Urban development in the southern Great Plains: effects of atmospheric NO<Subscript>x</Subscript> on the long-lived post oak tree (<Emphasis Type="Italic">Quercus stellata</Emphasis>)

Concentrated human activities such as the burning of fossil fuels have resulted in chronic nitrogen (N) additions to urban ecosystems. We predicted that urban development in North Texas (NTX; the largest “megapolitan” region in the Great Plains) would be positively correlated with atmospheric concentrations of nitrogen oxides (NO_x) and with the leaf tissue quality (lower C:N ratio) and herbivory of the long-lived native tree, post oak (Quercus stellata). Data from air monitoring stations were used to calculate distance-weighted estimates of atmospheric NO_x for 11 sites of differing urban development across NTX. Soil samples were collected at each site along with post oak leaves, estimates of herbivory, and measurements of tree size. Percent urban development was strongly positively correlated with atmospheric NO_x concentrations, though there was no correlation between atmospheric NO_x and soil N. There was a positive relationship between soil N and leaf tissue quality, but only where atmospheric NO_x was relatively low, possibly due to factors that covary with urban development. Herbivory was not significantly correlated with leaf tissue quality, but leaves from the two most urban sites had the greatest amount of insect herbivory. The NO_x concentrations in NTX were lower than other industrialized cities, which may be due to climate and topography differences or the relatively young age of this urban area. This study adds to the expanding body of literature examining how urban ecosystems are affected (or not) by N deposition and suggests that interactions among NO_x, soils, and plants are complex and sometimes, counterintuitive.     

The residential landscape: fluxes of elements and the role of household decisions

We assessed biogeochemical cycling of elements through residential household landscapes to evaluate the importance of annual to decadal household-level decisions for element fluxes that contribute to urban and regional pollution. We combined a mailed survey, vegetation measurements, and allometric and biogeochemical models to estimate fluxes and accumulation of carbon (C), nitrogen (N), and phosphorus (P) in landscapes of 360 single-family homes in the Minneapolis-Saint Paul, Minnesota metropolitan area. Carbon inputs and accumulation were strongly influenced by the presence of trees on the property. Nitrogen inputs to the landscape exceeded estimated ecosystem demand for N on average by 51% and were dominated by N fertilizer application. Because Minnesota state law restricts the use of P fertilizer, pet waste was responsible for 84% of P inputs to the landscape. The results have implications for understanding sources of urban pollution and the potential flexibility (i.e., the potential for change) in household behaviors such as tree planting, fertilization, and pet waste management that contribute to such pollution.     

Toward a pragmatic program for critical urban ecology

Our essay responds to the critique of Dooling et al. (Urban Ecosystems in press, 2007) of our previously published article “Goal attainment in urban ecology research: a bibliometric review 1975-2004 (Young and Wolf, Urban Ecosystems, 9:179–193, 2006). We identify our critics’ concerns as rooted in a project of deconstruction of scientific inquiry and a redefinition of the boundaries separating academic disciplines from each other and science from society. While we identify important differences with our critics, we largely support this critical project, as evidenced by our previously published empirical research. In exploring the relationship between critical and positivist approaches to urban ecology research and how we might work toward an integration of nature and society in thought and action, we defend pragmatic approaches to empirical research as well as disciplinary projects as legitimate and essential elements of urban ecology research. We argue in favor of theoretical and methodological pluralism. Rather than define urban ecology through exclusionary projects that would limit the scope and significance of urban ecology research, we reaffirm our call for diverse sets of actors inside and outside university settings to engage and support each other in order to develop and strengthen analysis and pursuit of sustainability.

Long-term urbanization effects on tree canopy cover along an urban–rural gradient

