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261.
Exploited species impacts on trophic linkages along reef-seagrass interfaces in the Florida Keys 总被引:1,自引:0,他引:1
John F Valentine Kenneth L Heck Derrick Blackmon Margene E Goecker Juliet Christian Ryan M Kroutil Bradley J Peterson Mathew A Vanderklift Kevin D Kirsch Mike Beck 《Ecological applications》2008,18(6):1501-1515
The removal of fish biomass by extensive commercial and recreational fishing has been hypothesized to drastically alter the strength of trophic linkages among adjacent habitats. We evaluated the effects of removing predatory fishes on trophic transfers between coral reefs and adjacent seagrass meadows by comparing fish community structure, grazing intensity, and invertebrate predation potential in predator-rich no-take sites and nearby predator-poor fished sites in the Florida Keys (USA). Exploited fishes were more abundant at the no-take sites than at the fished sites. Most of the exploited fishes were either omnivores or invertivores. More piscivores were recorded at no-take sites, but most (approximately 95%) were moderately fished and unexploited species (barracuda and bar jacks, respectively). Impacts of these consumers on lower trophic levels were modest. Herbivorous and smaller prey fish (< 10 cm total length) densities and seagrass grazing diminished with distance from reefs and were not negatively impacted by the elevated densities of exploited fishes at no-take sites. Predation by reef fishes on most tethered invertebrates was high, but exploited species impacts varied with prey type. The results of the study show that, even though abundances of reef-associated fishes have been reduced at fished sites, there is little evidence that this has produced cascading trophic effects or interrupted cross-habitat energy exchanges between coral reefs and seagrasses. 相似文献
262.
Work as good‐minded undertakings and effortless assignments: Chinese meaning of working for hospitality workers and its motivational implications 下载免费PDF全文
Meaning of working (MOW) or the understanding of the purpose of working is a cornerstone in organizational behavior. This study answers the call to explain the MOW in Eastern contexts characterized by interdependent identities. We collect our data from hospitality workers in Taiwan, where Chinese Confucian and Taoist cultural precepts are strong. Our findings reveal that our informants use 25 typical vocabularies of motive in establishing and maintaining five salient identities that gain significance through two Chinese work meanings (i.e., good‐minded undertakings and effortless assignments). These meanings demonstrate the theoretical contributions of our findings to the MOW literature. We also explore the interplay between our emic findings (grounded in Taoism and Confucianism Chinese cultures) with etic motivation theory to advance understanding of prevention and promotion foci. 相似文献
263.
Michael?R.?AllshouseEmail author Gregory?N.?Ivey Ryan?J.?Lowe Nicole?L.?Jones C.?J.?Beegle-Krause Jiangtao?Xu Thomas?Peacock 《Environmental Fluid Mechanics》2017,17(3):473-483
Windage, the additional direct, wind-induced drift of material floating at the free surface of the ocean, plays a crucial role in the surface transport of biological and contaminant material. Lagrangian coherent structures (LCS) uncover the hidden organizing structures that underlie material transport by fluid flows. Despite numerous studies in which LCS ideas have been applied to ocean surface transport scenarios, such as oil spills, debris fields and biological material, there has been no consideration of the influence of windage on LCS. Here we investigate and demonstrate the impact of windage on ocean surface LCS via a case study of the ocean surrounding the UNESCO World Heritage Ningaloo coral reef coast in Western Australia. We demonstrate that the inclusion of windage is necessary when applying LCS to the study of surface transport of any floating material in the ocean. 相似文献
264.
We review how Canadian Model Forests pursued forest and community sustainability over the course of two decades (1992–2012). Given its roots in the forest industry and forest science, Model Forest programming initially faced some challenges in pursuing the socio‐economic dimensions of sustainable forest management (SFM) in order to fulfil mandated community sustainability objectives. This was due, in part, to how objectives, stakeholders, and expertise were brought together to develop SFM. The programme helped to define sustainability and the SFM paradigm, advance forest science and social research, and bring together a mix of usually adversarial partners in the name of innovation. Ultimately, the termination of federal programming was linked to high‐level policy shifts, yet difficulty in delivering on the socio‐economic dimensions of SFM during a period of forest sector and community crisis was also a factor. 相似文献
265.
