Employment income of immigrants in metropolitan areas of Canada, 1980

This paper examines the economic achievements of immigrant groups and compares them with those of the Canadian-born population. Employment income in this study is income for members of the labor force who worked 40 weeks or more, full time, during 1980. The information is from the 1981 Census. The 15 birthplace groups considered in this study are classified into 2 major groups: those from traditional sources and those from non-traditional or new sources. Traditional sources are the US, UK, and Europe. The new sources are Africa, Asia, South and Central America, the Caribbean, and Oceania. More than 1/2 of the immigrants from traditional sources arrived before 1960, whereas more than 1/2 of immigrants from new sources arrived after 1970. The analysis is only for those areas called Census Metropolitan Areas. Results of analysis show that 1) immigrant men and women in metropolitan areas earned 1.9% and 5.9% respectively less than their Canadian-born counterparts; 2) when differences in age and educational attainment were considered, incomes of immigrant men and women were about 7.5% below those of their Canadian-born counterparts; 3) the new immigrant groups earned far less than those of the Canadian-born counterparts; 4) traditional-source immigrants' incomes were equal to or slightly higher than Canadians'; and 5) as length of residence increases, most immigrant groups improve their relative economic position and achieve incomes comparable to Canadians'. The authors discuss the economic adaptation of immigrants in the light of various models: assimilation, Marxist class conflict, ethnic stratification and segmentation, structural pluralism, and structural change. No theory can be applied to the economic adaptation of all types of immigrants. Finally, refugees and sponsored relatives, who are not admitted on the basis of education and occupational need, are likely to have more difficulties than independent immigrants.     

Hospital competition in major U.S. metropolitan areas: An empirical evidence

In response to dramatic rises in health care costs, policymakers have been debating the relative merits of competitive strategies as a means of containing costs. We study the 29 largest metropolitan statistical areas for 1991, and controlling for environmental conditions in each market, we examined the impact of competition on hospital costs. We conclude that competition had a significant positive impact on overall hospital costs.     

Variation in urban forest productivity and response to extreme drought across a large metropolitan region

The growth and survival of urban trees and maintenance of urban forest canopy are important considerations in adaptation of urban regions to climate change, especially in relation to increasing frequency of extreme climatic events such as drought. However, urban forest growth and drought response may vary considerably within large urban landscapes across gradients in land use, urbanization, forest composition and structure, and environmental factors. We quantified urban forest growth and resilience and resistance to extreme drought in the greater Chicago metropolitan region based on patterns of annual basal area production from increment core analysis. We evaluated variation in growth and drought response in relation to a broad urban to rural gradient, land-use categories, local-scale environmental predictors, and forest community characteristics. Urban forest growth varied greatly among land-use classes and major genera. Plot-level variation in productivity was predicted most strongly (R² = 0.53) by total plot-level basal area, canopy height, species composition, soil and ground-cover characteristics, and position within the urban-rural gradient. Urban forest growth was strongly related to regional meteorological drought. In periods of extreme drought conditions growth declined in the year of the drought (i.e., was not resistant to drought effects), but was highly resilient to drought in the subsequent 5 year period. Drought response did not vary consistently across land-use classes or among major genera, and site or community characteristics had little explanatory power in predicting drought response. Improved understanding of factors driving variation in urban forest growth and drought response could help inform adaptation-focused urban forest management strategies.

     

Patterns of gay and lesbian partnering in the larger metropolitan areas of the United States

This paper had two objectives. First, we developed for each large metropolitan area of the United States with a population of 500,000 or more in 1990 four indexes of gay partnering and four indexes of lesbian partnering. We compared and related these indexes and their variable measurements with one another. Second, using what we argue is the statistically and demographically preferred set of gay and lesbian partnering rates, we proposed and tested an assortment of ecological hypotheses relating characteristics of the metropolitan areas with the gay and lesbian partnering rates. Rates of gay and lesbian partnering, we show, are more influenced by such metropolitan characteristics as physical climate and the crime rate than by a religious characteristic such as the number of Southern Baptist adherents. Among the conclusions of the paper is our claim that there needs to be greater consideration of the methodological issues related to the use of government data for the development of rates of gay and lesbian partnering.     