Urban forestry can benefit from improved knowledge of urbanization??s effects on tree canopy cover (TCC), a prominent urban forest indicator. This study examined changes in TCC over a long time frame, with respect to land cover (LC) changes, and across municipal boundaries. Specifically, I used air photos at 14 dates from 1937 to 2009 to develop an exceptionally long record of TCC change in Minnesota??s Twin Cities Metropolitan Area. During the study period overall TCC nearly doubled from 17% to 33% while the proportion urban land cover rose by 47%, highlighting the opportunity for substantial TCC gains following urbanization in previously agricultural landscapes, even in regions that were forested prior to European settlement. Results demonstrate that more intensely developed sites generally had lower TCC, and older urban sites had higher TCC. Modern TCC was not adequately characterized by linear distance along the urban?Crural gradient, but instead peaked near the center of the gradient where mature residential neighborhoods are prevalent. Compared to other land cover changes, urbanization events caused the highest rate of immediate TCC loss (9.6% of events), yet urban areas had the second highest TCC (>35%) in 2009, indicating that urban land gained TCC relatively efficiently following development. The results of this study provide new historical context for urban forest management across an urban?Crural gradient, and emphasize the need to consider ecological legacies and temporal lags following land cover changes when considering TCC goals in urban settings.     

Urban human ecology

Cities are human ecosystems. Eight primary concepts assist us in understanding human ecosystems in terms of variability, time, and complexity. These concepts include: systems thinking; language, culture, and technology; structure, function, and change; edges, boundaries, and ecotones; interaction, integration, and institution; diversity; adaptation; and holism. Hierarchy theory presents a framework for organizing these concepts. Human settlements can be viewed hierarchically, that is, from a more immediate scale to the global. In this paper, the eight concepts will be explored and applied to the urban context. The exploration of human ecology is useful to design and plan the built environment. The ability to respond to change and to adjust actions positively helps to determine the resilience of cities     

Spatial variation in soil inorganic nitrogen across an arid urban ecosystem

We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO₃-N and NH₄-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO₃-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH₄-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO₃-N and NH₄-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO₃-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.     

Promoting the Health of Young Adults in Urban Public Universities: A Case Study From City University of New York

Abstract

Changing demographics of college students and new insights into the developmental trajectory of chronic diseases present universities with opportunities to improve population health and reduce health inequalities. The reciprocal relationships between better health and improved educational achievement also offer university health programs a chance to improve retention and graduation rates, a key objective for higher education. In 2007, City University of New York (CUNY), the nation's largest urban public university, launched Healthy CUNY, an initiative designed to offer life-time protection against chronic diseases and reduce health-related barriers to educational achievement. In its first 5 years, Healthy CUNY has shown that universities can mobilize students, faculty, and other constituencies to modify environments and policies that influence health. New policies on tobacco and campus food, enrollment of needy students in public food and housing assistance programs, and a dialogue on the role of health in academic achievement are first steps towards healthier universities.     

Management mitigates the impact of urbanization on meadow vegetation

Urban regions often contain remnants of ecologically valuable habitats. Whilst meadow habitats have been recognized as ecologically important and much studied, little attention has been given to meadow assemblages of urban locations. We studied the effects of meadow type, urbanization level, and management on vascular plant species richness, field layer diversity and soil chemistry in 18 grassland sites in the Helsinki Metropolitan Area (60°E, 25°N), on the southern coast of Finland during the summer of 2007. We recorded a total of 252 species, though the average number of species per m² was only 12.6. The negative effects of urbanization on forbs seemed to result in particular from increased soil nitrate (NO₃^- -N) concentration. The highest NO₃^- -N and Fe concentrations and ratios of total inorganic nitrogen (N_tot) to phosphorus (P) and potassium (K), were recorded from the soils of urban rocky meadows. Management by mowing decreased soil NO₃^- -N and Fe concentrations, ratios of N_tot:P and N_tot:K, and increased species richness and diversity. Elevated NO_x deposition is considered as a major driver of urbanization effects on vegetation, though changes in soil pH and metal concentrations, such as zinc (Zn), may also negatively affect the frequency of both forbs and grasses. This study shows that regular management by mowing and removal of hay mitigates these effects. We also recommend increasing the provision of dry meadows and maintaining more areas of supplementary semi-natural grassland habitats in urban green space as concrete measures for the conservation of dry meadow assemblages and urban biodiversity.     

