Kristen C. Nelson

Ecological homogenization of urban USA

A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis–St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales.

Making global initiatives local realities: carbon mitigation projects in Chiapas,Mexico

Global,environmental initiatives create macro-level agreements,but the true test is how local communities respond. From 1995 to 2001,we investigated the evolution of Fondo Bioclimatico,a carbon mitigation project,using interviews and document review. Even under tremendous uncertainty the project grew seven-fold. Its social structure shifted from a development emphasis to a brokering relationship,from shared to concentrated power,from social fund to carbon bank. Social selection of systems with fewer tree species and single ecosystems is a concern for biodiversity. The challenge is to remain critical,monitor,and support indigenous communities in their endeavor to implement clean development mechanism projects. r 2003 Elsevier Science Ltd. All rights reserved.

Carbon, nitrogen, and phosphorus fluxes in household ecosystems in the Minneapolis‐Saint Paul, Minnesota, urban region

Rapid worldwide urbanization calls for a better understanding of the biogeochemical cycling of those macroelements that have large environmental impacts in cities. This study, part of the Twin Cities Household Ecosystem Project, quantified fluxes of carbon (C), nitrogen (N), and phosphorus (P) at the scale of individual households in the Minneapolis-Saint Paul metropolitan area in Minnesota, USA. We estimated input and output fluxes associated with several components of household activities including air and motor vehicle travel, food consumption, home energy use, landscape, pets, and paper and plastic use for 360 owner-occupied, stand-alone households. A few component fluxes dominated total input fluxes of elements. For instance, air and motor vehicle transportation, together with home energy use, accounted for 85% of total C consumption and emissions. All total and component fluxes were skewed to varying degrees, suggesting that policies targeting disproportionately high fluxes could be an effective and efficient way to reduce pollution. For example, 20% of households contributed 75% of air travel emissions and 40% of motor vehicle emissions. Home energy use was more nearly normally distributed. Nitrogen fluxes were dominated by human diet and lawn fertilizer applications, which together accounted for 65% of total household N inputs. The majority of P inputs were associated with human diet, use of detergents, and pet food. A large portion of the variation among household fluxes of C, N, and P was related to a few biophysical variables. A better understanding of the biophysical, demographic, and behavioral drivers of household activities that contribute to C, N, and P fluxes is pivotal for developing accurate urban biogeochemical models and for informing policies aimed at reducing sources of pollution in urban ecosystems.

Social learning in a policy-mandated collaboration: community wildfire protection planning in the eastern United States

Policies such as the US Healthy Forests Restoration Act (HFRA) mandate collaboration in planning to create benefits such as social learning and shared understanding among partners. However, some question the ability of top-down policy to foster successful local collaboration. Through in-depth interviews and document analysis, this paper investigates social learning and transformative learning in three case studies of Community Wildfire Protection Planning (CWPP), a policy-mandated collaboration under HFRA. Not all CWPP groups engaged in social learning. Those that did learned most about organisational priorities and values through communicative learning. Few participants gained new skills or knowledge through instrumental learning. CWPP groups had to commit to learning, but the design of the collaborative-mandate influenced the type of learning that was most likely to occur. This research suggests a potential role for top-down policy in setting the structural context for learning at the local level, but also confirms the importance of collaborative context and process in fostering social learning.

Assessing the homogenization of urban land management with an application to US residential lawn care

