Urbanization impacts on the structure and function of forested wetlands

The exponential increase in population has fueled a significant demographic shift: 60% of the Earth's population will live in urban areas by 2030. While this population growth is significant in its magnitude, the ecological footprint of natural resource consumption and use required to sustain urban populations is even greater. The land use and cover changes accompanying urbanization (increasing human habitation coupled with resource consumption and extensive landscape modification) impacts natural ecosystems at multiple spatial scales. Because they generally occupy lower landscape positions and are linked to other ecosystems through hydrologic connections, the cascading effects of habitat alteration on watershed hydrology and nutrient cycling are particularly detrimental to wetland ecosystems. I reviewed literature relevant to these effects of urbanization on the structure and function of forested wetlands. Hydrologic changes caused by habitat fragmentation generally reduce species richness and abundance of plants, macroinvertebrates, amphibians, and birds with greater numbers of invasives and exotics. Reduction in soil saturation and lowered water tables result in greater nitrogen mineralization and nitrification in urban wetlands with higher probability of NO^– ₃ export from the watershed. Depressional forested wetlands in urban areas can function as important sinks for sediments, nutrients, and metals. As urban ecosystems become the predominant human condition, there is a critical need for data specific to urban forested wetlands in order to better understand the role of these ecosystems on the landscape.     

对我国城市化健康发展的理论思考——城乡统筹发展的视角

本文简要回顾了我国近10年来城市化快速发展的理论和政策背景,指出快速城市化进程中存在土地、能源等自然资源过渡消耗和浪费问题,也存在重城轻乡等突出社会问题;采用人口供需平衡的方法,分析评价了我国人口城市化水平同经济发展水平、工业化水平和土地城市化的关系;对城市化加速理论进行剖析,认为我国当前工业化技术体系不适用于机器技术体系下城市化加速的经验规律,应该结合我国新型工业化的要求走资源节约型的新型城市化道路;建议适当降低城市化发展目标与速度,纠正城市化过程中＂城市偏向＂和＂以物为本＂的做法,体现国家赋予城市化带动农村发展的重任,实现城乡统筹发展。     

Tourism-driven urbanization in China’s small town development: A case study of Zhapo Town, 1986-2003

This paper investigates the process of tourism-driven urbanization as a local strategy of town development in China. Existing literature has highlighted the role of industrialization in the urbanization process of China’s small towns, but here it is suggested that tourism - a development initiative based on the creation of space for consumption, rather than production - can also foster significant expansion of urbanized built environment and remarkable transformation of local socio-economic structures. The case study suggests that, in contrast to the recent process of industrialization-based urbanization in China’s small towns, tourism urbanization in Zhapo Town, Guangdong Province has been a highly localized development initiative characterized by the absence of foreign capital investment. Tourism-driven urbanization in Zhapo has involved several processes whose joint effect has reproduced the local socio-spatial organization: the rapid of expansion of urbanized built environment; a unique pattern of land use and land development; the booming of tertiary economic sectors; and the emergence of a flexible regime of labor force. In the meantime, the research also contests Mullins’ (1991) classical theorization of tourism urbanization, and suggests that recent tourism-driven urbanization process in Zhapo Town is not the product of the post-modernization of urban cultural manifestations, but is situated within the context-specific space of China’s modernity and is based on relatively standardized provision of tourism-related service and the mass consumption of nature.     

Interest distribution in the process of coordination of urban and rural construction land in China

Since the onset of rapid economic development and urbanization, China’s land resources—rather than capital, technology and human resources—have become the lead limiting factor in constraining economic growth. Coordination of urban and rural construction land (CURCL) can be a very effective means for reducing conflicts between economic development and land protection. This research examines the roles of stakeholders involved in the CURCL process. The reasons why the interests of legitimated stakeholders were encroached upon are analyzed and countermeasures to protect the interests of legitimated stakeholders are proposed. Ambiguously defined property rights for owners of rural construction land, unclear conceptions of the public interest, and overlap of power and interest among multiple levels of authority are the reasons why legitimated stakeholders’ interests were encroached upon. Legitimizing construction land ownership clearly, better defining the multiple conceptions of public interest, opening up express channels for expression of the public interest, and clarifying governments’ functions in land interest adjustment are the countermeasures to protect the interests of legitimated stakeholders.     

