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Urbanization
Kinds of Urbanization Selected AbstractsTHE EFFECT OF URBANIZATION ON LABOR TURNOVER,JOURNAL OF REGIONAL SCIENCE, Issue 2 2008Miles M. Finney ABSTRACT The paper empirically examines labor market matching as a source of urban agglomeration economies. We work from the hypothesis that job turnover leads to tighter labor matches and estimate the relationship between urbanization and the job mobility of young men. Using a panel from the National Longitudinal Survey of Youth, we find evidence that young men change jobs more frequently in their early career if they live in larger or in more educated urban areas. The sensitivity of the results to whether the young men were "movers" or "stayers" suggests the possible endogeneity of location. [source] INFLUENCES OF WATERSHED URBANIZATION AND INSTREAM HABITAT ON MACROINVERTEBRATES IN COLD WATER STREAMS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 5 2003Lizhu Wang ABSTRACT: We analyzed data from riffle and snag habitats for 39 small cold water streams with different levels of watershed urbanization in Wisconsin and Minnesota to evaluate the influences of urban land use and instream habitat on macroinvertebrate communities. Multivariate analysis indicated that stream temperature and amount of urban land use in the watersheds were the most influential factors determining macroinvertebrate assemblages. The amount of watershed urbanization was nonlinearly and negatively correlated with percentages of Ephemeroptera-Plecoptera-Trichoptera (EPT) abundance, EPT taxa, filterers, and scrapers and positively correlated with Hilsenhoff biotic index. High quality macroinvertebrate index values were possible if effective imperviousness was less than 7 percent of the watershed area. Beyond this level of imperviousness, index values tended to be consistently poor. Land uses in the riparian area were equal or more influential relative to land use elsewhere in the watershed, although riparian area consisted of only a small portion of the entire watershed area. Our study implies that it is extremely important to restrict watershed impervious land use and protect stream riparian areas for reducing human degradation on stream quality in low level urbanizing watersheds. Stream temperature may be one of the major factors through which human activities degrade cold-water streams, and management efforts that can maintain a natural thermal regime will help preserve stream quality. [source] The current status of urban-rural differences in psychiatric disordersACTA PSYCHIATRICA SCANDINAVICA, Issue 2 2010J. Peen Peen J, Schoevers RA, Beekman AT, Dekker J. The current status of urban,rural differences in psychiatric disorders. Objective:, Reviews of urban,rural differences in psychiatric disorders conclude that urban rates may be marginally higher and, specifically, somewhat higher for depression. However, pooled results are not available. Method:, A meta-analysis of urban,rural differences in prevalence was conducted on data taken from 20 population survey studies published since 1985. Pooled urban,rural odds ratios (OR) were calculated for the total prevalence of psychiatric disorders, and specifically for mood, anxiety and substance use disorders. Results:, Significant pooled urban,rural OR were found for the total prevalence of psychiatric disorders, and for mood disorders and anxiety disorders. No significant association with urbanization was found for substance use disorders. Adjustment for various confounders had a limited impact on the urban,rural OR. Conclusion:, Urbanization may be taken into account in the allocation of mental health services. [source] In Situ Urbanization in Rural China: Case Studies from Fujian ProvinceDEVELOPMENT AND CHANGE, Issue 2 2000Yu Zhu In most parts of the developing world, the urbanization process has been dominated by rural,urban migration and the growth of existing cities. However, case-studies in China's Fujian Province suggest that this process can also be achieved mainly by in situ transformation in rural areas. Such in situ transformation of rural areas has been driven mainly by two forces, the development of township and village enterprises (TVEs) and the inflow of foreign investment; and facilitated by the relevant policies adopted by the Chinese government since 1978. The former has been very effective in the transformation of rural employment structure, while the latter has brought many physical changes to the previously rural landscape. Being mutually complementary, these two ways of rural transformation have not only benefited and urbanized the rural areas, but kept many farmers in their hometowns, replacing the dominant role of rural,urban migration and the growth of existing cities in the urbanization process. [source] Stream communities across a rural,urban landscape gradientDIVERSITY AND DISTRIBUTIONS, Issue 4 2006Mark C. Urban ABSTRACT Rapid urbanization throughout the world is expected to cause extensive loss of biodiversity in the upcoming decades. Disturbances associated with urbanization frequently operate over multiple spatial scales such that local species extirpations have been attributed both to localized habitat degradation and to regional changes in land use. Urbanization also may shape stream communities by restricting species dispersal within and among stream reaches. In this patch-dynamics view, anthropogenic disturbances and isolation jointly reduce stream biodiversity in urbanizing landscapes. We evaluated predictions of stream invertebrate community composition and abundance based on variation in environmental conditions at five distinct spatial scales: stream habitats, reaches, riparian corridors and watersheds and their spatial location within the larger three-river basin. Despite strong associations between biodiversity loss and human density in this study, local stream habitat and stream reach conditions were poor predictors of community patterns. Instead, local community diversity and abundance were more accurately predicted by riparian vegetation and watershed landscape structure. Spatial coordinates associated with instream distances provided better predictions of stream communities than any of the environmental data sets. Together, results suggest that urbanization in the study region was associated with reduced stream invertebrate diversity through the alteration of landscape vegetation structure and patch connectivity. These findings suggest that maintaining and restoring watershed vegetation corridors in urban landscapes will aid efforts to conserve freshwater biodiversity. [source] Decline in the quality of suspended fine particulate matter as a food resource for chironomids downstream of an urban areaFRESHWATER BIOLOGY, Issue 5 2004Emma J. Rosi-MarshallArticle first published online: 16 APR 200 Summary 1. Urbanization and its associated contamination could degrade the quality of suspended fine particulate organic matter (SFPM) (20 ,m to 1 mm) as a food resource for aquatic insects. SFPM was collected at four sites along the main stem of the Chattahoochee River, which drains metropolitan Atlanta at base and high flow during four seasons. 