2009 Urban Fellow Justin Freiberg's short film about the Urban Foodshed Collaborative.


2011 Hixon Fellow Posters

Student Research Fellows

Following are brief project descriptions and research paper links for the 2000 through 2013 fellows.


2013 Urban Fellows Research Papers

Caitlin Feehan: "A Survey of Green Infrastructure Maintenance Programs in the United States"

Green infrastructure (GI) refers to a set of stormwater management practices that collect, infiltrate, and reuse stormwater runoff as it is created when rain falls on the streets, roofs, and other impervious areas found in cities. Cities across the United States are making significant commitments to the implementation of GI as part of their regulatory requirements to reduce untreated stormwater from flowing into waterways. While the use of GI is growing, little has been written on the need for and the importance of maintenance to keep these GI projects performing over time.  As part of a summer 2013 internship, eight of the cities in the United States leading the trend of GI implementation were surveyed about the current state of each city’s GI maintenance program. Consistent questions were asked of each program and the information collected included: GI maintenance program roles and responsibilities; the maintenance program’s structure; specific maintenance activities and frequencies for those activities; the methods for tracking the completion and results of maintenance activities; and maintenance program costs. This paper documents the results of those conversations and provides a summary of GI maintenance programs based on the eight different maintenance program examples.

Zulimar Lucena: "Factors Controlling Biogeochemical Removal of Nitrogen in Constructed Wetlands"

The Long Island Sound (LIS) estuary is affected by summer hypoxia as a result of high nitrogen loads from New York and Connecticut watersheds. In order to mitigate hypoxia, managers have established a goal of reducing the nitrogen load from nonpoint sources by 10%. One strategy to reduce N loads from nonpoint sources is the use of constructed wetlands, which provide an ecosystem service by removing pollutants from stormwater runoff. This study examined the effectiveness of constructed wetlands in Hamden and Woodbridge, Connecticut in improving the quality of stormwater runoff. Our main objective was to determine the factors that contribute to N removal to provide design recommendations that optimize constructed wetlands performance. A total of 9 to 21 storms were monitored at four sites during the summer and fall of 2013. Weirs and water level loggers were installed at the inlet and outlet of the wetlands to measure water flow. Stormwater samples were collected using ISCO autosamplers at regular intervals over the duration of storm events. These were composited to obtain flow-weighted samples from the inlet and outlet of each wetland to determine nitrogen loads and mean concentrations per storm event. We also surveyed each site to determine plant diversity, sediment organic carbon concentration, and treatment ratios to determine their influence on N removal. Only two sites showed statistically significant biogeochemical removal of N. Our results indicate that wetland heterogeneity and interspersion between open water and vegetation, as well as high sediment carbon concentrations, promote N concentration reduction. Additionally, we examined the effects of input N concentrations, storm size and intensity, and water temperature using multiple linear regression. The models showed that only influent N concentration influences N concentration reduction. Based on our results we recommend designing interspersed wetlands that offer more opportunities for a variety of biogeochemical processes to occur and using sediments with high carbon concentrations to promote denitrification. Considering these variables might result in more effective N concentration reduction. This information contributes to the limited knowledge of constructed wetland design in Connecticut and can promote higher nitrogen removal rates from stormwater in the Long Island Sound watershed.



2012 Urban Fellows Research Papers

Lisa Weber: "Examining the Inter-Storm Variability in Nitrogen Removal Efficiency in a Connecticut Constructed Wetland"

Encroaching development on natural landscapes is making the challenge of high-quality surface water increasingly important. This is perhaps best exemplified in urban stormwater runoff, which carries large amounts of nitrogen and other pollutants from fertilized lawns, septic systems, and ambient air. In New England, this polluted runoff contributes to deadzones in the Long Island Sound. Wetlands, including those that are manmade, may provide a valuable but understudied service by removing nitrogen from this runoff. My research objective this past summer was to evaluate the effectiveness of this service in order to ultimately determine which variables are most important in wetland efficiency (e.g.water temperature or residence time of the water). Managers of Long Island Sound have set a goal of achieving a 10 percent reduction in nitrogen. If constructed wetlands are to play a role in this reduction, they must be better understood.


