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101.
Eimear M. Nic Lughadha Vanessa Graziele Staggemeier Thais N. C. Vasconcelos Barnaby E. Walker Cátia Canteiro Eve J. Lucas 《Conservation biology》2019,33(3):511-522
The value of natural history collections for conservation science research is increasingly recognized, despite their well-documented limitations in terms of taxonomic, geographic, and temporal coverage. Specimen-based analyses are particularly important for tropical plant groups for which field observations are scarce and potentially unreliable due to high levels of diversity-amplifying identification challenges. Specimen databases curated by specialists are rich sources of authoritatively identified, georeferenced occurrence data, and such data are urgently needed for large genera. We compared entries in a monographic database for the large Neotropical genus Myrcia in 2007 and 2017. We classified and quantified differences in specimen records over this decade and determined the potential impact of these changes on conservation assessments. We distinguished misidentifications from changes due to taxonomic remodeling and considered the effects of adding specimens and georeferences. We calculated the potential impact of each change on estimates of extent of occurrence (EOO), the most frequently used metric in extinction-risk assessments of tropical plants. We examined whether particular specimen changes were associated with species for which changes in EOO over the decade were large enough to change their conservation category. Corrections to specimens previously misidentified or lacking georeferences were overrepresented in such species, whereas changes associated with taxonomic remodeling (lumping and splitting) were underrepresented. Among species present in both years, transitions to less threatened status outnumbered those to more threatened (8% vs 3%, respectively). Species previously deemed data deficient transitioned to threatened status more often than to not threatened (10% vs 7%, respectively). Conservation scientists risk reaching unreliable conclusions if they use specimen databases that are not actively curated to reflect changing knowledge. 相似文献
102.
Murphy JD Johnson DW Miller WW Walker RF Carroll EF Blank RR 《Journal of environmental quality》2006,35(2):479-489
A wildfire burned through a previously sampled research site, allowing pre- and post-burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post-fire erosion caused large and statistically significant (P < or = 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water-extractable SO4(2-) in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca2+ in most horizons, but no consistent or statistically significant effects on exchangeable K+ or Mg2+, or on Bray-, bicarbonate-, or water-extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH4+, NO3-, ortho-P, and (especially) SO4(2-) were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH4+ and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short-term effects of wildfire were on leaching whereas the major long-term effect was the loss of N from the forest floor and soil during the fire. 相似文献
103.
Performance rating research about individual performance may not necessarily generalize to rating performance of dyads. Using data from the 1992 Winter Olympics, this study demonstrates that observed interdimensional correlations are higher when dyads rather than individuals are being rated, particularly when raters have the opportunity to form prior general impressions of ratees. Implications of these results are discussed. © 1998 John Wiley & Sons, Ltd. 相似文献
104.
The breeding performance of higher predators has often been used to monitor fluctuations in the abundance of important prey
stocks in marine ecosystems. The development of electronic data-loggers in recent years has also provided the opportunity
of using wide-ranging marine animals to measure physical oceanographic conditions. In this study, time–depth recorders (TDRs)
programmed to record temperature were deployed on female Antarctic fur seals (Arctocephalus gazella) at Bird Island, South Georgia (54°00′S; 38°02′W) during the breeding seasons 1994 to 1998. Temperature sensors had relatively
slow response times, and thermal radiation errors occurred during the day when seals spent a large proportion of their time
at the surface. Nevertheless, measurements provided temperature–depth profiles which were typical of the vertical stratification
of the ocean. During the early stages of a foraging trip temperature increased, suggesting that fur seals travelled northwards
from South Georgia towards the warmer waters of the Polar Front. In addition, higher temperatures were recorded by females
that remained at sea for longer, implying that these individuals also travelled further. Mean sea-surface temperature (SST)
increased from ∼1 to 4 °C from December to March and agreed with SSTs from ship, buoy and satellite. Future studies on marine
mammals which combine satellite tracking with oceanographic measurements are likely to provide valuable information on biophysical
aspects of the ocean.
Received: 16 June 1998 / Accepted: 13 February 1999 相似文献
105.