2. Composition of SFPM was estimated using measures conventionally associated with food quality: bacteria, N/C ratio, caloric content, % inorganic, and % lipids, and metal (Cd, Cu, Pb, and Zn) concentration. In SFPM collected during base flow, % inorganic matter, calories, Cu, Pb, and Zn concentrations increased with cumulative permitted wastewater treatment discharge (an indicator of extent of urbanization upstream). In SFPM samples collected during high flow, % diatoms, Cu, Pb and Zn concentrations increased with urbanization. 3. A growth assay was used as an integrated and direct measure of SFPM quality as a food resource. The instantaneous growth rate (IGR) of chironomids fed SFPM collected during base flow declined downstream of the city. IGRs of chironomids fed SFPM collected at all sites during high flow were as low as the lowest IGR measured during base flow. 4. Insects fed SFPM collected from the Chattahoochee River had IGRs only 20% of those of chironomids fed SFPM collected from the Little Tennessee River, a relatively undisturbed river in North Carolina. The mortality rate of chironomids fed SFPM was not different among sites or rivers. While the decline in SFPM quality in the Chattahoochee River is probably attributable to some aspect of urbanization, the decline was not related to conventional measures of food quality or metal contamination. [source] LAND-USE DYNAMICS BEYOND THE AMERICAN URBAN FRINGE,GEOGRAPHICAL REVIEW, Issue 3 2001DAVID M. THEOBALD ABSTRACT. A deficiency common to both the historical debates over loss of agricultural land and the current discussions of urbanization and sprawl is a limited understanding of land-use dynamics beyond the urban fringe. Data aggregated at the county level poorly capture the fine-grained pattern of land-use change beyond the dynamic urban-rural interface. Furthermore, current urban-based definitions are poorly suited to delineate these areas, and low-density, exurban land use is difficult to measure using existing land-cover databases. Urbanization and the conversion of once-agricultural or other natural resource lands to other uses has traditionally been tracked using urban areas, as delimited in the U.S. census. Urban densities are typically defined as areas with more than 1,000 people per square mile, or 1.6 people per acre (U.S. Census Bureau 2000). Assuming an average of 2.5 people per housing unit, this translates to roughly 0.7 units per acre, or approximately 1 unit per 1.6 acres. The analytical units used in the census, however, both overbound and underbound areas with urban densities. About one-third of urban areas in 1990 comprised lower-than-urban housing density, thanks to overbounding. But, then, one-third of locations that had urban-level housing densities failed to be included in urban areas as a result of underbounding, which, if counted, would have constituted another 18 million acres of urban area. An increase over time of the average number of acres required per housing unit in exurban and higher-density locations occurred in roughly one-third of U.S. counties from 1960 to 1990 and persisted from 1990 to 2000. In 2000 roughly 38 million acres were settled at urban densities, and nearly ten times that much land was settled at rates from low, exurban density (as low as one house per 40 acres) to higher rates (up to one per 10 acres). This represents a continuing encroachment on land previously given over to other uses,habitat or agriculture. Practitioners of natural resource management need to recognize the ubiquity of exurban development and better incorporate the fine-scale patterns of land use beyond the urban fringe. [source] Does urbanization decrease diversity in ground beetle (Carabidae) assemblages?GLOBAL ECOLOGY, Issue 1 2010Tibor Magura ABSTRACT Aim, We wanted to test whether urbanization has similar effects on biodiversity in different locations, comparing the responses of ground beetle (Coleoptera, Carabidae) assemblages with an urbanization gradient. We also wanted to see if urbanization had a homogenizing effect on ground beetle assemblages. Locations, Nine forested temperate locations in Europe, Canada and Japan. Methods, Published results of the Globenet Project were used. At all locations, three stages were identified: (1) a forested (rural) area, (2) a suburban area where the original forest was fragmented and isolated, and (3) remnants of the original forest in urban parks. These habitats formed an urbanization series. Study arrangements (number and operation of traps) and methods (pitfall trapping) were identical, conforming to the Globenet protocol. Assemblage composition and diversity patterns were evaluated. Diversity relationships were analysed by the Rényi diversity ordering method considering all ground beetles and , separately , the forest specialist species. Taxonomic homogenization was examined by multivariate methods using assemblage similarities. Results, Overall biodiversity (compared by species richness and diversity ordering) showed inconsistent trends by either urbanization intensity or by geographic position. However, when only forest species were compared, diversity was higher in the original rural (forested) areas than in urban forest fragments. Within-country similarities of carabid assemblages were always higher than within-urbanization stage similarities. Main conclusions, Urbanization does not appear to cause a decrease in ground beetle diversity per se. Forest species decline as urbanization intensifies but this trend is masked by an influx of non-forest species. The rural faunas were more similar to the urban ones within the same location than similar urbanization stages were to each other, indicating that urbanization did not homogenize the taxonomic composition of ground beetle faunas across the studied locations. [source] Assessment of land-use impact on streamflow via a grid-based modelling approach including paddy fieldsHYDROLOGICAL PROCESSES, Issue 19 2005Seong Joon Kim Abstract