Molly Greene  "A Mountain by the Sea: Waste-Scapes, Life-Scapes and the Reinention of Fresh Kills"

The town of Travis in Staten Island sits at the foot of the Fresh Kills Landfill, a site that served as New York City’s dumping grounds for more than half a century during the apex of America’s throw-away era. Currently, even as the looming twenty-story mounds ooze leachate and hiss methane gas, operations are underway to convert the site into a 2,200-acre public park. The plan is touted as one of the world’s most ambitious reclamation projects to date – a complete conversion of a wasteland into a “park of the future.” But this present reinvention is just the latest in what has been a long series of transformations. A reexamination of the cultural, economic, and political history of Travis reveals the influence of industrial growth on the American rural landscape, as well as a story of resistance, resilience, and adaptation by local communities.


Max Lambert     "Suburban Neighborhoods and Endocrine Disruption in Developing Green Frogs"

In recent decades, research on endocrine disrupting chemicals (EDCs) has grown rapidly. EDCs alter hormonal regulation and can have effects like increases in breast cancer proliferation in humans or infertility in female livestock. New work has found that male frogs in suburban neighborhoods have higher frequencies of endocrine disruption than frogs from other landscapes. As of yet we have limited knowledge of which contaminants occur in suburban waterways or their effects on early development. This summer I assessed sex ratios and hormonal levels in metamorphosing green frogs. I used GIS software to locate suburban (treatment) and forested (control) ponds in southern Connecticut, measured sex ratios, and then quantified hormonal levels among the frogs. The work demonstrated that endocrine disruption is occurring early on in suburban frog development and that these abnormalities are associated with unusual concentrations of trace elements and organic chemicals.


Chris Shughrue    "A Model of Nonlinear Urbanization and Information Flows Across India"

Urbanization in the 21st century is increasingly shaped by distant flows of people, capital, and information across the landscape. In India, these flows are informed by the propagation of information across social networks, with rural-urban and urban-urban connections often underlying migration and investment patterns. These patterns shape and are shaped by the growth of city-regions. But how does the strength of these signals across social networks affect emergent patterns of urban land-use change? To examine this relationship, this summer I worked to develop a model for all of India that represents the decisionmaking dynamics between: land developers, families, state governments, corporations, and property management companies. Decisions made by family agents are based on information propagated across an adaptive social network. We varied the probability of data transmission across the network to simulate the effects of strong and weak social networks on spatial patterns of urbanization. 


2011 Urban Fellows Research Papers

 Amy K Coplen     "Cultivating Commnity: Bulding Cohesion and Forging Identities in New Haven's Community Gardens"

This research explores the ways in which community gardeners value their participation in New Haven’s community gardens and the processes through which they build community cohesion. Thought eight ethnographic interview and participant observation in six gardens I explore how gardeners value interaction with those from diverse backgrounds and cultures. The stories of these gardeners indicate that community gardens build community cohesion by facilitating cross-cultural exchange, creating networks for knowledge and resource sharing, and establishing new identities for immigrant and transplant populations. In some case, these processes cut across age groups, education backgrounds, and income levels. This research demonstrates that community gardens can serve as a vehicle for building community cohesion across cultural divides.


Troy D. Hill   " Sediment fluxes and exchange between an urban salt marsh and Long Island Sound"

Salt marshes provide a broad range of valuable ecological services. In urban settings these services are magnified in importance, as marshes are typically smaller, serve more concentrated human populations, and face more dramatic anthropogenic pressures. Unfortunately, our knowledge of material exchange between marshes and coastal waters is limited, particularly in urban areas. Tidal flux studies offer a means of understanding how marshes interact with coastal waters and how they affect water quality in the coastal zone.

The present study reports high resolution data on fluxes of water, salt, and sediment to and from an urban salt marsh in Norwalk, CT. This work focuses on shortterm sediment dynamics, and the role of storm events in sediment transport. Fieldbased measurements of precipitation, water velocity, salinity, and turbidity were collected continuously for two months. Uncertainties in the data are evaluated and compared with other flux studies. The feasibility of estimating particulate material fluxes based on these data benefits from low spatial variability of suspended sediment in the water column. A net influx of sediment was observed over the course of the study, but the system is characterized by large, short-term variations in sediment transport. Only a small fraction of the imported sediment appears to be deposited on the marsh surface.