Urban wildlife ecology and conservation:A brief history of the discipline

Urban wildlife ecology and conservation is a discipline worldwide in scope. Although some attention was given the subject in the early to mid-1900s, most activity in the field is of more recent origin. Many European countries have active programs and activities, including the United Kingdom-Man and the Biosphere (UK-MAB) Urban Forum and The Wildlife Trusts of England, the United Nations Educational, Scientific, and Cultural Organization's MAB Program, and urban ecology research in Germany and Poland. The Netherlands' concept of “ecological landscapes” introduced a new approach to design of urban open space. Durban, South Africa followed with “D'MOSS,” a metropolitan open space system founded on the principles of island biogeography theory. The park connector network of Singapore combines principles of conservation biology and landscape planning. Urban wildlife programs and activities exist in the United States at the federal, state, and local levels as well as in private conservation organizations. The Wildlife Society established an Urban Affairs and Regional Planning Committee in the mid-1970s that later became the Urban Wildlife Committee and then evolved into the Urban Wildlife Working Group. Urban wildlife research is providing knowledge of wildlife and plant populations and communities in urban areas that hopefully will lead to better understanding and greater sustainability of urban ecosystems.     

The role of urban indicators in city management: a proposal for Croatian cities

Cities are dynamic economic and social structures that play a dominant role in both national and international economies. They are centers of population, production, consumption, and development. Cities utilize all advantages of economy of scale, proximity, and concentration. On the other hand, they produce high environmental pressures and diminish thereby the quality of life for urban residents. Indicators (environmental, economic, and governance and management) are seen as a tool that would help policy-makers in formulating urban policy that would lead cities towards sustainability and provide assistance for monitoring their development and municipal performance. The aim of this paper is to consider the role that urban indicators can play in city management. We present basic features of urban indicators that will determine their usefulness in urban management. This paper provides the framework to include environmental and economic indicators, as well as governance and management indicators, in successful urban management.     

Contrasting soil nitrogen dynamics across a montane meadow and urban lawn in a semi-arid watershed

Urbanization substantially increases nitrogen (N) inputs and hydrologic losses relative to wildland ecosystems, although the fate of N additions to lawns and remnant grasslands remains contested. In montane semi-arid ecosystems, N cycling is often closely coupled to snowmelt (the dominant period of infiltration) and snow cover, which impact soil temperature and moisture. Here, we compared soil N dynamics between a fertilized and irrigated urban lawn and nearby riparian meadow in Salt Lake City, Utah during a snow manipulation experiment. Snow removal increased freeze/thaw events but did not affect N pools, microbial biomass, denitrification potential, or soil oxygen (O₂). Mineral N was similar between sites despite lawn fertilization, but dissolved organic N (DON) was four-fold greater (2.1 ± 0.1 mg N l^?1) in lawn soil water. Infiltration was lower in the lawn subsoil, and leaching losses (modeled with Hydrus) were small at both sites (< 2 kg N ha^?1 y^?1) despite substantial lawn fertilization. Lawn soil O₂ fluctuated between 20.9 and 1.6 % following snowmelt and irrigation, but remained near 20 % in the meadow; the lawn had more reducing microsites as indicated by iron speciation. Post-snowmelt potential denitrification was six-fold greater in the lawn than the meadow. Lawns can potentially provide hotspots of denitrification in a semi-arid landscape that exceed some natural riparian ecosystems, whereas DON may represent an increasingly important form of N loss from lawns.     

Fengshui theory in urban landscape planning

The spatial configuration of urban landscapes results from cumulative interactions between human activities and the physical environment. Traditional philosophies and cultural legacies have had important influences on urban development and planning in East Asia. In Seoul, traditional land use practices based on ‘Fengshui’ have significantly contributed to human-mediated patterns of landscape changes, in addition to the role of the socio-economic background (development) and other human activities. The concept of Fengshui was originally founded upon people’s empirical cognition of natural landscape patterns. Recently, however, advanced economic development, westernization and urbanization have been rapidly altering the old traditions of the holistic landscape systems through changing urban planning practices. Since the type, scale, frequency, distribution and spreading pattern of environmental and human disturbances have been changed, a new paradigm for urban landscape planning is necessary to maintain the ecological and cultural integrity of landscapes in Korea. In this paper, we discuss recent concepts and methods of landscape ecology and urban planning from the viewpoint of Fengshui, the traditional land use patterns in Seoul, whose application has so far been restricted only to traditional land evaluation. We conclude that, to maintain the sustainability of the urban landscape, it is necessary to develop a new urban planning framework for the region that is based on the integration between landscape ecology principles with the traditional concepts of Fengshui.     

