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1.
In urban areas the density of breeding tits (Paridae) is generally higher and reproductive performance lower compared to rural areas. To explain these landscape differences several hypotheses have been proposed, e.g. differences in habitat quality, inter- and intra-specific competition, predation and food abundance. How breeding performance of birds within remnants of natural vegetation in urban areas is affected by adjacent matrix has been less studied. We performed an experimental study in four urban woodlands surrounded by three types of habitat matrix: residential, high-rise building and grassland/golf course. We placed 300 nest boxes for tits (great tit Parus major and blue tit Cyanistes caeruleus) in 15 transects that were 200 m long, extending from the adjacent matrix 150 m into urban woodland. Density of breeding great tit pairs was highest in residential areas and hatch date was earlier in the residential habitat compared to the other two habitats, however, nestling condition was lower in residential areas. Hatching date was earlier but hatching spread (heaviest nestling/lightest nestling) higher in the three types of urban matrix than inside the urban woodlands. In contrast to previous large-scale comparisons of urban and rural matrix, we almost exclusively found differences in qualitative measures (nestling condition and hatchling spread) at the small scale in which this study was conducted. Adjacent matrix affect great tits breeding in remnant urban woodlands, thus we suggest that management of the surrounding matrix should be included in conservation plans for urban woodlands.  相似文献   

2.
Little is known about the environmental factors that limit the demography and abundance of wild vertebrates in highly modified urban environments. The House Sparrow Passer domesticus is a globally widespread species whose urban populations have recently undergone substantial declines particularly in Europe. The environmental drivers of these declines remain unknown. In a previous study we showed that invertebrate availability during the breeding season limited reproductive success but not population size in a suburban sparrow population. In this study we test experimentally whether year-round food availability limits demography and population size. Supplementary feeding involved the provision of invertebrate prey (during the breeding season) plus unlimited high-energy seed (year-round) at 33 sparrow colonies spread across suburban London over two successive calendar years. Thirty-three unfed colonies served as controls. Supplementary feeding increased fledgling abundance, but had no impact on overwinter survival or population size. We conclude that this depleted suburban sparrow population is not limited by food availability, and conservation efforts based primarily on food provision are unlikely to succeed. We also tested whether cross-colony variation in sparrow abundance was correlated with a set of potential environmental stressors including measures of predator abundance and pollution. Sparrows were more abundant, or showed more positive temporal changes in abundance, at localities containing large areas of seed-rich habitat and low levels of nitrogen dioxide air pollution. Further research is merited into the potential impacts of air pollution on the fitness of urban birds.  相似文献   

3.
Data collected out of the breeding season suggest that House sparrows (Passer domesticus) from the urban populations are characterized by a smaller body size and poorer body condition compared to birds from rural populations. Considering an urbanized Eurasian Sparrowhawk (Accipiter nisus) and other potential predators, a new predator-prey dependency is developing that can also be a reason for the House sparrow’s poorer condition. This study was aimed at comparing the multivariate biometrical characteristics and few body condition indices of adult birds from urban and rural populations during the breeding season. It was hypothesized that a higher predation risk during the breeding season concerns mainly males, thus affecting their poorer condition. Most of the condition indices of males were significantly lower in the urban population. Males from the urban populations had lower body mass, shorter tarsus, longer alula, greater Kipp’s distance and higher wing pointedness index in comparison to the birds from rural populations, whereas these differences were not found between females. We suggest that the lower body condition and biometric differences in the analyzed birds are a means of adapting to the new predator-prey scheme in accordance to the tradeoff theory between starvation and predation risks. A lower condition of birds in poor foraging urban habitats and higher predation risk may be indicative of a declining population.  相似文献   

4.

