Assessing post-industrial land cover change at the Pine Point Mine,NWT, Canada using multi-temporal Landsat analysis and landscape metrics

This study investigates land cover change near the abandoned Pine Point Mine in Canada’s Northwest Territories. Industrial mineral development transforms local environments, and the effects of such disturbances are often long-lasting, particularly in subarctic, boreal environments where vegetation conversion can take decades. Located in the Boreal Plains Ecozone, the Pine Point Mine was an extensive open pit operation that underwent little reclamation when it shut down in 1988. We apply remote sensing and landscape ecology methods to quantify land cover change in the 20 years following the mine’s closure. Using a time series of near-anniversary Landsat images, we performed a supervised classification to differentiate seven land cover classes. We used raster algebra and landscape metrics to track changes in land cover composition and configuration in the 20 years since the mine shut down. We compared our results with a site in Wood Buffalo National Park that was never subjected to extensive anthropogenic disturbance. This space-for-time substitution provided an analog for how the ecosystem in the Pine Point region might have developed in the absence of industrial mineral development. We found that the dense conifer class was dominant in the park and exhibited larger and more contiguous patches than at the mine site. Bare land at the mine site showed little conversion through time. While the combination of raster algebra and landscape metrics allowed us to track broad changes in land cover composition and configuration, improved access to affordable, high-resolution imagery is necessary to effectively monitor land cover dynamics at abandoned mines.     

Environmental benchmarks vs. ecological benchmarks for assessment and monitoring in Canada: Is there a difference?

Environmental benchmarks are widely used in Canadian environmental assessment as a standard against which to monitor air or water quality in response to human activities in the environment. Recent work in Canada has developed the concept of ecological benchmarks as a complement to environmental benchmarks. However, implementation of ecological benchmarks may be challenging. This paper presents an analogy between ecological benchmarks and the more commonly used environmental benchmarks, as an attempt to increase understanding and use of ecological benchmarks in resource management, assessment, and monitoring. Ecological benchmarks, and their corresponding indicators, will be challenging to identify and use. However, through the use of the principles of adaptive management, effective ecological indicators and benchmarks can be established. Although it is essential that ecological benchmarks are site-specific, the analogy and general principles outlined here are applicable to assessment and monitoring in any part of the world.     

Effects of chronic ammonium sulfate treatment on the forest at the Bear Brook Watershed in Maine

At the Bear Brook Watershed in Maine (BBWM), the forest tree composition was characterized and the effects of the chronic ammonium sulfate ((NH₄)₂SO₄) treatment on basal area growth, foliar chemistry, and gas exchange were investigated on forest species. The BBWM is a paired watershed forest ecosystem study with one watershed, West Bear (WB), treated since 1989 with 26.6 kg N ha^???1 year^???1 and 30 kg S ha^???1 year^???1applied bimonthly as (NH₄)₂SO₄, while the other watershed, East Bear (EB), serves as a reference. Tree species richness, density, and mortality were found to be similar between watersheds. Basal area increment was estimated from red spruce and sugar maple, showing that, for the first 7 years of treatment, it was significantly higher for sugar maple growing in WB compared to EB, but no differences were observed for red spruce between watersheds. However, the initial higher sugar maple basal area growth in WB subsequently decreased after 8 years of treatment. Foliar chemical analysis performed in trees, saplings, and ground flora showed higher N concentrations in the treated WB compared to the reference EB. But, foliar cation concentrations, especially Ca and Mg, were significantly lower for most of the species growing in WB compared with those growing in EB. For sugar maple, foliar N was higher on WB, but there were no differences in foliar Ca and Mg concentrations between treated and reference watersheds. In addition, only sugar maple trees in the treated WB showed significantly higher photosynthetic rates compared to reference EB trees.     

Organizational career development is not dead: a case study on managing the new career during organizational change

New forms of careers have received increased attention in contemporary organizational research. A prominent focus in this research has been whether and how, in an increasingly unpredictable career environment, individuals are taking responsibility for their own career development. The implication is that career is becoming less central to organizational management practices. At the same time there is evidence that organizational changes typically described in this literature (such as delayering the organization in a quest for flexibility) have had a negative impact on career progress, resulting in resistance to change. The implication here is that career concerns are more central to organizational management practices. This in‐depth qualitative case study examines whether individuals do in fact take more responsibility for their career development during times of organizational change. We also examine whether this does indeed mean that the organization takes less responsibility for career management. Our data indicate that individuals are, in fact, taking more responsibility for their own careers. At the same time we found that the organization in our case study also became more actively involved in career development and management. However, this active approach did not resemble traditional top‐down career management and development. To us, the pattern of organizational and individual career development actions appear to constitute a kind of ‘organizational dance,’ a highly interactive mutual influence process, in which both parties are at once the agent and the target of career influence. Strengths and limitations of the study are discussed, as are directions for future research. Copyright © 2007 John Wiley & Sons, Ltd.     

Nitrate and nitric acid concentrations at two Rocky Mountain baseline monitoring sites

A two-tiered, Teflon/nylon filterpack system was used to characterize spatial and temporal patterns of particulate nitrates and nitric acid vapors at two monitoring sites in the Rocky Mountains. Geometric means for particulate nitrates were 38.9 and 52.8 ng/m(3) for the upper and lower sites, respectively. For nitric acid, geometric means of 70.4 ng/m(3) for the upper site and 295 ng/m(3) for the lower site were observed. The relatively low concentrations found at these two sites are comparable to published values for these materials at other remote sites. Atmospheric concentrations of nitrates and nitric acid were correlated significantly at each site, and the total nitrate concentrations (NO(3)(-) plus HNO(3)) were correlated between sites. Comparisons between the two sites indicate that nitric acid concentrations were statistically greater at the lower elevation site, whereas nitrate concentrations were not significantly different. No general seasonal or annual pattern of nitrate or nitric acid concentrations were evident when comparable sampling periods were examined.     

Ecosystem monitoring at global baseline sites

Integrated ecosystem and pollutant monitoring is being conducted at prototype global baseline sites in remote areas of the Noatak National Preserve, Alaska, the Wind River Mountains, Wyoming, and Torres del Paine National Park, Chile. A systems approach has been used in the design of these projects. This approach includes: (1) evaluation of source-receptor relationships, (2) multimedia (i.e., air, water, soil, biota) monitoring of key contaminant pathways within the environment, (3) the use of selected ecosystem parameters to detect anthropogenic influence, and (4) the application of a systems conceptual framework as a heuristic tool.Initial short-term studies of air quality (e.g. SO₂, NO₂) plus trace metal concentrations in mosses generally indicate pristine conditions at all three of the above sites as expected although trace metals in mosses were higher at the Wyoming site. Selected ecosystem parameters for both terrestrial (e.g. litter decomposition) and aquatic (e.g. shredders, a macroinvertebrate functional feeding group) habitats at the Wyoming site reflected baseline conditions when compared to other studies.Plans also are being made to use U.S. Department of Energy Research Parks for global change monitoring. This will involve cross-site analyses of existing ecological databases and the design of a future monitoring network based on a systems approach as outlined in this paper.