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321.
Intensive fishing can cause dramatic, long-lasting shifts in benthic habitat. This study used three approaches to test whether
overharvesting of blacklip abalone (Haliotis rubra) can cause a shift in benthic habitat to a configuration that is unsuitable for abalone, on the east coast of Tasmania, Australia.
After 18 months of removing abalone from rocks, encrusting red algae (ERA) became overgrown by filamentous and foliose algae,
sessile invertebrates and accumulated sediment. The differences in the community composition between locations, sites nested
within locations and rocks were minor. Throughout the study, abalone were largely associated with areas of rock covered in
ERA but avoided other habitats. A transplant experiment demonstrated that abalone preferred areas of rock covered in ERA but
move away from overgrown rocks. These results suggest overharvesting of abalone results in a shift to benthic habitat poorly
preferred by abalone. This could form a positive feedback loop that limits recovery of abalone populations and ERA. 相似文献
322.
Psychological ownership is increasingly recognized as a core feeling in the experience of work. Within jobs and the work context, there is a wide range of opportunities to experience psychological ownership. Yet empirical work on how feelings of ownership develop is lacking, and thus ways to develop psychological ownership in the workplace are not well understood. We explore the routes traveled to feelings of ownership by using job complexity as one example of work environment structure that affects the formation of psychological ownership. In two studies, we develop measures of the routes and confirm that perceived differences in one's work meaningfully predict psychological ownership. Collectively, the two studies provide insight into and offer suggestions for how ownership develops and ways in which managers might foster employee feelings of ownership toward their work. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
323.
Peter I. Macreadie Paul H. York Craig D. H. Sherman Michael J. Keough D. Jeff Ross Aurora M. Ricart Timothy M. Smith 《Marine Biology》2014,161(12):2939-2944
Seagrass meadows are among the most efficient and long-term carbon sinks on earth, but disturbances could threaten this capacity, so understanding the impacts of disturbance on carbon stored within seagrass meadows—‘blue carbon’—is of prime importance. To date, there have been no published studies on the impacts of seagrass loss on ‘blue carbon’ stocks. We experimentally created several kinds of small-scale disturbances, representative of common grazer and boating impacts, within seagrass (Zostera nigracaulis) meadows in Port Phillip Bay (Australia) and measured the impacts on sediment organic carbon stocks (‘C org’, and other geochemical variables—%N, δ13C, δ15N). Disturbance had no detectable effect on C org levels within seagrass sediments, even for high-intensity disturbance treatments, which remained bare (i.e. no seagrass recovery) for 2 years after the disturbance. These findings challenge the widely held assumption that disturbance and concomitant loss of seagrass habitat cause release of carbon, at least for small-scale disturbances. We suggest that larger (e.g. meadow scale) disturbances may be required to trigger losses of ‘blue carbon’ from seagrass meadows. 相似文献
324.
325.
Hydrology, roadway traffic conditions, and atmospheric deposition are three essential data categories for the planning and implementation of highway-runoff monitoring and characterization programs. Causal variables pertaining to each data category could be site specific but have been shown to correlate with runoff pollutant loads. These data categories were combined to derive statistical relationships for characterization and prioritization of the respective pollutant loads at highway runoff sites. Storm runoff data of total suspended solids (TSS), total dissolved solid (TDS), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) collected from three highway sites in Charlotte, North Carolina, USA, were used to illustrate the development of site-specific highway-runoff pollutant loading models. This unified methodology provides a basis for initial assessment of the pollutant-constituent loads from highway runoff using hydrologic component variables. Improved reliability is achievable when additional traffic and/or atmospheric component variables are incorporated into the basic hydrologic regression model. In addition, operational guidance is suggested for implementing highway-runoff monitoring programs that are subject to sampling and resources constraints. 相似文献
326.
Assessing the Effects of Nutrient Management in an Estuary Experiencing Climatic Change: The Neuse River Estuary, North Carolina 总被引:1,自引:0,他引:1
Eutrophication is a serious water quality problem in estuaries receiving increasing anthropogenic nutrient loads. Managers
undertaking nutrient-reduction strategies aimed at controlling estuarine eutrophication are faced with the challenge that
upstream freshwater segments often are phosphorus (P)-limited, whereas more saline downstream segments are nitrogen (N)-limited.
Management also must consider climatic (hydrologic) variability, which affects nutrient delivery and processing. The interactive
effects of selective nutrient input reductions and climatic perturbations were examined in the Neuse River Estuary (NRE),
North Carolina, a shallow estuary with more than a 30-year history of accelerated nutrient loading and water quality decline.
The NRE also has experienced a recent increase in Atlantic hurricanes and record flooding, which has affected hydrology and
nutrient loadings. The authors examined the water quality consequences of selective nutrient (P but not N) reductions in the
1980s, followed by N reductions in the 1990s and an increase in hurricane frequency since the mid-1990s. Selective P reductions
decreased upstream phytoplankton blooms, but increased downstream phytoplankton biomass. Storms modified these trends. In
particular, upstream annual N and P concentrations have decreased during the elevated hurricane period. Increased flushing
and scouring from storms and flooding appear to have enhanced nutrient retention capabilities of the NRE watershed. From a
management perspective, one cannot rely on largely unpredictable changes in storm frequency and intensity to negate anthropogenic
nutrient enrichment and eutrophication. To control eutrophication along the hydrologically variable freshwater–marine continuum,
N and P reductions should be applied adaptively to reflect point-source–dominated drought and non–point-source–dominated flood
conditions. 相似文献
327.