To investigate the hydrologic impacts of land-use changes on streamflow for an urbanizing watershed with paddy fields, a grid-based daily hydrologic model was adopted. The model was calibrated with two years (2000,2001) of observed streamflow data and validated using 5 months (2001) of measured soil moisture data and 1 year (2002) of observed streamflow data. After the model was tested, it was run to estimate impacts of urbanization on each hydrologic component with the land-use data sets for 1986, 1994, and 2002 generated from Landsat TM satellite images. Total runoff increased from 41·4% (1986) to 44·9% (2002) for a 5·4% increase in urban area, implying that direct runoff increase exceeded baseflow decrease. Urbanization affected the proportions of direct runoff for each land-use category more than the change in total runoff and the ratio of direct runoff to total runoff. The change proportions in direct runoff for urban areas, paddy fields, and forest were 14·3%, ,9·8% and ,6·7% respectively for a 5·4% increase, 4·6% decrease and 3·4% decrease in each land-use area respectively. The results indicate that paddy fields play an important role in runoff regulation, and the evaluation method can assist regional policy makers in developing land management strategies that minimize hydrologic impacts on streamflow. Copyright © 2005 John Wiley & Sons, Ltd. [source] Habitat influences on urban avian assemblagesIBIS, Issue 1 2009KARL L. EVANS Urbanization is increasing across the globe and there is growing interest in urban ecology and a recognition that developed areas may be important for conservation. We review the factors influencing urban avian assemblages, focusing on habitat type and anthropogenic resource provision, and analyse data from a common bird monitoring scheme to assess some of these issues. The review suggests that (1) local factors are more important than regional ones in determining the species richness of urban avian assemblages, raising the potential for the management of urban sites to deliver conservation; (2) habitat fragmentation frequently influences urban avian assemblages, with the effects of patch size being greater than those of isolation, and (3) urban bird assemblages appear to respond positively to increasing the structural complexity, species richness of woody vegetation and supplementary feeding, and negatively to human disturbance. Data from Britain's Breeding Bird Survey, combined with habitat data obtained from aerial photographs, were used to assess a number of these issues at the resolution of 1-km squares. Green-space constituted 45% of these squares, and domestic gardens contributed 50% of this green-space, though their contribution to large continuous patches of green-space was negligible. There was no significant positive correlation between the densities of individual species in urban areas and surrounding rural areas. Rural species richness declined with increasing latitude, but urban species richness was not correlated with latitude. This contrast contributes to slightly higher avian species richness in rural squares in Southern England than urban ones. Occupancy and abundance were strongly positively correlated in urban avian assemblages, and some indicator species of conservation concern occurred in few urban areas and at low densities. Such species will require conservation action to be precisely targeted within urban areas. Of the urban indicators of conservation concern, only the House Sparrow Passer domesticus and Common Starling Sturnus vulgaris were more abundant in urban than rural areas. Moreover, the densities of these two species were strongly and positively correlated, indicating that they may be limited by shared resources, such as nest-sites or supplementary food. There was little evidence that high densities of nest-predating corvids were associated with reduced densities of their prey species. Species richness and the densities of individual species frequently declined with an increasing number of buildings. Current trends for the densification of many British urban areas are thus likely to be detrimental for many bird species. [source] Resurgent Metropolis: Economy, Society and Urbanization in an Interconnected WorldINTERNATIONAL JOURNAL OF URBAN AND REGIONAL RESEARCH, Issue 3 2008ALLEN J. SCOTT Abstract An urban problematic is identified by reference to the essential characteristics of cities as spatially polarized ensembles of human activity marked by high levels of internal symbiosis. The roots of the crisis of the classical industrial metropolis of the twentieth century are pinpointed, and the emergence of a new kind of urban economic dynamic over the 1980s and 1990s is discussed. I argue that this new dynamic is based in high degree upon the growth and spread of cognitive-cultural production systems. Along with these developments have come radical transformations of urban space and social life, as well as major efforts on the part of many cities to assert a role for themselves as national and international cultural centers. This argument is the basis of what we might call the resurgent metropolis hypothesis. The effects of globalization are shown to play a critical role in the genesis and geography of urban resurgence. Three major policy dilemmas of resurgent cities are highlighted, namely, their internal institutional fragmentation, their increasing character as economic agents on the world stage and the concomitant importance of collective approaches to the construction of localized competitive advantage, and their deepening social disintegration and segmentation. Résumé Une problématique urbaine est dégagée à propos des caractéristiques essentielles des villes définies comme des ensembles d'activité humaine polarisés dans l'espace et marqués par une symbiose interne poussée. Les racines de la crise qu'a subie la métropole industrielle classique au xxe siècle sont mises en évidence. Est aussi étudié un nouveau type de dynamique économique urbaine apparu au cours des années 1980-1990, cette dynamique étant largement fondée sur la croissance et la diffusion des systèmes de production cognitifs culturels. Parallèlement à ces évolutions, l'espace urbain et la vie sociale ont connu des transformations radicales, et nombre de villes ont entrepris de revendiquer un rôle de centre culturel national et international. Cet argument est à la base de ce qu'on pourrait appeler l'hypothèse d'une résurgence des métropoles. Il est montré que les effets de la mondialisation ont compté de façon cruciale dans la genèse et la géographie de la résurgence urbaine. Trois grands dilemmes politiques des ,villes résurgentes' sont soulignés: leur fragmentation institutionnelle interne; l'accentuation de leur place d'agents économiques sur la scène mondiale et l'importance concomitante des approches collectives pour construire des avantages concurrentiels localisés; ainsi que l'intensification de leur désintégration et de leur segmentation sociales. [source] Urbanization and the more-individuals hypothesisJOURNAL OF ANIMAL ECOLOGY, Issue 2 2010Claudia Chiari Summary 1.,Urbanization is a landscape process affecting biodiversity world-wide. Despite many urban,rural studies of bird assemblages, it is still unclear whether more species-rich communities have more individuals, regardless of the level of urbanization. The more-individuals hypothesis assumes that species-rich communities have larger populations, thus reducing the chance of local extinctions. 