Ecosystem function in alluvial tailings after biosolids and lime addition

Municipal biosolids and agricultural limestone were incorporated into the surface of alluvial highly acidic, metal-contaminated mine tailings in Leadville, CO, in 1998. Amended sites were seeded and a plant cover was subsequently established. A range of chemical and biological parameters were measured over time to determine if treatment was sufficient to restore ecosystem function. An uncontaminated upstream control (UUC), a contaminated vegetated area (CVA), and soils collected from the tailings deposits before amendment addition were used for comparison. Standard soil extracts showed decreases in extractable Pb, Zn, and Cd in the amended soils. Increased CO2 evolution, reduced N2O, and elevated NO3- in the amended tailings indicated an active microbial community. Levels of CO2 and NO3- were elevated in comparison with the CVA and UUC. Ryegrass (Lolium perenne L.) and earthworm (Eisenia foetida) survival and metal uptake values were similar in amended tailings to a laboratory control soil. Ryegrass and worms in unamended tailings died. Field plant diversity was lower in amended areas than in CVA or UUC, with a higher percentage of the vegetative cover consisting of grasses. Small mammal analysis showed a low potential for elevated body Cd and Pb in the amended tailings. A re-entrainment study using fathead minnows (Pimephales promelas) showed no danger for resuspended amended tailings, as survival of fish was similar to the laboratory control. Data suggest that ecosystem function has been restored to the amended tailings, but that these systems are not yet in equilibrium.     

Flow experiences at work: for high need achievers alone?

Applying Csikszentmihalyi's ( 1990 ) flow theory of optimal experience to the workplace, two studies examined the relationships of employees' perceived skill and challenge at work and need for achievement with their positive mood, intrinsic task interest, and extra‐role performance. Among achievement‐oriented employees only, high skill and challenge was associated with greater positive mood, task interest, and performance than other skill/challenge combinations. Additionally, positive mood mediated the interactive relationship of skill/challenge and need for achievement with performance. Copyright © 2005 John Wiley & Sons, Ltd.     

Interannual differences in the relative timing of southward migration of male and female western sandpipers (Calidris mauri)

In the shorebird subfamily Calidridinae, one of the parents shortens parental care and initiates southward migration before the other. We estimated the difference in passage date between male and female western sandpipers (Calidris mauri) at their first major stopover on the southward migration from breeding areas in Alaska, in 18 years between 1978 and 2000. Overall, adult females preceded adult males by 1.22 days. A novel finding was that among juveniles, which migrate approximately a month later than adults, females preceded males by similar magnitude (1.14 days). There was wide variation among years, however, and males actually preceded females in years with late hatch. We relate these findings to hypotheses for female-first southward migration in sandpipers.     

Mediating an invisible policy problem: Nottingham’s rejection of congestion charging

ABSTRACT

This paper presents a qualitative case study of community participation in local air quality management in Nottingham (UK). We analyse Nottingham’s response to a “clean air zone” mandate: despite national government and local community support of this congestion charging policy, the City Council rejected the measure. We focus on the policy framing, with data from policy documents, interviews with government and non-government actors, and observation in local activities. We found that community groups build links with local government in two ways: (1) as a coalition against the national government and austerity measures, and (2) as “neutral”, non-expert communicators of air pollution as an “invisible” policy problem. We show how this invisibility plays a significant role in factors such as trust, risk, responsibility, and policy communication. This research has theoretical implications for the communication of air pollution and practical implications for cities looking to implement similar transport-oriented strategies.     

