a variety of marine, lake, and stream habitats throughout the Pacific Northwest. We tested the shoaling tendencies of 113 wild-caught sticklebacks from 13 populations using a laboratory assay that was based on other published shoaling assays in sticklebacks. Using traditional behavioral measures for this assay, such as time spent shoaling and mean position in the tank, we were unable to find population differences in shoaling behavior. However, simple plotting techniques revealed differences in spatial distributions during the assay. When we collapsed individual trials into population-level data sets and applied information theoretic measurements, we found significant behavioral differences between populations. For example, entropy estimates confirm that populations display differences in the extent of clustering at various tank positions. Using log-likelihood analysis, we show that these population-level observations reflect consistent differences in individual behavioral patterns that can be difficult to discriminate using standard measures. The analytical techniques we describe may help improve the detection of potential behavioral differences between fish groups in future studies.     

Cumulative environmental change: Conceptual frameworks,evaluation approaches,and institutional perspectives

Cumulative environmental change or cumulative effects may result from the additive effect of individual actions of the same nature or the interactive effect of multiple actions of a different nature. This article reviews conceptual frameworks of cumulative environmental change and describes analytical and institutional approaches to cumulative effects assessment (CEA). A causal model is a common theoretical construct, although the frameworks vary in their emphasis on different components of the model. Two broad approaches to CEA are distinguished: one scientific and the other planning oriented. These approaches should not be interpreted as competing paradigms but rather different interpretations of the scope of CEA. Each approach can provide a distinct but complementary contribution to the analysis, assessment, and management of cumulative effects. A comparison of the institutional and legislative response to CEA in Canada and the United States shows that Canada is following the American example of incorporating the analysis and assessment of cumulative effects into regulatory actions and administrative procedures that also govern environmental impact assessment.     

Reducing risks of maintenance dredging on freshwater mussels (Unionidae) in the Big Sunflower River, Mississippi

In response to proposed dredging in a 122-km reach of the Big Sunflower River, Mississippi, we studied freshwater mussels (family: Unionidae) using qualitative, semi-quantitative, and quantitative (0.25 m(2) total substratum removal) methods in 1987, 1993, 1994, 2001, 2002, and 2003. Our objectives were to identify important mussel resources, to devise methods for minimizing dredging risks, and to identify habitat improvement features. Approximately 60% of the fauna was located on two high-density shoals characterized by extreme dominance of the commercially valuable threeridge (Amblema plicata). Shallow nearshore and main channel areas comprised approximately 10 and 88% of the aquatic habitat in the project area; however, these areas were of less importance for mussels and supported densities of approximately 5 and 0.5 individuals/m(2), respectively. Throughout the project area the mussel fauna exhibited little or no evidence of recent recruitment, dominance of relatively few species (either A. plicata, or the bank climber Plectomerus dombeyanus), and low species diversity (H') and evenness. No federally listed endangered or threatened mussels were found, although the pyramid pigtoe (Pleurobema pyramidatum), a species listed as endangered in Mississippi, was collected in and upstream of the project area. Two other state-listed species, Plethobasus cyphyus (sheepnose) and Quadrula cylindrica (rabbitsfoot), were only found on gravelly shoals upriver of the project area. Maintenance plans were redesigned to minimize environmental damage; a hydraulic cutterhead dredge will be used in most of the mainstem to reduce risk to nearshore habitats. High-density assemblages on four shoals will not be dredged and 150 and 100 m buffer zones will be left immediately up and downriver. Enhancements for aquatic biota will be created with gravel substratum and wing dams.     

Small-scale temporal variation and the effect of urbanisation on extracellular enzyme activity in streams

The activity of six extracellular enzymes involved in the degradation of dissolved organic carbon compounds was measured in two highly urbanised and two minimally impacted streams east of Melbourne, Australia, using 4-methylumbelliferyl-substrates. Small-scale temporal variation in enzyme activity was determined by repeatedly sampling the same point in the water column, while the effect of flow was determined by sampling in regions of higher and lower flow in both stream types. Replicate samples showed that enzyme activity was not significantly different over small (minutes) time scales. On five of six sampling occasions the enzyme activity was unaffected by flow. On one sampling occasion in a minimally disturbed stream, the difference between the high- and low-flow regions was statistically significant (ANOSIM, Global R= 0.78, P= 0.03). Enzyme activity profiles (activities of the suite of enzymes) of the streams in urbanised catchments were different to those in minimally disturbed catchments. The measurements made in four different streams showed high reproducibility over short time periods (minutes) which lends greater credibility to analogous spatial studies. Although these results determined that small-scale temporal variability was not significant, and that the effects of flow were generally minimal, it is recommended that spatial and temporal variability in the stream be at least considered before any studies measuring extracellular enzyme activity in stream waters are carried out. Such an approach will lead to conclusions from measurements that are not likely to be confounded by variables such as flow rate or time.     

