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201.
Resource management issues continually change over time in response to coevolving social, economic, and ecological systems.
Under these conditions adaptive management, or “learning by doing,” offers an opportunity for more proactive and collaborative
approaches to resolving environmental problems. In turn, this will require the implementation of learning-based extension
approaches alongside more traditional linear technology transfer approaches within the area of environmental extension. In
this paper the Integrated Systems for Knowledge Management (ISKM) approach is presented to illustrate how such learning-based
approaches can be used to help communities develop, apply, and refine technical information within a larger context of shared
understanding. To outline how this works in practice, we use a case study involving pest management. Particular attention
is paid to the issues that emerge as a result of multiple stakeholder involvement within environmental problem situations.
Finally, the potential role of the Internet in supporting and disseminating the experience gained through ongoing adaptive
management processes is examined. 相似文献
202.
乐安江沉积物酸可挥发硫化物含量及溶解氧对重金属释放特性的影响 总被引:13,自引:1,他引:13
本研究进行了乐安江沉积物不同溶解氧浓度条件下的重金属释放实验和沉积物样品酸可挥发硫化物(AVS)及同时可提取金属浓度(SEM)的测定。结果表明,乐安江沉积物中AVS含量较低,沉积物中重金属在存在再释放的可能性,铁锰氧化和可能是乐安江沉积结合重金属的主要成分。 相似文献
203.
Hermanutz RO Hedtke SF Arthur JW Andrew RW Allen KN Helgen JC 《Environmental pollution (Barking, Essex : 1987)》1987,47(4):249-283
Laboratory data on ammonia effects, the US EPA national water quality criteria for ammonia, and ammonia site-specific criteria were evaluated in four outdoor experimental streams (one control and three treatment streams) over a 76-week period. Calculated un-ionised ammonia concentrations varied daily and seasonally according to pH and temperature changes. Populations of four major microinvertebrate taxonomic groups (cladocerans, copepods, rotifers and protozoans) were monitored during a 4-week period early in the study, and six fish species (fathead minnows, bluegills, channel catfish, white suckers, walleyes, and rainbow trout) were tested for various time intervals, from 4 to 26 weeks, throughout the 76-week study period. Copepods and rotifers were unaffected in all three treatment streams, based on comparisons with the control stream. Cladoceran and protozoan populations were reduced in at least two treatment streams, but because of large variability, effects were considered to be inconclusive. However, complete mortality of cladocerans did occur in the high and medium treatments when placed in in situ biomonitor chambers. All six fish species were affected in one or more treatments. Generally, the fish effect values agreed with most laboratory effect values. Of 12 fish groups tested, one channel catfish group and one white sucker group were affected below the recommended protection levels of the national and site-specific criteria. The lowest effect concentrations tested for the other ten groups occurred above the criteria levels. 相似文献
204.
Integrating lidar and satellite optical depth with ambient monitoring for 3-dimensional particulate characterization 总被引:3,自引:0,他引:3
Jill A. Engel-Cox Raymond M. Hoff Raymond Rogers Fred Dimmick Alan C. Rush James J. Szykman Jassim Al-Saadi D. Allen Chu Erica R. Zell 《Atmospheric environment (Oxford, England : 1994)》2006,40(40):8056-8067
A combination of in-situ PM2.5, sunphotometers, upward pointing lidar and satellite aerosol optical depth (AOD) instruments have been employed to better understand variability in the correlation between AOD and PM2.5 at the surface. Previous studies have shown good correlation between these measures, especially in the US east, and encouraged the use of satellite data for spatially interpolating between ground sensors. This work shows that cases of weak correlation can be better understood with knowledge of whether the aerosol is confined to the surface planetary boundary layer (PBL) or aloft. Lidar apportionment of the fraction of aerosol optical depth that is within the PBL can be scaled to give better agreement with surface PM2.5 than does the total column amount. The study has shown that lidar combined with surface and remotely sensed data might be strategically used to improve our understanding of long-range or regionally transported pollutants in multiple dimensions. 相似文献
205.
An agenda for assessing and improving conservation impacts of sustainability standards in tropical agriculture
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Jeffrey C. Milder Margaret Arbuthnot Allen Blackman Sharon E. Brooks Daniele Giovannucci Lee Gross Elizabeth T. Kennedy Kristin Komives Eric F. Lambin Audrey Lee Daniel Meyer Peter Newton Ben Phalan Götz Schroth Bambi Semroc Henk Van Rikxoort Michal Zrust 《Conservation biology》2015,29(2):309-320
Sustainability standards and certification serve to differentiate and provide market recognition to goods produced in accordance with social and environmental good practices, typically including practices to protect biodiversity. Such standards have seen rapid growth, including in tropical agricultural commodities such as cocoa, coffee, palm oil, soybeans, and tea. Given the role of sustainability standards in influencing land use in hotspots of biodiversity, deforestation, and agricultural intensification, much could be gained from efforts to evaluate and increase the conservation payoff of these schemes. To this end, we devised a systematic approach for monitoring and evaluating the conservation impacts of agricultural sustainability standards and for using the resulting evidence to improve the effectiveness of such standards over time. The approach is oriented around a set of hypotheses and corresponding research questions about how sustainability standards are predicted to deliver conservation benefits. These questions are addressed through data from multiple sources, including basic common information from certification audits; field monitoring of environmental outcomes at a sample of certified sites; and rigorous impact assessment research based on experimental or quasi‐experimental methods. Integration of these sources can generate time‐series data that are comparable across sites and regions and provide detailed portraits of the effects of sustainability standards. To implement this approach, we propose new collaborations between the conservation research community and the sustainability standards community to develop common indicators and monitoring protocols, foster data sharing and synthesis, and link research and practice more effectively. As the role of sustainability standards in tropical land‐use governance continues to evolve, robust evidence on the factors contributing to effectiveness can help to ensure that such standards are designed and implemented to maximize benefits for biodiversity conservation. 相似文献
206.