Moving towards an assessment of minor constituent fluxes, this project began optimizing a method for measuring trace metals in sea water, to be deployed in 2012. Experiments using chelating resin columns have highlighted the challenges of analyzing trace metals in seawater. This preliminary work has clarified essential methodological details such as the volume of eluent required to displace metals sorbed to the resin, and the necessity of purifying reagents.


RanRan Wang      "Water-Energy Nexus: A Critical Review Paper"

The interdependency between the world’s two most critical resources: water and energy, is receiving more and more attention from the academia as well as the general public. A comprehensive and in-depth understanding of the water-energy nexus is essential to achieve sustainable resource management. Following the structure of hierarchy of knowledge, this paper reviewed the evolution and progress of information, methodology, knowledge, and wisdom that have grown out of this field throughout the past 40 years. By synthesizing previous work, the paper identified existing knowledge gaps, as well as directions and challenges for prospective research. System dynamics, featuring framing, understanding, simulating, and communicating dynamic behaviors within interrelated social, managerial, economic, and ecological systems over time, is proposed to be a promising research approach that could facilitate our understanding in the field of water-energy nexus in the future.


Chen Qian   LifeCycle Assessment of a Land Management: The PlaNYC Afforestation Initiative in the Kissena Corridor Park, New York


Bryan Yoon   "Control of Precipitation Events on Dynamics of Disinfection Byproduct Formation Potential"



2010 Urban Fellows Research Papers

Lauren Brooks: "Validation of genetic markers and application to detect fecal contamination at beaches in Coastal Connecticut"

Due to shortcomings in traditional methods for detecting and quantifying the presence of fecal waste in waters new methodologies are being explored, with special attention being given to the ability to identify sources of the contamination. In this study, an alternative methodology, which uses Real-Time Polymerase Chain Reaction (RT-PCR) to detect host specific genetic markers to distinguish between human and non-human sources of contamination, was applied to beaches in Connecticut that were experiencing various levels of contamination.  Despite some difficulties with this new approach, it was ultimately useful for identifying waste of human origin.  Though not quantitative, this study qualitatively provided important baseline information for further studies by indicating beaches to target for more in-depth tracking procedures to detect and correct these human sources impacting the contaminated waters.

Thomas Chase:  "Building Deconstruction in New Haven, Connecticut - A Systems Dynamics Analysis and Policy Tool"

This study is one of a growing number that seeks to address materials flows and management options from the scale of each building material type, up to the whole building, and further up to the range of buildings in an entire city – in this case, New Haven, Connecticut. Solid waste generated in the removal or renovation of buildings is a massive and often poorly described waste stream. Construction and demolition waste (C&D) is also largely unregulated in its quantity and composition, if not its disposal fate. Buildings are large, complex, and highly varied objects, and their component materials differ by building type, construction cohort, size, style, and many, many other factors. Reducing the solid waste generated in building removal and renovation, recouping building material for reuse or recycling, preventing some of the greenhouse gas emissions associated with C&D disposal, shifting jobs towards construction laborers, and reducing costs are all goals of deconstruction, a source separation building removal technique. A dynamic systems model was built using a bottom up approach to accounting for the building material flows in New Haven. Several scenarios for different waste management options were tested over a 25 year time horizon to evaluate the relative advantages and disadvantages in terms of waste diverted from landfill, greenhouse gas emissions, cost, and jobs created of each of the scenarios. The model was also provided to City of New Haven policy-makers to use as a building waste management tool.