2.,Using newly collated avian distribution data for 1 km2 grid cells across Florence, Italy, we show a significantly positive relationship between species richness and assemblage abundance for the whole urban area. This richness,abundance relationship persists for the 1 km2 grid cells with less than 50% of urbanized territory, as well as for the remaining grid cells, with no significant difference in the slope of the relationship. These results support the more-individuals hypothesis as an explanation of patterns in species richness, also in human modified and fragmented habitats. 3.,However, the intercept of the species richness,abundance relationship is significantly lower for highly urbanized grid cells. Our study confirms that urban communities have lower species richness but counters the common notion that assemblages in densely urbanized ecosystems have more individuals. In Florence, highly inhabited areas show fewer species and lower assemblage abundance. 4.,Urbanized ecosystems are an ongoing large-scale natural experiment which can be used to test ecological theories empirically. [source] Breeding bird species richness in Taiwan: distribution on gradients of elevation, primary productivity and urbanizationJOURNAL OF BIOGEOGRAPHY, Issue 2 2004Pei-Fen Lee Abstract Aim, To examine the richness of breeding bird species in relation to elevation, primary productivity and urbanization. Location, The island of Taiwan (120°,122° E, 22°,25° N). Methods, We arranged bird species richness (BSR) data from 288 bird censuses undertaken in Taiwan into a 2 × 2 km quadrat system and calculated average values of elevation, primary productivity [surrogated by normalized difference vegetation index (NDVI)], and urbanization (surrogated by road density and percentage of built area) for each 2 × 2 km quadrat. Results, Bird species richness showed a hump-shaped relationship with elevation. It increased with elevation from sea level (10,64 species per 2 × 2 km quadrat), peaked around 2000 m (43,76 species), and then decreased with elevation towards its minimum at the highest elevation. Road density and percentage of built area decreased with elevation, and NDVI showed a hump-shaped relationship with elevation and inverse relationships with road density and percentage of built area. BSR increased with NDVI and decreased with road density and percentage of built area. Linear and cubic terms of elevation together explained 31.3% of the variance in BSR, and road density explained additional 3.4%. The explanatory power of NDVI on BSR was insignificant after the effects of elevation and road density had been justified. Main conclusions, We argue that urbanization plays an important role in the BSR of Taiwan. Urbanization might indirectly decrease BSR through decreasing primary productivity and therefore change the hypothetical inverse relationship between BSR and elevation into a hump-shaped relationship. We also propose a time hypothesis that the biotic communities in the mid-elevation zone of Taiwan had relatively longer periods of existence during the Pleistocene glacial cycles, which might be one underlying process of the observed hump-shaped relationship between species diversity and elevation. [source] Explaining Black-White Disparity in Maltreatment: Poverty, Female-Headed Families, and UrbanizationJOURNAL OF MARRIAGE AND FAMILY, Issue 3 2005Amie M. Schuck The purpose of the current study was to assess a structural level explanation of racial disparity in child maltreatment. Using data from Florida counties (1998,2001) and the 2000 census, the effects of poverty, concentrated poverty, and female-headed families in poverty on Black, White, and the difference between Black-White rates of child maltreatment were assessed (N= 67). Results suggested that the structural covariates of maltreatment vary by race and that differences in female-headed families in poverty can explain some, but not all, of the Black-White racial disparity in child maltreatment. Increasing programs that focus on reducing poverty among female-headed Black families and the exposure of Black families to concentrated poverty should decrease some of the overrepresentation of Black children in the child welfare system. [source] Stream Temperature Surges Under Urbanization and Climate Change: Data, Models, and Responses,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2007Kären C. Nelson ABSTRACT: Multiple anthropogenic stressors, including increased watershed imperviousness, destruction of the riparian vegetation, increased siltation, and changes in climate, will impact streams over the coming century. These stressors will alter water temperature, thus influencing ecological processes and stream biota. Quantitative tools are needed to predict the magnitude and direction of altered thermal regimes. Here, empirical relationships were derived to complement a simple model of in-stream temperature [developed by Caissie et al. Canadian Journal of Civil Engineering25 (1998) 250; Journal of Hydrology251 (2001) 14], including seasonal temperature shifts linked to land use, and temperature surges linked to localized rainstorms; surges in temperature averaged about 3.5°C and dissipated over about 3 h. These temperature surges occurred frequently at the most urbanized sites (up to 10% of summer days) and could briefly increase maximum temperature by >7°C. The combination of empirical relationships and model show that headwater streams may be more pervasively impacted by urbanization than by climate change, although the two stressors reinforce each other. A profound community shift, from common cold and coolwater species to some of the many warmwater species currently present in