Comparing spatial conservation prioritization methods with site- versus spatial dependency-based connectivity

Larval dispersal is an important component of marine reserve networks. Two conceptually different approaches to incorporate dispersal connectivity into spatial planning of these networks exist, and it is an open question as to when either is most appropriate. Candidate reserve sites can be selected individually based on local properties of connectivity or on a spatial dependency-based approach of selecting clusters of strongly connected habitat patches. The first acts on individual sites, whereas the second acts on linked pairs of sites. We used a combination of larval dispersal simulations representing different seascapes and case studies of biophysical larval dispersal models in the Coral Triangle region and the province of Southeast Sulawesi, Indonesia, to compare the performance of these 2 methods in the spatial planning software Marxan. We explored the reserve design performance implications of different dispersal distances and patterns based on the equilibrium settlement of larvae in protected and unprotected areas. We further assessed different assumptions about metapopulation contributions from unprotected areas, including the case of 100% depletion and more moderate scenarios. The spatial dependency method was suitable when dispersal was limited, a high proportion of the area of interest was substantially degraded, or the target amount of habitat protected was low. Conversely, when subpopulations were well connected, the 100% depletion was relaxed, or more habitat was protected, protecting individual sites with high scores in metrics of connectivity was a better strategy. Spatial dependency methods generally produced more spatially clustered solutions with more benefits inside than outside reserves compared with site-based methods. Therefore, spatial dependency methods potentially provide better results for ecological persistence objectives over enhancing fisheries objectives, and vice versa. Different spatial prioritization methods of using connectivity are appropriate for different contexts, depending on dispersal characteristics, unprotected area contributions, habitat protection targets, and specific management objectives. Comparación entre los métodos de priorización de la conservación espacial con sitio y la conectividad espacial basada en la dependencia     

Antecedents and consequences of relational components of the new psychological contract

The literature regarding the new psychological contract suggests that the traditional paternalistic employer–employee relationship in U.S. companies has eroded. We investigated the relationship between relational components of the new psychological contract (personal responsibility for career development, commitment to type of work, and expectations of job insecurity), work experiences (involuntary job loss, organizational change, voluntary job change, and violation of obligations), and work outcomes (job satisfaction, participation in development activities, and intention to remain with the employer). We hypothesized that managerial and professional employees' level of agreement with relational components of the new psychological contract would mediate the relationship between their work experiences and work outcomes. In partial support of the model, we found that level of agreement with relational components of the new psychological contract mediated the relationship between work experiences and intention to remain with the employer and job satisfaction. Contrary to the model, no relationship was found among work experiences, level of agreement with relational components of the new psychological contract, and participation in development activities. Copyright © 1999 John Wiley & Sons, Ltd.     

Is career management related to employee development and performance?

The career management process involves career exploration, development of career goals, and use of career strategies to obtain career goals. The relationship between different aspects of the career management process and employee development behavior and performance was examined in this study. Employees provided information concerning their personal characteristics, career management strategies, their manager's support for career development, and willingness to participate in development activities. Managers provided ratings of each employee's job performance and developmental behavior. Position, manager's support for development, environmental exploration, and distance from career goal explained significant variance in employees' willingness to participate in development activities and developmental behavior. Career management was not significantly related to performance ratings. Research and practical implications of the study findings are discussed.     

Fine-scale habitat modeling of a top marine predator: do prey data improve predictive capacity?