Urbanisation constitutes one of the most rapid human-induced environmental changes, developing at the expense of natural and semi-natural habitats. It often implies alterations of many abiotic and biotic factors and contributes to create new environmental conditions, including temperature, food resources, competition and predation. Despite increasing empirical evidence of intra-specific divergence in phenotypic traits (e.g., physiological, behavioural or morphological) between urban and rural individuals, such patterns have often remained disconnected from the underlying mechanisms involved. In the current study, we tested for divergence in functional morphological traits that are related to feeding ecology (i.e., bill morphology, body mass and condition) and/or to the locomotory performance in escaping from predators (i.e., wing, tarsus and tail morphology, body mass and condition) along a chronological gradient of urbanisation (old urban, recent urban and rural areas), using the New Zealand fantail, an endemic insectivorous passerine species. We found divergences in phenotypic traits related to bill morphology along the urban–rural gradient: birds inhabiting the old urban area had stubbier bills (i.e., shorter, deeper and wider bills) than those inhabiting the recent urban and rural areas. We did not detect any difference in locomotion-related morphological traits. Our results suggest the urbanisation-induced alteration in food resources may drive morphological divergence in bird populations. We emphasized the need for mechanistic and experimental studies, with a particular focus on resource-based mechanisms, to identify more precisely the morphological responses of urban populations to changes in food composition, and the resulting implications for communities in urban ecosystems.

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5.
Norwalk-like viruses (NLVs) are transmitted by fecally contaminated food, water, fomites, and person-to-person contact. They are a leading cause of acute gastroenteritis epidemics in industrialized countries. NLV outbreaks are characterized by a 12- to 48-hour incubation period; nausea, vomiting, and diarrhea for 24 to 72 hours; and high secondary attack rates. NLV infections spread rapidly on college and university campuses because of close living quarters, shared bathrooms and common rooms, many food handlers, popular self-service salad bars in dining halls, and person-to-person contact through sports and recreational activities. The illness is generally mild and self-limited but an outbreak can strain the resources of campus health services and cause high absenteeism among both students and staff. Treatment is primarily through antiemetic medication and oral rehydration. Prevention and control of NLV outbreaks rests on promoting hand washing; enforcement of strict hygiene in all food preparation areas; and prompt, rigorous cleaning of potentially contaminated areas where someone has been ill.  相似文献   

6.
Urban afforestation improves life quality in urban centers providing social and environmental benefits. Understanding growth of urban trees exposed to air pollution will support planning, managing and expanding urban areas. This approach intends to determine growth patterns of urban trees to support future urban planning. Non-destructive samples were collected from trees of Araucaria angustifolia (Bertol.) Kuntze in Araucaria city, Parana State, Brazil. Growth rings were related to pollutant concentrations and meteorological series. Growth reduction was observed except in the border areas of the city. Trees established during or after the period of industrialization incentives were most affected by air pollution, indicating that immature plants are more vulnerable. Sulphur dioxide and nitric oxide significantly affected growth of smaller trees. Those greater than 60 cm dbh did not demonstrate significant correlation with any identified pollutant. As the trees established before accentuated urbanization were less affected by air pollution, it is reinforced the importance of preserving remaining urban trees. We suggest that planning urban afforestation should precede industries placing. When urban planning is impossible, new planted trees should not be expected to grow as in free pollution areas, but they will still present satisfactory diameter increment, contributing to improve local urban environment.  相似文献   

7.
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   

8.
河流污染状况及治理效果评价的指标体系   总被引:1,自引:0,他引:1  
河流治理工程中,必须了解河流环境的现状和治理后改善的效果。该文全面介绍了感观指标、水质和底泥的理化指标、河流生态系统的结构、河流生态系统的功能等评价河流污染状况的指标体系。  相似文献   