The (affective) dispositional approach to job satisfaction: sorting out the policy implications

The dispositional approach to job attitudes has played an important role in refocusing attention in organizational behavior on person factors, in addition to situational factors, as determinants of job attitudes and behaviors. I focus on what have been suggested as policy implications of research on dispositions, in particular, research on affective dispositions. My reading of the evidence suggests that affective dispositional factors may be useful in employee selection, and I identify questions that need to be resolved for this case to be stronger. On the other hand, I find little in the way of logic or evidence to support the claim that dispositions constrain the success of situational interventions designed to improve employee attitudes (or behaviors). Consistent with recent developments in the personality literature and with arguments made by Gerhart and Davis‐Blake and Pfeffer in the organizational behavior literature, I show that within‐person consistency in attitudes and behaviors can coexist with mean level changes in attitudes and behaviors induced by situational changes in the workplace. Copyright © 2005 John Wiley & Sons, Ltd.     

Occurrence and human dietary assessment of sulfonamide antibiotics in cultured fish around Tai Lake,China

As the most important fishery medicines, sulfonamides are widely used to prevent diseases caused by pathogens in aquaculture. However, relatively little is known about the residues and dietary risks associated with cultured fish around Tai Lake. In the present study, a sampling strategy for a complete aquaculture period was conducted. Specifically, 12 selected sulfonamide antibiotics were measured among 116 fish samples recruited from four sampling periods, four species, four areas, and 18 fish ponds. All 12 antibiotics were detected at detection frequencies of 4.31–28.45%. Total sulfonamides were detected in 77.59% of the fish samples, with 57.76% of fish samples containing from 0.1 to 10 μg kg^?1. Sulfadiazine (SDZ), sulfamethoxazole (SMZ), sulfamethazine (SDD), and sulfamonomethoxine (SMM) were the main types of antibiotics used, and these were present at high concentrations (>100 μg kg^?1) with high occurrences, especially in the middle of the aquaculture season. Dietary assessment showed that residual antibiotics in all fish that were being sent to market were far below the maximum residue limit (MRL) of total sulfonamides and that there was almost no risk associated with fish consumption. The results of the present study will facilitate development of effective measures to produce safe aquatic products and meaningful suggestions for consuming aquatic products.     

The development of cryoprobe nuclear magnetic resonance spectroscopy for the rapid detection of organic contaminants in potable water

The detection of trace levels of a range of organic contaminants (including pesticides, toxins and an explosive) in potable water, using cryoprobe NMR spectroscopy with limited sample preparation and rapid acquisition times, is described. Emphasis is placed on the applicability of NMR spectroscopy for use in emergency scenarios as the unbiased nature of the technique facilitates the detection and characterization of unknown compounds at levels as low as 50 microg L(-1).     

Data Sharing – a Case of Shared Databases and Community Use of On-Line GIS Support Systems

Data management is becoming increasingly simple and complex at the same time. The challenge is to effectively use the increasing number of tools available to manage increasing amounts of environmental information for purposes of data capture, analysis, display, sharing and storage. Government is no longer the main collector and provider of data. Community groups possess vast amounts of data collected through daily work of monitoring the environment in their local community. The chief concerns are data access, sharing, integrity and comparability. The capacity of groups to sustain data management is the key to making the sharing possible. The Southeast Environmental Association has been working with Environment Canada to develop a community, on-line database that will be linked to other geo-spatial data sets to allow instant access to geo-referenced data.     

A combined model–observation approach to estimate historic gridded fields of PM2.5 mass and species concentrations

This paper introduces a methodology for estimating gridded fields of total and speciated fine particulate matter (PM_2.5) concentrations for time periods and regions not covered by observational data. The methodology is based on performing long-term regional scale meteorological and air quality simulations and then integrating these simulations with available observational data. To illustrate this methodology, we present an application in which year-round simulations with a meteorological model (the National Center for Atmospheric Research/Penn State Mesoscale Model, hereafter referred to as MM5) and a photochemical air quality model (the Community Multiscale Air Quality Model, hereafter referred to as CMAQ) have been performed over the northeastern United States for 1988–2005. Model evaluation results for total PM_2.5 mass and individual species for the time period from 2000 to 2005 show that model performance varies by species, season, and location. Therefore, an approach is developed to adjust CMAQ output with factors based on these three variables. The adjusted model values for total PM_2.5 mass for 2000–2005 are compared against independent measurements not utilized for the adjustment approach. This comparison reveals that the adjusted model values have a lower root mean square error (RMSE) and higher correlation coefficients than the original model values. Furthermore, the PM_2.5 estimates from these adjusted model values are compared against an alternate method for estimating historic PM_2.5 values that is based on PM_2.5/PM₁₀ ratios calculated at co-located monitors. Results reveal that both methods yield estimates of historic PM_2.5 mass that are broadly consistent; however, the adjusted CMAQ values provide greater spatial coverage and information for PM_2.5 species in addition to total PM_2.5 mass. Finally, strengths and limitations of the proposed approach are discussed in the context of potential uses of this method.