Significance This paper offers conceptual and empirical contributions to sustainability science in general and urban-ecological studies in particular. We present a new analytical framework for classifying socioecological measures along a homogenization–differentiation spectrum. This simple 2 × 2 matrix highlights the multiscale nature of the processes and outcomes of interest. Our application of the conceptual framework produces needed empirical insights into the extent to which land management appears to be homogenizing in differing biophysical settings. Results suggest that US lawn care behaviors are more differentiated in practice than in theory. Thus even if the biophysical outcomes of urbanization are homogenizing, managing the associated sustainability implications may require a multiscale, differentiated approach. Changes in land use, land cover, and land management present some of the greatest potential global environmental challenges of the 21st century. Urbanization, one of the principal drivers of these transformations, is commonly thought to be generating land changes that are increasingly similar. An implication of this multiscale homogenization hypothesis is that the ecosystem structure and function and human behaviors associated with urbanization should be more similar in certain kinds of urbanized locations across biogeophysical gradients than across urbanization gradients in places with similar biogeophysical characteristics. This paper introduces an analytical framework for testing this hypothesis, and applies the framework to the case of residential lawn care. This set of land management behaviors are often assumed—not demonstrated—to exhibit homogeneity. Multivariate analyses are conducted on telephone survey responses from a geographically stratified random sample of homeowners (n = 9,480), equally distributed across six US metropolitan areas. Two behaviors are examined: lawn fertilizing and irrigating. Limited support for strong homogenization is found at two scales (i.e., multi- and single-city; 2 of 36 cases), but significant support is found for homogenization at only one scale (22 cases) or at neither scale (12 cases). These results suggest that US lawn care behaviors are more differentiated in practice than in theory. Thus, even if the biophysical outcomes of urbanization are homogenizing, managing the associated sustainability implications may require a multiscale, differentiated approach because the underlying social practices appear relatively varied. The analytical approach introduced here should also be productive for other facets of urban-ecological homogenization.

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.

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.

The Value of Assessing Public Perceptions: Wildland Fire and Defensible Space.

Fire is a challenge in the wildland-urban interface. Although resource managers encourage residents to create defensible space, many do not. This study illustrates the value of using a needs assessment to better understand perceptions of an audience in order to develop meaningful messages and materials. In this case, our audience is residents of forested areas of Florida and Minnesota at risk of wildland fire. By using in-depth interviews, we explore their perceptions of their landscape, their perception of risk, and their willingness to reduce that risk. Their perceptions can be used to evaluate current wildfire communication tools and suggest ways to modify them to inform and change the behavior of residents. Printed materials emphasis the threat of fire and what to do. Interview data suggest that emphasizing relevant values: privacy, wildlife, and recreation opportunities, as well as acknowledging neighborhood norms, could be helpful to motivate residents when the threat of fire is not sufficient.

Community wildfire protection planning: is the Healthy Forests Restoration Act's vagueness genius?

The Healthy Forests Restoration Act of 2003 (HFRA) encourages communities to develop community wildfire protection plans (CWPPs) to reduce their wildland fire risk and promote healthier forested ecosystems. Communities who have developed CWPPs have done so using many different processes, resulting in plans with varied form and content. We analysed data from 13 case-study communities to illustrate how the characteristics of HFRA have encouraged communities to develop CWPPs that reflect their local social and ecological contexts. A framework for analysing policy implementation suggests that some elements of HFRA could have made CWPP development and implementation problematic, but these potential shortcomings in the statute have provided communities the freedom to develop CWPPs that are relevant to their conditions and allowed for the development of capacities that communities are using to move forward in several areas.

Volunteer Macroinvertebrate Monitoring in the United States: Resource Mobilization and Comparative State Structures

Emergence of local citizen monitoring groups has provided a structure for public participation in environmental issues but little is known about how these groups are achieving their goals. We examine a subset of citizen monitoring groups in the United States that conduct volunteer macroinvertebrate monitoring (VMM) as a tool for investigating stream health. Through a survey of VMM groups throughout the United States and interviews with state leaders, we found that VMM groups vary in size and character, and utilize a variety of means to achieve their goals. The majority of VMM groups rely on in-kind support from state and regional programs. Overall, these groups are more interested in conducting VMM to foster public awareness, rather than bringing about structural or legislative change. Based on resource mobilization theory, we illustrate that the opportunity structures at the state level significantly impact the character and success of U.S. VMM groups.