首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 302 毫秒
1.
This study evaluates the impact of a civil remedy program (Beat Health) on drug and disorder problems under experimental field trial conditions. Using calls for service data, the authors find statistically significant differences between the control and experimental groups, when drug problem calls prior to the start of the intervention were compared to drug calls during a 12-month follow-up period. The Beat Health sites, especially the residential sites, improved relative to the control sites. By contrast, the control treatment (patrol response) led to significant increases in drug problems, particularly at the commercial properties included in this study. The authors also examined the spatial influences of the Beat Health and patrol responses in catchment areas surrounding each of the 100 study sites. The results show some improvement in the experimental residential sites. The authors found, however, a possible displacement of drug problems in and around both the commercial experimental and control sites. They show that the displacement effect is most notable in the commercial control sites.  相似文献   

2.
A gap exists between the relationship-building potential of traditional Web sites, the objectives of public relations practitioners, and the actual design of organizational Web sites. This study extends the investigation of online relationship building through a content analysis of 50 environmental weblogs. A comparison of weblogs to traditional Web sites suggests that weblogs incorporate dialogic communication principles to a greater degree than traditional Web sites, potentially making them better suited for online relationship building.  相似文献   

3.
Waterbird species were used to assess the consequences of developed habitat on wildlife behaviour in an urban riparian system along the Rideau River in Ottawa, Canada. Fourteen developed sites and 14 undeveloped sites were surveyed from October 2004 to February 2005. Each site was approached on foot and the first observed behaviour (i.e., fleeing, foraging, resting or swimming) of each individual was recorded. A total of 10,604 behavioural observations were made across 12 taxa. Overall, the fleeing behaviour was observed more often at undeveloped sites. Foraging, resting and swimming behaviours were observed more often at developed sites. We found that seven species fled more often at undeveloped sites, including hooded merganser. This species was also more abundant at undeveloped sites, suggesting that hooded merganser may be more sensitive to anthropogenic disturbance in urban environments than other species that are habituated toward humans. For sensitive species, undeveloped shoreline may serve as a refuge from human disturbance in urban ecosystems.  相似文献   

4.
In 2010 France enacted a law to regulate supply and consumption of online gambling. Its primary aim was to protect citizens from gambling-related harm. This study aims to assess differences in gambling patterns and related harm between online gamblers who use licensed versus unlicensed sites. Participants (N = 3860) completed a self-administered online survey on gambling practices. Pairwise logistic regressions examined the association between the legal statuses of gambling sites people patronized and demographic variables and gambling types. Multivariate logistic regression models explored associations between gambling patterns and related problems according to the legal status of sites people have gambled on. Overall, 53.7 % of online gamblers report gambling exclusively on licensed sites. Those who bet on regulated activities on unlicensed sites, versus licensed sites, are more likely to be female, younger, less educated, inactive in the labor market and are more likely to perceive their financial situation to be difficult. Gambling on unlicensed sites is associated with more intense gambling patterns and more gambling-related problems compared to licensed sites. Findings demonstrate that gambling activities carried out on state licensed sites are associated with less overall harm to gamblers. Implications of these findings on future policy are discussed and prospective research directions are outlined.  相似文献   

5.
If climate limits the geographical distribution of a species, local variation in microclimate may affect the species' local distribution at the edge of its range. We hypothesized that warm urban microclimates may explain the distribution of the Virginia opossum (Didelphis virginiana) in central Massachusetts. We recorded winter temperatures with data-logging sensors in urban, coniferous, deciduous, and open habitats in the human-dominated landscape of the Connecticut River Valley of Massachusetts. Overall, temperatures decreased with elevation. Daily maximum temperatures, a variable used in models of opossum biophysical constraints, were lowest at forested sites, intermediate at urban sites, and highest at open sites; however these were a poor indicator of evening temperatures, which are important to the nocturnal opossum. Open sites had the highest daily temperature fluctuations, and were the coldest at night. Urban and coniferous sites had the least pronounced daily fluctuations in temperature, and urban sites had the warmest nights. Habitat-specific winter temperatures in the Connecticut River Valley indicated that urban sites were most conducive to opossum persistence, but even they were unlikely to sustain populations. Other factors likely help mitigate the influence of harsh climatic conditions on persistence of opossum populations in western Massachusetts.  相似文献   