Barnaby E. Walker Tarciso C. C. Leão Steven P. Bachman Eve Lucas Eimear Nic Lughadha 《Conservation biology》2023,37(1):e13992
Assessing species’ extinction risk is vital to setting conservation priorities. However, assessment endeavors, such as those used to produce the IUCN Red List of Threatened Species, have significant gaps in taxonomic coverage. Automated assessment (AA) methods are gaining popularity to fill these gaps. Choices made in developing, using, and reporting results of AA methods could hinder their successful adoption or lead to poor allocation of conservation resources. We explored how choice of data cleaning type and level, taxonomic group, training sample, and automation method affect performance of threat status predictions for plant species. We used occurrences from the Global Biodiversity Information Facility (GBIF) to generate assessments for species in 3 taxonomic groups based on 6 different occurrence-based AA methods. We measured each method's performance and coverage following increasingly stringent occurrence cleaning. Automatically cleaned data from GBIF performed comparably to occurrence records cleaned manually by experts. However, all types of data cleaning limited the coverage of AAs. Overall, machine-learning-based methods performed well across taxa, even with minimal data cleaning. Results suggest a machine-learning-based method applied to minimally cleaned data offers the best compromise between performance and species coverage. However, optimal data cleaning, training sample, and automation methods depend on the study group, intended applications, and expertise. 相似文献
106.
Water Use for Hydraulic Fracturing of Oil and Gas in the South Platte River Basin,Colorado
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Ella L. Walker Aspen M. Anderson Laura K. Read Terri S. Hogue 《Journal of the American Water Resources Association》2017,53(4):839-853
Water use for oil and gas development (i.e., hydraulic fracturing) is a concern in semiarid basins where water supply is often stressed to meet demands, and oil and gas production can exacerbate the situation. Understanding the impacts of water use for hydraulic fracturing (HF) on water availability in semiarid regions is critical for management and regulatory decisions. In the current work, we quantify water use for HF at several scales — from municipal to state‐wide — using the IHS Enerdeq database for the South Platte Basin. In addition, we estimate produced water (a by‐product of oil and gas production), using data from the Colorado Oil and Gas Conservation Commission to explore reuse scenarios. The South Platte River Basin, located in northeastern Colorado, encompasses the Denver‐Metro area. The basin has one of the most productive oil and gas shale formations in Colorado, with much of the production occurring in Weld County. The basin has experienced higher horizontal drilling rates coupled with an increasing population. Results show water use for horizontal and vertical wells averages 11,000 and 1,000 m3, respectively. Water use for HF in the South Platte Basin totaled 0.63% of the basin's 2014 total water demand. For Weld County, water use for HF was 2.4% of total demand, and for the city of Greeley, water use was 7% of total demand. Produced water totaled 9.4 Mm3 in the basin for 2014, which represents 42% of the total water used for HF. 相似文献
107.
In places like Canada, fast-paced wind turbine development combined with policy that limits local decision-making power has resulted in strong opposition to specific projects. Some studies suggest that anti-wind sentiment is tied to inadequate financial benefits – especially sharing at the local level. Thus, ideas of distributive economic justice have received traction, particularly in the form of praise for community-based development models. This paper reports on the findings from a mixed-methods study concerning preferred distributive justice elements in rural communities in Ontario (technocratic-based model) and Nova Scotia (community-based model) living with turbines. Residents’ perceptions of economic benefits are nuanced, but unlike other studies, this empirical work shows that both the fair distribution and the amount of local benefits are important predictors of project support. Yet, concerns around the fair distribution of benefits dominate in a regression on the adequacy of those benefits. A variety of interview and survey findings further point to the strength of traditional, profit-sharing community-based models for distributing benefits, but also more novel ideas including lowered electricity bills and tax rebates in areas home to turbines. 相似文献
108.
