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781.
We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand,
to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing
or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted
negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu
occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest
cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream
mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence
was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount
of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being
greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover
undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification.
We also modeled potential future scenarios to project potential fish distribution. 相似文献
782.
Tim Chatterton Stephen Dorling Andrew Lovett Michael Stephenson 《Water, Air, & Soil Pollution: Focus》2002,2(5-6):173-187
This study uses a combination of data from U.K. monitoringstations and from modelling undertaken with the U.K.Meteorological Office's NAME Model to investigate therelative influences of primary and secondary particulateson total PM10 levels at sites in the United Kingdom. Co-located PM10 and sulphate aerosol measurementsindicate that sulphate has a disproportionately largeinfluence on the variation of PM10 levels incomparison to its contribution to their total mass.Comparisons of measured PM10 at urban centre, roadsideand rural sites suggest that local primary sources havevery little influence on daily mean levels. NAME has beenused to model both primary particles and sulphate aerosolfrom sources across the whole of Europe. The discrepanciesbetween modelled and observed PM10 suggest that coarseparticles, such as windblown dust and resuspended roaddust,may comprise a very large, if not dominant, proportion ofobserved PM10 levels. The apparently minor role ofprimary particles (especially locally-sourced ones) raisesa number of issues regarding the suitability of current U.K.and European legislation to addressing the particle problem. 相似文献
783.
The US Department of Defense (DOD) manages over 10.1 million ha of land, much of which is used for training military personnel.
However, vast sections receive little or no use, and military lands have become refuges for many species. At Fort McCoy, Wisconsin,
USA, populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis) are found in oak and pine barren communities where wild lupine (Lupinus perennis), a perennial forb required by Karner blue butterfly larvae, still occurs. Oak and pine barren communities are disturbance-dependent,
and the barrens ecosystems in the Midwest have declined in extent by 98% because of fire suppression, succession, and habitat
fragmentation. We studied the effects of disturbance by military manuever training on the density of lupine and Karner blue
butterfly at Fort McCoy. We also wanted to determine whether military training activity could enhance Karner blue butterfly
habitat.
At locations where tracked vehicles had driven through lupine patches, the abundance of lupine and nectar-producing plants
was greater in the median strip between vehicle ruts than in vehicle ruts or 5 m outside the vehicle ruts. The proportion
of lupine stems with Karner blue butterfly larvae feeding sign (the ratio of stems fed upon to stems examined) was greater
in areas where military vehicles had traveled than where they had not. The proportion of lupine stems with feeding sign and
lupine stem density was also positively related to the occurrence of prior bivouacs and fires caused by military munitions.
Shrub and forest canopy abundance were lower in areas traveled by tracked vehicles. At the scale of the lupine patch, lupine
abundance and the proportion of lupine stems with feeding sign were positively correlated with military training activities,
suggesting that maintenance of lupine habitat can be achieved in concert with military training. 相似文献
784.
A. Allen Bradley Christa Peters‐Lidard Brian R. Nelson James A. Smith C. Bryan Young 《Journal of the American Water Resources Association》2002,38(5):1393-1407
ABSTRACT: A general framework is proposed for using precipitation estimates from NEXRAD weather radars in raingage network design. NEXRAD precipitation products are used to represent space time rainfall fields, which can be sampled by hypothetical raingage networks. A stochastic model is used to simulate gage observations based on the areal average precipitation for radar grid cells. The stochastic model accounts for subgrid variability of precipitation within the cell and gage measurement errors. The approach is ideally suited to raingage network design in regions with strong climatic variations in rainfall where conventional methods are sometimes lacking. A case study example involving the estimation of areal average precipitation for catchments in the Catskill Mountains illustrates the approach. The case study shows how the simulation approach can be used to quantify the effects of gage density, basin size, spatial variation of precipitation, and gage measurement error, on network estimates of areal average precipitation. Although the quality of NEXRAD precipitation products imposes limitations on their use in network design, weather radars can provide valuable information for empirical assessment of rain‐gage network estimation errors. Still, the biggest challenge in quantifying estimation errors is understanding subgrid spatial variability. The results from the case study show that the spatial correlation of precipitation at subgrid scales (4 km and less) is difficult to quantify, especially for short sampling durations. Network estimation errors for hourly precipitation are extremely sensitive to the uncertainty in subgrid spatial variability, although for storm total accumulation, they are much less sensitive. 相似文献
785.
Michael C. Appleby Neil Cutler John Gazzard Peter Goddard John A. Milne Colin Morgan Andrew Redfern 《Journal of Agricultural and Environmental Ethics》2003,16(4):395-408
This paper is the report of a meetingthat gathered many of the UK's most senioranimal scientists with representatives of thefarming industry, consumer groups, animalwelfare groups, and environmentalists. Therewas strong consensus that the current economicstructure of agriculture cannot adequatelyaddress major issues of concern to society:farm incomes, food security and safety, theneeds of developing countries, animal welfare,and the environment. This economic structure isbased primarily on competition betweenproducers and between retailers, driving foodprices down, combined with externalization ofmany costs. These issues must be addressed by acombination of legislation, restructuring ofthe market, and use of public funds. Themeeting included workshops that made otherrecommendations for research and education. Themost urgent requirement is recognition thatchange is needed and development of a visionfor what that change must achieve. 相似文献
786.