Urban growth management-the Saudi experience

Saudi Arabia experienced a high rate of urbanization during the period 1970–1986 resulting in accelerated annual growth rates for Saudi cities averaging more than 6.4%. Higher than usual growth rates created demand for the opening up of huge areas to meet housing, commercial, industrial and other land uses. Government's land grant policy and liberal interest free loans resulted in massive expansion of cities and towns all over the country with major cities of Riyadh, Jeddah, and Dammam having the biggest share. Lack of planning frameworks and weak city institutions could not direct the growth properly leading to sprawl and lop-sided development. This meant rapid extension of road network and utilities with high financial outlays. The slow-down in the economy and ever-increasing demand for infrastructure provision forced the government to initiate growth boundaries to tackle these problems in 1986. The paper discusses the methodology adopted and the process of devising urban limits and evaluates their impact on urban structures of Saudi cities. The paper draws some conclusions in the realization of objectives of the exercise with respect to, (a) control urban sprawl by encouraging infill development where utilities were generally available; (b) reduce cost of provision of infrastructure through better coordination tied to commonly agreed phasing; (c) maintain natural environment around the cities.     

Land fragmentation under rapid urbanization: A cross-site analysis of Southwestern cities

Explosive population growth and increasing demand for rural homes and lifestyles fueled exurbanization and urbanization in the western USA over the past decades. Using National Land Cover Data we analyzed land fragmentation trends from 1992 to 2001 in five southwestern cities associated with Long Term Ecological Research (LTER) sites. We observed two general fragmentation trends: expansion of the urbanized area leading to fragmentation in the exurban and peri-urban regions and decreased fragmentation associated with infill in the previously developed urban areas. We identified three fragmentation patterns, riparian, polycentric, and monocentric, that reflect the recent western experience with growth and urbanization. From the literature and local expert opinion, we identified five relevant drivers ?C water provisioning, population dynamics, transportation, topography, and institutions ?C that shape land use decision-making and fragmentation in the southwest. In order to assess the relative importance of each driver on urbanization, we linked historical site-specific driver information obtained through literature reviews and archival analyses to the observed fragmentation patterns. Our work highlights the importance of understanding land use decision-making drivers in concert and throughout time, as historic decisions leave legacies on landscapes that continue to affect land form and function, a process often forgotten in a region and era of blinding change.     

Changing views on urbanisation,migration and squatters

A general review of the literature on urbanization in developing countries is presented. The review covers works written between the 1950s and the present day. Particular attention is given to the various opinions regarding squatter settlements in and around urban areas.     

A comparison of carbon and nitrogen stocks among land uses/covers in coastal Florida

Coastal areas are rapidly developing due to population growth and the appeal of coastlines. In order to gain insight into how land use/cover affects carbon (C) storage in a coastal context, we examined soil and vegetation C and soil nitrogen (N) across land uses near Apalachicola, FL. Forested wetlands had the greatest soil C and N storage, while natural pine forests and pine plantations had the least. In paired plots, urban lawns had significantly greater mineral soil N content compared to urban forest remnants. Total ecosystem C (soil + vegetation) was higher in forested wetlands than all other land uses/covers combined due to the high organic content of those wetland soils. Urban forest remnants and lawns had greater total ecosystem C than natural pine forests and pine plantations, which likely reflects the differential influence of prescribed fire and less frequent anthropogenic disturbances between the rural and urban areas, respectively. Projections of land use change in Franklin County, FL combined with these data suggest that increases in C storage are possible with continued urbanization along the Gulf Coast, if forest remnants are left and lawns are incorporated in built-up areas. However, this study does not account for C emissions during land conversion, or any emissions associated with maintaining urban built-up and residential areas. A better understanding of land use/cover influences on C pools has applications for planning and development, as well as ecological and environmental protection in the region.     

