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131.
132.
Brian E. Reichert Mylea Bayless Tina L. Cheng Jeremy T. H. Coleman Charles M. Francis Winifred F. Frick Benjamin S. Gotthold Kathryn M. Irvine Cori Lausen Han Li Susan C. Loeb Jonathan D. Reichard Thomas J. Rodhouse Jordi L. Segers Jeremy L. Siemers Wayne E. Thogmartin Theodore J. Weller 《Ambio》2021,50(4):901
Collaborative monitoring over broad scales and levels of ecological organization can inform conservation efforts necessary to address the contemporary biodiversity crisis. An important challenge to collaborative monitoring is motivating local engagement with enough buy-in from stakeholders while providing adequate top-down direction for scientific rigor, quality control, and coordination. Collaborative monitoring must reconcile this inherent tension between top-down control and bottom-up engagement. Highly mobile and cryptic taxa, such as bats, present a particularly acute challenge. Given their scale of movement, complex life histories, and rapidly expanding threats, understanding population trends of bats requires coordinated broad-scale collaborative monitoring. The North American Bat Monitoring Program (NABat) reconciles top-down, bottom-up tension with a hierarchical master sample survey design, integrated data analysis, dynamic data curation, regional monitoring hubs, and knowledge delivery through web-based infrastructure. NABat supports collaborative monitoring across spatial and organizational scales and the full annual lifecycle of bats. 相似文献
133.
Rebecca L. Phillips Moffatt K. Ngugi John Hendrickson Aaron Smith Mark West 《Environmental management》2012,50(5):914-928
Managers of the nearly 0.5 million ha of public lands in North and South Dakota, USA rely heavily on manual measurements of canopy height in autumn to ensure conservation of grassland structure for wildlife and forage for livestock. However, more comprehensive assessment of vegetation structure could be achieved for mixed-grass prairie by integrating field survey, topographic position (summit, mid and toeslope) and spectral reflectance data. Thus, we examined the variation of mixed-grass prairie structural attributes (canopy leaf area, standing crop mass, canopy height, nitrogen, and water content) and spectral vegetation indices (VIs) with variation in topographic position at the Grand River National Grassland (GRNG), South Dakota. We conducted the study on a 36,000-ha herbaceous area within the GRNG, where randomly selected plots (1?km2 in size) were geolocated and included summit, mid and toeslope positions. We tested for effects of topographic position on measured vegetation attributes and VIs calculated from Landsat TM and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data collected in July 2010. Leaf area, standing crop mass, canopy height, nitrogen, and water content were lower at summits than at toeslopes. The simple ratio of Landsat Band 7/Band 1 (SR71) was the VI most highly correlated with canopy standing crop and height at plot and landscape scales. Results suggest field and remote sensing-based grassland assessment techniques could more comprehensively target low structure areas at minimal expense by layering modeled imagery over a landscape stratified into topographic position groups. 相似文献
134.
J T Smith O V Voitsekhovitch L H?kanson J Hilton 《Journal of environmental radioactivity》2001,56(1-2):11-32
Following a radioactive fallout event, there are a number of possible intervention measures to reduce radioactive doses to the public via the surface water pathway. We have critically reviewed the options available to decision-makers in the event of radioactive contamination of surface waters. We believe that the most effective and viable measures to reduce radioactivity in drinking water are those which operate at the water treatment and distribution stage. Intervention measures to reduce concentrations of radioactivity in rivers and reservoirs are expected to be much less viable and efficient at reducing doses via the drinking water pathway. Bans on consumption of freshwater fish can be effective, but there are few viable measures to reduce radioactivity in fish prior to the preparation stage. Lake liming and biomanipulation have been found to be ineffective for radiocaesium, although the addition of potassium to lakewaters appears promising in some situations. Lake liming may be effective in reducing radiostrontium in fish, though this has not, to our knowledge, been tested. De-boning fish contaminated by strontium is probably the most effective food preparation measure, but salting and freezing can also reduce radiocaesium concentrations in fish. The provision of accurate information to the public is highlighted as a key element of countermeasure implementation. 相似文献
135.