9.
A substantial body of sociological research has examined the relationship between farmers’ environmental attitudes and their conservation behaviors, but little research has compared the attitudes of producers and consumers toward the environment with their behaviors or practices in support of sustainable agri-food systems. This paper addresses these shortcomings by analyzing the intersection between producer and consumer attitudes toward environmental sustainability with their actual practices, drawing data from focus group interviews and surveys with producers and consumers in Washington State, USA. We compare farmers’ attitudes toward several agricultural and environmental policies with their self-reported practices to examine whether support for environmental policies aligns with sustainable farming practices. For consumers, we investigate the relationship between their attitudes toward the same agricultural and environmental policy issues with their interest in purchasing food produced in an environmentally sustainable manner. Through our analyses, we find that consumers’ and producers’ practices are not always consistently correlated with their environmental attitudes, but that support for agricultural land preservation is one policy area in which the interests of producers and consumers intersect with their interest in sustainable farming and food. Findings from our individual and focus group interviews assist us in understanding the multiple, sometimes competing, factors that consumers and producers must weigh in making decisions about environmentally sustainable food and farming.  相似文献   

10.
This article describes environmental conditions in Iran including air pollution, pesticide pollution, soil depletion and erosion, water pollution, natural resource loss, lack of appropriate waste management, lead poisoning, and desertification. Environmental policy and implementation is described under the Shah and the Islamic Republic. Iran is beset with interrelated problems of environmental degradation, unemployment, poverty, and population growth. Sustainability is being undermined at the cost of future generations. In 1995, Iran had a population of 67 million and a growth rate of 3.6%. Population is expected to exceed 100 million by the year 2000. The country is having difficulty in maintaining its current infrastructure, housing, food, and educational facilities. Competition for admission in higher education discourages women. Women with lower levels of education results in continued supremacy of men over women, more polygamy, and a lower quality of life for women. Iran was food self-sufficient in 1970, and exported its surplus. Today, Iran may be permanently dependent on food imports. Iran has abundant oil reserves, natural gas, copper, lead, and marketable items. Exchanging natural resources for food and technology has time and resource limits. Iran needs monetary assistance from wealthy nations. Population growth leads to increased demand for infrastructure and resources. Iran has signed many international environmental agreements and has enacted detailed environmental policies and regulations, but actual enforcement is lacking.  相似文献   

11.
Animal body sizes in urban areas often differ from nearby rural areas, which may impact population fitness and dynamics. We examined the effects of urbanization on larval body sizes of two species of salamanders, the two-lined salamander (Eurycea cirrigera) and the northern dusky salamander (Desmognathus fuscus). Specifically, we utilized a before-after control-impact (BACI) study design which allowed for the assessment of differences in larval body size between multiple control and impacted sites over a 5 year period. We found a decrease in larval body size in both species at the impacted sites compared to control sites in the first year after urbanization, followed by generally larger body sizes in urban sites compared to control sites in years 3–5, and significantly so in year 4. Using generalized linear models, we found support that larger body sizes post impact in urbanized streams may be due to warmer stream water temperature and decreased abundance of larvae. Both E. cirrigera and D. fuscus are well known for their ability to persist in urbanized streams; our data suggest that despite overall lower abundances in urban streams, persistence may be due to increases in larval body size and, potentially, post-metamorphic benefits.  相似文献   

12.
The scarcity of green areas in urban landscapes hinders connectivity among sites reducing the flux of organisms and seed dispersal. Ramphastos toco is an effective plant disperser in tropical landscapes, playing an important role in conserving plant connectivity. In this study we combined two methods of landscape connectivity analysis, in a way not yet explored, to assess the potential contribution of Ramphastos toco to enhancing connectivity among urban vegetation patches. We used spatial modeling techniques to evaluate least cost routes, or those that facilitate bird movement through green urban areas, in Belo Horizonte, a city in Southeast Brazil. We also assessed the relative importance of forest patches for conserving both bird and seed dispersal fluxes using the integral index of connectivity. The resulting least cost route of greater accessibility for the species included in its course an important forest patch under environmental licensing for the construction of a residential condominium. The number of green urban areas covered by forest, of highest habitat quality for the species, summed to 155 patches. Of this total only 5.2% were relevant for regional connectivity, while the four most important patches are targeted by the city’s expansion plans. Ramphastos toco is an effective connector for tropical green urban areas given its adaptability, wide range of movement and seed dispersal effectiveness. We emphasize the need for incorporating ecological knowledge and the prioritization of green areas into city planning, since current expansion projects jeopardize forest patches that are crucial to the functional connectivity of the urban landscape.  相似文献   

