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271.
Research shows that public commitment making helps promote pro-environmental behavior. However, not everyone may be willing to make such commitments. Therefore, it is important to investigate the conditions under which commitment making is likely to occur. We expected dispositional trust and situational expectations to determine the willingness to install a system of public commitments. Two studies are presented which show that group members low in dispositional trust (low trusters) are likely to choose for a public commitment system when their situational expectations concerning other group members' contributions are high, while those high in dispositional trust (high trusters) are likely to choose for a public commitment system when their situational expectations concerning other group members' contributions are low. It appears that for both low and high trusters the choice for a system of public commitments is instigated by a motivation to further the collective outcomes. 相似文献
272.
Linking Theory and Practice for Restoration of Step-Pool Streams 总被引:1,自引:0,他引:1
Chin A Anderson S Collison A Ellis-Sugai BJ Haltiner JP Hogervorst JB Kondolf GM O'Hirok LS Purcell AH Riley AL Wohl E 《Environmental management》2009,43(4):645-661
Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in
theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches
into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due
to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance
stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences,
however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration
using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following
restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural
adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential
development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel
form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest,
Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural
scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded
a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate
how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world
settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of
design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning
appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing
theoretical work. 相似文献
273.
Katja Kangas Anne Tolvanen Tarja Kälkäjä Pirkko Siikamäki 《Environmental management》2009,44(3):408-419
Outdoor recreation and nature-based tourism represent an increasingly intensive form of land use that has considerable impacts
on native ecosystems. The aim of this paper is to investigate how revegetation and management of ski runs influence soil nutrients,
vegetation characteristics, and the possible invasion of nonnative plant species used in revegetation into native ecosystems.
A soil and vegetation survey at ski runs and nearby forests, and a factorial experiment simulating ski run construction and
management (factors: soil removal, fertilization, and seed sowing) were conducted at Ruka ski resort, in northern Finland,
during 2003–2008. According to the survey, management practices had caused considerable changes in the vegetation structure
and increased soil nutrient concentrations, pH, and conductivity on the ski runs relative to nearby forests. Seed mixture
species sown during the revegetation of ski runs had not spread to adjacent forests. The experimental study showed that the
germination of seed mixture species was favored by treatments simulating the management of ski runs, but none of them could
eventually establish in the study forest. As nutrient leaching causes both environmental deterioration and changes in vegetation
structure, it may eventually pose a greater environmental risk than the spread of seed mixture species alone. Machine grading
and fertilization, which have the most drastic effects on soils and vegetation, should, therefore, be minimized when constructing
and managing ski runs. 相似文献
274.
Natalie A. Jones Pascal Perez Thomas G. Measham Gail J. Kelly Patrick d’Aquino Katherine A. Daniell Anne Dray Nils Ferrand 《Environmental management》2009,44(6):1180-1195
Participatory modeling is increasingly recognized as an effective way to assist collective decision-making processes in the
domain of natural resource management. This article introduces a framework for evaluating projects that have adopted a participatory
modeling approach. This evaluation framework—known as the “Protocol of Canberra”—was developed through a collaboration between
French and Australian researchers engaged in participatory modeling and evaluation research. The framework seeks to assess
the extent to which different participatory modeling initiatives not only modify perceptions among and interactions between
participants, but also contribute to collective decision-making. The article discusses the development of the framework and
it’s application to three case-studies, two from Australia and one from the Pacific Island of the Republic of Kiribati. The
article concludes with some comments for future use of the framework in a range of participatory modeling contexts. 相似文献
275.
Vives I Canuti E Castro-Jiménez J Christoph EH Eisenreich SJ Hanke G Huber T Mariani G Mueller A Skejo H Umlauf G Wollgast J 《Journal of environmental monitoring : JEM》2007,9(6):589-598
Samples of air (gas and particulate phases), bulk deposition, aquatic settling material and sediments were collected in Lake Maggiore (LM) in order to determine their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Air (gas and particulate phases) concentrations were 0.5 pg m(-3), 80 pg m(-3), 13 pg m(-3) and 106 pg m(-3) for SigmaPCDD/Fs, SigmaPCBs, Sigma dioxin-like PCBs (DL-PCBs) and SigmaPBDEs, respectively. Deposition fluxes ranged from 0.7 ng m(-2) d(-1) for SigmaPCDD/Fs to 32 ng m(-2) d(-1) for SigmaPCBs. Aquatic settling material presented concentrations of 0.4 ng g(-1) dry weight (dw) for SigmaPCDD/Fs, 13 ng g(-1) dw for SigmaPCB, 3.4 ng g(-1) dw for SigmaDL-PCBs and 5.7 ng g(-1) dw for SigmaPBDEs. Mean sediment concentrations were 0.4 ng g(-1) dw for SigmaPCDD/Fs, 11 ng g(-1) dw for SigmaPCB, 3 ng g(-1) dw for SigmaDL-PCBs and 5.1 ng g(-1) dw for SigmaPBDEs. Similar PCDD/F and DL-PCB congener patterns in all the environmental compartments of LM point to an important, if not dominant, contribution of atmospheric deposition as source of these pollutants into LM. In contrast, PBDE congener distribution was not similar in the different environmental compartments. BDE 47 dominated air and settling material, while BDE 209 was the predominant congener in the bulk atmospheric deposition. Moreover, sediments showed two distinct PBDE congener profiles. Lower PBDE concentrated sediments were dominated by congeners 47 and 99, while BDE 209 dominated in higher PBDE concentrated samples. This suggests the influence of local sources as well as atmospheric input of PBDEs into LM. 相似文献
276.