David Henry: "The Social Cost of Trading: Measuring the Increased Damages from Sulfur Dioxide Trading in the United States"

The sulfur dioxide (SO2) cap and trade program established in the 1990 Clean Air Act Amendments is celebrated for reducing abatement costs ($0.7 to $2.1 billion per year) by allowing emissions allowances to be traded. Unfortunately, places with high marginal costs also tend to have high marginal damages. Ton for ton trading reduces emissions in low damage areas (rural) while increasing emissions in high damage areas (cities). From 2000 to 2007, conservative estimates of the value of mortality risk suggest that trades increased damages from $0.8 to $1.1 billion annually relative to the initial allowance allocation and from $1.5 to $1.9 billion annually relative to a uniform performance standard. With USEPA values, trades increased damages from $2.4 to $3.2 billion annually compared to the initial allowance allocation and from $4.4 to $5.4 billion compared to a uniform performance standard. It is not clear that the ton for ton SO2 cap and trade program is actually more efficient than comparable command and control programs. The trading program needs to be modified so that tons are weighted by their marginal damage.

Kristin Pene: "Maximizing environmental and socioeconomic benefits of green roofs in Washington, D.C."

My report, inspired by the work of a non-profit organization in Washington, D.C. that seeks to promote social revitalization through environmental restoration, offers recommendations for the development of green roof subsidy and promotional programs targeting Washington D.C.’s underserved communities. I used results from sewer system modeling, academic studies on green roof performance, and thermal satellite imaging to identify areas of the District that would benefit most from the stormwater and cooling benefits green roofs provide. Lessons learned from first-hand involvement in past green roof subsidy programs inform my recommendations on how future programs could more effectively serve underprivileged communities. While the recommendations are specifically intended to give rise to programs that will more strategically maximize the environmental and socioeconomic benefits of green roofs in Washington, D.C., many of the findings could have implications for organizations working towards similar goals in other urban areas.

Emily Stevenson: "Closing the Loop: Alternative Land Management at Yale"

Compost tea is a soil amendment often used as an organic alternative to synthetic nitrogen fertilizers. Compost tea is purported to increase soil microbial biomass and organic matter, creating a healthy and dynamic soil ecosystem that supports various ecosystem services. Healthy urban soils promote healthy vegetation, mitigate storm-water surges, improve nutrient cycling to minimize losses by leaching and run-off, and increase soil’s capacity for carbon storage. This research project established a pilot program on Yale University’s campus that assessed the above and below-ground responses to the use of compost tea versus the synthetic fertilizer and herbicide used under current management. Soil samples taken from twelve experimental plots located across the university’s campus were analyzed to assess microbial community response to the alternative land management program. Compost tea application took place over a twelve week period in Fall 2010; soil microbial biomass and catabolic evenness were measured across the treatment timeline to see how microbial communities differentiated under the different treatments. The tea applications effected microbial dynamics, but not as hypothesized. Compost tea treatments showed relative decreases in microbial biomass and catabolic evenness when compared to soils under current treatment. This study, after just 12 weeks of treatment, provides an early look into the dynamics of shifting soil communities under differing treatments.

2009 Urban Fellows Research Papers

Saalem Adera:  "An exploration in constructed wetlands and EAF steel slag filters"

Excess phosphorus inputs to Lake Champlain are causing unwanted algal growth resulting in decreased lake water transparency, odor, and reduced dissolved oxygen levels, while the presence of pathogen-indicating bacteria in the lake cause occasional beach closings.  This has implications for both recreational and drinking water uses of the lake.  It has been determined that non-point sources of phosphorus, mostly from surface runoff, are responsible for 80% of the phosphorus inputs to Lake Champlain, mostly from agricultural runoff.  Pathogenic bacteria are also associated with agricultural runoff – particularly from livestock operations.  Simple, low-cost technologies for phosphorus and pathogen removal from stormwater and agricultural wastewater are needed.  One such technology is an on-site, combined constructed wetland-EAF steel slag filter system.

