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971.
Fisheries catches are known to be widely underreported, and much of their value flows in informal markets. Goods and services that are not directly sold in a market also have a corresponding economic value, here termed ‘shadow value’, which can apply to discarded fish—or those that are consumed but not sold (e.g., subsistence catches). Here, we estimate the monetary value of fisheries catches in Panama that are landed but not reported, or that are discarded at sea; this includes catches from artisanal and industrial fleets, as well as recreational and subsistence fisheries. Based on available data, we estimate that the market and shadow value of unreported catches in Panama in 2010 was around US$92 million, equal to approximately 43% of the total reported landed value. In the case of discarded fish, the shadow value represents the potential but entirely unrealized economic benefit of landing such fish; in the case of unreported landings, unreported market value represents only the first link in the potentially sophisticated informal seafood economy. One must be careful in considering these results for policy. It is possible that, rather than seeking to capture these ‘lost’ benefits, fish that are discarded or unreported should not have been caught at all, for example, if they are juveniles or of threatened species; conversely, unreported subsistence catches are crucial for food security throughout the world. These results help contextualize the scale of unreported fisheries in economic terms, and can inform subsequent policies and strategies to ensure social, ecological, and economic sustainability. 相似文献
972.
Gregory C. Luther Joko Mariyono Raden M. Purnagunawan Ben Satriatna Martin Siyaranamual 《Natural resources forum》2018,42(2):71-82
This study assesses the impact of farmer field schools (FFS) on the productivity of vegetable farming in vegetable‐producing areas of East Java and Bali, Indonesia. The FFS have equipped over 3,000 vegetable farmers with integrated crop management knowledge applicable to chilies and tomatoes. The FFS are expected to enhance farmers’ capacity such that they can increase production. This study employs a difference‐in‐differences (DiD) method to overcome selection bias. A survey of 250 FFS‐graduated farmers and 250 non‐FFS farmers were purposively randomly selected from the overall community of farmers. Focus group discussion was used to support the survey. The results indicate that FFS were successful for enhancing farmers’ capability in vegetable farming. Farmers who participated in FFS have higher productivity than those who did not. Farmers also could adapt and adopt the knowledge gained from FFS as they underwent a process of learning by doing. The impacts of the increase in farmers’ capacity can be more evident if weaknesses during the FFS preparation and implementation can be overcome, to ensure more participation, flexibility to fit different conditions/needs and continuous learning. 相似文献
973.
Floodplain Trapping and Cycling Compared to Streambank Erosion of Sediment and Nutrients in an Agricultural Watershed 下载免费PDF全文
Jaimie L. Gillespie Gregory B. Noe Cliff R. Hupp Allen C. Gellis Edward R. Schenk 《Journal of the American Water Resources Association》2018,54(2):565-582
Floodplains and streambanks can positively and negatively influence downstream water quality through interacting geomorphic and biogeochemical processes. Few studies have measured those processes in agricultural watersheds. We measured inputs (floodplain sedimentation and dissolved inorganic loading), cycling (floodplain soil nitrogen [N] and phosphorus [P] mineralization), and losses (bank erosion) of sediment, N, and P longitudinally in stream reaches of Smith Creek, an agricultural watershed in the Valley and Ridge physiographic province. All study reaches were net depositional (floodplain deposition > bank erosion), had high N and P sedimentation and loading rates to the floodplain, high soil concentrations of N and P, and high rates of floodplain soil N and P mineralization. High sediment, N, and P inputs to floodplains are attributed to agricultural activity in the region. Rates of P mineralization were much greater than those measured in other studies of nontidal floodplains that used the same method. Floodplain connectivity and sediment deposition decreased longitudinally, contrary to patterns in most watersheds. The net trapping function of Smith Creek floodplains indicates a benefit to water quality. Further research is needed to determine if future decreases in floodplain deposition, continued bank erosion, and the potential for nitrate leaching from nutrient‐enriched floodplain soils could pose a long‐term source of sediment and nutrients to downstream rivers. 相似文献
974.
Physical and Chemical Connectivity of Streams and Riparian Wetlands to Downstream Waters: A Synthesis 下载免费PDF全文
Ken M. Fritz Kate A. Schofield Laurie C. Alexander Michael G. McManus Heather E. Golden Charles R. Lane William G. Kepner Stephen D. LeDuc Julie E. DeMeester Amina I. Pollard 《Journal of the American Water Resources Association》2018,54(2):323-345
Streams, riparian areas, floodplains, alluvial aquifers, and downstream waters (e.g., large rivers, lakes, and oceans) are interconnected by longitudinal, lateral, and vertical fluxes of water, other materials, and energy. Collectively, these interconnected waters are called fluvial hydrosystems. Physical and chemical connectivity within fluvial hydrosystems is created by the transport of nonliving materials (e.g., water, sediment, nutrients, and contaminants) which either do or do not chemically change (chemical and physical connections, respectively). A substantial body of evidence unequivocally demonstrates physical and chemical connectivity between streams and riparian wetlands and downstream waters. Streams and riparian wetlands are structurally connected to downstream waters through the network of continuous channels and floodplain form that make these systems physically contiguous, and the very existence of these structures provides strong geomorphologic evidence for connectivity. Functional connections between streams and riparian wetlands and their downstream waters vary geographically and over time, based on proximity, relative size, environmental setting, material disparity, and intervening units. Because of the complexity and dynamic nature of connections among fluvial hydrosystem units, a complete accounting of the physical and chemical connections and their consequences to downstream waters should aggregate over multiple years to decades. 相似文献
975.