Despite intensive efforts over the last century to eradicate bovine tuberculosis (TB) in North America, several hotspots of infected wildlife and livestock remain, raising concerns that the disease will never be eradicated. The stress and frustration for a farmer caused by having a herd test positive for TB or living in an infected region can be substantial. The goal of this study was to investigate the concerns of farmers around Riding Mountain National Park (RMNP) regarding the presence of TB in wildlife and livestock and conduct an exploratory analysis of causal factors. Data were collected from 786 farmers within 50 km of RMNP using a mail-back questionnaire. Overall, farmers indicated a high level of concern toward diseases in both wildlife and cattle relative to other concerns. The spatial variables that had the greatest influence on TB concern were both the distance of farms to the RMNP boundary and distance of farms to previous cases of TB. The most important aspatial factor associated with high TB concern was the frequency with which farmers observed elk on their land. These results underscore the important differences between 'objective' measures of risk, such as epidemiological estimates of disease prevalence, and subjective measures of disease concern, such as risk perception and acceptability of management actions. Written responses suggest that concerns regarding disease may affect how farmers view wildlife on their land and their relationship with neighbouring protected areas. Management activities that reduce the frequency of elk interactions with farms, but also recognize the complex relationship that farmers have with wildlife and protected areas, will be most effective in mitigating farmer concern regarding this important problem. 相似文献
266.
Golet GH Roberts MD Larsen EW Luster RA Unger R Werner G White GG 《Environmental management》2006,37(6):862-879
Studies have shown that ecological restoration projects are more likely to gain public support if they simultaneously increase important human services that natural resources provide to people. River restoration projects have the potential to influence many of the societal functions (e.g., flood control, water quality) that rivers provide, yet most projects fail to consider this in a comprehensive manner. Most river restoration projects also fail to take into account opportunities for revitalization of large-scale river processes, focusing instead on opportunities presented at individual parcels. In an effort to avoid these pitfalls while planning restoration of the Sacramento River, we conducted a set of coordinated studies to evaluate societal impacts of alternative restoration actions over a large geographic area. Our studies were designed to identify restoration actions that offer benefits to both society and the ecosystem and to meet the information needs of agency planning teams focusing on the area. We worked with local partners and public stakeholders to design and implement studies that assessed the effects of alternative restoration actions on flooding and erosion patterns, socioeconomics, cultural resources, and public access and recreation. We found that by explicitly and scientifically melding societal and ecosystem perspectives, it was possible to identify restoration actions that simultaneously improve both ecosystem health and the services (e.g., flood protection and recreation) that the Sacramento River and its floodplain provide to people. Further, we found that by directly engaging with local stakeholders to formulate, implement, and interpret the studies, we were able to develop a high level of trust that ultimately translated into widespread support for the project. 相似文献
267.
Sather ME Mathew J Nguyen N Lay J Golod G Vet R Cotie J Hertel T Aaboe E Callison R Adam J Keese D Freise J Hathcoat A Sakizzie B King M Lee C Oliva S San Miguel G Crow L Geasland F 《Journal of environmental monitoring : JEM》2008,10(11):1319-1325
Ambient ammonia monitoring using Ogawa passive samplers was conducted in the Four Corners area and eastern Oklahoma, USA during 2007. The resulting data will be useful in the multipollutant management of ozone, nitrogen oxides, and visibility (atmospheric regional haze) in the Four Corners area, an area with growing oil/gas production and increasing coal-based power plant construction. The passive monitoring data also add new ambient ammonia concentration information for the U.S. and will be useful to scientists involved in present and future visibility modeling exercises. Three week integrated passive ammonia samples were taken at five sites in the Four Corners area and two sites in eastern Oklahoma from December, 2006 through December, 2007 (January, 2008 for two sites). Results show significantly higher regional background ammonia concentrations in eastern Oklahoma (1.8 parts per billion (ppb) arithmetic mean) compared to the Four Corners area (0.2 ppb arithmetic mean). Annual mean ammonia concentrations for all Four Corners area sites for the 2007 study ranged from 0.2 ppb to 1.5 ppb. Peak ambient ammonia concentrations occurred in the spring and summer in both areas. The passive samplers deployed at the Stilwell, Oklahoma site compared favorably with other passive samplers and a continuous ammonia monitoring instrument. 相似文献
268.