Combined effects of constant versus variable intensity simulated rainfall and reduced tillage management on cotton preemergence herbicide runoff 总被引:1,自引:0,他引:1
Potter TL Truman CC Strickland TC Bosch DD Webster TM Franklin DH Bednarz CW 《Journal of environmental quality》2006,35(5):1894-1902
Pesticide runoff research relies heavily on rainfall simulation experiments. Most are conducted at a constant intensity, i.e., at a fixed rainfall rate; however, large differences in natural rainfall intensity is common. To assess implications we quantified runoff of two herbicides, fluometuron and pendimethalin, and applied preemergence after planting cotton on Tifton loamy sand. Rainfall at constant and variable intensity patterns representative of late spring thunderstorms in the Atlantic Coastal Plain region of Georgia (USA) were simulated on 6-m2 plots under strip- (ST) and conventional-tillage (CT) management. The variable pattern produced significantly higher runoff rates of both compounds from CT but not ST plots. However, on an event-basis, runoff totals (% applied) were not significantly different, with one exception: fluometuron runoff from CT plots. There was about 25% more fluometuron runoff with the variable versus the constant intensity pattern (P = 0.10). Study results suggest that conduct of simulations using variable intensity storm patterns may provide more representative rainfall simulation-based estimates of pesticide runoff and that the greatest impacts will be observed with CT. The study also found significantly more fluometuron in runoff from ST than CT plots. Further work is needed to determine whether this behavior may be generalized to other active ingredients with similar properties [low K(oc) (organic carbon partition coefficient) approximately 100 mL g(-1); high water solubility approximately 100 mg L(-1)]. If so, it should be considered when making tillage-specific herbicide recommendations to reduce runoff potential. 相似文献
328.
Su T Shu S Shi H Wang J Adams C Witt EC 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):944-950
This study provided a comprehensive assessment of seven toxic trace elements (As, Pb, V, Cr, Cd, Cu, and Hg) in the soil/sediment of Katrina affected greater New Orleans region 1 month after the recession of flood water. Results indicated significant contamination of As and V and non-significant contamination of Cd, Cr, Cu, Hg and Pb at most sampling sites. Compared to the reported EPA Region 6 soil background inorganic levels, except As, the concentrations of other six elements had greatly increased throughout the studied area; St. Bernard Parish and Plaquemines Parish showed greater contamination than other regions. Comparison between pre- and post-Katrina data in similar areas, and data for surface, shallow, and deep samples indicated that the trace element distribution in post-Katrina New Orleans was not obviously attributed to the flooding. This study suggests that more detailed study of As and V contamination at identified locations is needed. 相似文献
329.
Jill S. Baron Lance Gunderson Craig D. Allen Erica Fleishman Donald McKenzie Laura A. Meyerson Jill Oropeza Nate Stephenson 《Environmental management》2009,44(6):1033-1042
Past and present climate has shaped the valued ecosystems currently protected in parks and reserves, but future climate change
will redefine these conditions. Continued conservation as climate changes will require thinking differently about resource
management than we have in the past; we present some logical steps and tools for doing so. Three critical tenets underpin
future management plans and activities: (1) climate patterns of the past will not be the climate patterns of the future; (2)
climate defines the environment and influences future trajectories of the distributions of species and their habitats; (3)
specific management actions may help increase the resilience of some natural resources, but fundamental changes in species
and their environment may be inevitable. Science-based management will be necessary because past experience may not serve
as a guide for novel future conditions. Identifying resources and processes at risk, defining thresholds and reference conditions,
and establishing monitoring and assessment programs are among the types of scientific practices needed to support a broadened
portfolio of management activities. In addition to the control and hedging management strategies commonly in use today, we
recommend adaptive management wherever possible. Adaptive management increases our ability to address the multiple scales
at which species and processes function, and increases the speed of knowledge transfer among scientists and managers. Scenario
planning provides a broad forward-thinking framework from which the most appropriate management tools can be chosen. The scope
of climate change effects will require a shared vision among regional partners. Preparing for and adapting to climate change
is as much a cultural and intellectual challenge as an ecological challenge. 相似文献
330.
Enforced institutional settings such as penitentiaries provide environments to raise awareness, carry out research, and implement
and assess practices for sustainable living. Institutions where residence is enforced due to health, recreational, military,
or legal reasons (e.g., assisted living centers, summer camps, army bases, prisons) house people who may lack scientific training
but have time and need for intellectual stimulation that can be filled by supervised research. These institutions have stable
populations, structured social organization, and measurable inputs and outputs of materials and energy to carry out sustainable
practices in tasks that affect regional resources such as groundwater quality and landfill use. We report on three examples
at a corrections center resulting from partnerships among visiting academic ecology researchers, sustainability practitioners,
corrections administrators, and prisoners: (1) research on how to sustainably “farm” moss for the horticulture trade to reduce
harvesting pressure on wild moss populations; (2) a vermiculture and thermophilic composting system to reduce the kitchen
waste; and (3) a monthly seminar series at the prison. Over 26 months: (1) participants developed methods to optimize moss
growth; (2) landfill-bound waste and particulate flow rate destined for wastewater treatment decreased by 50%, to less than
50% of permit limits; (3) resulting compost (ca. 5000 kg) fertilized institutional vegetable gardens; (4) water quality improved
so that the prison could return funds allocated to upgrade the prison’s water quality. The lectures encouraged intellectual
exchange among researchers, convicts, and guards. Researchers derived new perspectives and broader impacts for their work.
This can be a model for other correctional facilities and other enforced residential institutions (ERIs).
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献