Habitat structure: A fundamental concept and framework for urban soil ecology

Habitat structure is defined as the composition and arrangement of physical matter at a location. Although habitat structure is the physical template underlying ecological patterns and processes, the concept is relatively unappreciated and underdeveloped in ecology. However, it provides a fundamental concept for urban ecology because human activities in urban ecosystems are often targeted toward management of habitat structure. In addition, the concept emphasizes the fine-scale, on-the-ground perspective needed in the study of urban soil ecology. To illustrate this, urban soil ecology research is summarized from the perspective of habitat structure effects. Among the key conclusions emerging from the literature review are: (1) habitat structure provides a unifying theme for multivariate research about urban soil ecology; (2) heterogeneous urban habitat structures influence soil ecological variables in different ways; (3) more research is needed to understand relationships among sociological variables, habitat structure patterns and urban soil ecology. To stimulate urban soil ecology research, a conceptual framework is presented to show the direct and indirect relationships among habitat structure and ecological variables. Because habitat structure serves as a physical link between sociocultural and ecological systems, it can be used as a focus for interdisciplinary and applied research (e.g., pest management) about the multiple, interactive effects of urbanization on the ecology of soils.     

Alternative Formulas for Distributing Parental Incomes at Divorce

The current study applied five formulas for distributing parental incomes at divorce to 414 court case records in Minnesota and evaluated which formulas and actual court orders provided sufficient incomes for male and female-headed households. The study further explored influences of pre-divorce gross income levels, household/genders, and lengths of marriage on the post-divorce income-to-needs ratios (ITN) produced by the five formulas and actual court orders, using MANOVA. Results were interpreted using distributive justice principles of equity, needs, and contributions. Males have higher ITN with each alternative, except the income-sharing formula. The actual court orders and the income-sharing formula produce the largest discrepancy between male and female ITN and the highest percentage of females living below poverty level guidelines.Kathrine C. Daniels, University of Minnesota, 290 McNeal Hall, 1985 Buford Avenue, Saint Paul, MN 55108-6140; e-mail: dani0022@umn.edu.Kathryn D. Rettig, University of Minnesota, 290 McNeal Hall, 1985 Buford Avenue, Saint Paul, MN 55107-6140; e-mail: krettig@che.umn.edu.Robert delMas, General College of the University of Minnesota, 354 Appleby Hall, 28 Pleasant Street SE, Minneapolis, MN 55455; e-mail: delma001@umn.edu.This paper originated from Kathrine Daniels’ doctoral dissertation entitled, alternative strategies of dissolving the economic partnership of marriage. Further, the research was funded by a grant from The McKnight Foundation to the Child Support Enforcement Division of the Minnesota Department of Human Services, and a subcontract to the University of Minnesota Department of Family Social Science. Additional support was provided through a grant from, The University of Minnesota Center for Urban and Regional Affairs’ Faculty Interactive Research Program, as well as a project grant from the Minnesota Agricultural Experiment Station, Project 53–054, Decision-Making Integral to Relationship Transitions in Families, Kathryn D. Rettig, Principal Investigator.     

Cultural Identity and Place in Adult Korean-American Intercountry Adoptees

ABSTRACT

This study explores the interrelationship between cultural identity and place in the lives of adult Korean adoptees living primarily in the Twin Cities area of Minnesota. Using life histories derived through multiple semi-structured interviews, a web of related themes emerged which reveal the interplay between ethnicity, identity, gender, and place. From childhood to adulthood, most Korean adoptees followed a similar developmental trajectory of denial, self-awareness, and emerging cultural consciousness about their Korean heritage, particularly upon their departure from their adoptive homes after high school. These journeys were mediated and nuanced by environmental factors including -but not limited to -places adoptees lived or visited in Korea, the U.S. or elsewhere abroad. This study highlights the limitations of previous studies that focused only on adoptive parents or adoptees as children, an approach which loses the life course perspective of inter-country adoptees' search for identity, belonging, and a sense of home.     