6.
As part of their "information age' policy agenda, the UK government sees "universal' access to information and communications technology (ICT) being achieved via new and existing public sites, where shared access to new technologies can be made available at little or no cost. State-sponsored augmentation of public ICT access in the UK has involved a variety of initiatives, most notably the recent establishment of a network of over 7,000 "UK Online Centres' located in a variety of distributed sites such as libraries, museums and colleges. Whilst there have been a number of localized case studies of users of public ICT sites, there has been little large-scale "mapping' of how these facilities are being used (and not used) by the general public. Based on a randomized household survey with 1,001 individuals in twelve research areas in the West of England and South Wales - augmented with a "booster' sample of 100 interviews with individuals carried out in public ICT sites in these areas - the present paper seeks to explore: (i) who has access to what forms of public ICT sites; and (ii) who is (and who is not) making use of different forms of public ICT sites. The survey data suggest that, in terms of people's effective access to ICT, public access sites have a relatively slight profile when compared with household and wider family access - perceived to offer ready access to ICT by only a minority of respondents. Moreover, when the use of these public ICT sites is examined, there is little evidence of public ICT sites attracting those social groups who may otherwise be excluded or marginalized from the information age. Given these findings, the paper considers the influences underlying the currently modest impact of public ICT sites on the general population and suggests changes to current public ICT provision that may prompt wider usage of these sites.  相似文献   

7.
Habitat alteration via urbanization has very different effects on even closely related taxa. Most research investigating the ecological effects of urbanization has focused on birds or mammals, resulting in a relatively poor understanding of how the species richness and community composition of invertebrates may change. We quantified differences in species richness of adult odonates (dragonflies and damselflies) at lentic and lotic sites in urban and rural landscapes, and we examined environmental factors that might drive the differences in community composition that we observed. For lotic sites, species richness did not differ between urban versus rural sites for either dragonflies or damselflies. For lentic sites, urban and rural sites contained similar dragonfly species richness, but damselfly species richness was significantly lower at urban sites than at rural sites. Differences in lentic odonate community composition were associated with the amount of urban development within 150 m of each site, mean algal coverage, and distance to the urban center. At lotic sites, water temperature and distance to the urban center were correlated with differences in odonate community composition. The differing responses to urbanization observed in this study were probably a consequence of differences between lentic versus lotic ecosystems and between dragonflies versus damselflies in dispersal capability and habitat specificity. Given that different environmental factors affected these taxa differently in lentic and lotic sites, maintaining the highest level of odonate diversity possible across a landscape will require the use of different management practices for each ecosystem type.  相似文献   

8.
Beauty queens are symbolic representations of collective cultural indentities and beauty pageants are fields of active 'cultural production'. This article surveys the growing literature on beauty pageants to better understand how culture is produced within the contexts of pageants. To do so, the article examines how beauty pageants operate as sites of commodification and consumption in a world increasingly influenced by global markets and media institutions. It also illustrates how culture is produced in beauty pageants by examining beauty pageants as sites of oppression, sites to articulate cultural agency, and sites of ethnic, gender, cultural, and sexual identity production.  相似文献   

9.
Time of peak bat activity during the night differs among bat species due to temperature, prey availability, habitat availability, and/or interactions between species. Habitat availability is altered in urban areas, which may affect insect prey availability and interspecies interactions. Our objectives were to use mobile acoustic monitoring to determine when bat species were active in a single night in urban and nonurban sites and if nightly bat activity patterns differed in urban versus nonurban sites. Bat echolocation call sequences were recorded using Anabat acoustic detectors while driving transects through the night at five sites (three “urban” and two “nonurban”) located in the Piedmont region of north-central North Carolina from May through August 2016. Transects were driven three times per night starting 45 min, 180 min, and 300 min after sunset. Recorded echolocation call sequences were analyzed manually using AnalookW and automatically using Bat Call Identification and Echoclass software. Total bat activity was not different between urban and nonurban sites. However, total bat activity was lower later in the night in urban sites, but stayed the same in nonurban sites. Species specifically, there were more Eptesicus fuscus, Lasionycteris noctivagans, and Tadarida brasiliensis call sequences and fewer Lasiurus borealis, Nycticeius humeralis, and Perimyotis subflavus call sequences in urban sites than nonurban sites. There were also fewer E. fuscus, L. noctivagans, and N. humeralis call sequences later in the night in both urban and nonurban sites. Only Lasiurus borealis activity in urban sites later in the night reduced and L. borealis activity in nonurban sites remained at the same. These results suggest that bats in urban areas partition time differently, which is important to consider for urban conservation efforts and planning.  相似文献   