D.C. Goodrich W.G. Kepner L.R. Levick P.J. Wigington Jr. 《Journal of the American Water Resources Association》2018,54(2):400-422
Ephemeral and intermittent streams are abundant in the arid and semiarid landscapes of the Western and Southwestern United States (U.S.). Connectivity of ephemeral and intermittent streams to the relatively few perennial reaches through runoff is a major driver of the ecohydrology of the region. These streams supply water, sediment, nutrients, and biota to downstream reaches and rivers. In addition, they provide runoff to recharge alluvial and regional groundwater aquifers that support baseflow in perennial mainstem stream reaches over extended periods when little or no precipitation occurs. Episodic runoff, as well as groundwater inflow to surface water in streams support limited naturally occurring riparian communities. This paper provides an overview and comprehensive examination of factors affecting the hydrologic, chemical, and ecological connectivity of ephemeral and intermittent streams on perennial or intermittent rivers in the arid and semiarid Southwestern U.S. Connectivity as influenced and moderated through the physical landscape, climate, and human impacts to downstream waters or rivers is presented first at the broader Southwestern scale, and secondly drawing on a specific and more detailed example of the San Pedro Basin due to its history of extensive observations and research in the basin. A wide array of evidence clearly illustrates hydrologic, chemical, and ecological connectivity of ephemeral and intermittent streams throughout stream networks. 相似文献
976.
Richard C. Warner Carmen T. Agouridis Page T. Vingralek Alex W. Fogle 《Journal of the American Water Resources Association》2010,46(4):724-732
Warner, Richard C., Carmen T. Agouridis, Page T. Vingralek, and Alex W. Fogle, 2010. Reclaimed Mineland Curve Number Response to Temporal Distribution of Rainfall. Journal of the American Water Resources Association (JAWRA) 46(4): 724-732. DOI: 10.1111/j.1752-1688.2010.00444.x Abstract: The curve number (CN) method is a common technique to estimate runoff volume, and it is widely used in coal mining operations such as those in the Appalachian region of Kentucky. However, very little CN data are available for watersheds disturbed by surface mining and then reclaimed using traditional techniques. Furthermore, as the CN method does not readily account for variations in infiltration rates due to varying rainfall distributions, the selection of a single CN value to encompass all temporal rainfall distributions could lead engineers to substantially under- or over-size water detention structures used in mining operations or other land uses such as development. Using rainfall and runoff data from a surface coal mine located in the Cumberland Plateau of eastern Kentucky, CNs were computed for conventionally reclaimed lands. The effects of temporal rainfall distributions on CNs was also examined by classifying storms as intense, steady, multi-interval intense, or multi-interval steady. Results indicate that CNs for such reclaimed lands ranged from 62 to 94 with a mean value of 85. Temporal rainfall distributions were also shown to significantly affect CN values with intense storms having significantly higher CNs than multi-interval storms. These results indicate that a period of recovery is present between rainfall bursts of a multi-interval storm that allows depressional storage and infiltration rates to rebound. 相似文献
977.
Tatiana Calvete Eder C. Lima Natali F. Cardoso Júlio C.P. Vaghetti Silvio L.P. Dias Flavio A. Pavan 《Journal of environmental management》2010,91(8):1695-1706
Activated (AC-PW) and non-activated (C-PW) carbonaceous materials were prepared from the Brazilian-pine fruit shell (Araucaria angustifolia) and tested as adsorbents for the removal of reactive orange 16 dye (RO-16) from aqueous effluents. The effects of shaking time, adsorbent dosage and pH on the adsorption capacity were studied. RO-16 uptake was favorable at pH values ranging from 2.0 to 3.0 and from 2.0 to 7.0 for C-PW and AC-PW, respectively. The contact time required to obtain the equilibrium using C-PW and AC-PW as adsorbents was 5 and 4 h at 298 K, respectively. The fractionary-order kinetic model provided the best fit to experimental data compared with other models. Equilibrium data were better fit to the Sips isotherm model using C-PW and AC-PW as adsorbents. The enthalpy and entropy of adsorption of RO-16 were obtained from adsorption experiments ranging from 298 to 323 K. 相似文献
978.
