Smart Growth and Sustainable Development: Challenges,solutions and policy directions

In this paper, we focus on the issues related to development densities that emerged from our study of sprawl and development issues in three regions of British Columbia, Canada. We chose to focus on this aspect of the Smart Growth agenda because, while many of its other elements enjoy wide support across social interests, the goal of achieving a higher density urban fabric is highly controversial. We proceeded by collecting data on development densities and 13 indicators of community sustainability in 26 municipalities. The results suggest that the density of communities is associated with efficiencies in infrastructure and with reduced automobile dependence, with the ecological and economic implications which flow from that. However, it does not necessarily correlate with greater affordability of housing or more access to green space. In fact, if anything, we discovered a negative relationship between housing affordability and green space per capita and higher land-use densities. In a second stage of the research, we conducted a qualitative analysis of a subset of six municipalities and identified key policy issues for moving ahead with the Smart Growth agenda. The paper concludes with a discussion of the policy issues that emerged from these case studies.     

Linking direct and indirect data on dispersal: isolation by slope in a headwater stream salamander

There is growing recognition of the need to incorporate information on movement behavior in landscape-scale studies of dispersal. One way to do this is by using indirect indices of dispersal (e.g., genetic differentiation) to test predictions derived from direct data on movement behavior. Mark-recapture studies documented upstream-biased movement in the salamander Gyrinophilus porphyriticus (Plethodontidae). Based on this information, we hypothesized that gene flow in G. porphyriticus is affected by the slope of the stream. Specifically, because the energy required for upstream dispersal is positively related to slope, we predicted gene flow to be negatively related to change in elevation between sampling sites. Using amplified DNA fragment length polymorphisms among tissue samples from paired sites in nine streams in the Hubbard Brook Watershed, New Hampshire, USA, we found that genetic distances between downstream and upstream sites were positively related to change in elevation over standardized 1-km distances. This pattern of isolation by slope elucidates controls on population connectivity in stream networks and underscores the potential for specific behaviors to affect the genetic structure of species at the landscape scale. More broadly, our results show the value of combining direct data on movement behavior and indirect indices to assess patterns and consequences of dispersal in spatially complex ecosystems.     

Mating tactics and mating system of an aquatic-mating pinniped: the harbor seal, <Emphasis Type="Italic">Phoca vitulina</Emphasis>

Our best understanding of marine mammal mating systems comes from land-mating pinnipeds. Logistical problems of observing behavior at sea have limited our ability to make inferences about species with aquatic-mating systems, which comprise over half the pinnipeds. The mating systems of these species likely involve different mating tactics than land-mating species. We used several methods in combination (e.g., animal-borne cameras, radio telemetry, time-depth recorders, and DNA paternity assessment) to provide a comprehensive study of the aquatic-mating tactics of harbor seal males. Males decreased time offshore (26.0 vs 14.8%) and increased time near shore (33.8 vs 43.7%) between premating and mating periods, respectively. Concomitantly, males reduced foraging effort and increased activities associated with competition for females (e.g., visual/vocal displays and threats). As females come into estrus near the end of lactation and spend more time at sea, males reduced their near-shore ranges (4.2 vs 1.0 km²), which were clustered within 1–1.5 km of the beach where females attended their pups. Body mass of males was not a major factor affecting their reproductive behavior. From a small number of paternity assignments to study males, it appears that females select males. These combined results are more consistent with a lek-type mating system than with the territorial or female defense systems characteristic of land-mating pinnipeds.     

Ripples in a pond: an open system model of the evolution of safety culture.

The development of an effective safety culture is essential to promote safe operations. Previous studies have either identified the characteristics of effective safety culture analytically, inferring them from signs and symbols derived from working practices, or have restricted the study of the development of safety culture to workers within an organisation. This paper describes a large-scale survey-based study in which the factors influencing the evolution of safety culture are identified empirically and, drawing upon open systems theory, are also extended beyond the bounds of the organisation. Three major determinants of safety culture are identified: safety concerns, influences and actions. Sub-components within each of these categories are also identified and the relationship between them is hypothesised.     

