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991.
Unrine JM Hopkins WA Romanek CS Jackson BP 《Environmental pollution (Barking, Essex : 1987)》2007,149(2):182-192
Despite the influence that amphibians have on the flow of energy and nutrients in ecological systems, the role that amphibians play in transporting contaminants through food webs has received very little attention. This study was undertaken to investigate bioaccumulation of trace elements in amphibians relative to other small aquatic organisms in a contaminated wetland. We collected bullfrog larvae (Rana catesbeiana) along with three other species of small vertebrates and four species of invertebrates from a site contaminated with a wide array of trace elements and analyzed them for trace element concentrations and stable nitrogen and carbon isotope composition. We found that amphibian larvae accumulated the highest concentrations of most trace elements, possibly due to their feeding ecology. These results suggest that omnivorous amphibian larvae can serve as a critical link for trace element trophic transfer. Their propensity to accumulate trace elements may have important implications for amphibian health in contaminated environments and should be further investigated. 相似文献
992.
993.
Ecological communities typically change along gradients of human impact, although it is difficult to estimate the footprint of impacts for diffuse threats such as pollution. We developed a joint model (i.e., one that includes multiple species and their interactions with each other and environmental covariates) of benthic habitats on lagoonal coral reefs and used it to infer change in benthic composition along a gradient of distance from logging operations. The model estimated both changes in abundances of benthic groups and their compositional turnover, a type of beta diversity. We used the model to predict the footprint of turbidity impacts from past and recent logging. Benthic communities far from logging were dominated by branching corals, whereas communities close to logging had higher cover of dead coral, massive corals, and soft sediment. Recent impacts were predicted to be small relative to the extensive impacts of past logging because recent logging has occurred far from lagoonal reefs. Our model can be used more generally to estimate the footprint of human impacts on ecosystems and evaluate the benefits of conservation actions for ecosystems. 相似文献
994.
Otto Ilona M. Reckien Diana Reyer Christopher P. O. Marcus Rachel Le Masson Virginie Jones Lindsey Norton Andrew Serdeczny Olivia 《Regional Environmental Change》2017,17(6):1651-1662
Regional Environmental Change - This article provides a review of recent scientific literature on social vulnerability to climate change, aiming to determine which social and demographic groups,... 相似文献
995.
996.
Jonathan Mitchell Luc Vandeperre Rob Dvorak Ed Kosior Karnik Tarverdi Christopher Cheeseman 《Waste management (New York, N.Y.)》2014,34(11):2113-2119
The majority of disposable cups are made from paper plastic laminates (PPL) which consist of high quality cellulose fibre with a thin internal polyethylene coating. There are limited recycling options for PPLs and this has contributed to disposable cups becoming a high profile, problematic waste. In this work disposable cups have been shredded to form PPL flakes and these have been used to reinforce polypropylene to form novel paper plastic composites (PPCs). The PPL flakes and polypropylene were mixed, extruded, pelletised and injection moulded at low temperatures to prevent degradation of the cellulose fibres. The level of PPL flake addition and the use of a maleated polyolefin coupling agent to enhance interfacial adhesion have been investigated. Samples have been characterised using tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis. Use of a coupling agent allows composites containing 40 wt.% of PPL flakes to increase tensile strength of PP by 50% to 30 MPa. The Young modulus also increases from 1 to 2.5 GPa and the work to fracture increases by a factor of 5. The work demonstrates that PPL disposable cups have potential to be beneficially reused as reinforcement in novel polypropylene composites. 相似文献
997.
998.
We present the first systematic research on green fairs in the USA. We provide a summary analysis of the frequency, trends, goals, structure, and operations of green fairs being held in the USA. We also present an initial assessment of their potential contributions to civic engagement through a study of the intentions and behaviour of fair organisers and fair goers. This assessment is premised on previous research in civic engagement and similar local events with environmental themes, such as farmers' markets. Green fairs are recent, yet now common, events in the USA. Although brief and informal experiences for attendees, green fairs are rich with opportunities to engage people in their community on sustainability and other environmental issues. They are important venues for civic engagement that are distinct from both farmers' markets and from more formal settings for engagement. 相似文献
999.
1000.
Christopher Potter 《Journal of Coastal Conservation》2014,18(3):213-220
There is a long history of livestock grazing on the California Central Coast, dating back over 150 years. In this study, methods were reviewed and results presented for analysis of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor data to monitor year-to-year variation of forage production on Central Coast rangelands around Big Sur, California. Time series plots from 2000 to 2012 of vegetation greenness for ten rangeland sites showed similar inter-annual patterns in satellite yield index (SYI) values. Most sites reached their maximum greenness levels each year in early May. The year with the highest observed SYI level across most sites was 2005. In the northern portion of the region (north of Pfeiffer Big Sur State Park), 2007 was the year with the lowest observed SYI level, whereas in the southern allotments, 2007 was a year with a relatively high SYI level. These methods have the potential to monitor the differing seasonal growing cycles of rangeland production across the area of individual grazing allotments on the Central Coast. Such a cost-effective and timely approach is required for conservation monitoring in the Big Sur coastal ecosystems where rapid climate change may shift vegetation cover in favor of more extensive rangelands at the expense of forested lands. 相似文献