smaller numbers, may be expected, as shown by a count of days on which temperature exceeds the "good growth" range for coldwater species. [source] Changing patterns of diet, physical activity and obesity among urban, rural and slum populations in north IndiaOBESITY REVIEWS, Issue 5 2008K. Yadav Summary Rapid urbanization and accompanying lifestyle changes in India lead to transition in non-communicable disease risk factors. A survey was done in urban, urban slum and rural population of Haryana, India, in a sample of 4129 men and 3852 women using WHO STEPS questionnaire. A very high proportion of all the three populations reported inadequate intake of fruits and vegetables. Rural men reported five times physical activity as compared with urban and urban slum men and rural women reported seven times physical activity as compared with women in the other two settings. Mean body mass index (BMI) was highest among urban men (22.8 kg m,2) followed by urban slum (21.0 kg m,2) and rural men (20.6 kg m,2) (P -value < 0.01). Similar trend was seen for women but at a higher level than men. Prevalence of obesity (BMI , 30 kg m,2) was highest for urban population (male = 5.5%, female = 12.6%) followed by urban slum (male = 1.9%, female = 7.2%) and rural populations (male = 1.6%, female = 3.8%). Urbanization increases the prevalence of the studied non-communicable disease risk factors, with women showing a greater increase as compared with men. Non-communicable disease control strategy needs to address urbanization and warrants gender sensitive strategies specifically targeting women. [source] New Evidence on the Urbanization of Global PovertyPOPULATION AND DEVELOPMENT REVIEW, Issue 4 2007Martin Ravallion One-quarter of the world's consumption poor live in urban areas, and that proportion has been rising over time. Over 1993,2002, the count of the "$1 a day" poor fell by 150 million in rural areas but rose by 50 million in urban areas. The poor have been urbanizing even more rapidly than the population as a whole. By fostering economic growth, urbanization helped reduce absolute poverty in the aggregate. There are marked regional differences: Latin America has the most urbanized poverty problem, East Asia has the least; there has been a "ruralization" of poverty in Eastern Europe and Central Asia; in marked contrast to other regions, Africa's urbanization process has not been associated with falling overall poverty. [source] HIV/AIDS and UrbanizationPOPULATION AND DEVELOPMENT REVIEW, Issue 3 2003Tim Dyson It is well known that levels of HIV prevalence tend to be appreciably higher inurban areas. This article considers the reasons for this and shows that within world regions that are relatively homogeneous with respect to their experience of HIV/AIDS, variation in the level of urbanization corresponds to about one-third of variation in estimated HIV prevalence. Furthermore, for populations in the world's worst-affected area,eastern and southern Africa,there are signs that, partly by differentially raising urban death rates and depressing urban birth rates, HIV/AIDS is slowing the pace of urbanization. Finally, in countries with very high levels of HIV infection and relatively low birth rates, such as in South Africa, the urban sector will soon constitute a "demographic sink",with death rates exceeding birth rates. [source] The dynamic nature of social disadvantage: implications for hazard exposure and vulnerability in Greater VancouverTHE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 2 2008JEAN ANDREY défavorisation sociale; dangers; milieux urbains; Canada; Vancouver Urbanization and re-urbanization continually alter spatial patterns of social disadvantage and hazard exposure, which in turn affect social vulnerability. The current study explores vulnerability to hazards in Greater Vancouver over a 15-year period (1986 to 2001). Results illustrate how social disadvantage is multi-dimensional and emerges from the social geography of a city. The study illustrates the speed with which both the structure and spatial patterns of social disadvantage can change in cities experiencing rapid growth or redevelopment. The study also suggests that Greater Vancouver does not display consistent patterns of minority- or income-based environmental inequity in hazard exposure, which raises questions about the role of various policies in ameliorating vulnerability to natural and technological hazards. La nature dynamique de la défavorisation sociale: conséquences sur l'exposition au risque et la vulnérabilité dans le Grand Vancouver L'urbanisation et la réurbanisation modifient sans cesse les schémas spatiaux de la défavorisation sociale et de l'exposition au risque qui, à leur tour, contribuent à la vulnérabilité sociale. Cette étude présente une analyse de la vulnérabilité aux risques dans le Grand Vancouver pendant une période de quinze ans (1986,2001). Les résultats de l'analyse font ressortir combien la défavorisation sociale comporte plusieurs dimensions et se dégage de la géographie sociale d'une ville. L'étude illustre la vitesse avec laquelle la structure et les schémas spatiaux de la défavorisation sociale peuvent se modifier au sein de villes qui connaissent une forte croissance ou un réaménagement. Il ressort également de l'étude que le Grand Vancouver ne présente pas de schémas cohérents d'inégalité environnementale à l'exposition aux risques liés au statut minoritaire ou au revenu. Ceci soulève la question de savoir comment les diverses politiques peuvent contribuer à la vulnérabilité aux dangers naturels et technologiques. [source] The response of herpetofauna to urbanization: Inferring patterns of persistence from wildlife databasesAUSTRAL ECOLOGY, Issue 5 2010ANDREW J. HAMER Abstract Urbanization involves the conversion of natural habitats into human-modified ecosystems and is known to reduce the diversity and abundance of indigenous plant and animal communities. Urbanization may lead to the extinction of indigenous species or facilitate the establishment of non-indigenous communities in cities and towns. We analysed sighting records held in wildlife databases to infer the probability of persistence of reptiles and amphibians (,herpetofauna') within Melbourne, Victoria, Australia. Throughout greater Melbourne, 81% (13) of the 16 frog species recorded had ,95% probability of being extant in 2006, compared with 56% (22) of the 39 species of reptiles recorded. The number of frog species that had ,95% probability of being extant in inner local government areas (LGAs) within 10 km of the centre of Melbourne was higher (86%) than in the outer LGAs (69%). Conversely, only 46% of reptile species had ,95% probability of being extant in inner and outer LGAs. The proportion of reptile species with <50% probability of being extant in inner LGAs was higher than for frog species (25% and 7%, respectively), suggesting that reptiles have been negatively affected by urbanization to a much greater extent than frogs. Based on the probability of species being extant, frogs and reptiles exhibited variations in their response to urbanization between species that persisted (urban-adapters) and species that did not (urban-sensitive or urban-avoiders). These differences in response were likely related to individual species' life-history and their requirements for habitat, space and dispersal. To conserve herpetofauna in urban areas we need to maintain structural complexity in remnant habitat patches, and implement strategic policies and management actions that protect habitat remnants and habitat corridors. [source] Child health in an urbanizing worldACTA PAEDIATRICA, Issue 1 2002M Gracey The aim of this study is to document and comment on the effects of urbanization on child health, internationally, using published reports and the author's personal experience. Urbanization is having profound effects on the health and well-being of infants and children in industrialized and developing countries. This will affect generations into the future. The changes are not confined to cities and large towns; they rapidly influence transitional societies in remote and rural areas, because globalization is changing infant feeding practices and children's diets and lifestyles. In developing countries, overcrowding and environmental pollution are massive problems made worse by undernutrition and infections, particularly respiratory and diarrhoeal diseases. In developed societies there are many other problems, e.g. injuries, poisonings, violence, drug abuse, exposure to industrial and atmospheric pollutants, including pesticides, sexually transmissible diseases, and "lifestyle", diseases including obesity and cardiovascular disease risk. There is an urgent need for paediatricians, health planners, policy-makers, governments and the community to understand these issues and work towards minimizing their harmful effects on children. Conclusion: Urbanization has profound effects on child health, globally; these must be recognised so that harmful influences of urbanization can be reduced for the benefit of all children. [source] Conservation of Brazilian AmphibiansCONSERVATION BIOLOGY, Issue 3 2005DÉBORA L. SILVANO The Brazilian Official List of Threatened Species and the results of a workshop for the Global Amphibian Assessment indicate that 26 species are threatened. The majority of these occur in the Atlantic Forest, one of the world's biodiversity hotspots. The main threat to amphibians is the destruction of their habitats through deforestation, conversion into agricultural land, mining, wildfires, and infrastructure development and urbanization. In Brazil little is known about other causes of amphibian decline observed worldwide, such as pesticides, infectious diseases, climate change, invasive species, or wildlife trade. Brazilian conservation policies include such important legal instruments as the Official List of Threatened Species and the selection of priority areas for conservation measures in all of Brazil's major biomes. Although there is little information on geographic distributions and the natural history and ecology of the large majority of the currently recognized species, a number of important regional studies for amphibian conservation are under way. New species are discovered each year. Resumen:,Brasil es el líder mundial en diversidad de anfibios, con 765 especies, la mayoría de las cuales han sido descritas en los últimos 40 años. La Lista Brasileña Oficial de Especies Amenazadas y los resultados de un taller para la Evaluación Global de Anfibios indican que 26 especies están amenazadas, la mayoría de ellas ocurre en el Bosque Atlántico, uno de los sitios de importancia para la biodiversidad global. La principal amenaza a los anfibios es la destrucción de sus hábitats por la deforestación, conversión a tierras agrícolas, minería, fuego no controlado, desarrollo de infraestructura y urbanización. En Brasil se conoce poco sobre otras causas de la declinación de anfibios observadas en todo el mundo, como pesticidas, enfermedades infecciosas, cambio climático, especies invasoras o comercio de vida silvestre. Las políticas Brasileñas de conservación incluyen importantes instrumentos legales como la Lista Oficial de Especies Amenazadas y la selección de áreas prioritarias para la conservación en todos lo biomas principales de Brasil. Existe escasa información sobre la distribución geográfica y la historia natural y ecología de la gran mayoría de las especies reconocidas actualmente, aunque se está desarrollando un importante número de estudios regionales para la conservación de anfibios. Cada año se descubren nuevas especies. [source] The current status of urban-rural differences in psychiatric disordersACTA PSYCHIATRICA SCANDINAVICA, Issue 2 2010J. Peen Peen J, Schoevers RA, Beekman AT, Dekker J. The current status of urban,rural differences in psychiatric disorders. Objective:, Reviews of urban,rural differences in psychiatric disorders conclude that urban rates may be marginally higher and, specifically, somewhat higher for depression. However, pooled results are not available. Method:, A meta-analysis of urban,rural differences in prevalence was conducted on data taken from 20 population survey studies published since 1985. Pooled urban,rural odds ratios (OR) were calculated for the total prevalence of psychiatric disorders, and specifically for mood, anxiety and substance use disorders. Results:, Significant pooled urban,rural OR were found for the total prevalence of psychiatric disorders, and for mood disorders and anxiety disorders. No significant association with urbanization was found for substance use disorders. Adjustment for various confounders had a limited impact on the urban,rural OR. Conclusion:, Urbanization may be taken into account in the allocation of mental health services. [source] Type 2 diabetes mellitus and obesity in sub-Saharan AfricaDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2010Vivian C. Tuei Abstract While communicable diseases such as human immunodeficiency virus/acquired immune deficiency syndrome, malaria, and tuberculosis have continued to pose greater threats to the public health system in sub-Saharan