Relation of urbanization to stream fish assemblages and species traits in nine metropolitan areas of the United States

We examined associations of fish assemblages and fish traits with urbanization and selected environmental variables in nine major United States metropolitan areas. The strongest relations between fishes and urbanization occurred in the metropolitan areas of Atlanta, Georgia; Birmingham, Alabama; Boston, Massachusetts; and Portland, Oregon. In these areas, environmental variables with strong associations (r_s ≥ 0.70) with fish assemblages and fish traits tended to have strong associations with urbanization. Relations of urbanization with fish assemblages and fish traits were weaker in Denver, Colorado; Dallas-Fort Worth, Texas; Milwaukee-Green Bay, Wisconsin; and Raleigh, North Carolina. Environmental variables associated with fishes varied among the metropolitan areas. The metropolitan areas with poor relations may have had a limited range of possible response because of previous landscape disturbances. Given the complexities of urban landscapes in different metropolitan areas, our results indicate that caution is warranted when generalizing about biological responses to urbanization.     

Black widow spiders in an urban desert: Population variation in an arthropod pest across metropolitan Phoenix, AZ

The effects of urban disturbance are critical to understand, as the majority of the world??s population now resides in urban centers. For example, urbanization often leads to reduced species diversity at the expense of a few urban-adapted taxa. However, it remains unclear why some taxa thrive following human disturbance whereas others do poorly. The western black widow spider, Latrodectus hesperus, thrives in disturbed, urban habitat??often forming dense aggregations (i.e., infestations) relative to typical low-density, desert populations. We examined the population dynamics of ten black widow aggregations spread across metropolitan Phoenix, AZ, during the peak of the breeding season (June?CAugust). Here we show that prey abundance, female mass, web volume and population density exhibit minimal temporal variation across the breeding season, but that prey abundance, female mass and population density show significant spatial variation across the ten urban aggregations. Our measure of prey abundance and foraging success, the number of prey carcasses found in black widow webs, shared a strong positive relationship with female mass and population density, but not with web volume. Surprisingly, female mass, web volume and population density were not correlated with each other. The abiotic variables we measured at each site did a poor job of explaining black widow population parameters, although we did find a marginal trend for more recent developments to harbor denser black widow aggregations. Our findings support the generalization that urbanization heightens spatial variation, and we suggest that local urban prey abundance is influential in promoting urban infestations full of heavy, fecund female black widows. Studies of the population ecology of urban pests are necessary to identify the mechanisms allowing some species to thrive following human disturbance while much native biodiversity is lost following urbanization.     

Potential impacts of emerald ash borer invasion on biogeochemical and water cycling in residential landscapes across a metropolitan region

Trees provide important ecological services in cities, yet the vulnerability of the urban forest to massive tree losses from pest outbreaks could threaten those services, with unknown environmental consequences. The outbreak of emerald ash borer is an imminent threat to the ash population in North America. In the Minneapolis?CSaint Paul, Minnesota, metropolitan area, ash trees are present in 50?% of residential landscapes in Ramsey and Anoka Counties. We used a large survey of household activities, a tree inventory, a Household Flux Calculator accounting tool, and a set of annual evapotranspiration measurements, to quantify the current carbon, nitrogen, and phosphorus storage in ash trees, the cycling of these elements, and the total evapotranspiration from ash trees in residential areas in the metropolitan region. Ash represented 6?% of the trees in residential areas and the removal of the entire ash population would correspondingly reduce net primary production and carbon sequestration by only a few percent and would have negligible effects on losses of nitrogen and phosphorus from residential landscapes. Similarly, the effects of ash loss on the hydrologic cycle would be minimal and would depend largely on management choices for the ground currently underneath ash tree canopies. Overall, the percentage change in biogeochemical and hydrological fluxes corresponded closely with the percent of the total urban tree population that was represented by ash, suggesting that areas with higher densities of ash would experience correspondingly larger effects. A hypothetical tree replacement scenario with similar broadleaf species was determined to be likely to re-establish the original biogeochemical and hydrological conditions once the replacement trees reach maturity.     

