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101.
102.
Crystal Lesmeister Larry Pochop Greg Kerr Shaun S. Wulff Drew Johnson 《Journal of the American Water Resources Association》2007,43(4):938-946
Abstract: The effectiveness of measuring lawn sprinkler application rates using the catch‐can test was evaluated. A survey of sources recommending the catch‐can test for measuring application rates show that catch‐can test procedures differ in the collector type, collector placement, number of collectors, and test duration. Analyses of catch‐can tests were performed to address these procedural differences, with emphasis on the type and number of collectors required to provide a reasonable level of confidence in test results. The accuracy of the catch‐can test generally improves as the number of randomly placed collectors increases. In order to achieve an accuracy of ±25% for 90 out of 100 catch‐can tests, the number of randomly placed collectors required ranged from 6 to over 50 for hand‐move systems, while for in‐ground systems, the number of randomly placed collectors required ranged from 2 to 8, depending on the pressure and percent overlap of the water distribution pattern. As long as a reasonable number of collectors were used when performing a catch‐can test, no consistent differences were observed in catch‐can test results due to type of collectors when using tuna fish cans, soup cans, or coffee mugs. 相似文献
103.
Numbers of elephants have declined in Africa and Asia over the past 30 years while numbers of humans have increased, both substantially. Friction between these two keystone species is reaching levels which are worryingly high from an ecological as well as a political viewpoint. Ways and means must be found to keep the two apart, at least in areas sensitive to each species' survival. The aggressive African bee might be one such method. Here we demonstrate that African bees deter elephants from damaging the vegetation and trees which house their hives. We argue that bees can be employed profitably to protect not only selected trees, but also selected areas, from elephant damage. 相似文献
104.
Isolation of Atlantic cod (<Emphasis Type="Italic">Gadus morhua</Emphasis>) nursery areas 总被引:2,自引:0,他引:2
This study examines the degree of isolation among 0-group Atlantic cod in a region where a number of resident adult congregations
have been found. The location of key nursery areas in Scottish coastal waters was identified from trawl surveys of settled
0-group cod around the Scottish coast. Segregation among four of these key areas; within the Clyde, Shetland Isles, Moray
Firth and Buchan was investigated using otolith elemental composition. Isotope concentrations in the otoliths of cod were
analysed by solution-based inductively coupled plasma mass spectrometry of the whole otolith. Discriminant analyses showed
a clear separation between nursery areas based on the concentrations of three elements (manganese, barium and magnesium).
The concentration of these elements was not affected by the age or size of individuals. Classification accuracy exceeded 90%
for all four sites. Evidence of temporal persistence in the relative spatial differences in elemental concentrations between
two sites for 2 year-classes was found. The results suggest limited exchange between sites during some period of the early
life history. The significance of this limited exchange is discussed in relation to recent evidence for adult fidelity and
the utility of closed areas for protecting nursery grounds. 相似文献
105.
The influence of naturally occurring uraniferous black shales on cadmium, molybdenum and selenium concentrations in soils
and plants is examined. The possible implications of element concentrations to animal and human health are considered for
the Deog-Pyoung area.
Geochemical surveys have been undertaken within 13 river tributary valleys in the area underlain by uraniferous black shales
and black slates or grey chlorite schists. Sampling of rocks, soils and plants has been carried out along transect lines within
each valley. Samples were analysed for trace elements by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)
and for uranium by Neutron Activation Analysis (NAA). Soil pH, cation exchange capacity, loss on ignition and particle size
distribution have been measured for selected samples.
Average trace element concentrations of the Okchon uraniferous black shales were 6.3 μg g−1 Cd, 136 μg g−1 Mo and 8.6 μg g−1 Se. Soils derived from these rocks tend to reflect their extreme geochemical composition. Trace element concentrations in
alluvial soils derived in part from these black shales averaged 1.2 μg g−1 Cd, 20 μg g−1 Mo and 1.5 μg g−1 Se. Trace element concentrations in plants were found to be influenced by those of soils. Cadmium accumulated in tobacco
leaves up to 46 μg g−1 (D.M.) and leafy plants such as lettuce contain up to 0.5 μg g−1 Se (D.M.).
In addition to total concentrations in soils, soil pH is a major factor influencing uptake of Mo into crop plants and soil
texture for Se. Concentrations of trace elements in plants also varied between plant species. The relative concentrations
of Cd were found to vary in the order tobacco > lettuce > red pepper > rice grain.
Elevated concentrations of Cd in crop plants and in tobacco may possibly have deleterious effects on human health in this
area. The low Cu:Mo ratio in rice stalk of 2.65:1 may be associated with disturbed Cu metabolism in ruminant animals which
regularly consume this material. 相似文献
106.
Arthur C. Miller Sonja N. Kerr Donald J. Spaeder 《Journal of the American Water Resources Association》1983,19(4):625-630
ABSTRACT Unit hydrograph theory is one of the most widely used techniques to predict surface runoff. The present study is concerned with the Snyder unit hydrograph and the calibration of the Snyder coefficients for Pennsylvania. Twenty-seven study basins were selected, located randomly across the state. With the rainfall and runoff recorded for several events for each basin (more than 500 events were analyzed) unit hydrographs were calculated and the Snyder coefficients determined. A map of the coefficients was drawn to illustrate the variability in the coefficients and two equations using multiple regression theory were developed. The unexplained variability of the coefficients suggests that upper and lower bounds on the peak flow might be placed on storm hydrographs developed for ungaged watersheds. 相似文献
107.