Peter Christensen: “The Form of Change: Inter-Annual Analysis of Urban Expansion using Landscape Metrics”

The past few years have witnessed a proliferation of studies using spatial metrics to examine spatial structure of land cover change.  Urban analysts are no exception, applying landscape metrics to study and model patterns of urban growth.  While the majority of this research examines emerging urban structures by measuring changes in their aggregate forms, these spatial patterns are often dominated by stable regions at the urban core.  This study proposes the direct measurement of discrete changes across the urban landscape, testing the technique through a comparative assessment of aggregate and discrete land cover changes across seven classified Landsat images from China’s Pearl River Delta.  The study presents results on area and compactness metrics computed with Fragstats 3.3 software, which reveal distinct trends between two complimentary methods.  Analysis of this data suggests a potential role for discrete pattern analysis as a compliment to aggregate change analysis, particularly suited to detecting and characterizing process dynamics involved in urban expansion.

Emily Jack-Scott: "Survival and Growth Factors Affecting Community-Planted Urban Street Trees"

Urban street trees face adverse growing conditions: compacted soils, extreme heat, lack of nutrients, drought, car damage and vandalism. Limited funding, however, is cited by urban tree-planting organizations as their major obstacle. To maximize budgets, many organizations along the eastern United States have planted bare root trees as a less expensive alternative to balled-and-burlapped (B&B) trees. Existing research indicates equivalent survival rates between bare root and B&B trees; but no research has examined this in community group-planted urban street trees. Bare root trees are additionally advantageous in community-based plantings because they are much lighter and easier for volunteers to handle. This study evaluated the influence of stock and other site factors on street tree survival and growth measures (diameter at breast height, percent canopy cover, and percent live crown), while controlling for species and age. Site factors included street traffic intensity, site type (curbside, park, yard, or commercial corridor),wound presence, and sidewalk pit cut dimensions. 1159 trees (representing ten species) planted by Philadelphia community groups under the guidance of the Pennsylvania Horticultural Society from 2006-2009 were sampled. Overall, trees showed a high survival rate of 95%, with no significant difference between B&B and bare root trees. Species with the highest survival rates were Prunus virginiana (chokecherry), Platanus x acerifolia (London plane tree), and Acerginnala (Amur maple). Heavily trafficked streets exhibited lower survival, percent canopy cover and percent live crown. Larger growth measures were expected and found in B&B trees, as they have historically been planted larger than their bare root counterparts. Findings support planting larger trees (such as B&B and/or larger bare root trees) along commercial corridors. Species in the Rosaceae family (Amelanchier spp., Malus spp, and Prunus virginiana) exhibited lower percents canopy cover. Wound presence and pit cut size were not major factors affecting the 1-5year old street trees sampled in this study. The major management implication of these findings is that bare root trees are a viable alternative to B&B trees in community-based urban forestry initiatives. Tree-planting campaigns with similar climactic conditions to Philadelphia can use this study to inform selection of stock and species.

Justin Freiberg: "The Urban Foodshed Collaborative"

The Urban Foodshed Collaborative (UFC) aims to provide a space and structure for New Haven youth and Yale FES students to connect to the potential of the land around them right in New Haven, and to realize the potential in local, collaborative solutions. It does so through the transformative act of growing food within an entrepreneurial model. I founded UFC in the spring of 2009 in response to a number of trends that I hoped would allow it to succeed: the desire of restaurants and markets to source locally-produced, community-enhancing produce, the many vacant lots that could be turned into productive space, and importantly, the continued need for urban youth to have valuable experiences that also pay a deserved wage. This paper examines the first summer of work of UFC, looking at some of the groups we partnered with, some of the lessons learned, and of course, the context in which it was founded. Alternative solutions to new challenges illuminated during this first summer of work will be evaluated. Further, I have developed a guidebook that will be used to welcome in the next generation of urban farmers to the Urban Foodshed Collaborative. Website:

2008 Urban Fellows Research Papers

Lauren Adams: "Perceived and Actual Urban Water Quality Risks"

Ubiquitous non-point source (NPS) pollution is a dominant cause of biogeophysical degradation in urban catchment systems, the residual effects of which damage community health, safety and property values. Remediation of water resources contaminated by NPS requires both political participation as well as scientific information, particularly for drinking water supply sources, where the human impacts of NPS pollution are more acutely realized. To better understand the relationship between the demand for clean water and the supply of scientific education and information, my research compared actual and perceived pollution risks within the urban Mill River watershed in New Haven, Connecticut to determine the magnitude and characteristics of the watershed’s manufactured risk. The preliminary results from this study found that people have a difficult time describing their local water supplies both at the source and from the tap and that a general lack of interest in and understanding of the mechanistic links between watershed, human and ecosystem health prevails, despite people’s intense preference for the trusted delivery of clean water supplies within their urban homes.