Predators and prey assort themselves relative to each other, the availability of resources and refuges, and the temporal and spatial scale of their interaction. Predictive models of predator distributions often rely on these relationships by incorporating data on environmental variability and prey availability to determine predator habitat selection patterns. This approach to predictive modeling holds true in marine systems where observations of predators are logistically difficult, emphasizing the need for accurate models. In this paper, we ask whether including prey distribution data in fine-scale predictive models of bottlenose dolphin (Tursiops truncatus) habitat selection in Florida Bay, Florida, U.S.A., improves predictive capacity. Environmental characteristics are often used as predictor variables in habitat models of top marine predators with the assumption that they act as proxies of prey distribution. We examine the validity of this assumption by comparing the response of dolphin distribution and fish catch rates to the same environmental variables. Next, the predictive capacities of four models, with and without prey distribution data, are tested to determine whether dolphin habitat selection can be predicted without recourse to describing the distribution of their prey. The final analysis determines the accuracy of predictive maps of dolphin distribution produced by modeling areas of high fish catch based on significant environmental characteristics. We use spatial analysis and independent data sets to train and test the models. Our results indicate that, due to high habitat heterogeneity and the spatial variability of prey patches, fine-scale models of dolphin habitat selection in coastal habitats will be more successful if environmental variables are used as predictor variables of predator distributions rather than relying on prey data as explanatory variables. However, predictive modeling of prey distribution as the response variable based on environmental variability did produce high predictive performance of dolphin habitat selection, particularly foraging habitat.     

Northern Rivers Ecosystem Initiative: Nutrients and Dissolved Oxygen – Issues and Impacts

Anthropogenic inputs of nitrogen (N), phosphorus (P) and oxygen-consuming material to aquatic ecosystems can change nutrient dynamics, deplete oxygen, and change abundance and diversity of aquatic plants and animals. The Northern Rivers Ecosystem Initiative required a research and assessment program to establish the contribution of pulp mill and sewage discharges to eutrophication and depressions in dissolved oxygen (DO) in the Athabasca and Wapiti rivers of northern Alberta, Canada and examine the adequacy of existing guidelines for protecting these systems. Analysis of long-term data showed that total N (TN) and total P (TP) concentrations in exposed river reaches exceeded concentrations in reference reaches by ≤ 2 times for the Athabasca River, and by 9.6 (TP) and 2.6 (TN) times for the Wapiti River. Results from nutrient limitation experiments conducted in situ and in mesocosms showed that benthic algal production was nutrient sufficient downstream of pulp mill discharges but constrained in upper river reaches by insufficient P (Athabasca River) or N + P (Wapiti River). Dissolved oxygen (DO) concentrations in both rivers declined during winter such that median concentrations in the Athabasca River 945 km downstream of the headwaters were approximately 8 mg L⁻¹ in mid-February. Although water column DO rarely approached the guideline of 6.5 mg L⁻¹, DO studies undertaken in the Wapiti River showed that pore water DO often failed to meet this guideline and could not be predicted from water column DO. Results from this integrated program of monitoring and experimentation have improved understanding of the interactions between nutrients, DO and aquatic ecosystem productivity and resulted in recommendations for revisions to nutrient and DO guidelines for these northern rivers.The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.     

Airborne exposure and biological monitoring of bar and restaurant workers before and after the introduction of a smoking ban

The aims were to assess the impact of a total smoking ban on the level of airborne contaminants and the urinary cotinine levels in the employees in bars and restaurants. In a follow up design, 13 bars and restaurants were visited before and after the implementation of a smoking ban. Ninety-three employees in the establishments were initially included into the study. The arithmetic mean concentration of nicotine and total dust declined from 28.3 microg m(-3) (range, 0.4-88.0) and 262 microg m(-3) (range, 52-662), respectively, to 0.6 microg m(-3) (range, not detected-3.7) and 77 microg m(-3) (range, not detected-261) after the smoking ban. The Pearson correlation coefficient between airborne nicotine and total dust was 0.86 (p < 0.001; n = 48). The post-shift geometric mean urinary cotinine concentration declined from 9.5 microg g(-1) creatinine (cr) (95% CI 6.5-13.7) to 1.4 microg g(-1) cr (95% CI 0.8-2.5) after the ban (p < 0.001) in 25 non-snuffing non-smokers. A reduction from 1444 microg g(-1) cr (95% CI 957-2180) to 688 microg g(-1) cr (95% CI 324-1458) was found (p < 0.05) in 29 non-snuffing smokers. The urinary cotinine levels increased from 11.7 microg g(-1) cr (95% CI 7.0-19.6) post-shift to 21.9 microg g(-1) cr (95% CI 13.3-36.3) (p < 0.01) in the next morning in 24 non-snuffing non-smokers before the smoking ban. A substantial reduction of airborne nicotine and total dust was observed after the introduction of a smoking ban in bars and restaurants. The urinary cotinine levels were reduced in non-smokers. The decline found in smokers may suggest a reduction in the amount of smoking after intervention. In non-smokers cotinine concentrations were higher based on urine sampled the morning after a shift than based on urine sampled immediately post-shift.     