10.
Traffic noise is becoming a more prominent fixture in urban environments as cities and highways expand to accommodate the growing human population. Birds, in particular, rely heavily on vocal communication and have recently been shown to change the structure of their signals in response to environmental noise. Our objective was to determine the impact of traffic noise on Red-winged Blackbird (Agelaius phoeniceus) song structure and song timing. We recorded bird songs using a directional microphone and installed permanent recording devices to monitor daily song patterns at both high traffic noise sites and low traffic noise sites throughout southern Ontario, Canada. Our results indicate that at sites with high traffic noise, Red-winged Blackbirds sing songs with fewer introductory syllables, which are an important component of individual recognition and repertoire formation. In addition, the typical diurnal singing pattern of birds associated with noisy urban sites is more homogeneous than that of birds associated with quiet rural marshes. In the early morning and evening, singing effort was higher at rural sites than at urban sites, while in the midday singing effort at urban sites was higher than at rural sites. Birds at our noisy urban sites appear to be avoiding acoustic masking by increasing song production during the quiet part of the day and decreasing song production during the noisy rush hour periods. Based on our results, urban noise is impacting communication structure and the daily pattern of song production in a marsh-nesting species. These results have important implications for avian conservation and land use planning for urban development.  相似文献   

11.
Sacred sites are important not only for their traditional, spiritual or religious significance, but may also potentially be valuable for biodiversity conservation in human transformed landscapes. Yet, there has been little consideration of sacred sites in urban areas in this respect. Consequently, to better understand the ecosystem service and conservation value of urban sacred sites, inventories of their floral communities are needed. We examined the richness, composition and structure of the trees and shrubs in 35 urban churchyards and cemeteries in the City of Saints (Grahamstown). The combined area of urban sacred sites (38.7 ha) represented 2.2% of the city area and 13.6% of the public green space area. Species richness of woody plants was high, albeit dominated by non-native species. Levels of similarity among sites were low, indicating the effects of individual management regimens. There was no relationship between age of the site and measured attributes of the vegetation, nor were there any significant differences in vegetation among different religious denominations. However, the basal area and number of woody plants was significantly related to site size. These results indicate the significant heterogeneity of urban sacred sites as green spaces within the urban matrix. The significance of this heterogeneity in providing ecosystem services to users of sacred sites and the broader urban communities requires further investigation.  相似文献   

12.
Historic urban sites are set by cultural and social diversities, generating multiple activities and use and access to these sites should be available to all people including those with disabilities. Taking into consideration that using the same methodology that was used in different historic sites researches with positive results facilitates replication, we aimed to develop methodological procedures that identify conditions of physical accessibility in open public spaces and access to public buildings in historic urban sites to support proposals about design requirements for improvements to the problems diagnosed and control inadequacies of the physical environment. The study methods and techniques from different areas of knowledge culminated in a proposal built with an emphasis on user participation that could be applied with low cost and in relatively short period of time.  相似文献   

13.
Urban agriculture has been growing in popularity around the globe. As more land is allocated to urban agriculture, there is a greater need to understand arthropod herbivores and natural enemies in these sites. The area and production type of urban agriculture could influence the risk of pest outbreaks, since larger food production areas are hypothesized to host more abundant herbivore populations. To determine the potential for pest outbreaks, we sampled for pests and above-ground natural enemies at three types of sites with variable amounts of cultivated areas: residential gardens, community gardens, and urban farms. We focused on pests of brassica, a widely cultivated crop family attacked by cabbageworms and aphids. We investigated the relationships of garden characteristics and surrounding land cover on natural enemies and herbivores of brassica. More herbivores and plant damage were expected in larger community gardens and urban farms. However, herbivore populations were low across sites and not explained by garden characteristics or area of production. Herbivory on brassica averaged less than 15% at all sites. Limited plant damage and low herbivore numbers may be attributed to the positive effects of garden flowers on parasitoids and high numbers of parasitoids and generalist predators across sites. Garden area and floral resources had positive relationships with natural enemy abundance, although community composition was similar across sites. Since arthropod natural enemies were abundant across all types of food production, this suggests that urban agriculture is a beneficial habitat that could support regulating ecosystem services such as biological control.  相似文献   