Meg Arenberg: "Motivating and Sustaining Urban Ecological Stewardship at the Neighborhood Scale: Case Studies in Three Baltimore Neighborhoods"

My research grant from the Hixon Center allowed me to spend the summer exploring the motivations and resources for sustaining neighborhood level urban ecological stewardship activities in the Madison/East-End, Southwest Baltimore and Pigtown communities of Baltimore City. Using the ethnographic methods of semi-structured interviews, oral history and participant observation, I gathered qualitative data from community members and institutional informants on past and present urban ecological stewardship projects in these three communities. I sought to supplement the on-going research findings of the larger-scale Baltimore Ecosystem Study and the Stewardship Mapping and Assessment Project by contributing a richer understanding of what motivates urban stewards to initiate neighborhood-scale projects and what resources, both material and social, they depend upon to sustain them. My final paper includes both a typology of motivations for neighborhood-level stewardship and an analysis of the social and funding networks built around and depended upon by stewards in these neighborhoods.

Haley Gilbert: "East Rock Park: Inside and Out"

East Rock Park: Inside and Out is an interactive web based project empowering local communities to map how they use a local park – East Rock Park. The website was created to explore emerging community mapping technologies and uses like neogeography. Since the introduction of geobrowsers, like Google Maps, the layperson has been empowered to create and share spatial information over the internet with ease. This project examines community mapping trends, the technologies associated with neogeography, and details the process of creating the Inside and Out website. Can community groups or neighbors band together to apply these technologies to map their communities and local ecosystems? Experience from the website and research supports the position that the technologies are easier to use, the financial investments have been reduced, and people are actively engaging with these types of interactive mapping websites. In conclusion, community groups and neighbors can create, engage and utilize interactive mapping websites. However, more research still needs to be conducted to learn if groups are using these sites to improve, enhance, or protect their communities and/or local ecosystems.

Helen McMillan: "Urbanization of New England Wetlands: Evaluating the Effects on Pond-Breeding Amphibians"

Urbanization often causes wetland loss and alteration, which can have significant effects on amphibian populations that utilize wetlands for breeding and adult habitat. Reduced connectivity and density of ponds, alteration of the surrounding terrestrial habitat, and changes to the chemical, physical or biological characteristics of wetlands may all be possible contributors to decreases in amphibian populations. This study evaluated these potential causes of decline on two species of tree frogs in Connecticut: the gray tree frog (Hyla versicolor) and the spring peeper (Pseudacris crucifer). I surveyed 30 ponds located along an urbanization gradient in the Salmon River watershed of eastern Connecticut during the spring/summer of 2008. Many pond characteristics, such as salinity and the presence of fish, showed clear differences with increased urbanization. In contrast to other studies, I found amphibian diversity to be highest in suburban areas, likely due to the combination of more permanent ponds that many species require and the relatively close proximity to forested areas. However the factors that best predicted amphibian density varied with each species, indicating that in order to effectively protect amphibians a variety of habitats need to be protected.

Norio Takaki: "Municipal Waste Management in Two Brazilian Cities"

The present work compares municipal waste management practices in two Brazilian cities in terms of their potential as mechanisms for the social inclusion of trash pickers. The Federal District, home to the Capital, is taking measures to implement an integrated waste management program that aims to improve recycling rates through curbside collection of separated recyclables and support the work of trash pickers through the creation of cooperatives. In contrast, the city of Porto Alegre has had such a program since 1990 and thereby constitutes a valuable reference framework for Brasília. The comparison focuses on the advances Brasilia’s cooperatives have achieved as well as the obstacles they face to establish themselves structurally and administratively. Some of the more important lessons learned from this investigation come from the recognition that Porto Alegre’s program, despite its near twenty-year experience, has not contributed significantly to the social inclusion of trash pickers, neither in terms of income nor in terms of effecting operational and financial self-sufficiency amongst cooperatives. Since the situation in Brasilia is still in a process of incubation, local stakeholders and institutions could use Porto Alegre’s case as a cautionary example of the potential political and economic pitfalls facing the emerging system of cooperatives.