Africa (SSA), it is now apparent that non-communicable diseases such as diabetes mellitus are undoubtedly adding to the multiple burdens the peoples in this region suffer. Type 2 diabetes mellitus (T2DM) is the most common form of diabetes (90,95%), exhibiting an alarming prevalence among peoples of this region. Its main risk factors include obesity, rapid urbanization, physical inactivity, ageing, nutrition transitions, and socioeconomic changes. Patients in sub-Saharan Africa also show manifestations of ,-cell dysfunction and insulin resistance. However, because of strained economic resources and a poor health care system, most of the patients are diagnosed only after they have overt symptoms and complications. Microvascular complications are the most prevalent, but metabolic disorders and acute infections cause significant mortality. The high cost of treatment of T2DM and its comorbidities, the increasing prevalence of its risk factors, and the gaps in health care system necessitate that solutions be planned and implemented urgently. Aggressive actions and positive responses from well-informed governments appear to be needed for the conducive interplay of all forces required to curb the threat of T2DM in sub-Saharan Africa. Despite the varied ethnic and transitional factors and the limited population data on T2DM in sub-Saharan Africa, this review provides an extensive discussion of the literature on the epidemiology, risk factors, pathogenesis, complications, treatment, and care challenges of T2DM in this region. Copyright © 2010 John Wiley & Sons, Ltd. [source] The changing world demography of type 2 diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2003Anders Green Abstract In recent years it has been estimated that the current global prevalence of type 2 diabetes amounts to about 150 million patients. Projections suggest that by the year 2025 the number of prevalent patients in the world will reach approximately 300 million. It is assumed that the increase in the number of patients will be most pronounced in nations currently undergoing socio-economic development including increasing urbanization. The technique used to provide these estimates is based on results from available, contemporary survey results, combined with expected future trends in demographic indicators. We suggest that the currently available methods for the estimation of the future global burden of type 2 diabetes mellitus yield underestimates. Further modifications and validity tests of the modelling techniques are necessary in order to develop a reliable instrument to globally monitor the effects of the struggle against the diabetes problem. Copyright © 2002 John Wiley & Sons, Ltd. [source] Neophyte species richness at the landscape scale under urban sprawl and climate warmingDIVERSITY AND DISTRIBUTIONS, Issue 6 2009Michael P. Nobis Abstract Aim, Land use and climate are two major components of global environmental change but our understanding of their simultaneous and interactive effects upon biodiversity is still limited. Here, we investigated the relationship between the species richness of neophytes, i.e. non-native vascular plants introduced after 1500 AD, and environmental covariates to draw implications for future dynamics under land-use and climate change. Location, Switzerland, Central Europe. Methods, The distribution of vascular plants was derived from a systematic national grid of 1 km2 quadrates (n = 456; Swiss Biodiversity Monitoring programme) including 1761 species, 122 of which were neophytes. Generalized linear models (GLMs) were used to correlate neophyte species richness with environmental covariates. The impact of land-use and climate change was thereafter evaluated by projections for the years 2020 and 2050 using scenarios of moderate and strong changes for climate warming (IPCC) and urban sprawl (NRP 54). Results, Mean annual temperature and the amount of urban areas explained neophyte species richness best, with a high predictive power of the corresponding model (cross-validated D2 = 0.816). Climate warming had a stronger impact on the potential increase in the mean neophyte species richness (up to 191% increase by 2050) than ongoing urban sprawl (up to 10% increase) independently from variable interactions and model extrapolations to non-analogue environments. Main conclusions, In contrast to other vascular plants, the prediction of neophyte species richness at the landscape scale in Switzerland requires few variables only, and regions of highest species richness of the two groups do not coincide. The neophyte species richness is basically driven by climatic (temperature) conditions, and urban areas additionally modulate small-scale differences upon this coarse-scale pattern. According to the projections climate warming will contribute to the future increase in neophyte species richness much more than ongoing urbanization, but the gain in new neophyte species will be highest in urban regions. [source] Threats and biodiversity in the mediterranean biomeDIVERSITY AND DISTRIBUTIONS, Issue 2 2009Emma C. Underwood ABSTRACT Aim, Global conservation assessments recognize the mediterranean biome as a priority for the conservation of the world's biodiversity. To better direct future conservation efforts in the biome, an improved understanding of the location, magnitude and trend of key threats and their relationship with species of conservation importance is needed. Location, Mediterranean-climate regions in California-Baja California, Chile, South Africa, Australia and the Mediterranean Basin. Methods, We undertook a systematic, pan-regional assessment of threats in the mediterranean biome including human population density, urban area and agriculture. To realize the full implications of these threats on mediterranean biodiversity, we examined their relationship with species of conservation concern: threatened mammals at the global scale and threatened plants at the subecoregional scale in California, USA. Results, Across the biome, population density and urban area increased by 13% and agriculture by 1% between 1990 and 2000. Both population density and urban area were greatest in California-Baja California and least in Australia while, in contrast, agriculture was greatest in Australia and least in California-Baja California. In all regions lowlands were most affected by the threats analysed, with the exception of population density in the Chilean matorral. Threatened species richness had a significant positive correlation with population density at global and subecoregional scales, while threatened