Measuring Suspended‐Sediment Concentration and Turbidity in the Middle Mississippi and Lower Missouri Rivers Using Landsat Data

The Middle Mississippi River (MMR) and lower Missouri River (MOR) provide critical navigation waterways, ecological habitat, and flood conveyance. They are also directly linked to processes affecting geomorphic and ecological conditions in the lower MR and Delta. For this study, a method was developed to measure suspended‐sediment concentration (SSC) and turbidity along the MMR and the lower MOR using Landsat imagery. Data from nine United States Geological Survey water‐quality monitoring stations were used to create a model‐development dataset and a model‐validation dataset. Concurrent gaging data were identified for available Landsat images to generate the datasets. Surface‐reflectance filters were developed to eliminate images with cirrus cloud coverage or vessel traffic. Using the filtered model‐development dataset, unique reflectance‐SSC and reflectance‐turbidity models were developed for three Landsat sensors: Landsat 8 Operational Land Imager, Landsat 7 Enhanced Thematic Mapper Plus, and Landsat 4–5 Thematic Mapper. Coefficient of determination values for the models ranged from 0.72 to 0.88 for the model‐development dataset. The model‐validation dataset was used to evaluate the performance of the models and had coefficient of determination values ranging from 0.62 to 0.79.     

An Ecosystem Approach to Combat Desertification on the Colorado Plateau

Desertification of shrub and grassland into pinyon-juniper woodland is occurring over much of the Colorado Plateau in the southwestern United States. As trees invade, they out-compete shrubs and grasses, increasing erosion rates and reducing infiltration of moisture into the soil. This has caused habitat problems for wildlife, and reduced forage for livestock. These impacts also affect the human communities that rely on ranching and tourism related to hunting. Past land use and management practices including heavy livestock grazing, fire suppression and introduction of exotic annual plants are believed to have led to current conditions. The Montrose office of the Bureau of Land Management has implemented an ecosystem-based program to reverse the desertification process on public land. The program is centered on detailed landscape objectives describing the desired vegetation mosaic on 360 000 ha of public land. The objectives outline proportions of plant seral stages and arrays of patch sizes for each planning unit. These objectives are based on priority management issues and the need to replicate a natural vegetation mosaic. Where the existing mosaic does not meet objectives, mechanical vegetation treatments and prescribed fire are used to create early and mid-seral patches on the ground. This restored vegetation pattern and type should be sustained over time through a natural fire regime and improved livestock management. Because many uncertainties exist, an adaptive management process is being used that allows mosaic objectives to be changed or processes modified where monitoring or scientific research indicate a need.     

CHANGES IN HYDROLOGIC RESPONSE DUE TO STREAM NETWORK EXTENSION VIA LAND DRAINAGE ACTIVITIES1

ABSTRACT: The objective of this work is to determine the effects of extension of a stream network through land drainage activities during the late 1800s on the hydrologic response of a watershed. The Mackinaw River Basin in Central Illinois was chosen as the focus and the pre‐land and post‐land drainage activity hydrologic responses were obtained through convolution of the hill slope and channel responses and compared. The hill slope response was computed using the kinematic wave model and the channel response was determined using the geomorphologic instantaneous unit hydrograph method. Our hypothesis was that the hydrologic response of the basin would exhibit the characteristic effects of settlement (i.e., increases in peak discharges and decreases in times to peak). This, indeed, is what occurred; however, the increase in peak discharges diminishes as scale increases, leaving only the decrease in times to peak. At larger scales, the dispersive effects of the longer hill slope lengths in the pre‐settlement scenario seem to balance the depressive effects of the longer path lengths in the post‐settlement scenario, thus the pre‐settlement and post‐settlement peak discharges are approximately equivalent. At small scales, the dispersion caused by the hill slope is larger in the pre‐settlement case; thus, the post‐settlement peak discharges are greater than the pre‐settlement.     

Networks of Co-operation and Knowledge in 'Wider Countryside' Planning

Approaches to biodiversity and catchment planning increasingly recognize the importance of the 'wider countryside' rather than the more site-specific focus of traditional environmental management programmes. Biodiversity depends on the viability of ecosystems across the whole countryside, and not only in designated reserves; equally, the quantity and quality of inland waters reflect overall conditions within river catchments, as well as the hydrological conditions of specific river channels. However, planning of these wider areas involves partnerships and agreements between a range of actors, which generally must be negotiated on a consensual basis and are vulnerable to subsequent dissent. This paper examines the actor-networks which have arisen in some innovative examples of 'wider countryside' planning and assesses their durability and contribution to the attainment of environmental objectives.