Rural development and urban migration: can we keep them down on the farm?

This study tests the hypothesis that rural development projects and programs reduce rural-urban migration. The author presents various factors in the social theories of migration, including those relating to origin and destination, intervening obstacles such as distance, and personal factors. 3 economic models of migration are the human capital or cost-benefit approach, the expected income model, and the intersectoral linkage model. Empirical studies of migration indicate that: 1) rural areas with high rates of out-migration tend to have high population densities or high ratios of labor to arable land, 2) distance inhibits migration, 3) rural-urban migration is positively correlated with family income level, and 4) selectivity differences in socioeconomic status between migrants and nonmigrants often are grouped into development packages which might include irrigation, new varieties of seed, subsidized credit, increased extension, and improved marketing arrangements. The migration impacts of some of these efforts are described: 1) land reform usually is expected to slow rural out-migration because it normally increases labor utilization in rural areas, but this is a limited effect, 2) migration effects of the Green Revolution technology are mainly in rural-rural migration, and 3) agricultural mechanization may stimulate rural-urban migration in the long run. Development of rural social services migh have various effects on rural-urban migration. Better rural education, which improves the chances of urban employment, will stimulate rural-urban migration, while successful rural family planning programs will have a negative effect in the long run as there will be reduced population pressure on arable land. Better rural health services might reduce the incentive for rural-urban migration as well. It is suggested that governments reconsider policies which rely on rural development to curb rural-urban migration and alleviate problems of urban poverty and underemployment.     

Farmland preservation,development rights and the theory of the growth machine: the views of planners 1

We examine the effectiveness of farmland preservation measures in challenging efforts to convert agricultural land to nonfarm uses in rural/urban fringe areas. Our focus is on programs based on the exchange of development rights in the northeastern United States. We employ theoretical constructs from Logan and Molotch's theory of the urban growth machine. They argue that the commodification of land associated with urbanization is the most important source of wealth and power for land-based elites. Yet, the activities of these elites are sometimes challenged with growth control measures like farmland preservation. To evaluate the effectiveness of these programs to defend farm land-use over purely commercial land exchange for speculative gain, we draw on data from focus group discussions and a survey of planners in metropolitan areas of the region. Our analysis also considers the limitations of such programs in the context of the absence of regional land-use planning. We find that farmland preservation programs based on the exchange of development rights do challenge some aspects of urban growth, but are also the result of those same development dynamics. Thus, they reflect certain class biases associated with the development of rural/urban fringe areas. However, we conclude that these programs could become more effective farmland protection tools with the implementation of comprehensive land-use planning.     

How small cities affect the biodiversity of ground-dwelling mammals and the relevance of this knowledge in planning urban land expansion in terms of urban wildlife

Fundamental principles regarding urban biodiversity are based on studies conducted in large cities. However we cannot know whether the same phenomena occur in smaller cities or how small cities affect biodiversity. Small cities are an inherent element of urbanization and in the future, most global urban growth is expected to take place in small and medium-sized cities. Understanding the effects of small cities on biodiversity will be an important aspect in planning urban land expansion. Our study examined the effects of a small city on communities of small ground-dwelling mammals on 41 sites arranged in a four step gradient of urbanization. In 6700 trap-days, we caught 2333 individuals comprising 15 species. In the downtown area the same phenomena as those described for large cities were observed: a reduction in species richness and diversity, a decline in the abundance of urban sensitive species and an increase in synurbic species. However, in contrast to large city studies, green areas outside the downtown area did not differ from rural sites in small mammal population parameters. This phenomenon of relatively unchanged fauna outside the downtown area shows that small cities have the potential to maintain a high level of diversity of small ground-dwelling mammals if appropriate planning of further building expansion is implemented. More studies of small cities are needed to better assess their impact on biodiversity. This knowledge can then be applied in better planning for urban wildlife. Generalizations based solely on large city studies are inadequate and may lead to incomplete or inappropriate conservation strategies for small cities.     