Natália C. Archilha Catarina S.A. Canto Suzana M. Ratusznei José A.D. Rodrigues Marcelo Zaiat Eugenio Foresti 《Journal of environmental management》2010,91(8):1756-1765
The objective of this work was to analyze the effect of the interaction between feeding strategy and COD/sulfate ratio on the removal efficiency of sulfate and organic matter from a synthetic wastewater. An anaerobic sequencing batch reactor with recirculation of the liquid phase and containing immobilized biomass on polyurethane foam (AnSBBR) was used. The AnSBBR with a total volume of 3.7 L, treated 2.0 L synthetic wastewater in 8-h cycles at 30 ± 1 °C and was inoculated with anaerobic biomass from a UASB. Two feeding strategies were assessed: (a) batch and (b) batch followed by fed-batch. In strategy (a) the reactor was fed in 10 min with 2 L wastewater containing sulfate and carbon sources. In strategy (b) 1.2 L wastewater (containing only the sulfate source) was fed during the first 10 min of the cycle and the remaining 0.8 L (containing only the carbon source) in 240 min. The COD/sulfate ratios assessed were 1 and 3. Based on these values and on the concentrations of organic matter (0.5–11.25 gCOD/L) and sulfate (0.5 and 2.5 gSO42?/L), the sulfate and organic matter loading rates applied equaled 1.5 and 4.5 gSO42?/L d for sulfate and 1.5, 4.5 and 13.5 gCOD/L d for organic matter. After stabilization of the system time profiles were run of monitored parameters (COD, sulfate, sulfide and sulfite). In general, the reactor showed to be robust for use in the anaerobic treatment of wastewaters containing sulfate. Gradual feeding (strategy b) of the carbon source favored sulfate reduction, resulting in sulfate removal efficiencies of 84–98% and organic matter removal efficiencies of 48–95%. The best results were observed under COD/sulfate ratio equal to 1 (loading rates of 1.5 and 4.5 gSO42?/L d for sulfate, and 1.5 and 4.5 gCOD/L d for organic matter). When COD/sulfate ratio was 3 (loading rates of 1.5 and 4.5 gSO42?/L d for sulfate, and 4.5 and 13.5 gCOD/L d for organic matter) the effect of feed mode became less significant. These results show that the strategy batch followed by fed-batch is more advantageous for COD/sulfate ratios near the stoichiometric value (0.67) and higher organic matter and sulfate concentrations. 相似文献
979.
Patrick C. Tobin Julie Van Stappen Laura M. Blackburn 《Journal of environmental management》2010,91(10):1991-1996
The introduction of non-native species has accelerated due to increasing levels of global trade and travel, threatening the composition and function of ecosystems. Upon arrival and successful establishment, biological invaders begin to spread and often do so with considerable assistance from humans. Recreational areas can be especially prone to the problem of accidental non-native species transport given the number of visitors that arrive from geographically diverse areas. In this paper, we examine camping permit data to the Apostle Islands National Lakeshore in northwestern Wisconsin, USA, from 1999 to 2007 relative to gypsy moth distribution, phenology and outbreak data. During this time, gypsy moth populations became established in this area ahead of the moving population front of the gypsy moth, suggesting anthropogenic introduction. The permit data revealed that the majority of visitors arrived from outside of the gypsy moth established area. However, there was a consistent yearly trend of visitors that arrived from areas of high gypsy moth populations and who arrived during the gypsy moth life stage (egg masses) most likely to be successfully introduced. Using available data on the gypsy moth and its relationship to camping permit data, we describe how recreational managers could optimize park strategies to mitigate unwanted introductions of the gypsy moth as well as develop analogous strategies for managing other biological invaders in recreational areas. 相似文献
980.
Colin Scott Steve E. Lewis Rob Milla Matthew C. Taylor Andrew J.W. Rodgers Geoff Dumsday Jon E. Brodie John G. Oakeshott Robyn J. Russell 《Journal of environmental management》2010,91(10):2075-2078
Herbicide contamination from agriculture is a major issue worldwide, and has been identified as a threat to freshwater and marine environments in the Great Barrier Reef World Heritage Area in Australia. The triazine herbicides are of particular concern because of potential adverse effects, both on photosynthetic organisms and upon vertebrate development. To date a number of bioremediation strategies have been proposed for triazine herbicides, but are unlikely to be implemented due to their reliance upon the release of genetically modified organisms. We propose an alternative strategy using a free-enzyme bioremediant, which is unconstrained by the issues surrounding the use of live organisms. Here we report an initial field trial with an enzyme-based product, demonstrating that the technology is technically capable of remediating water bodies contaminated with the most common triazine herbicide, atrazine. 相似文献