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531.
Sustainable management of fisheries is often compromised by management delaying implementation of regulations that reduce harvest, in order to maintain higher catches in the short-term. Decreases or increases in fish population growth rate driven by environmental change, including ecosystem and climate change, affect the harvest that can be taken sustainably. If not acted on rapidly, environmental change could result in unsustainable fishing or missed opportunity for higher catches. Using simulation models of harvested fish populations influenced by environmental change, we explore how long fisheries managers can afford to wait before changing harvest regulations in response to changes in population growth. If environmental change causes population declines, delays greater than five years increase the probability of population collapse. Species with fast and highly variable population growth rates are more susceptible to collapse under delays and should be a priority for revised management where delays occur. Generally, the long-term cost of delay, in terms of lost fishing opportunity, exceeds the short-term benefits of overfishing. Lowering harvest limits and monitoring for environmental change can alleviate the impact of delays; however, these measures may be more costly than reducing delays. We recommend that management systems that allow rapid responses to population growth changes be enacted for fisheries management to adapt to ecosystem and climate change. 相似文献
532.
The objective of this Incubator is to stimulate research in the area of multiple jobholding (MJH), a long‐neglected topic in organizational behavior. We first discuss the prevalence of, and motivation for, MJH and then discuss possible dangers and benefits of MJH. Throughout, we discuss ideas for future research. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Douglas J. McCauley Fiorenza Micheli Hillary S. Young Derek P. Tittensor Daniel R. Brumbaugh Elizabeth M. P. Madin Katherine E. Holmes Jennifer E. Smith Heike K. Lotze Paul A. DeSalles Suzanne N. Arnold Boris Worm 《Marine Biology》2010,157(12):2739-2750
Large animals are severely depleted in many ecosystems, yet we are only beginning to understand the ecological implications of their loss. To empirically measure the short-term effects of removing large animals from an ocean ecosystem, we used exclosures to remove large fish from a near-pristine coral reef at Palmyra Atoll, Central Pacific Ocean. We identified a range of effects that followed from the removal of these large fish. These effects were revealed within weeks of their removal. Removing large fish (1) altered the behavior of prey fish; (2) reduced rates of herbivory on certain species of reef algae; (3) had both direct positive (reduced mortality of coral recruits) and indirect negative (through reduced grazing pressure on competitive algae) impacts on recruiting corals; and (4) tended to decrease abundances of small mobile benthic invertebrates. Results of this kind help advance our understanding of the ecological importance of large animals in ecosystems. 相似文献
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Elizabeth Ann Brunner 《Environmental Communication: A Journal of Nature and Culture》2018,12(3):402-413
Art has long been an important force in environmental movements. In China, environmental art is a fast-growing sector of the art scene. This new area of emphasis is expanding the function of art and aiding in China’s environmental movement by challenging both imported Western practices and Maoist era philosophy, thereby opening up new ways of considering the relationship between human “progress,” political systems, economic practices, and their repercussions on existing ecosystems. I turn to artist Xu Xiaoyan’s paintings to explore how the notion of “progress” can be challenged through art. I use Deleuze and Guattari’s theory of deterritorialization and reterritorialization to map how Xu’s art offers viewers space to think outside dominant paradigms, creates the potential for changes in human consciousness, considers the environment as a composition of relationships and interactions, and provokes discussion concerning the impact of linear notions of time on human conceptions of nature. 相似文献
538.