Terri Smith 《补救:环境净化治理成本、技术与工艺杂志》2003,13(3):81-86
The enactment of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) created a complex liability scheme for owners, operators and prospective purchasers of contaminated properties, particularly brownfields. As the program developed, liability issues related to contiguous property, prospective purchasers, and no further action determinations became barriers to brownfield property redevelopment. The national effort on the cleanup and redevelopment of brownfield sites took on new emphasis with the passing of the federal “Small Business Liability Protection and Brownfields Revitalization Act” in January 2002. This new law provides liability clarifications as well as funding to facilitate the cleanup of brownfield sites. President Bush stated in his 2003 State of the Union address, “In this century, the greatest environmental progress will come about not through endless lawsuits or command‐and‐control regulations, but through technology and innovation.” The subject of this article is the Interstate Technology Regulatory Commission's Brownfield team, its current initiative, goals, and areas of special focus. © 2003 Wiley Periodicals, Inc. 相似文献
787.
788.
Soil microbial and faunal community responses to bt maize and insecticide in two soils 总被引:2,自引:0,他引:2
Griffiths BS Caul S Thompson J Birch AN Scrimgeour C Cortet J Foggo A Hackett CA Krogh PH 《Journal of environmental quality》2006,35(3):734-741
The effects of maize (Zea mays L.), genetically modified to express the Cry1Ab protein (Bt), and an insecticide on soil microbial and faunal communities were assessed in a glasshouse experiment. Soil for the experiment was taken from field sites where the same maize cultivars were grown to allow comparison between results under glasshouse conditions with those from field trials. Plants were grown in contrasting sandy loam and clay loam soils, half were sprayed with a pyrethroid insecticide (deltamethrin) and soil samples taken at the five-leaf stage, flowering, and maturity. The main effect on all measured parameters was that of soil type and there were no effects of Bt trait or insecticide on plant growth. The Bt trait resulted in more soil nematodes and protozoa (amoebae), whereas insecticide application increased plant Bt concentration and altered nematode community structure. The only significant effects on soil microbial community structure, microarthropods, and larvae of a nontarget root-feeding Dipteran, were due to soil type and plant growth stage. The results indicate that, although there were statistically significant effects of the Bt trait on soil populations, they were small. The relative magnitude of the effect could best be judged by comparison with the insecticide treatment, which was representative of current best practice. The Bt trait had no greater effect than the insecticide treatment. Results from this glasshouse experiment were in broad agreement with conclusions from field experiments using the same plant material grown in the same soils. 相似文献
789.
Atwill ER Pereira MD Alonso LH Elmi C Epperson WB Smith R Riggs W Carpenter LV Dargatz DA Hoar B 《Journal of environmental quality》2006,35(1):200-206
The first step in assessing the risk of water contamination by Cryptosporidium parvum oocysts from feedlot cattle (Bos taurus) production systems is to quantify the number of C. parvum oocysts present in the fecal material deposited by feedlot cattle. Our primary objective for this project was to estimate the daily environmental load of C. parvum oocysts in fecal material deposited by feedlot cattle from across the central and western USA. Our secondary goal was to genotype isolates of C. parvum from feedlot cattle to help facilitate proper identification of mammalian sources of waterborne C. parvum. Based on 5274 fecal samples from 22 feedlots in seven states (California, Washington, Colorado, Oklahoma, Texas, Nebraska, and South Dakota), we estimated a point prevalence of C. parvum of 0.99 to 1.08% in fecal material from feedlot pens from a wide range of climates and a diverse range of feedlot management systems. On average, fresh fecal material from throughout feedlot systems (recent arrivals to nearing slaughter) contained about 1.3 to 3.6 oocysts/g feces, which roughly translates to about 2.8 x 10(4) to 1.4 x 10(5) oocysts/animal per day. 相似文献
790.
What Makes Them Pay? Values of Volunteer Tourists Working for Sea Turtle Conservation 总被引:1,自引:0,他引:1
As charismatic mega-fauna, sea turtles attract many volunteers to conservation programs. This article examines the ways in
which volunteers value sea turtles, in the specific context of volunteers working with the Caribbean Conservation Corporation,
at Tortuguero, Costa Rica. The complexity of volunteer values is explored using a qualitative approach. In-depth interviews
with 31 volunteers were conducted in July of 1999 and 2000. Interviews probed, among other things, interest in sea turtles
and their conservation, motives for participating, and the most gratifying parts of their volunteer experience. Results show
that volunteers hold multiple and complex values for sea turtles, but particular values dominate. Results have implications
for understanding human–environment relations and the emerging study of volunteer tourism. There are also management implications
for volunteer programs hoping to attract participants. 相似文献