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Sandra A. Bryce David P Larsen Robert M. Hughes Philip R. Kaufmann 《Journal of the American Water Resources Association》1999,35(1):23-36
ABSTRACT: Aquatic monitoring aims to assess the condition of aquatic habitats and biota. To make statements about condition, the range of human activities and the risks they pose to aquatic ecosystems must be identified. Assessing relative risk and placing sample sites on a human disturbance gradient is necessary for interpreting biological response and distinguishing human disturbance from natural controls in aquatic systems. We describe a process that uses readily available sources, such as topographic maps, aerial photographs, and field information, to identify and prioritize stream reach and watershed stressors for 102 streams in the mid-Appalachian region of the United States. All perceptible human alterations to riparian and upland areas along with their number, type, intensity, and extent of impact were recorded and ranked; a relative risk index was developed to assign scores to the watersheds. The resulting risk index scores were consistent with measures of stream condition based on water chemistry and benthic macroinvertebrates. The risk index gives a cost-effective, regional picture of the relative risk of impairment to aquatic ecosystems in the mid-Appalachian region of the USA and could be modified for other regions or ecosystem types. 相似文献
94.
Rania Bou Kheir Mogens H. Greve Peder K. Bøcher Mette B. Greve René Larsen Keith McCloy 《Journal of environmental management》2010,91(5):1150-1160
Soil organic carbon (SOC) is one of the most important carbon stocks globally and has large potential to affect global climate. Distribution patterns of SOC in Denmark constitute a nation-wide baseline for studies on soil carbon changes (with respect to Kyoto protocol). This paper predicts and maps the geographic distribution of SOC across Denmark using remote sensing (RS), geographic information systems (GISs) and decision-tree modeling (un-pruned and pruned classification trees). Seventeen parameters, i.e. parent material, soil type, landscape type, elevation, slope gradient, slope aspect, mean curvature, plan curvature, profile curvature, flow accumulation, specific catchment area, tangent slope, tangent curvature, steady-state wetness index, Normalized Difference Vegetation Index (NDVI), Normalized Difference Wetness Index (NDWI) and Soil Color Index (SCI) were generated to statistically explain SOC field measurements in the area of interest (Denmark). A large number of tree-based classification models (588) were developed using (i) all of the parameters, (ii) all Digital Elevation Model (DEM) parameters only, (iii) the primary DEM parameters only, (iv), the remote sensing (RS) indices only, (v) selected pairs of parameters, (vi) soil type, parent material and landscape type only, and (vii) the parameters having a high impact on SOC distribution in built pruned trees. The best constructed classification tree models (in the number of three) with the lowest misclassification error (ME) and the lowest number of nodes (N) as well are: (i) the tree (T1) combining all of the parameters (ME = 29.5%; N = 54); (ii) the tree (T2) based on the parent material, soil type and landscape type (ME = 31.5%; N = 14); and (iii) the tree (T3) constructed using parent material, soil type, landscape type, elevation, tangent slope and SCI (ME = 30%; N = 39). The produced SOC maps at 1:50,000 cartographic scale using these trees are highly matching with coincidence values equal to 90.5% (Map T1/Map T2), 95% (Map T1/Map T3) and 91% (Map T2/Map T3). The overall accuracies of these maps once compared with field observations were estimated to be 69.54% (Map T1), 68.87% (Map T2) and 69.41% (Map T3). The proposed tree models are relatively simple, and may be also applied to other areas. 相似文献
95.
Severin Olesen Larsen Karen R. Wøjdemann Anne-Cathrine Shalmi Karin Sundberg Michael Christiansen Ann Tabor 《黑龙江环境通报》2002,22(13):1207-1208
The influence of fetal gender on the level in the first trimester of the serological markers alpha-fetoprotein (AFP), pregnancy-associated plasma protein-A (PAPP-A) and free beta human chorionic gonadotropin (βhCG) and on nuchal translucency is described for 2637 singleton pregnancies with normal outcome. Mean log MoM values for pregnancies with female and male fetuses were calculated using regression of log marker values on gestational age expressed as crown rump length and on maternal weight. A pronounced gender impact was found for free βhCG, being 16% higher for female than for male fetuses. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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Kirstin?Anderson?HansenEmail authorView authors OrcID profile Alyssa?Maxwell Ursula?Siebert Ole?N?sbye?Larsen Magnus?Wahlberg 《Die Naturwissenschaften》2017,104(5-6):45
In-air hearing in birds has been thoroughly investigated. Sound provides birds with auditory information for species and individual recognition from their complex vocalizations, as well as cues while foraging and for avoiding predators. Some 10% of existing species of birds obtain their food under the water surface. Whether some of these birds make use of acoustic cues while underwater is unknown. An interesting species in this respect is the great cormorant (Phalacrocorax carbo), being one of the most effective marine predators and relying on the aquatic environment for food year round. Here, its underwater hearing abilities were investigated using psychophysics, where the bird learned to detect the presence or absence of a tone while submerged. The greatest sensitivity was found at 2 kHz, with an underwater hearing threshold of 71 dB re 1 μPa rms. The great cormorant is better at hearing underwater than expected, and the hearing thresholds are comparable to seals and toothed whales in the frequency band 1–4 kHz. This opens up the possibility of cormorants and other aquatic birds having special adaptations for underwater hearing and making use of underwater acoustic cues from, e.g., conspecifics, their surroundings, as well as prey and predators. 相似文献
98.
D. P. Larsen K. W. Thornton N. S. Urquhart S. G. Paulsen 《Environmental monitoring and assessment》1994,32(2):101-134
In order to meet a growing need to determine the condition of the nation's ecosystems and how their condition is changing, the U.S. Environmental Protection Agency (EPA) developed EMAP, the Environmental Monitoring and Assessment Program. A common survey design serves as the foundation on which to base monitoring of status and trends among diverse ecosystem types. In this paper, we describe the need for a statistically based survey design, briefly summarize the basic EMAP design, describe how that design is tailored for the selection of a probability sample of lakes on which to make measurements of lake condition, and illustrate the process for selecting a sample of lakes in the northeastern United States. Finally, we illustrate how measurements taken on the sample of lakes can be summarized, with known uncertainty, to describe the condition of a population of lakes.The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. 相似文献
99.
Petter Næss Per Gunnar Røe Synnøve Larsen 《Journal of Environmental Planning and Management》1995,38(3):349-370
A study of the use of car and public transport among residents in 30 residential areas in Greater Oslo indicates that urban planning variables have a significant influence on the energy use per capita for local transport. Residents in local communities with a high density and a short distance to downtown Oslo travel considerably shorter distances and use considerably less energy per capita than those who live in low-density, outer areas. This is true also when the effects of other variables are neutralized. The influence of urban planning variables on the modal split is lower than on energy use. The distribution between public and private transport is influenced most of all by car ownership. 相似文献
100.
Ieva Miceikaite Christina Fagerberg Charlotte Brasch-Andersen Pernille Mathiesen Torring Britta Schlott Kristiansen Qin Hao Lene Sperling Mette Holm Ibsen Katrin Löser Eske Alf Bendsen Lilian Bomme Ousager Martin Jakob Larsen 《黑龙江环境通报》2023,43(9):1132-1141