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61.
Fungicides are moderately hydrophobic and have been detected in water and sediment, particularly in agricultural watersheds, but typically are not included in routine water quality monitoring efforts. This is despite their widespread use and frequent application to combat fungal pathogens. Although the efficacy of these compounds on fungal pathogens is well documented, little is known about their effects on nontarget fungi. This pilot study, a field survey in southwestern Idaho from April to December 2010 on four streams with varying pesticide inputs (two agricultural and two reference sites), was conducted to assess nontarget impact of fungicides on gut fungi, or trichomycetes. Tissues of larval black flies (Diptera: Simuliidae), hosts of gut fungi, were analyzed for pesticide accumulation. Fungicides were detected in hosts from streams within agricultural watersheds but were not detected in hosts from reference streams. Gut fungi from agricultural sites exhibited decreased percent infestation, density and sporulation within the gut, and black fly tissues had elevated pesticide concentrations. Differences observed between the sites demonstrate a potential effect on this symbiotic system. Future research is needed to parse out the details of the complex biotic and abiotic relationships; however, these preliminary results indicate that impacts to nontarget organisms could have far‐reaching consequences within aquatic ecosystems.  相似文献   
62.
We examined the cost of conserving species as climate changes. We used a Maxent species distribution model to predict the ranges from 2000 to 2080 of 74 plant species endemic to the forests of Madagascar under 3 climate scenarios. We set a conservation target of achieving 10,000 ha of forest cover for each species and calculated the cost of achieving this target under each scenario. We interviewed managers of projects to restore native forests and conducted a literature review to obtain the net present cost per hectare of management actions to maintain or establish forest cover. For each species, we added hectares of land from lowest to highest cost per additional year of forest cover until the conservation target was achieved throughout the time period. Climate change was predicted to reduce the size of species' ranges, the overlap between species' ranges and existing or planned protected areas, and the overlap between species' ranges and existing forest. As a result, climate change increased the cost of achieving the conservation target by necessitating successively more costly management actions: additional management within existing protected areas (US$0-60/ha); avoidance of forest degradation (i.e., loss of biomass) in community-managed areas ($160-576/ha); avoidance of deforestation in unprotected areas ($252-1069/ha); and establishment of forest on nonforested land within protected areas ($802-2710/ha), in community-managed areas ($962-3226/ha), and in unprotected areas ($1054-3719/ha). Our results suggest that although forest restoration may be required for the conservation of some species as climate changes, it is more cost-effective to maintain existing forest wherever possible.  相似文献   
63.
Using a large national sample based on Workplace and Employee Survey data collected by Statistics Canada in 2001 and 2002, we examined the effects of employee usage of seven organizational work–life interface benefits on promotions. Analysis predicted promotions in 2002 when number of promotions received by 2001 were controlled. The main effect of using work–life interface benefits on promotions was positive, indicating that using these benefits is not a career‐limiting move. Gender, presence of young children, and marital status interacted with the use of work–life interface benefits. Single parents benefitted less than other employees from using work–life interface options. Altogether, these findings suggest that the ongoing positive effects of conservation of time and energy resources for employees outweigh the initial short‐term negative effects of signaling and stigmatization. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
64.
Conservation of biodiversity relies heavily on protected areas but their role and effectiveness under a warming climate is still debated. We estimated the climate-driven changes in the temperature niche compositions of bird communities inside and outside protected areas in southern Canada. We hypothesized that communities inside protected areas include a higher proportion of cold-dwelling species than communities outside protected areas. We also hypothesized that communities shift to warm-dwelling species more slowly inside protected areas than outside. To study community changes, we used large-scale and long-term (1997–2019) data from the Breeding Bird Survey of Canada. To describe the temperature niche compositions of bird communities, we calculated the community temperature index (CTI) annually for each community inside and outside protected areas. Generally, warm-dwelling species dominated communities with high CTI values. We modeled temporal changes in CTI as a function of protection status with linear mixed-effect models. We also determined which species contributed most to the temporal changes in CTI with a jackknife approach. As anticipated, CTI was lower inside protected areas than outside. However, contrary to our expectation, CTI increased faster over time inside than outside protected areas and warm-dwelling species contributed most to CTI change inside protected areas. These results highlight the ubiquitous impacts of climate warming. Currently, protected areas can aid cold-dwelling species by providing habitat, but as the climate warms, the communities’ temperature compositions inside protected areas quickly begin to resemble those outside protected areas, suggesting that protected areas delay the impacts of climate warming on cold-dwelling species.  相似文献   
65.