Charles T. Garten Deanne J. Brice Hector F. Castro Robin L. Graham Melanie A. Mayes Jana R. Phillips Wilfred M. Post Christopher W. Schadt Stan D. Wullschleger Donald D. Tyler Phillip M. Jardine Julie D. Jastrow Roser Matamala R. Michael Miller Kelly K. Moran Timothy W. Vugteveen R. Cesar Izaurralde Allison M. Thomson Tristram O. West James E. Amonette Jeffrey L. Smith 《Agriculture, ecosystems & environment》2011,140(1-2):289-297
Switchgrass (Panicum virgatum) is a perennial, warm-season grass that has been identified as a potential biofuel feedstock over a large part of North America. We examined above- and belowground responses to nitrogen fertilization in “Alamo” switchgrass grown in West Tennessee, USA. The fertilizer study included a spring and fall sampling of 5-year old switchgrass grown under annual applications of 0, 67, and 202 kg N ha?1 (as ammonium nitrate). Fertilization changed switchgrass biomass allocation as indicated by root:shoot ratios. End-of-growing season root:shoot ratios (mean ± SE) declined significantly (P ≤ 0.05) at the highest fertilizer nitrogen treatment (2.16 ± 0.08, 2.02 ± 0.18, and 0.88 ± 0.14, respectively, at 0, 67, and 202 kg N ha?1). Fertilization also significantly increased above- and belowground nitrogen concentrations and decreased plant C:N ratios. Data are presented for coarse live roots, fine live roots, coarse dead roots, fine dead roots, and rhizomes. At the end of the growing season, there was more carbon and nitrogen stored in belowground biomass than aboveground biomass. Fertilization impacted switchgrass tissue chemistry and biomass allocation in ways that potentially impact soil carbon cycle processes and soil carbon storage. 相似文献
136.
M. L. Smith O. L. Pellett M. M. J. Cass N. G. Kennaway N. R. M. Buist J. Buckmaster M. Golbus G. S. Spear J. A. Schneider 《黑龙江环境通报》1987,7(1):23-26
The prenatal diagnosis of cystinosis is currently based on the increased amount of free-cystine present in amniotic fluid cells. Amniocyte cultures must be grown for at least 2 weeks to obtain sufficient cells for such measurements. Thus, the diagnosis cannot be made until close to 20 weeks gestational age by this method. We report a case in which chorionic villi were used for direct cystine measurement resulting in the in utero diagnosis of cystinosis at 9 weeks gestational age. The diagnosis was confirmed by the study of cultured chorionic villus cells, and of the 10-week abortus. 相似文献
137.
Honey-bee (Apis mellifera) colonies exhibit extreme reproductive division of labour. Workers almost always have inactive ovaries and the queen monopolises
egg laying. Although extremely rare, ’anarchistic’ colonies exist in which workers produce male offspring despite the presence
of the queen. By comparing the rates of ovary activation in anarchistic and wild-type bees fostered to host colonies of different
genotype (i.e. anarchist and non-anarchist) and queen status (i.e. queenless and queenright), we investigated the factors
involved in inhibiting ovary activation. Fostered anarchist workers always had a higher level of ovary development than fostered
wild-type bees in both anarchist and non-anarchist host colonies. Fostered workers of both genotypes had more active ovaries
in anarchistic than in wild-type hosts. Fostered workers of both strains also had more active ovaries in queenless than in
queenright hosts. The results suggest that selection for worker reproduction in the anarchistic line has both reduced the
effects of brood and queen pheromones on worker ovary inhibition and increased the likelihood that workers of the anarchistic
line will develop ovaries compared to wild-type workers.
Received: 14 June 2000 / Revised: 26 September 2000 / Accepted: 7 October 2000 相似文献
138.
Corals are the primary reef-building organisms, therefore it is key to understand their recruitment patterns for effective reef management. Coral recruitment rates and juvenile coral abundance were recorded in the Wakatobi National Marine Park, Indonesia, on two reefs (Sampela and Hoga) with different levels of environmental degradation (12.5 vs. 44 % coral cover with high and low sedimentation rates, respectively) to examine consistencies in recruitment patterns between years and seasons. Recruitment was measured on multiple panels at two sites on each reef (6–7 m depth) and cleared areas of natural reef. Although coral recruitment was twofold higher in 2008–2009 than in 2007–2008, and seasonal differences were identified, consistent significant differences in recruitment rates were found between the two reefs even though they are separated by only ~1.5 km. Recruitment rates and juvenile abundance were lower on the more degraded reef. These patterns are likely a consequence of differential pre- and post-settlement mortality as a result of the high sedimentation rates and degraded conditions and possibly reduced larval supply. 相似文献
139.
140.
Zachary A. Smith 《Journal of the American Water Resources Association》1987,23(5):873-877
ABSTRACT: Federal-state relations over the management and regulation of ground water resources have undergone a number of changes in recent years. There are a variety of reasons that the role of the federal government in ground water management may increase in the future. One important reason federal policymakers may become involved concerns the extent of competition for ground water resources that cross state and national borders. This article summarizes reasons that interstate and international competition for ground water resources may provide the impetus for federal intervention in ground water management and presents the results of a survey conducted to determine the extent of that competition. 相似文献