Robert F. Herrick James H. Stewart Joseph G. Allen 《Environmental science and pollution research international》2016,23(3):1975-1985
PCBs in building materials such as caulks and sealants are a largely unrecognized source of contamination in the building environment. Schools are of particular interest, as the period of extensive school construction (about 1950 to 1980) coincides with the time of greatest use of PCBs as plasticizers in building materials. In the USA, we estimate that the number of schools with PCB in building caulk ranges from 12,960 to 25,920 based upon the number of schools built in the time of PCB use and the proportion of buildings found to contain PCB caulk and sealants. Field and laboratory studies have demonstrated that PCBs from both interior and exterior caulking can be the source of elevated PCB air concentrations in these buildings, at levels that exceed health-based PCB exposure guidelines for building occupants. Air sampling in buildings containing PCB caulk has shown that the airborne PCB concentrations can be highly variable, even in repeat samples collected within a room. Sampling and data analysis strategies that recognize this variability can provide the basis for informed decision making about compliance with health-based exposure limits, even in cases where small numbers of samples are taken. The health risks posed by PCB exposures, particularly among children, mandate precautionary approaches to managing PCBs in building materials. 相似文献
207.
208.
Given that triploid adult bivalves reportedly grow larger and faster than their diploid siblings, such differences should be traceable to variation in energy allocation. In one proposed mechanism, retarded gametogenesis found in triploid adults may allow them more energy for somatic growth. Another hypothesis states that triploids are more heterozygous; increased heterozygosity has been positively correlated with enhanced growth. Juvenile soft-shelled clams, Mya arenaria, were treated with cytochalasin B to induce triploidy and examined with respect to components of a balanced energy equation (C=P+R+E). The variables measured were oxygen uptake (V
o
2), filtration rate (FR), dry tissue weight, shell length, shell height and shell inflation. Energy budgets were constructed and diploid and triploid groups compared. Few significant differences were found between diploid and triploid juvenile clams with respect to energy budget components. However, at seven loci assayed electrophoretically the triploid individuals were nearly twice as heterozygous as their diploid siblings. Moreover, tripoloid variances were less than diploid variances for every variable measured. Increased heterozygosity has been correlated with the decreased variance of morphological parameters. This study is believed to be the first to show decreased variance of physiological properties as well as morphological characters. Overall the data clearly indicate that energy allocation in juvenile M. arenaria is not related to ploidy. 相似文献
209.
Donald R. Allen 《Journal of the American Water Resources Association》1972,8(2):250-256
Deep within the earth there exist immense reservoirs of energy in the form of heat-commonly referred to as geothermal resources. Unfortunately, most of these resources are at such depths that it is unlikely they will be recoverable in the foreseeable future. Nevertheless, the lure of seemingly inexhaustible amounts of relatively clean energy continues to hold a fascination for man. In certain limited situations man has already been able to tap these reservoirs and harness the energy to his own uses. More of this activity can be expected in the future. While geothermal energy will chiefly be used to produce electric power, persons responsible for water resources management must concern themselves with geothermal resources for water, and water law concepts will continue to play an important role in the development of this resource. 相似文献
210.
Jeffrey S. Duncan Martha T. Fernandez Patricia L. Abbitt Siva Thiagarajah Stuart S. Howards W. Allen Hogge M.D. 《黑龙江环境通报》1990,10(3):175-182
To delineate the natural history of fetal multicystic dysplastic kidneys (MDKs), all cases that were prenatally detected in the Prenatal Diagnosis Center of the University of Virginia from September 1985 to 31 August 1988 were reviewed. All patients were followed through the Center with serial ultrasound evaluations at approximately 4-week intervals, and each liveborn infant was evaluated and followed by one of the authors (S.S.H.) Of the 14 cases detected, ten were detected in the second trimester, the earliest at 16·5 weeks' gestation. Of the nine fetuses with non-lethal disease, there were two cases in which the lesion remained unchanged during observation. Both had an initial diagnosis in the third trimester. In those cases diagnosed in the second trimester (7), all showed an initial increase in the size and number of cysts, followed by involutional changes either in utero (2) or in the neonatal period (3). Two infants had immediate surgical removal of the MDK, one because of respiratory compromise, and the other because of an uncertain diagnosis on renal scan. Abnormalities of the contralateral kidney were found in 7 of 14 fetuses. Five were lethal conditions. Associated non-renal abnormalities were common in bilateral MDK (80 per cent), but rare in unilateral MDK (11 per cent). 相似文献