Cláudia Ribeiro Miguel Ângelo Pardal Maria Elizabeth Tiritan Eduardo Rocha Rui Miguel Margalho Maria João Rocha 《Environmental monitoring and assessment》2009,159(1-4):415-427
The important Portuguese Sado River estuary has never been investigated for the presence of potentially endocrine-disrupting chemicals (EDCs), such as natural estrogens (estradiol, estrone), pharmaceutical estrogens (17α-ethynylestradiol), phytoestrogens (daidzein, genistein and biochanin A), or industrial chemicals (4-octylphenol, 4-nonylphenol, and bisphenol A). Thus, the main objective of this study was to evaluate their presence at 13 sampling points distributed between both the industrial and the natural reserve areas of the estuary, zones 1 and 2, respectively. For that, water samples collected in summer and winter were processed by solid phase extraction and analyzed by high-performance liquid chromatography with photodiode array detection and gas chromatography–mass spectroscopy. Results showed that estrone, ethynylestradiol, all the aforementioned phytoestrogens as well as bisphenol A and 4-octylphenol were found in zone 1. In zone 2, neither estrogens nor 4-OP were found. However, in the same zone, daidzein (500 ng/L) and genistein (320 ng/L) attained their highest levels in summer, whereas biochanin A peaked in winter (170 ng/L). Furthermore, bisphenol A was also found in some areas of zone 2, but showed similar concentrations in both surveys (about 220 ng/L). This study demonstrated that the Sado River estuary had low EDCs levels, suggesting that the Sado’s high hydrodynamic activity may be involved in the dilution of local pollution. It was suggested that at the current levels of concentrations, all assayed EDCs are unlikely to individually cause endocrine disruption in local animals. However, under a continuous exposure scenario, an additive and/or synergistic action of the estrogenic chemicals load can not be excluded, and so, continuous monitoring is advisable. 相似文献
539.
Rubio MA Lissi E Jorquera H Salinas E Castro J Cádiz M 《Environmental monitoring and assessment》2008,140(1-3):161-173
Carbon monoxide concentrations were measured at ground level (1 m) near heavy traffic streets in downtown Santiago de Chile
in periods of low (November and December), intermediate (April) and high (May) ambient concentrations. Also, measurements
were carried out at several heights (from 1 to 127 m) in Santiago’s main street during winter time. Measurements carried out
at ground level show maximum values during the morning rush hour, with values considerably higher than those reported by the
urban air quality network, particularly in summer time. However, the measured values are below air quality standards. Vertical
CO profiles were measured in a tower located in the center of downtown. Below 40 m (average altitude of neighboring buildings),
the profiles do not show a consistent vertical gradient, with CO concentrations increasing or decreasing with height, regardless
of atmospheric stability. In this low altitude range, the observed vertical profiles are poorly predicted by a street canyon
model, and the measured concentrations can not be described by a simple exponential decay. At higher altitudes (40 and 127 m)
a negative gradient in CO concentrations is observed, both for stable and unstable atmospheric conditions. The values of CO
measured at 127 m are relatively well described by an Eulerian dispersion model running with current CO emission inventories
for Santiago, although this model tends to predict stepper CO gradients than the observed ones. 相似文献
540.
Renshaw CE Bostick BC Feng X Wong CK Winston ES Karimi R Folt CL Chen CY 《Journal of environmental quality》2006,35(1):61-67
Increasing development of historic farmlands raises questions regarding the fate of pesticides applied when these land were in cultivation. We quantified As and Pb budgets in field soils in two orchards where arsenical pesticides were applied in the early 20th century and a third uncontaminated control field. Sequential extractions and X-ray analyses also were used to determine mineral phases. In addition, we measured metal loads in drainages adjacent to the fields and in two common macroinvertebrate taxa within the wetland at the outlet of the drainages. We find that the applied As and Pb have undergone little vertical redistribution; concentrations of As and Pb in the top 25 cm of contaminated orchard soils are higher than in the uncontaminated control field. However, none of the applied lead arsenate (PbHAsO4) remains in its original mineral phase. Instead, the metals are now primarily adsorbed onto fine silt and clay-sized amorphous oxides and organic matter. Further, physical erosion associated with tilling and replanting appears to have mobilized the fine-particulate-bound As and Pb in one orchard. The remobilized metals are found in sediments in the stream channel draining the tilled orchard. It is unclear if the As and Pb transported sediments are biologically active; average macroinvertebrate metal burdens in the wetland are not elevated above those observed elsewhere in the region. However, little of the mobilized metals may have reached the wetland. These results demonstrate that land use change can significantly impact the retention of arsenical pesticides. 相似文献