Field and remotely sensed measures of soil and vegetation carbon and nitrogen across an urbanization gradient in the Boston metropolitan area

Understanding the impact of urbanization on terrestrial biogeochemistry is critical for addressing society’s grand challenge of global environmental change. We used field observations and remotely sensed data to quantify the effects of urbanization on vegetation and soils across a 100-km urbanization gradient extending from Boston to Harvard Forest and Worcester, MA. At the field-plot scale, the normalized difference vegetation index (NDVI) was positively correlated with aboveground biomass (AGB) and foliar nitrogen (N) content and negatively correlated with impervious surface fraction. Unlike previous studies, we found no significant relationship between NDVI or impervious surface area (ISA) fraction and foliar N concentration. Patterns in foliar N appeared to be driven more strongly by changes in species composition rather than phenotypic plasticity across the urbanization gradient. For forest and non-residential development, soil nitrogen content increased with urban intensity. In contrast, residential land had consistently high soil N content across the gradient of urbanization. When field observations were scaled-up to the Boston Metropolitan Statistical Area (MSA), we found that soil and vegetation N content were negatively correlated with ISA fraction, an indicator of urban intensity. Our results demonstrated the importance of accounting for the influence of impervious surfaces when scaling field data across urban ecosystems. The combination of field data with remote sensing holds promise for disentangling the complex interactions that drive biogeochemical cycling in urbanizing landscapes. Empirical data that accurately characterize variations in urban biogeochemistry are critical to gain a mechanistic understanding of urban ecosystem function and to guide policy makers and planners in developing ecologically sensitive development strategies.     

Urban Morphology types and open space distribution in urban core areas

Urban cores are primarily associated with economic activity: they are places where people live, work and engage in a range of leisure activities. Natural elements within the environment are recognised as having an important role in promoting quality of life. An investigation into the urban character of Manchester City Centre (UK) combining an analysis of the surface cover with the mapping of urban morphology types (UMTs) shows the extent to which green space permeates the built matrix. Around 20% of the urban core was covered by evapotranspiring surfaces. UMTs were differentiated along axes which were characterised by the intensity of grassland management and the density of building. The results presented here contribute to the on going debate around the development of cities and the relationship between the natural and built environments and provide guidance for those challenged with designing these environments.     

Racial residential segregation and the concentration of low- and high-income households in the 45 largest U.S. metropolitan areas

"The objectives of this paper are to determine the relationship between racial residential segregation and (1) the spatial concentration of low- and high-income households, and (2) the socioeconomic characteristics of racial minority households. The three largest racial minority groups are compared (blacks, Hispanics, and Asians) in the largest 45 metropolitan areas in the United States. Data were obtained from the U.S. bureau of the Census' Population and Housing Summary Tape files. The results revealed that residential segregation of blacks was distinctly different from Asians and Hispanics. Moreover, for Asians and Hispanics, their socioeconomic characteristics matter in their level of residential segregation. For black households, however, their socioeconomic characteristics matter little."     

浅析中国城市的都市区划研究

城市总是在发展的过程中,城市地域在不断地扩大,和周边的联系在不断强化,相对稳定的区划格局很显然不能持续反映城市体系的变化,更不能长久地促进以城市为核心的整个区域的发展,所以发达国家积极探讨设立独立于行政区外的地域概念实体来解决这个矛盾,美国、加拿大等发达国家通过"都市区"来解决行政区划和城市发展脱节的问题.     

International research master in metropolitan studies

Ohne Zusammenfassung

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International research master in metropolitan studies

     

Characteristics of atmospheric PM2.5 in stands and non-forest cover sites across urban-rural areas in Beijing,China

Urban Ecosystems - Monitoring air pollution at a city scale is essential for controlling urban air pollution in cities, especially megacities, in China. In this paper, data for 1 city center site...     

国内外大都市带的发展经验及启示--兼论京津冀的联合发展

一、国际大都市带的产生和发展 大都市带的概念最早由法国地理学家戈特曼(J.Gottman)提出,主要是指由在地域上集中分布的若干大城市和特大城市集聚而成的庞大的、多核心的、多层次的城市群,是大都市区的联合体.其实质是由一组不同等级城市所形成的相互串连、高度集中的经济中心地带.大都市带的产生是经济发展、科技进步、聚集效应等因素导致的产业、资源与人口在空间上的集聚与扩散运动的结果,交通运输和信息化的高度发达是大都市带得以产生和发展的重要推动力量.     

Recent European immigration to the Chicago metropolitan area

Patterns of European migration to the Chicago metropolitan area are examined to determine the urban spatial distribution of various ethnic groups. Data are from petitions of 1,185 male immigrants 18 years old and over from Greece, Italy, Poland, and Yugoslavia who applied for U.S. citizenship between June 2, 1975, and June 1, 1976. It is found that the majority of those studied chose to live within the city of Chicago. It is suggested that "residential locations of relatives, availability of low-cost housing, religious affiliations, proximity and access to employment opportunities, and avoidance of Black and Hispanic neighborhoods...were involved in the decision of where to reside." (summary in FRE, SPA)