14.
The occurrence of carabid beetles in relation to trampling was examined in urban forest sites located in the city of Helsinki, southern Finland. The degree of wear of the forest floor was assessed and used as a measure of trampling intensity. In particular, we examined the following predictions: (1) carabid diversity should decrease with increasing trampling intensity, (2) mean body size of the dominating carabid species should decrease with increasing trampling intensity, and (3) opportunistic species should gain dominance in severely trampled sites. In total, 1,326 beetles representing 27 species were captured. The first prediction was not supported, as there was no correlation between species richness or Hill's N2 diversity index and trampling intensity. However, there was a positive correlation between number of carabids captured and trampling intensity of the site. The second hypothesis gained some support, as there was a marginally significant negative correlation between body size and trampling intensity. The hypothesis that opportunistic species should gain dominance in severely trampled sites was supported as one species was very dominant (Pterostichus melanarius, 60.0%) in the heavily trampled sites, while there were two equally and less dominant species in the less trampled sites. Individual species did show different responses to the effects of trampling, and the most sensitive forest species may not survive in the heavily trampled sites. We conclude that at the community level (e.g., species richness, diversity), the effects of trampling on carabids in urban forests are subtle, but impacts are pronounced for some sensitive species.  相似文献   

15.
Urbanisation is a growing global phenomenon having multiple ecological consequences. However, the effects of urbanisation on biodiversity remain ambiguous, and some evidence exists that cities provide valuable secondary habitats for many species, possibly mitigating regional biodiversity loss. Therefore, the value of urban sites for biodiversity depends on local habitat conditions and the configuration of the surrounding landscape. We aimed to disentangle the effects of local habitat parameters (management, plant diversity) and urban matrix variables (urbanisation, isolation) on carabid beetle and spider diversity and traits in informal urban green spaces in Berlin, Germany. Habitat management and isolation were the most important influences on carabid beetle and spider species and trait compositions. Spider communities of irregular managed sites contained 2.5 times more species of conservation concern than extensive (regular) managed sites. Moreover, irregular managed sites contained larger species (both for carabid beetles and spiders) and affected the hunting mode of spiders. Isolated sites tended to have lower spider species richness and number of spider species of conservation concern. Moreover, isolated sites were characterised by small, mobile and herbivorous carabid beetles. In contrast, urbanisation and local plant diversity had no effect on carabid beetles and spiders. We conclude that urban grasslands within residential areas – even if not targeted for conservation plans – can provide important habitats for conserving biodiversity, including species of conservation concern. Reducing the intensity of habitat management and increasing the connectivity of urban grassland sites can promote diverse arthropod communities and should therefore be considered in urban planning.  相似文献   

16.
The seed bank of a restored tidal freshwater marsh in Washington,DC   总被引:1,自引:0,他引:1  
The species composition of seed banks may be a useful indicator of vegetation structure and dynamics, but seed bank studies have rarely been applied to monitoring of wetland restoration projects. We studied the seed banks and vegetation of three distinct sites within a restored tidal freshwater marsh and of two nearby natural marsh sites. Surface soil samples were collected and subjected to flooded and nonflooded conditions in a greenhouse for enumeration of emerging seedlings. Percent coverage of vegetation was estimated in permanent 1-m2 plots at each soil sampling location.Species composition of the seed bank and vegetation differed considerably; only 43% of the species observed were common to both. The seed bank of restored marsh sites had higher species richness and seed density than the natural marsh sites, but both had similar species diversity. Annual species were more important in the seed bank and less important in the vegetation of restored sites than reference sites. Flooding significantly reduced the species richness, diversity, and density of emerging seedlings. Most species planted at the site were rare in the seed bank, with Leersia oryzoides being an important exception. Other species abundant in the seed bank included Cyperus odoratus, Juncus effusus, and the nonindigenous Lythrum salicaria. A possible mechanism explaining the higher densities of seeds in restored areas is that ruderal vegetation colonized the restoration site, reproduced, and set seed shortly following placement of dredge material. Perennial species subsequently colonized and were planted, and expanded to reduce the abundance of annuals in restored marsh vegetation. Our study suggests that the plant regeneration dynamics of the restored marsh sites are considerably different from those of natural marshes. Additionally, we suggest that seed bank studies are a useful technique for assessing the community structure and vegetation dynamics of restored wetlands.  相似文献   