With urban areas responsible for a significant share of total anthropogenic emissions, greenhouse gas (GHG) emissions due to land-use change (LUC) induced by peri-urban (PU) development have the potential to be considerable. Despite this, there is little research into the transition from PU cropland to housing in terms of contribution to global warming. This paper presents a cross-sectoral integrative method for prospective climate change evaluation of PU LUC. Specifically, direct LUC (dLUC) GHG emissions from converting PU cropland to greenfield housing were examined. Additionally, GHG emissions due to displaced crop production inducing indirect LUC (iLUC) elsewhere were assessed. GHG impacts of dLUC and iLUC were each determined to be approximately 8 per cent of total GHG emissions due to a greenfield housing development displacing PU cropland. This magnitude of dLUC and iLUC emissions suggests that both have importance in future land-use decision making with respect to PU environments.  相似文献   
66.
Lead contamination is a significant health hazard in communities around the world, but this environmental toxin often remains unknown to residents living near hazardous sites. This research investigates a unique case where residents were informed of lead contamination but rejected official and scientific narratives regarding environmental risks. The case study involves a decommissioned smelter in Colorado. Drawing from data collected over three years, the researchers examine how officials and experts communicated the severity of environmental health hazards. Despite these efforts, residents opposed the Environmental Protection Agency’s attempts to place the site on the National Priorities List for federal cleanup. The government’s framing of science and environmental risk failed to resonate with homeowners, despite the known and significant scientific evidence confirming environmental health hazards, and residents’ perceptions of lead contamination were mitigated by material concerns, including property values and community stigma. Implications for future research on lead contamination, environmental risk, and trust in science are discussed.  相似文献   
67.
Linking Theory and Practice for Restoration of Step-Pool Streams   总被引:1,自引:0,他引:1  
Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences, however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest, Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing theoretical work.  相似文献   
68.
Abstract: Identifying and conserving faunal habitat on private lands has been conducted largely on a site-by-site basis as development proposals arise. We sought to map koala habitat at a scale suitable for use by a local planning authority so that habitat remnants could be protected and managed while remaining in private ownership. At this scale, the level of detail and accuracy needed by local planners required a new approach to mapping koala habitat. Two independent techniques, community and field surveys, were employed. We mailed a survey to every household in Coffs Harbour shire. Respondents told of 3309 koala sightings. We conducted a field survey, a plot-based scat (  fecal pellet) search, to determine which vegetation types and tree species were preferred by koalas. We surveyed 119 sites, which contained 42 different vegetation types. Of these, 37 (31%) had been used by koalas. The outcomes of the community and field surveys were combined to produce a distribution map of koala habitat. The most striking outcome has been the use of our results by the local government authority, Coffs Harbour City Council: planners have incorporated the koala habitat map into their local environmental plan. Our procedure offers a rigorous, repeatable, and publicly accessible method for identifying and mapping important habitat for the purposes of land-use planning, an essential procedure for conserving habitat outside the reserve system.  相似文献   
69.
Sperm allocation in an uncertain world   总被引:3,自引:0,他引:3  
Models of optimal sperm allocation are constructed using stochastic dynamic programming techniques, yielding predictions about sperm allocation when males mate sequentially, breeding time is finite, sperm stores are limited and females vary in quality. The models suggest that uncertainty of future reproductive opportunities should favour withholding of sperm, so that males tend to allocate less (for a given level of stored sperm) earlier in the breeding season. This effect is more pronounced the greater the variance in female quality. We also show that while allocation will be influenced by mate value, it is not necessarily optimal to allocate preferentially to high-quality females, since the benefits of a higher-quality mate may be offset by increased risk of rejection of sperm or higher sperm competition. The relationship between mate quality and level of allocation will depend strongly on the amount of remaining stored sperm, with males whose supplies are depleted being more likely to favour lower-quality partners. Received: 12 September 1997 / Accepted after revision: 28 June 1998  相似文献   
70.
Measurements of concentrations and size distributions of particles 4.7 to 160 nm were taken using an SMPS during the bonfire and firework celebrations on Bonfire Night in Leeds, UK, 2006. These celebrations provided an opportunity to study size distributions in a unique atmospheric pollution situation during and following a significant emission event due to open biomass burning. A log-normal fitting program was used to determine the characteristics of the modal groups present within hourly averaged size distributions. Results from the modal fitting showed that on bonfire night the smallest nucleation mode, which was present before and after the bonfire event and on comparison weekends, was not detected within the size distribution. In addition, there was a significant shift in the modal diameters of the remaining modes during the peak of the pollution event. Using the concept of a coagulation sink, the atmospheric lifetimes of smaller particles were significantly reduced during the pollution event, and thus were used to explain the disappearance of the smallest nucleation mode as well as changes in particle count mean diameters. The significance for particle mixing state is discussed.  相似文献   
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