Birds of a neotropical green city: an up-to-date review of the avifauna of the city of Xalapa with additional unpublished records

Although urbanization poses severe threats to biodiversity, some wildlife groups manage to thrive within urban areas. Among wildlife, birds are a highly diverse, charismatic and well-known group, establishing complex communities in human settlements around the world, making them suitable bioindicators. However, it is often difficult to have historical species lists that allow understanding current urban ecology trends. In this paper, we compile the available bird records, including unpublished information, for one of the best studied and well vegetated urban areas in México: the city of Xalapa. We gathered records for 329 species, representing ~30 % of the national avifauna in this medium-sized neotropical city. This important avian diversity in the city of Xalapa is mostly due to its environmental heterogeneity, underlining the relevance of its location, and the nature of its surroundings. The information provided in this paper will not only provide an environmental education baseline and represent a starting point for ornithologists, but will represent a reference document on the birds that have been recorded within the limits of Xalapa in the last three decades.     

Toward Spatial Homogeneity of the Elderly Population

The growth of the elderly population is occurring at a much faster rate in suburban areas than in central cities. Using Annual Housing Survey data from both national and individiual SMSA surveys, the authors examine patterns of elderly residential location in forty-four suburban areas. A strong positive relationship is identified between the age of the population and the age of the housing stock. The aging in place of older households contributes significantly to this pattern. The authors argue that growth races among the suburban elderly will exceed central-city elderly growth rates, until a stabilization point is reached, characterized by homogeneous elderly population proportions across central-city and suburban areas.     

Large urban developments as the new driver for land development in Jeddah

Land development in most Saudi cities including Jeddah is generated by formal land subdivision and informal land development usually referred to as unplanned settlements. Both types of developments contributed to urban sprawl and other urban challenges. Jeddah Municipality attempted to improve land development by encouraging large urban developments. Recently, Jeddah Municipality approved four large urban developments which appear to manifest encouraging implications for urban growth and land development that this paper aims to explore. The paper examines the policy and market contexts that govern land development in general and large urban developments in particular, in order to pave the way to uncover their implications for city growth and land development. The data gathered for this purpose is drawn from published and unpublished reports from relevant authorities. It is found that large urban developments as new mechanisms of land development appear incapable of overcoming key challenges that face city growth and existing land development.     

全面推进上海“城中村”改造土地政策研究

“城中村”作为城市化的一种特有现象,已逐渐演化为影响城市品质和居住品质的巨大障碍,同时制约着城市土地的集约利用水平的提高。在上海市城市化进程加速、人口日益膨胀、中心城区土地资源供应越来越少的背景下,“城中村”所贮存土地的战略重要性越加明显。上海可通过健全现有土地储备制度、完善土地出让办法、完善安置补偿政策、加大规划政策支持力度等举措,全面推进“城中村”改造。     

Temporary versus permanent population mobility in Melanesia: a case study from Vanuatu

A case study of temporary and circular Melanesian population mobility and labor migration focuses on the island of Paama in the Republic of Vanuatu (an archipelago of 80 islands) in Melanesia and on urbanization, which is a relatively recent phenomena. A critical analysis is provided of temporary and permanent migration and methodological inadequacies in explanations of mobility. Mobility is neither a cause nor a result of economic, social, and political change; it is the interrelationship among the general structural setting, people's personal and social environment, and their perceptions and actions. In the case of Paamese mobility, changes appeared in the source of migration and destination areas. There was a period of original land acquisition, when migrants returning from Queensland with tools were the only ones who could actually acquire land. Inequalities of land access date from this period. The population is dependent on external income sources as well as the need for plantation migration and a huge increase in bridewealth. Concurrently, "kampani" or community work, which ensures the continuous authority of local chiefs and village elders, creates problems for those seeking work for their own families. These conditions encourage out-migration. Rapid urban growth began in the 1960s with a diversified economy. Employment opportunities were available for women; single employee residence spaces declined. This meant families could permanently settle in urban areas. Retirement benefits were also available and contributed to securing permanent migration. There were growing needs for a stable, skilled labor force. Another change was the abolishment of the tripartite colonial administration. Rural disasters and price declines also triggered urban migration. Migration to the town of Port Vila by Paamese men and women between 1953 and 1982 is analyzed, based on 258 employment related mobility histories collected in 1982-83. Two processes are evident: continued periodic, short-term, rural-based circulation and permanent urban migration among Paamese to Port Vila. A major reversal of mobility is unlikely in the future. The reasons why are indicated.     