Bashir W McGovern F O'Brien P Ryan M Burke L Paull B 《Journal of environmental monitoring : JEM》2008,10(6):730-738
A major Irish study, based upon more than 8000 samples collected over the measurement period of 22 years, for sulfur dioxide (SO2-S), sulfate (SO4-S) and nitrogen dioxide (NO2-N) concentrations (microg m(-3)) within air, and the ionic composition of precipitation samples based on sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), chloride (Cl-), sulfate (SO4-S), non-sea salt sulfate (nssSO4-S), ammonium (NH4-N), and nitrate (NO3-N) weighted mean concentrations (mg l(-1)), has been completed. For the air samples, the sulfur dioxide and sulfate concentrations decreased over the sampling period (1980-2004) by 75% and 45%, respectively, whereas no significant trend was observed for nitrogen dioxide. The highest concentrations for sulfur dioxide, sulfate and nitrogen dioxide were associated with wind originating from the easterly and northeasterly directions i.e. those influenced by Irish and European sources. The lowest concentrations were associated with the westerly directions i.e. for air masses originating in the North Atlantic region. This was further verified with the use of backward (back) trajectory analysis, which allowed tracing the movement of air parcels using the European Centre for Medium range Weather Forecasting (ECMWF) ERA-40 re-analysis data. High non-sea salt sulfate levels were being associated with air masses originating from Europe (easterlies) with lower levels from the Atlantic (westerlies). With the precipitation data, analysis of the non-sea salt sulfate concentrations showed a decrease by 47% since the measurements commenced. 相似文献
269.
Stronen AV Schumaker NH Forbes GJ Paquet PC Brook RK 《Environmental monitoring and assessment》2012,184(11):6923-6934
Landscape fragmentation affects wildlife population viability, in part, through the effects it has on individual dispersal. In addition, some forms of human disturbance impinge on dispersal without physically fragmenting habitats. Here, we use the term "landscape resistance" to capture constraints to dispersal that cannot be linked directly to fragmentation. The extent to which landscape resistance can influence population persistence is not well understood. Agricultural development over the past 60?years has resulted in considerable habitat fragmentation in the Riding Mountain National Park (RMNP) region in southwestern Manitoba, Canada. We examined how park boundaries, roads outside park boundaries and negative human attitudes have altered dispersal success and population persistence. We examined whether stochastic disturbance, representing infectious disease epidemics, further reduced long-term population persistence for various scenarios. Finally, we assessed whether the simultaneous occurrence of the three features had additive effects. We simulated dispersal using HexSim, a spatially explicit individual-based population model, parameterised with data on wolves (Canis lupus) in the RMNP region. Simulations that separately accounted for negative human attitudes and roads outside the park boundaries exhibited lower mean population size than those that ignored these details. Increasing deflection from park boundaries did not appear to have significant impacts. Our results did not indicate the presence of additive effects, and scenarios incorporating all three features had similar results as that of roads. Stochastic disturbance further reduced mean population size. Our results do illustrate how less-visible human disturbances (i.e. those that do not clearly alter landscape characteristics) can significantly limit dispersal and population persistence. 相似文献
270.
Demand for environmental policies to improve health: Evaluating community-level policy scenarios 总被引:1,自引:0,他引:1
Ryan Bosworth Trudy Ann Cameron J.R. DeShazo 《Journal of Environmental Economics and Management》2009,57(3):293-308
Using a national survey and a discrete choice experiment format, we estimate demand for environmental polices to improve health. We use a richly detailed community-level approach that describes illnesses avoided, premature deaths avoided, policy duration, and the affected population size. We allow preferences for policy attributes to vary systematically with the scenario design, with the source of risk and type of health threat, and with respondent characteristics. Using a willingness to pay (WTP) framework similar to that used for studies of individual risk, we find that omission of illness information leads to an upward bias in estimates of the value of avoided premature deaths and that individuals view avoided deaths and avoided illnesses as substitutes. We also find evidence of strongly diminishing marginal utility in policy scope. Differences in marginal WTP from different sources of risk or types of illness appear very small relative to differences associated with respondent characteristics and/or perceptions. Self-interest strongly dominates altruistic considerations. 相似文献