13.
Considerable attention has been devoted to the effects of people and their vehicles on birds and mammals, but possible effects on reptiles in populated areas have received less attention. Moreover, the effects of human activities on reptile reproductive success itself has been harder to demonstrate. This paper examines the effect of management of off-road vehicles in New Jersey’s pinelands on the reproductive success of pine snakes (Pituophus melanoleucus) from 1986 to 2005. We used the percentage of snakes in each hibernaculum that were young of the year (hatchlings) as an indicator of reproductive success, and compared this percent for five hibernacula that were in an area with varying degrees of off-road vehicle (ORV) disturbance, with 12 hibernacula in areas with no ORV disturbances (reference sites). This percent took into account differences in absolute numbers from one location to another, and over time due to hibernacula destruction (by people or predators) and natural variations (food supply). The ORV pressure in the pinelands is intense because it lies within the most densely populated urban area in the United States. Although the number of snakes in the reference hibernacula varied over the years from 46 to 63, the percent of young in these hibernacula did not vary significantly over the 20 year period (21–29%). In contrast, the percent-young in the disturbed sites differed significantly in years without ORV disturbance (28%) compared to those with ORV disturbance (15 and 16%, P < 0.01). Further, there were no differences between the percent of young in the reference sites and those in the disturbed site in years without ORV disturbance. ORV disturbance ceased only with the creation of large dirt berms coupled with fences that could not be easily broken. These data indicate the importance of having detailed population data on pine snakes in hibernacula, on ORV use (or indications of such use), and of managing ORV use to protect sensitive populations. Maintenance of healthy pine snake populations in urban areas may require continued adaptive management.  相似文献   

14.
Research on risk perceptions are replete with race- and gender-specific hypotheses attempting to account for attitudinal variation. However, race and gender differences may mask more notable patterns across subgroups, patterns that lie at the intersection of race and gender. Recent national studies suggest that being a White male leads to lower risk perceptions and greater willingness to accept risks. This article extends this research by examining the “White male” effect in a chronically polluted context, an area where industrial pollution is palpable and well-documented. Data are drawn from a survey of a population living in “Cancer Alley,” a stretch of the Mississippi River from Baton Rouge to New Orleans. We find that women more than men and Blacks more than Whites perceive environmental risks as serious. Further, evidence suggests that these differences are mostly due to the relatively extreme perceptions of risk accepting White males and risk adverse Black females. After controlling for select variables in hierarchical multiple regression analyses, being a White male or Black female still has a statistically significant impact on risk perceptions.  相似文献   

15.
This article is based on interviews with U.S. veterans diagnosed with combat‐related posttraumatic stress disorder (PTSD). In remembering war, the veterans consistently described grotesque death and injury. These stories of “blood, guts, and gore” were often closely associated with negative moral evaluations of war, which included outright moral claims, moralistic allusions, and expressions of moral emotions. I argue that memories of grotesque death and injury “code” combat as moral pollution, and as these veterans present it, combat pollutes every soldier who passes through it. Furthermore, this classification represents a modern moral culture in which the body is sacred, subject to sustained ritual cleanliness and to strict prohibitions against encroachment by others. A mutilated body is severely disordered and filthy, and when a product of human design, it represents an extremely cruel trespass. Consequently, mutilated bodies are doubly polluted and can code combat as negative in the extreme. This article illustrates that personal traumatic memories are sociologically and historically organized, that the traditional religious ideas of purity and pollution still order moral life, and that autobiographical memory can be approached as a classificatory structure.  相似文献   