species were found to increase with the amount of urban area and decrease as the amount of natural area and unfragmented core area increased. Main conclusions, Threats to mediterranean biodiversity have increased from 1990 to 2000, although patterns vary both across and within the five regions. The need for future conservation efforts is further underlined by the positive correlation between species of conservation concern and the increase in population density over the last decade. Challenges to reducing threats extend beyond those analysed to include human,environmental interactions and their synergistic effects, such as urbanization and invasive species and wildfires. [source] New York's nature: a review of the status and trends in species richness across the metropolitan regionDIVERSITY AND DISTRIBUTIONS, Issue 1 2009Linda M. Puth ABSTRACT Aim, The world's population is urbanizing, yet relatively little is known about the ecology of urban areas. As the largest metropolitan area in the USA, New York City is an ideal location to study the effects of urbanization. Here, we aim to produce a better understanding of the state of the research for species richness of flora and fauna across the New York metropolitan region. Location, New York metropolitan region, USA. Methods, We conducted a review of the published and grey literature, in which we targeted studies of species richness, and categorized each study by habitat, location and taxonomic group. Results, We found 79 studies reporting location-specific species richness data, resulting in 261 location-taxonomic group records. Of these, 26 records had data from multiple time periods; 17 showed decreases in species richness, six reported increases and three showed stable species richness. Of these 26 records, most declines were attributed to anthropogenic causes, such as habitat loss/degradation and invasive species, while most increases reflected recovery from major habitat loss or increases in exotic species. Overall, most records (84) were terrestrial, followed by those in freshwater (72) and mixed habitats (61). When parsed by taxonomic group, the most commonly studied groups were plants (76) and mammals (48). Main conclusions, In general, we discovered fewer studies than expected reporting species richness, especially studies reporting species richness for more than one point in time. Most studies that did contain data over time reported declines in species richness, while several studies reporting increasing or stable species richness reflected increases in exotic species. This survey provides a crucial first step in establishing baseline ecological knowledge for the New York metropolitan region that should help prioritize areas for protection, research and development. Furthermore, this research provides insights into the impacts of urbanization across the USA and beyond and should help establish similar frameworks for ecological understanding for other metropolitan regions throughout the world. [source] Stream communities across a rural,urban landscape gradientDIVERSITY AND DISTRIBUTIONS, Issue 4 2006Mark C. Urban ABSTRACT Rapid urbanization throughout the world is expected to cause extensive loss of biodiversity in the upcoming decades. Disturbances associated with urbanization frequently operate over multiple spatial scales such that local species extirpations have been attributed both to localized habitat degradation and to regional changes in land use. Urbanization also may shape stream communities by restricting species dispersal within and among stream reaches. In this patch-dynamics view, anthropogenic disturbances and isolation jointly reduce stream biodiversity in urbanizing landscapes. We evaluated predictions of stream invertebrate community composition and abundance based on variation in environmental conditions at five distinct spatial scales: stream habitats, reaches, riparian corridors and watersheds and their spatial location within the larger three-river basin. Despite strong associations between biodiversity loss and human density in this study, local stream habitat and stream reach conditions were poor predictors of community patterns. Instead, local community diversity and abundance were more accurately predicted by riparian vegetation and watershed landscape structure. Spatial coordinates associated with instream distances provided better predictions of stream communities than any of the environmental data sets. Together, results suggest that urbanization in the study region was associated with reduced stream invertebrate diversity through the alteration of landscape vegetation structure and patch connectivity. These findings suggest that maintaining and restoring watershed vegetation corridors in urban landscapes will aid efforts to conserve freshwater biodiversity. [source] Evolution of channel morphology and hydrologic response in an urbanizing drainage basinEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2006Peter A. Nelson Abstract The Dead Run catchment in Baltimore County, Maryland, has undergone intense urbanization since the late 1950s. Reconstruction of the channel planform from topographic maps dating back to the 1890s and aerial photographs dating back to the 1930s indicates that the channel has remained stable in planform since at least the 1930s. The relative stability of Dead Run contrasts with the alterations in channel morphology reported for other urbanizing streams in the Piedmont physiographic province of the eastern United States. Trend analyses of discharge records in Dead Run show that urban development and stormwater control measures have had significant impacts on the hydrologic response of the catchment. The flood hydraulics of the Dead Run catchment are examined for the event that occurred on 22 June 1972 in association with Hurricane Agnes. A two-dimensional hydraulic model, TELEMAC-2D, was used with a finite-element mesh constructed from a combination of high-resolution LiDAR topographic data and detailed field survey data to analyse the distribution of boundary shear stress and unit stream power along the channel and floodplain during flooding from Hurricane Agnes. The spatial and temporal distributions of these parameters, relative to channel gradient and channel/valley bottom geometry, provide valuable insights on the stability of the Dean Run channel. The stability of Dead Run's channel planform, in spite of extreme flooding and decades of urban development, is most likely linked to geological controls of channel and floodplain morphology. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||