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81.
82.
This study assessed the relationship among land use, riparian vegetation, and avian populations at two spatial scales. Our objective was to compare the vegetated habitat in riparian corridors with breeding bird guilds in eight Rhode Island subwatersheds along a range of increasing residential land use. Riparian habitats were characterized with fine-scale techniques (used field transects to measure riparian vegetation structure and plant species richness) at the reach spatial scale, and with coarse-scale landscape techniques (a Geographic Information System to document land-cover attributes) at the subwatershed scale. Bird surveys were conducted in the riparian zone, and the observed bird species were separated into guilds based on tolerance to human disturbance, habitat preference, foraging type, and diet preference. Bird guilds were correlated with riparian vegetation metrics, percent impervious surface, and percent residential land use, revealing patterns of breeding bird distribution. The number of intolerant species predominated below 12% residential development and 3% impervious surface, whereas tolerant species predominated above these levels. Habitat guilds of edge, forest, and wetland bird species correlated with riparian vegetation. This study showed that the application of avian guilds at both stream reach and subwatershed scales offers a comprehensive assessment of effects from disturbed habitat, but that the subwatershed scale is a more efficient method of evaluation for environmental management.  相似文献   
83.
While collating contributions and comments from 36 researchers, the coordinating authors accidentally omitted Dr. Suzanne Carrière from the list of contributing co-authors. Dr. Carrière’s data are described in Tables 1 and 3, Figure 2 and several places in the narrative. The new author list is thus updated in this article.  相似文献   
84.
We examined relationships between hepatic concentrations of halogenated organic contaminants and ethoxyresorufin O-deethylase (EROD) activity and retinoid (vitamin A) concentrations in livers, as well as retinol and thyroid hormone (TT3, TT4) levels in blood plasma, of northern fulmars at two breeding colonies in the Canadian High Arctic. Biomarker levels or responses did not differ significantly between males and females at either colony, nor was there any significant difference between colonies. No significant relationships were found between thyroid hormone or hepatic retinoid concentrations and any of the dioxin-like compounds or their Toxic Equivalents (TEQs) although significant positive correlations were found with plasma retinol (p < 0.03). EROD activity was significantly correlated with hepatic dioxin-like compounds and their TEQs (p < 0.001) as well as total PCBs (p < 0.01), which suggests that EROD induction occurs in northern fulmars at environmentally-relevant concentrations.  相似文献   
85.
The use of copper-based fungicides leads to an accumulation of copper (Cu) in vineyard soils, potentially causing adverse effects to the microbial function and fertility of the soil. This study used a soil microcosm approach to assess the effects of Cu accumulation on microbial function in vineyard soils. Surface soil samples were collected from 10 vineyards and a number of un-impacted reference sites in each of three different viticultural regions of Australia. The field-collected soils were transferred to microcosms and maintained for up to 93 days in the laboratory at 20–22 °C and 60 % of their maximum water-holding capacity. The microbial function of the soils was indicated by measuring phosphomonoesterase, arylsulfatase, urease, and phenol oxidase activities. In general, the vineyard soils had greater concentrations of Cu and lower enzyme activities than in the reference soils, although a weak negative relationship between Cu and enzyme activity could only be found for phosphomonoesterase activity. The results show that soil physical–chemical properties (i.e., organic carbon, pH) are greater determinants of soil enzyme activity than increased soil Cu concentration at the Cu concentrations present in vineyard soils.  相似文献   
86.
In the 1960s, the Baltic Sea was severely polluted by organic contaminants such as PCBs, HCHs, HCB, and DDTs. Elevated concentrations caused severe adverse effects in Baltic biota. Since then, these substances have been monitored temporally and spatially in Baltic biota, primarily in herring (Clupea harengus) and in guillemot (Uria aalge) egg, but also in cod (Gadus morhua), perch (Perca fluviatilis), eelpout (Zoarces viviparous), and blue mussel (Mytilus edulis). These chemicals were banned in Sweden in the late 1970s/early 1980s. Since the start of monitoring, overall significant decreases of about 70–90 % have been observed. However, concentrations are still higher in the Baltic Sea than in, for example, the North Sea. CB-118 and DDE exceed the suggested target concentrations (24 µg kg?1 lipid weight and 5 µg kg?1 wet weight, respectively) at certain sites in some of the monitored species, showing that concentrations may still be too high to protect the most sensitive organisms.  相似文献   
87.
The public health consequences of extreme heat events are felt most intensely in metropolitan areas where population density is high and the presence of the urban heat island phenomenon exacerbates the potential for prolonged exposure. This research develops an approach to map potential heat stress on humans by combining temperature and relative humidity into an index of apparent temperature. We use ordinary kriging to generate hourly prediction maps describing apparent temperature across the Greater Toronto Area, Canada. Meteorological data were obtained from 65 locations for 6?days in 2008 when extreme heat alerts were issued for the City of Toronto. Apparent temperature and exposure duration were integrated in a single metric, humidex degree hours (HDH), and mapped. The results show a significant difference in apparent temperature between built and natural locations from 3?pm to 7?am; this discrepancy was greatest at 12?am where built locations had a mean of 2.8 index values larger, t(71)?=?5.379, p?<?0.001. Spatial trends in exposure to heat stress (apparent temperature, ≥30°C) show the downtown core of the City of Toronto and much of Mississauga (west of Toronto) as likely to experience hazardous levels of prolonged heat and humidity (HDH?≥?72) during a heat alert. We recommend that public health officials use apparent temperature and exposure duration to develop spatially explicit heat vulnerability assessment tools; HDH is one approach that unites these risk factors into a single metric.  相似文献   
88.
Some of the principal controlling factors affecting the Everglades marsh system were combined in a simple model including growth of grass, water levels, rain, transpiration, peat deposition, fire and phosphorus and controlled inflow of water containing nutrients. Using data from published sources, coefficients were estimated and the model was simulated for several regimes, for varying concentrations of nutrient in the inflows and for varying access to fire. The resulting graphs resemble patterns reported from the Everglades, with some regimes producing regular repeating patterns and frequent small fires, whereas other regimes produced erratic and widely fluctuating patterns of vegetation, flood and fire. High phosphorus increased water loss by affecting plant transpiration: oscillations of vegetation and fire caused nutrient oscillations. Inflow of low nutrient water decreased nutrient levels by binding nutrients in plant masses. Continuous high water levels developed large accumulations of vegetation and peat, binding the nutrients, making larger fires when water levels were lowered. If this model is pertinent, a regular period of variation of water inflow and limited nutrients may be means for management of marshes for long range stability.  相似文献   
89.
90.
Food and Environmental Virology - Quantitative PCR (qPCR) is a convenient tool for monitoring virus concentrations in water and wastewater treatment trains, though it only informs about virus...  相似文献   
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