16.
Local food movements have emerged in many parts of Canada to support local farmers, sustain the regional food supply, encourage the consumption of healthier foods, and address environmental concerns associated with conventional agriculture. The implementation of food localism to date, however, has remained primarily the responsibility of consumers. This paper seeks to examine the practical realities of individual consumer localism in order to understand how food localism operates at the household level. Local food scholarship and empirical data from a recent study of Canadian farmwomen’s food provisioning practices are used to assess the feasibility and implications of buy local and eat local messages for consumers. In particular, physical access to local food markets, financial constraints to buying local and food self-provisioning, and (gendered) labor requirements are examined in detail. Findings suggest that encouragement by local food advocates to ‘buy local’ and ‘grow food’ are not simple transactions for households; rather, such practices must be considered within the broader food provisioning context and the structural constraints therein. Although well-intentioned, these urgings delegitimize real constraints that exist for many individuals and households, in particular those outside of well-serviced urban areas, those who are food insecure, and those without the necessary resources (time, labor, skill, and expertise) to engage in local food provisioning. The ability of consumers to engage in individual localism will be limited as long as the broader context in which food provisioning activities are undertaken is ignored.  相似文献   

17.
Abstract The concept of the food desert, an area with limited access to retail food stores, has increasingly been used within social scientific and public health research to explore the dimensions of spatial inequality and community well‐being. While research has demonstrated that food deserts are frequently characterized by higher levels of poverty and food insecurity, there has been relatively little research examining the relationship between food deserts and obesity, particularly in rural areas. In this article we use Geographic Information System (GIS) techniques to identify food desert areas in rural Pennsylvania. We then analyze student body mass index (BMI) data along with census and school district‐level data to determine the extent to which the percentage of a school district's population residing within a food desert is positively associated with increased incidence of child overweight among students within the district. We find that school districts with higher percentages of populations located within food deserts are more likely to be structurally and economically disadvantaged. Net of these district‐level structural and economic characteristics, we additionally find a positive relationship between increased rates of child overweight and the percentage of the district population residing in a food desert.  相似文献   

18.
In this study the relationship between obesity, alcohol misuse, smoking and changes in quantity of labor supplied during an economic meltdown are examined. The data used stem from a health and lifestyle panel survey carried out by the Public Health Institute of Iceland in 2007 and 2009. Probit analysis was used to assess if pre-crisis body weight, alcohol misuse or smoking were related to subsequent job-loss or a reduction in hours worked following the 2008 economic collapse in Iceland. Results indicated that body weight, alcohol misuse and smoking are related to reductions in quantity of labor supplied for females only. Female body mass index was positively related to the probability of a reduction in quantity of labor supplied, while alcohol misuse and smoking were negatively related to the probability of decreasing hours worked for females.  相似文献   

19.
Children (N = 130) in grades 4 and 6 from various schools in the Greater Montreal Region completed a questionnaire concerning their gambling behavior and played a computer-simulated roulette game individually (baseline trial & post-test trial) and in groups (same and mixed gender dyads or triads: group trial). The purpose of this design was to measure children's betting behavior (via average wagers) and to determine if any changes in betting occur as a result of playing in groups of two, three, same and/or different gender peers. Results of repeated measures analyses reveal that during individual and group play, males consistently exhibit higher average wagers than females. Average wagers of females and mixed gender groupings appear to be most affected by the group condition. Females were found to increase their average wagers when playing with females and males. Female dyads' wagers increase significantly during group play, indicating they are dramatically affected by the group game. Most changes resulting from group play were generally maintained over a relatively short period of time in the post-test condition. Results are interpreted with respect to the importance of the influence of the peer group on children's gambling behavior. Future directions for research are suggested.  相似文献   

20.
The present study replicated Jastrow's 1891 experiment concerning differences between male and female vocabulary. Participants were 20 male and 20 female Caucasian middle‐class college students. They recorded up to 100 nouns in a 15‐minute period. Results indicate that women have increased their use of unusual words compared to women in 1891. Males used more scientific words and more body part words than females. In contrast to the previous study, there are no significant differences between the sexes in use of animal, nature, and food words. Females used more clothing words than males in this study, as in the previous study, and produced more different words than males. Vocabulary changes appear to reflect changes in the social structure of the society.  相似文献   

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