Soil and pasture herbage samples from some historical metalliferous mining and smelting areas in England were analysed for
As, Sb and Bi by ICP-AES using a hydride generation method after ashing with Mg(NO3)2. The results showed that As, Sb and Bi concentrations in soils were elevated because of their associations with the Pb-Zn
mineralisation in Derbyshire and Somerset, and Sn-Cu mineralisation in Cornwall. The distribution of As, Sb and Bi in soils
reflected the chemical nature of different mine waste materials, and on a regional basis clearly reflected the geochemistry
of the three mineral provinces. Historical smelting and calcination have caused intensive contamination in soils in the immediate
vicinity of these activities. Antimony was highly elevated in soils at an old Pb smelter site in Derbyshire. Although the
concentrations of As, Sb and Bi were generally low in the pasture herbage samples examined, the concentrations of As and Sb
in herbage often reflected those of the corresponding soils. Soil pH had a large effect on the plant uptake of Bi from soils.
The pasture herbage contaminated by soil can be an important exposure pathway of these elements to livestock grazing on contaminated
land. 相似文献
108.
Pip Wallace Ross Martin Iain White 《Journal of Environmental Planning and Management》2018,61(7):1271-1288
This paper analyses regulatory responses to rapid intensification of the use of drones/remotely piloted aircraft (RPA) in the context of wildlife protection. Benefits and disadvantages of the technology to wildlife are examined, before three key limitations in policy and law are identified: failure to address wildlife disturbance in RPA regulation; reliance upon insufficiently comprehensive existing wildlife protection legislation to manage disturbance effects; and limited species-specific research on disturbance. A New Zealand case study further reveals an inconsistent regulatory approach struggling to keep pace with innovation, inadequate regulatory capture of environmental effects due to exemption as “aircraft”, and no recognition that specific geographical locations, such as coastal areas, distinguished by recreational pressures and high numbers of threatened species require special consideration. Recommendations include acknowledging the impact on wildlife in policy, gap analysis of legal arrangements for protection from disturbance (including airspace), and adoption of minimum approach distances to threatened species. 相似文献
109.
Ben J. Rushbrook Megan L. Head Ioanna Katsiadaki Iain Barber 《Behavioral ecology and sociobiology》2010,64(12):1927-1935
Animals usually build nests to provide protection, for themselves or their offspring, from adverse environmental conditions.
However, different nest structures may be better at providing protection in different environments. The ability to adjust
building behaviour and design of nests in response to variation in environmental conditions is therefore likely to be important
in determining individual fitness. Here, we look at how the nests of three-spined stickleback (Gasterosteus aculeatus) males differ between still and flowing water conditions. Within flowing water treatments, we find that males select nesting
sites with lower than average flow. We also find that nests built in flowing water are smaller and more streamlined than those
built in still water. Nests built in flowing water contain more spiggin—an endogenous glycoprotein secreted by nesting males—per
gramme of nest material than still water nests, though the absolute spiggin content of nests did not vary with flow regime.
These results suggest that male sticklebacks may adjust nest-site selection and nest structure to suit environmental conditions
in which they are building. Because flow regime is a factor that is often altered by anthropogenic activities, such as impoundment,
channelization and abstraction, this study may also have implications for the conservation of freshwater fish populations. 相似文献
110.
A global evaluation of metabolic theory as an explanation for terrestrial species richness gradients 总被引:5,自引:0,他引:5
Hawkins BA Albuquerque FS Araujo MB Beck J Bini LM Cabrero-Sañudo FJ Castro-Parga I Diniz-Filho JA Ferrer-Castan D Field R Gómez JF Hortal J Kerr JT Kitching IJ León-Cortés JL Lobo JM Montoya D Moreno JC Olalla-Tárraga MA Pausas JG Qian H Rahbek C Rodríguez MA Sanders NJ Williams P 《Ecology》2007,88(8):1877-1888
We compiled 46 broadscale data sets of species richness for a wide range of terrestrial plant, invertebrate, and ectothermic vertebrate groups in all parts of the world to test the ability of metabolic theory to account for observed diversity gradients. The theory makes two related predictions: (1) In-transformed richness is linearly associated with a linear, inverse transformation of annual temperature, and (2) the slope of the relationship is near -0.65. Of the 46 data sets, 14 had no significant relationship; of the remaining 32, nine were linear, meeting prediction 1. Model I (ordinary least squares, OLS) and model II (reduced major axis, RMA) regressions then tested the linear slopes against prediction 2. In the 23 data sets having nonlinear relationships between richness and temperature, split-line regression divided the data into linear components, and regressions were done on each component to test prediction 2 for subsets of the data. Of the 46 data sets analyzed in their entirety using OLS regression, one was consistent with metabolic theory (meeting both predictions), and one was possibly consistent. Using RMA regression, no data sets were consistent. Of 67 analyses of prediction 2 using OLS regression on all linear data sets and subsets, two were consistent with the prediction, and four were possibly consistent. Using RMA regression, one was consistent (albeit weakly), and four were possibly consistent. We also found that the relationship between richness and temperature is both taxonomically and geographically conditional, and there is no evidence for a universal response of diversity to temperature. Meta-analyses confirmed significant heterogeneity in slopes among data sets, and the combined slopes across studies were significantly lower than the range of slopes predicted by metabolic theory based on both OLS and RMA regressions. We conclude that metabolic theory, as currently formulated, is a poor predictor of observed diversity gradients in most terrestrial systems. 相似文献