National crop loss assessment network: quality assurance program

A quality assurance program was incorporated into the National Crop Loss Assessment Network (NCLAN) program, designed to assess the economic impacts of gaseous air pollutants on major agricultural crops in the United States. To satisfy US EPA requirements that all environmental data collected be of known and documented quality, adequate for the intended use, the quality assurance program developed standardized research and monitoring protocols among sites, and included a range of audit and review procedures. The goal of the quality assurance program was to quantitatively describe the overall quality of data collected in terms of precision, accuracy, completeness, representativeness, and comparability. From this program, it can be concluded that (1) project data quality objectives were valuable for determining the acceptability of data from diverse sites, (2) standardized protocols ensured data comparability among research sites, (3) independent on-site audits served to evaluate protocol adherence, and (4) precision and accuracy measurements provided a way to assess data quality, determine data acceptability, and indicate the need for instrument adjustment or repair.     

Managing troubled data: coastal data partnerships smooth data integration

Understanding the ecology, condition, and changes of coastal areas requires data from many sources. Broad-scale and long-term ecological questions, such as global climate change, biodiversity, and cumulative impacts of human activities, must be addressed with databases that integrate data from several different research and monitoring programs. Various barriers, including widely differing data formats, codes, directories, systems, and metadata used by individual programs, make such integration troublesome. Coastal data partnerships, by helping overcome technical, social, and organizational barriers, can lead to a better understanding of environmental issues, and may enable better management decisions. Characteristics of successful data partnerships include a common need for shared data, strong collaborative leadership, committed partners willing to invest in the partnership, and clear agreements on data standards and data policy. Emerging data and metadata standards that become widely accepted are crucial. New information technology is making it easier to exchange and integrate data. Data partnerships allow us to create broader databases than would be possible for any one organization to create by itself.     

西昌邛海水体污染及其综合整治与保护管理问题研究

本文阐述了邛海水体污染及其生态环境破坏的状况，剖析了污染源及其危害。同时，针对问题提出了全方位综合整治与保护管理具体措施。     

A study on organotin levels in Canadian drinking water distributed through PVC pipes

A study on organotin compounds in Canadian drinking water was carried out in winter-spring 1996 (28 sites) and autumn 1996 (21 sites). Approximately 29% and 40% of distribution waters supplied through PVC pipes installed recently (typically less than 6 months) contained organotin compounds in the winter-spring and autumn surveys respectively. Monomethyl-, dimethyl-, monobutyl- and dibutyltin levels ranged up to 291 ng Sn/L, 49.1 ng Sn/L, 28.5 ng Sn/L and 52.3 ng Sn/L, respectively. An additional study in summer 1996, of locations where the highest organotin levels were detected in the winter-spring survey, indicated that organotin levels had decreased in most distribution water samples. Samples of PVC pipe/tubing contained organotin compounds consistent with the organotin patterns found in the distribution water samples.     

Open Air Laboratories (OPAL): a community-driven research programme

OPAL is an English national programme that takes scientists into the community to investigate environmental issues. Biological monitoring plays a pivotal role covering topics of: i) soil and earthworms; ii) air, lichens and tar spot on sycamore; iii) water and aquatic invertebrates; iv) biodiversity and hedgerows; v) climate, clouds and thermal comfort. Each survey has been developed by an inter-disciplinary team and tested by voluntary, statutory and community sectors. Data are submitted via the web and instantly mapped. Preliminary results are presented, together with a discussion on data quality and uncertainty. Communities also investigate local pollution issues, ranging from nitrogen deposition on heathlands to traffic emissions on roadside vegetation. Over 200,000 people have participated so far, including over 1000 schools and 1000 voluntary groups. Benefits include a substantial, growing database on biodiversity and habitat condition, much from previously unsampled sites particularly in urban areas, and a more engaged public.     

A comparison of flux chambers and ambient air sampling to measure gamma-hexachlorocyclohexane volatilisation from canola (Brassica napus) fields

The insecticide gamma-hexachlorocyclohexane (gamma-HCH) is primarily used in Canada in treatments of canola (Brassica napus) seed. It has been shown that gamma-HCH so applied will volatilise with 12-30% entering the atmosphere within 6 wk after the seed is planted. Both flux chambers and high-volume air samplers were used to measure gamma-HCH volatilisation from a canola field and the results from each method compared. Daily samples were collected from three flux chambers located on the field. gamma-HCH was found in the air of the chambers on the first day after planting. Volatilisation rates were low for the first 7d (40.0 mg ha(-1) wk(-1)) but increased during the second week (143.8 mg ha(-1) wk(-1)). This was consistent with previous studies. Weekly composite air samples, from three heights above the canola field, were used to calculate volatilisation rates from the field. These were 190 mg ha(-1) wk(-1) (week 1) and 420 mg ha(-1) wk(-1) (week 2). Soil temperatures in the open field were warmer than those under the flux chambers and this may have contributed to the higher ambient air measurements.     