Sandra L. Wilson Gerrit Voordouw Virginia K. Walker 《Environmental science and pollution research international》2014,21(17):10254-10261
Economic concerns associated with the recovery of non-conventional hydrocarbon reserves include unexpected ice as well as ice-like gas hydrate formation. Antifreeze proteins (AFPs) inhibit ice growth, and experiments with fish, plant, and insect AFPs have shown promise of effective gas hydrate inhibition in lab-scale experiments. If produced on an industrial scale, AFPs could provide a more environmentally friendly alternative to kinetic inhibitors, but a large-scale production of these AFPs is not currently feasible. We believe that these difficulties could be surmounted by the production of microbial AFPs, but to date, only a few such proteins have been identified and purified, and none of these are associated with hydrocarbon reserves. Here, we have used ice-affinity and freeze-thaw stress to select microbes derived from oil and gas formation water, or produced water, as a source of anaerobic microbial communities. Ice-affinity successfully incorporated anaerobic bacteria under aerobic conditions, and the mixed culture had ice-associating properties. Under these conditions, ice-affinity selection does not result in cultivatable isolates, but similar, cultivable microbes were obtained following freeze-thaw selection under anaerobic conditions. Since these mixed cultures inhibited the growth of ice crystals, they also have the potential to inhibit hydrate growth. Overall, freeze-thaw selection provides a promising first step towards the isolation of microbes capable of the inhibition of ice and gas hydrate growth, for possible application for energy exploration and recovery at high-latitudes and in-deep, cold waters. 相似文献
109.
J. A. Raven D. I. Walker K. R. Jensen L. L. Handley C. M. Scrimgeour S. G. McInroy 《Marine Biology》2001,138(3):537-545
any sacoglossans (opisthobranch gastropods) have the potential for carbon acquisition from photosynthesis by plastids sequestered
from their macroalgal food as well as by ingestion, digestion and assimilation of the organic carbon derived from the alga.
A new method for obtaining a minimum estimate of the fraction of sacoglossan carbon supplied from photosynthesis by kleptoplastids
is suggested, based on the mass balance of stable carbon isotopes at the natural abundance level. The method involves comparison
of 13C/12C ratios in sacoglossans with those of the algae on which they are found. Differences in ratios between alga and sacoglossan
are used to give a minimum estimate of carbon acquisition by kleptoplasty, granted assumptions about the range of 13C/12C fractionation values which can occur for marine photolithotrophs. The new method is applied to several green (ulvophycean)
alga–sacoglossan associations from Rottnest Island, Western Australia, and the values compared with those obtained previously
by other means. The method suggests values of up to 0.6 of the total carbon input to the sacoglossans from photosynthesis
by their kleptoplastids. To improve the estimates of the minimum role of kleptoplastidy in the carbon nutrition of sacoglossans,
further information is needed: (1) on the fidelity of a given sacoglossan to a given algal individual (or species), (2) on
the 13C/12C ratio of the part of the alga ingested by the sacoglossan, and (3) on the allocation of dietary organic carbon and of kleptoplastidic
photosynthate to carbon lost in respiration, mucopolysaccharide production and gametes (and hence not sampled with the animal).
Received: 24 November 1999 / Accepted: 20 October 2000 相似文献
110.
Using mussels as monitoring tools we measured water quality in Sydney Harbour during a large scale, multi-year remediation project of the Sydney Tar Ponds (STPs); one of Canada's most contaminated sites. Chemical contaminants were measured in blue mussels (Mytilus edulis) in Sydney Harbour, which were used as monitoring tools to assess the spatio-temporal distribution of polycyclic aromatic hydrocarbons (PAHs); polychlorinated biphenyls (PCBs); metals (As, Cd, Cu, Hg, Pb, Zn) and lipid content during baseline and 3 years of remediation. The overall spatio-temporal distribution of chemicals in mussels was also compared to contaminants in other marine indicators (e.g., sediment, water and crab tissue). Measured metal concentrations in mussels showed some minor temporal variability (4 years), but these did not appear to be directly related to remediation activities, with the highest concentrations of As, Hg and Zn measured at reference stations. Most measured contaminants showed stable or potentially decreasing concentrations during the study, except Pb and Zn. Individual PAH compounds were mostly undetected during baseline and remediation, except for fluoranthene and pyrene. Concentrations of fluoranthene in mussels and deep water samples were moderately related. Generally, PCBs were undetected (<0.05 μg g?1), except during year 2 remediation at some near-field stations. Contaminants measured during this study were at much lower concentrations than previously reported in other studies of mussels in Sydney Harbour and eastern Canada. This is likely due to the ongoing natural recovery of Sydney Harbour and to a lesser extent because of the environmental mitigation protection measures implemented during remediation activities at the STPs. The lack of detection of most individual PAHs and PCBs, plus relatively low bio-accumulation of metals observed during baseline and remediation attest to the effectiveness of using mussels as monitoring tools for environmental quality. 相似文献