GOVERNMENT INTERVENTION,LAND MARKET,AND URBAN DEVELOPMENT: EVIDENCE FROM CHINESE CITIES

This article investigates how government intervention in land market affects China's urban development, using data from prefecture‐level cities between 2000 and 2010. We find that government intervention enlarges the impact of positive productivity shocks on housing price appreciation, through mainly the government control over residential land supply. However, we find no significant evidence that high government intervention constrains population growth and leads to wage increase. Such patterns of urban dynamics can be explained by the fact that migrant workers are the driving force behind China's urbanization, but they have limited housing demand and are not well compensated. (JEL P52, R12, H11)     

The production of space in the negotiation of water and electricity supply in a bosti of Dhaka

Dhaka Water Supply and Sewerage Authority (DWASA) and Dhaka Electricity Supply Company (DESCO) do not provide any direct utility supply in the informal settlements of Dhaka where more than one third of the total city population live. Large numbers of the population thus access utilities from local vendors who maintain relationships with administrative staff of the authorities concerned, political leaders and influential community leaders, thus making the supply available in the settlement and continuing their informal utility business. Access to these utilities is negotiated in the continuously changing arrangements of a complex hybrid institutional sphere and under informal regulation. In this process, the changing nature of the state and urban groups and the complicated and dynamic relationship between and within urban groups indicate that urban governance operates in a ‘third space’ of constant negotiation and contestation. Against this background this paper presents the informal practice of water and electricity supply by a local association, the regulations in place, and the inter-linkage between different forms of regulatory space whose presence is a necessary condition for the continuation of the informal practice.     

Urban policy,economic policy,and the growth of large cities in China

It is argued that despite a Chinese national urban policy large cities are still growing rapidly. Policy implementation is considered weak. It is suggested that a better strategy for increased urbanization in large Chinese cities would include integrating urban with economic policy, improving urban facilities, and planning and managing large cities. A short review is given of theories on city size and development in developing countries. Chinese economic reforms and their impact on urban growth are described. During 1978-90 the level of urbanization rose from 17.9% to 26.4%. Five periods during 1949 to present are identified as exhibiting distinct development profiles. Over the 40 year period, policies pertaining to cities of a particular population size changed constantly. During the early 1950s, development focused on major coastal cities and newly expanding industrial centers. After the 1950s and the Great Leap Forward (1958-60), rural areas and small urban places were the focus of Maoist development. Large cities were de-emphasized. The early 1970s emphasized the development of rural industries and small urban places in order to reduce rural-urban inequalities. A national urban policy was prepared in the early 1980s. The aim was to control the size of large cities, to develop medium sized cities, and to develop small cities. This policy was amended later and is now China's Urban Planning Law. However, the percentage of the nonagricultural population (NAP) living in cities of a million or more persons increased from 37.5% in 1978 to 41.6% in 1990. The share of NAP living in small cities increased to 21.5% in 1990. Temporary migrants were an estimated 5-15% of large city populations. Most cities were beyond their population control limit. Large cities had served important roles in development: greater efficiency in the industrial labor force and more profits; centers for culture, education, politics, and transportation; and links to foreign countries. Economic reforms fueled growth. At present controlled growth is an obstacle to economic development in large cities. Improvement is needed in urban management.