Phylogenetic relatedness and ecological interactions determine antipredator behavior

Interspecific recognition of alarm cues among guild members through "eavesdropping" may allow prey to fine-tune antipredator responses. This process may be linked to taxonomic relatedness but might also be influenced by local adaptation to recognize alarm cues from sympatric species. We tested this hypothesis using antipredator responses of a freshwater gastropod Lymnaea stagnalis (L.) to alarm cues from damaged conspecific and 10 heterospecific gastropod species. As predicted, the magnitude of antipredator response decreased significantly with increasing phylogenetic distance, but increased when species were naturally sympatric (defined as species cohabiting in the same water body) with the source population of L. stagnalis. The responses to sympatric species were higher overall, and the relationship between genetic distance and alarm cue response was stronger when tested with sympatric species. This is the first study to demonstrate that population sympatry influences innate antipredator responses to alarm cues from intraguild members and suggests that responses based on phylogenetic relationships can be modified through local adaptation. Such adaptation to heterospecific alarm cues suggests that species could be at a disadvantage when they encounter novel intraguild members resulting from species invasion or range expansion due to a reduction in the presence of reliable information about predation risk.     

Observations of urban airborne particle number concentrations during rush-hour conditions: analysis of the number based size distributions and modal parameters

A summertime study of the number concentration and the size distribution of combustion derived nanometre sized particles (termed nanoparticles) from diesel and spark-ignition (SI) engine emissions were made under rush-hour and free-flow traffic conditions at an urban roadside location in Leeds, UK in July 2003. The measured total particle number concentrations (N(TOTAL)) were of the order 1.8 x 10(4) to 3.4 x 10(4) cm(-3), and tended to follow the diurnal traffic flow patterns. The N(TOTAL) was dominated by particles < or =100 nm in diameter which accounted for between 89-93% of the measured particle number. By use of a log-normal fitting procedure, the modal parameters of the number based particle size distribution of urban airborne particulates were derived from the roadside measurements. Four component modes were identified. Two nucleation modes were found, with a smaller, more minor, mode composed principally of sub-11 nm particles, believed to be derived from particles formed from the nucleation of gaseous species in the atmosphere. A second mode, much larger in terms of number, was composed of particles within the size range of 10-20 nm. This second mode was believed to be principally derived from the condensation of the unburned fuel and lube oil (the solvent organic fraction or SOF) as it cooled on leaving the engine exhaust. Third and fourth modes were noted within the size ranges of 28-65 nm and 100-160 nm, respectively. The third mode was believed to be representative of internally mixed Aitken mode particles composed of a soot/ash core with an adsorbed layer of readily volatilisable material. The fourth mode was believed to be composed of chemically aged, secondary particles. The larger nucleation and Aitken modes accounted for between 80-90% of the measured N(TOTAL), and the particles in these modes were believed to be derived from SI and diesel engine emissions. The overall size distribution, particularly in modes II-IV, was observed to be strongly related to the number of primary particle emissions, with larger count median diameters observed under conditions where low numbers of primary soot based particles were present.     

Measuring Plant Cover in Sagebrush Steppe Rangelands: A Comparison of Methods

Methods that are more cost-effective and objective are needed to detect important vegetation change within acceptable error rates. The objective of this research was to compare visual estimation to three new methods for determining vegetation cover in the sagebrush steppe. Fourteen management units at the US Sheep Experiment Station were identified for study. In each unit, 20 data collection points were selected for measuring plant cover using visual estimation, laser-point frame (LPF), 2 m above-ground-level (AGL) digital imagery, and 100-m AGL digital imagery. In 11 of 14 management units, determinations of vegetation cover differed (P < 0.05). However, when combined, overall determinations of vegetation cover did not differ. Standard deviation, corrected sums of squares, coefficient of variation, and standard error for the 100 m AGL method were half as large as for the LPF and less than the 2-m AGL and visual estimate. For the purpose of measuring plant cover, all three new methods are as good as or better than visual estimation for speed, standard deviation, and cost. The acquisition of a permanent image of a location is an important advantage of the 2 and 100 m AGL methods because vegetation can be reanalyzed using improved software or to answer different questions, and changes in vegetation over time can be more accurately determined. The reduction in cost per sample, the increased speed of sampling, and the smaller standard deviation associated with the 100-m AGL digital imagery are compelling arguments for adopting this vegetation sampling method.     

Ground-Cover Measurements: Assessing Correlation Among Aerial and Ground-Based Methods

Wyoming’s Green Mountain Common Allotment is public land providing livestock forage, wildlife habitat, and unfenced solitude, amid other ecological services. It is also the center of ongoing debate over USDI Bureau of Land Management’s (BLM) adjudication of land uses. Monitoring resource use is a BLM responsibility, but conventional monitoring is inadequate for the vast areas encompassed in this and other public-land units. New monitoring methods are needed that will reduce monitoring costs. An understanding of data-set relationships among old and new methods is also needed. This study compared two conventional methods with two remote sensing methods using images captured from two meters and 100 meters above ground level from a camera stand (a ground, image-based method) and a light airplane (an aerial, image-based method). Image analysis used SamplePoint or VegMeasure software. Aerial methods allowed for increased sampling intensity at low cost relative to the time and travel required by ground methods. Costs to acquire the aerial imagery and measure ground cover on 162 aerial samples representing 9000 ha were less than $3000. The four highest correlations among data sets for bare ground—the ground-cover characteristic yielding the highest correlations (r)—ranged from 0.76 to 0.85 and included ground with ground, ground with aerial, and aerial with aerial data-set associations. We conclude that our aerial surveys are a cost-effective monitoring method, that ground with aerial data-set correlations can be equal to, or greater than those among ground-based data sets, and that bare ground should continue to be investigated and tested for use as a key indicator of rangeland health.