17.
Stormwater wetlands are a common part of urban and suburban landscapes. These constructed wetlands provide first-order treatment of effluent from roads, parking lots, lawns and other surfaces. They also provide habitat for wetland-associated birds. Thus, there is a concern that birds may be attracted to potentially toxic habitats. This study assesses nesting success and forging behavior of Red-winged Blackbirds (Agelaius phoeniceus) in retention stormwater wetlands based on drainage type. Drainage categories included residential, commercial, and highway sites. Commercial sites had the lowest nesting success and the lowest diversity of invertebrate foods. Mean nest success values for all three types of wetlands, especially for highway drainages, were comparable to published values from natural wetlands. Over two years of study highway ponds collectively served as source populations whereas residential and commercial sites were population sinks in one year and sources in the other. Red-wings using highway sites had the highest foraging efficiency as determined by the frequency and duration of forays. Residential sites had the greatest human disturbance and generally had intermediate-quality habitat and nesting success. We conclude that while stormwater wetlands collect run off and accompanying pollutants, they can still be valuable habitats for nesting birds in urban and suburban areas. We recommend a few management strategies that can increase avian use of these habitats.  相似文献   

18.
Comparing moral panic with the potential catastrophes of the risk society, Sheldon Ungar contends that new sites of social anxiety emerging around nuclear, medical, environmental and chemical threats have thrown into relief many of the questions motivating moral panic research agendas. He argues that shifting sites of social anxiety necessitate a rethinking of theoretical, methodological and conceptual issues related to processes of social control, claims making and general perceptions of public safety. This paper charts an alternative trajectory, asserting that analytic priority rests not with an understanding of the implications of changing but converging sites of social anxiety. Concentrating on the converging sites of social anxiety in late modernity, the analysis forecasts a proliferation of moral panics as an exaggerated symptom of the heightened sense of uncertainty purported to accompany the ascendency of the risk society.  相似文献   

19.
Urban growth is considered to be a major driver of environmental change. Urbanisation can affect urban biodiversity in different ways. So far, most studies focused on the impact of urbanisation on single taxa in one habitat type. In this study, we used data of species inventories and GIS-based landscape elements to examine the effects of habitat size and landscape composition on the species diversity of three taxonomic groups (vascular plants, Orthoptera and Lepidoptera) in meadows and ruderal sites in the urban region of Basel, Switzerland. We also related the responses of three species traits (body size, dispersal ability and food specialisation) to habitat size in Orthoptera and Lepidoptera. We found that species of the different taxonomic groups differed in their response to habitat size and landscape composition both in meadows and ruderal sites depending on the traits examined. The species richness of Orthoptera and Lepidoptera was positively related to meadow size but not to the size of ruderal sites, while the opposite was true for plants. For Lepidoptera in ruderal sites, the percentage cover of ruderal area in the closer surroundings was a better predictor of species richness than habitat size per se. To sustain high levels of urban biodiversity, we recommend that urban planners develop adequate management strategies to satisfy the different requirements of various taxonomic groups and to increase the quality of green sites surrounding the target habitat.  相似文献   

20.
The present study deals with human thermal comfort, as it is quantified by two well-known human biometeorological indices, Physiologically Equivalent Temperature (PET) and Humidex, in selected urban areas with different tree and building structures. The study took place during July 2003, at Agricultural University of Athens, Greece. Meteorological and environmental measurements were carried out at six sites. The selected sites differ in regard to sky view factor (SVF) values, environmental configuration and green (vegetation) coverage. The results of this study indicate a striking influence of site configuration on human thermal comfort. For example, in an outdoor lawn area surrounded by trees (green atrium) the PET was greater than 41 °C (human perception of “very hot”) for 13 % of the measurement time, while in an open building atrium (courtyard) PET was greater than 41 °C for 28 % of the time. In addition, ‘comfortable’ conditions as PET quantifies formed during 26 % of the measurement time in green atrium but less than 15 % of the time in the building atrium. Especially during daytime the difference between these two sites reached 8.7 °C according to the PET and 4.3 °C according to the Humidex. At sites with low SVF values and dense green coverage the human biometeorological conditions were improved compared to sites with high SVF values and those with buildings nearby. Significant relationships between SVF and biometeorological indices classes were indicated. The PET index better represented human comfort than Humidex.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号