Molecular methods are useful both to monitor natural communities of bacteria, and to track specific bacterial markers in complex environments. Length-heterogeneity polymerase chain reaction (LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP) of 16S rDNAs discriminate among 16S rRNA genes based on length polymorphisms of their PCR products. With these methods, we developed an alternative indicator that distinguishes the source of fecal pollution in water. We amplify 16S rRNA gene fragments from the fecal anaerobic genus Bacteroides with specific primers. Because Bacteroides normally resides in gut habitats, its presence in water indicates fecal pollution. Molecular detection circumvents the complexities of growing anaerobic bacteria. We identified Bacteroides LH-PCR and T-RFLP ribosomal DNA markers unique to either ruminant or human feces. The same unique fecal markers were recovered from polluted natural waters. We cloned and sequenced the unique markers; marker sequences were used to design specific PCR primers that reliably distinguish human from ruminant sources of fecal contamination. Primers for more species are under development. This approach is more sensitive than fecal coliform assays, is comparable in complexity to standard food safety and public health diagnostic tests, and lends itself to automation and high-throughput. Thus molecular genetic markers for fecal anaerobic bacteria hold promise for monitoring bacterial pollution and water quality. 相似文献
277.
278.
Anthony S. Pait S. Ian Hartwell Andrew L. Mason Robert A. Warner Christopher F. G. Jeffrey Anne M. Hoffman Dennis A. Apeti Simon J. Pittman 《Environmental monitoring and assessment》2014,186(8):4793-4806
The St. Thomas East End Reserves or STEER is located on the southeastern end of the island of St. Thomas, USVI. The STEER contains extensive mangroves and seagrass beds, along with coral reefs, lagoons, and cays. Within the watershed, however, are a large active landfill, numerous marinas, resorts, various commercial activities, an EPA Superfund Site, and residential areas, all of which have the potential to contribute pollutants to the STEER. As part of a project to develop an integrated assessment for the STEER, 185 chemical contaminants were analyzed in sediments from 24 sites. Higher levels of chemical contaminants were found in Mangrove Lagoon and Benner Bay in the western portion of the study area. The concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), zinc, copper, lead, and mercury were above a NOAA Effects Range-Low (ERL) sediment quality guideline at one or more sites, indicating impacts may be present in more sensitive species or life stages. Copper at one site in Benner Bay was above a NOAA Effects Range-Median (ERM) guideline indicating effects on benthic organisms were likely. The antifoulant boat hull ingredient tributyltin (TBT) was found at the third highest concentration in the history of NOAA’s National Status and Trends (NS&T) Program, which monitors the nation’s coastal and estuarine waters for chemical contaminants and bioeffects. The results from this project will provide resource managers with key information needed to make effective decisions affecting coral reef ecosystem health and gauge the efficacy of restoration activities. 相似文献
279.
Building inductively on twenty-four in depth interviews, the authors argue that boundaryless organizations will alter both career theories and actual career mobility patterns. The paper illustrates how both organizational and population level learning can affect individual job transitions within and cross organizations. The three evolutionary learning steps of variation, selection and retention all remain important, but the impact of variation processes may increase. Boundaryless organizations will thus generate career patterns reflecting an underlying logic of organizational learning rather than producing simple atomistic exchange between unfettered actors. 相似文献
280.
Summary Dwarf mongooses in the Taru desert region of Kenya form foraging communities with a variety of endemic bird species, especially hornbills. The prey spectra of the mongooses and hornbills overlap almost completely. For the other bird species forming the foraging community only partial overlap exists. The association between the birds and mongooses is actively sought by both parties. The birds wait in tress around the termite mound where the monogooses are sleeping for them to emerge and the mongooses delay their foraging departure if no birds are present. There is a positive relationship between the number of mongooses in the group and the number of birds accompanying them. A true mutualism only exists between the mongooses and the two hornbill species Tockus deckeni and T. flavirostris since their presence or arrival affects the subsequent start of foraging. These two hornbill species have also been observed to influence the start of foraging actively by means of two behaviour patterns termed chivvying and waking. Both the mongooses and birds are exposed to a high predator pressure from raptors with an overlap in the birds of prey predating the various species. This predator pressure is counteracted behaviourally by the mongooses by means of an altruistic behaviour pattern, guarding. Both mongooses and birds warn vocally and flee when a raptor is sighted. The mongooses modify their guarding behaviour to compensate for the warning behaviour of the birds in two ways: (a) fewer mongooses guard when large numbers of birds are present and vice versa, (b) the frequency of the mongooses' intraspecific warning calls is significantly reduced in cases where birds are present in comparison with those where they are absent. The birds also sight and respond to the raptor first on significantly more occasions than the mongooses. In addition, the birds also warn for raptor species which do not predate them but which are mongoose predators, not, however, for raptors which are not mongoose predators. This mutualistic association with its high degree of compensatory behaviour by both parties appears to be unique for free-living vertebrates and has its closest parallel in the trophobiosis described for ants and aphids. 相似文献