Relations between macroinvertebrates, nutrients, and water quality criteria in wadeable streams of Maryland, USA

In an ongoing effort to propose biologically protective nutrient criteria, we examined how total nitrogen (TN) and its forms were associated with macroinvertebrate communities in wadeable streams of Maryland. Taxonomic and functional metrics of an index of biological integrity (IBI) were significantly associated with multiple nutrient measures; however, the highest correlations with nutrients were for ammonia-N and nitrite-N and among macroinvertebrate measures were for Beck’s Biotic Index and its metrics. Since IBI metrics showed comparatively less association, we evaluated how macroinvertebrate taxa related to proposed nutrient criteria previously derived for those same streams instead of developing nutrient–biology thresholds. We identified one tolerant and three intolerant taxa whose occurrence appeared related to a TN benchmark. Individually, these taxa poorly indicated whether streams exceeded the benchmark, but combining taxa notably improved classification rates. We then extracted major physiochemical gradients using principal components analysis to develop models that assessed their influence on nutrient indicator taxa. The response of intolerant taxa was predominantly influenced by a nutrient-forest cover gradient. In contrast, habitat quality had a greater effect on tolerant taxa. When taxa were aggregated into a nutrient sensitive index, the response was primarily influenced by the nutrient-forest gradient. Multiple lines of evidence highlight the effects of excessive nutrients in streams on macroinvertebrate communities and taxa in Maryland, whose loss may not be reflected in metrics that form the basis of biological criteria. Refinement of indicator taxa and a nutrient-sensitive index is warranted before thresholds in aquatic life to water quality are quantified.     

Invasive species change detection using artificial neural networks and CASI hyperspectral imagery

For monitoring and controlling the extent and intensity of an invasive species, a direct multi-date image classification method was applied in invasive species (salt cedar) change detection in the study area of Lovelock, Nevada. With multidate Compact Airborne Spectrographic Imager (CASI) hyperspectral data sets, two types of hyperspectral CASI input data and two classifiers have been examined and compared for mapping and monitoring the salt cedar change. The two types of input data are all two-date original CASI bands and 12 principal component images (PCs) derived from the two-date CASI images. The two classifiers are an artificial neural network (ANN) and linear discriminant analysis (LDA). The experimental results indicate that (1) the direct multitemporal image classification method applied in land cover change detection is feasible either with original CASI bands or PCs, but a better accuracy was obtained from the CASI PCA transformed data; (2) with the same inputs of 12 PCs, the ANN outperforms the LDA due to the ANN’s non-linear property and ability of handling data without a prerequisite of a certain distribution of the analysis data.     

Using Multiple Taxonomic Groups to Index the Ecological Condition of Lakes

Biological indicators of communitiestypically reflect a common environmental signalreflecting the general condition of the ecosystem, as well asindividual signals by indicators differentiallysensitive to particular environmental conditions. Wedescribe here a method of integrating and interpretingsuch indicators from 19 New England lakes for fivetaxonomic groups (diatoms, benthos, zooplankton, fish,and birds). Our approach provides a systematicstandardized way to integrate multiple metrics fromdifferent taxonomic groups by addressing four elementscrucial to analyzing data from multiple indicators: covariate control, re-scaling of data, standardizing the sign of responses, and dimensional reduction. We evaluated the biologicalmetrics against individual environmental stressors andagainst multivariate physicochemical metricscharacterizing general anthropogenic stress among thelakes. The method detected a response to variationin the gross environmental condition of the lakes thatwas correlated across taxa and metrics. In addition,a differential response to near shore conditions wasdemonstrated for fish. The success of the approach inthis study lends support to its general application toecological monitoring involving complex data sets.