Integrative trophic network assessments of a lentic ecosystem by key ecological approaches of water chemistry, trophic guilds, and ecosystem health assessments along with an ECOPATH model

The objective of this study was to describe the trophic structure and energy flow in a lentic ecosystem in South Korea. Physicochemical water conditions were evaluated along with the reservoir ecosystem health using a multimetric IBI model. Nutrient analyses of the reservoir showed a nutrient rich and hypereutrophic system. Guild analysis revealed that tolerant and omnivorous species dominated the ecosystem. Tolerant fish, as a proportion of the number of individuals, were associated (R² > 0.90, p < 0.01) with TN and TP, the key indicators of trophic state in lentic ecosystems. The mean Reservoir Ecosystem Health Assessment (REHA) score was 19.3 during the study, which was judged as in ‘fair to poor’ condition. A trophic analysis of the reservoir estimated by the ECOPATH model shows that most activity in terms of energy flow occurred in the lower part of the trophic web, where there was intensive use of primary producers as a food source. Consequently, of the 10 consumer groups, nine fell within trophic levels <2.8. Trophic levels (TL) estimated from the weighted average of prey trophic levels varied from 1.0 for phytoplankton, macrophytes, and detritus to 3.25 for the top predator, Pseudobagrus fulvidraco. Our integrated approach to trophic network analysis may provide a key tool for determining the effects of nutrient influx on energy flow pathways in lentic ecosystems.     

Cytotoxicity induced by the mixture components of nickel and poly aromatic hydrocarbons

Environmental Geochemistry and Health - Although particulate matter (PM) is composed of various chemicals, investigations regarding the toxicity that results from mixing the substances in PM are...     

Resolving future fire management conflicts using multicriteria decision making

Management strategies to reduce the risks to human life and property from wildfire commonly involve burning native vegetation. However, planned burning can conflict with other societal objectives such as human health and biodiversity conservation. These conflicts are likely to intensify as fire regimes change under future climates and as growing human populations encroach farther into fire‐prone ecosystems. Decisions about managing fire risks are therefore complex and warrant more sophisticated approaches than are typically used. We applied a multicriteria decision making approach (MCDA) with the potential to improve fire management outcomes to the case of a highly populated, biodiverse, and flammable wildland–urban interface. We considered the effects of 22 planned burning options on 8 objectives: house protection, maximizing water quality, minimizing carbon emissions and impacts on human health, and minimizing declines of 5 distinct species types. The MCDA identified a small number of management options (burning forest adjacent to houses) that performed well for most objectives, but not for one species type (arboreal mammal) or for water quality. Although MCDA made the conflict between objectives explicit, resolution of the problem depended on the weighting assigned to each objective. Additive weighting of criteria traded off the arboreal mammal and water quality objectives for other objectives. Multiplicative weighting identified scenarios that avoided poor outcomes for any objective, which is important for avoiding potentially irreversible biodiversity losses. To distinguish reliably among management options, future work should focus on reducing uncertainty in outcomes across a range of objectives. Considering management actions that have more predictable outcomes than landscape fuel management will be important. We found that, where data were adequate, an MCDA can support decision making in the complex and often conflicted area of fire management.     

Can pollution tax rebates protect low-wage earners?

Pollution taxes are believed to burden low-income households that spend a greater than average share of income on pollution-intensive goods. Some proposals offset that effect by returning revenue to low-income workers via reduced labor tax. We build analytical general equilibrium models with both high-skilled and low-skilled labor, and we solve for the change in real net wage of each group. Decomposition shows the separate effects of the tax rebate, higher product prices, and the changes in relative wage rates. We also include numerical examples. Even though the pollution tax injures both types of labor, in most cases we find that returning all of the revenue to low-skilled workers is still not enough to offset higher product prices. Changes in relative wage rates may further hurt low-skilled labor. Protecting low-income workers is possible in this model only if they are defined as those below a relatively low wage threshold, but we discuss many possible elaborations of this model that could affect those results.     

Site characterization to support permeable reactive barrier design

Careful design studies and selection of an effective technique for the installation of permeable reactive barriers (PRBs) are important contributors to the overall success of zero‐valent iron PRBs. This article provides a case study summarizing the successful design and construction of a PRB installed at the former Carswell Air Force Base located in Fort Worth, Texas. Expedited site characterization using a cone penetrometer rig equipped with a mass spectrometer was employed to provide real‐time characterization and lithologic data. These data proved to be invaluable for the design of the PRB and allowed for the development of an accurate preconstruction cost estimate. Field data gained from the expedited water quality and geologic characterization along with aquifer testing and a bench‐scale treatability study provided a comprehensive basis for the design. The biopolymer slurry construction technique provided additional unanticipated benefits to the designed zero‐ valent iron treatment by promoting the development of anaerobic conditions favorable for microbial degradation of trichloroethene. Postconstruction monitoring data are discussed to illustrate the successful performance of the PRB. © 2005 Wiley Periodicals, Inc.