Extension-Based Divorce Education: A Quasi-Experimental Design Study of the Parents Forever Program

The field of divorce education is calling for greater rigor in evaluating program effectiveness and University Extension programs are no exception. Parents Forever, a University of Minnesota Extension divorce education program developed in the 1990s, conducted a quasi-experimental design study, with a sample of in-person class participants and a comparison sample of divorcing parents. Independent samples t tests were conducted between the unstandardized residuals of each group. In support of the program’s goals, results indicated positive program effects for several variables related to parenting practices, adult quality of life, self-efficacy, and parent report of child conduct problems and peer problems (p < .01). No effect was found for coparenting conflict, adult social health, and child hyperactivity, and marginal program effects (p < .05), both positive and negative, were found for coparenting alliance (–), positive parenting (+), child emotional symptoms (+), and child prosocial behavior (–).     

Value of park reserves to migrating and breeding landbirds in an urban important bird area

Increasing urban development threatens not only breeding habitat for migratory landbirds but also critical stopover habitat. The purpose of this study was to investigate the relationship between landbird community composition and land cover in and surrounding urban park reserves in the Mississippi River Twin Cities Important Bird Area (IBA) in order to evaluate this area’s value during both spring migration and summer breeding seasons. This IBA includes a mosaic of residential, commercial, and park reserve land running along the Mississippi River between Minneapolis and Hastings, Minnesota. Using citizen-science data collected at 8 park reserve sites in the IBA between 2007 and 2010, we calculated species richness, diversity, and evenness for the migrating and breeding landbird community at each site and categorized species into three conservation statuses (species of greatest conservation need, native and exotic) and four migratory behavior classes (permanent residents, short-distance migrants, resident neotropical migrants, and en-route neotropical migrants). We used AIC to rank multiple regression models to evaluate how these groupings vary across sites in comparison to the land cover in and surrounding each site. We found that most measures of both the spring migration and breeding communities were negatively related to increased impervious cover. Exotic species and permanent residents were less affected by surrounding land use, while breeding season resident and transitory neotropical migrants were greatly affected. Patterns of landbird richness and density suggest that removing impervious cover within lower quality sites can improve habitat supporting migrating birds.     

Potential nitrogen mineralization responses of urban and rural forest soils to elevated temperature in Louisville,KY

Soil nitrogen (N) mineralization is an important process determining terrestrial N availability, and evidence suggests elevated temperatures will enhance N mineralization rates. Along a 40 km urban-rural gradient of chestnut oak forest stands in Louisville, KY, we expected N mineralization rates would be higher in urban than in rural forests in part due to increased temperatures caused by the urban heat island. However, a 12-month field study along this Louisville gradient showed that annual N mineralization rates were lower in urban than in rural stands. Since variation in precipitation inputs and other factors across this land-use gradient may be influencing soil N mineralization rates, we conducted a three-month soil incubation experiment in the lab to determine the extent to which a + 2 °C temperature difference could affect soil N mineralization in urban and rural soils. Across the range of temperatures tested, rural soils mineralized N at twice the rate of urban soils under base (7.86 vs. 3.65 mg N kg^?1 AFDW soil d^?1) and elevated (9.08 vs. 4.76 mg N kg^?1 AFDW soil d^?1) temperatures (p < 0.01). A 2 °C temperature difference, did not significantly alter total inorganic N production in urban (p = 0.272) or rural soils (p = 0.293). The proportion of nitrate produced was lower in the urban (15.1 %) than in the rural soils (72.3 %; p < 0.01). These results suggest that differences in soil organic matter quality and potentially decomposer community composition are the primary explanatory factors for forests along this Louisville gradient.     

Effect of consumption choices on fluxes of carbon,nitrogen and phosphorus through households

Households are an important scale of analysis for human ecosystems because they are a major source of pollutants and could thus be a new focus for pollution management, particularly for education-based source reduction strategies. The household is also a meaningful unit for analysis of human ecosystems, being common to all human cultures. This study develops a Household Flux Calculator (HFC) to compute C, N, and P fluxes for scenarios intended to represent three levels of household consumption: low, typical, and high. All three scenarios were developed for suburban households with two adults and two children in the Minneapolis-St. Paul (Twin Cities) metropolitan area, Minnesota. Calculated ratios of fluxes between high and low consumption households were 3.5:1 for C, 2.7:1 for N and 1.4:1 for P. Results suggest a high level of discretionary consumption that could be reduced without a substantial reduction in standard of living. Thus, modest changes in behavior in high consumption households would greatly reduce fluxes of C, N, and P without major changes in lifestyle.