2007 Urban Fellows Research Papers

Gerald Bright: "Modeling the Hydraulic Effects of Instream Habitat Restoration"

Gerald Bright analyzed how an instream habitat restoration application affects both instream flow variability and habitat quality for invertebrates, on the main stem of Pennypack Creek in Philadelphia, PA. Often, restoration applications are completed without a full understanding of process and violate the dimension, pattern and profile of a stable river. Using River2D, a two-dimensional (2D) hydrodynamic model, Gerald modeled natural and modified instream hydraulic conditions at a range of discharges to test for differences in hydraulic conditions and habitat suitability. Analysis of model outputs from River2D yields promising conclusions as to the utility of modeling the effects instream habitat restoration structures. The ability of 2D hydrodynamic models to resolve spatial variability in hydraulic conditions can provide opportunities for their use in making predictions about hydraulic conditions in systems with altered flow regimes. Conditions present in impacted urban systems could support the use of 2D models in the development of watershed management strategies given the influence of anthropogenic and land-use effects on flow regimes and habitat quality.

Steven P. Brady: "Wetlands in disturbed landscapes support higher avian biodiversity"

Steve Brady examined the distribution of wetland dependent birds across three types of land cover: urban/ suburban, agricultural, and forest. Many studies indicate the negative consequences of habitat conversion on native wildlife, however recent investigations suggest that some species may respond positively to human dominated landscapes. While the negative response of forest songbirds to land development is well documented, the response of wetland dependent birds is less known. Steve conducted this research in the CT River Valley and the Yale Forest in Union, CT. He used point count surveys to record bird abundance and diversity at each of 16 wetlands. His findings indicate that wetlands in human dominated landscapes support larger and more diverse communities of birds. These results suggest that the response of wildlife to land conversion is context dependent, and that human dominated landscapes may offer opportunities for conservation of wetland dependent birds.

Jennifer A. Lewis:  "Continuum of Tenure and Services: Fundamental consideration for MDG implementation in Mexican cities"

Jen Lewis conducted her research with support from The United Nations Human Settlements Programme in Mexico. She focused on land tenure legalization and service provision in peri-urban communities in Mexico. She worked in Xalapa, Veracruz developing criteria for future initiatives that link legalization and service provision processes. Key elements of this initiative included a comprehensive study of historical land use planning, environmental indicators, and political processes for property rights and services. Ultimately, the results of this research project offer an initial historical review of land rights and planning programs in Mexico. An additional outcome is an innovative proposal for sustainable development in peri-urban communities of growing cities as well as an academic analysis of current urban land use policy in Mexico.

Alicia Senauer: "Urban Habitat and Health: Understanding Children’s Exposure to their Outdoor Physical Environment in Urban Areas"

Ali Senauer evaluated and is currently testing a novel method, based on global positioning system (GPS) technology, to better understand children’s exposure to their outdoor physical environment in urban areas. Through numerous studies and the development and application of new tools and techniques over the past several decades, we have become acutely aware of the direct linkage between non-human organisms’ distribution, health, and survival and the quality, quantity, and spatial distribution of their habitat. Unfortunately, while there has been increasing emphasis on understanding non-human organisms and their habitat needs, there has been relatively little focus on understanding human habitat needs. Ali is interested in using GPS technology to advance our understanding in this area. Towards this end, she evaluated a number of commercially available GPS instruments and is currently developing a custom unit to meet her research needs. This work will directly inform and advance Ali’s dissertation research, which is focused on understanding how the structure of children’s physical environment impacts their experiences and health.

Brenna E. Vredevel: "Subjectivity of Land Cover Change Trajectories in Peri-urban Quito, Ecuador: Community characteristics, migration and participation in land use planning"

Brenna Vredeveld examined how specific economic, social, political and biophysical variables motivate or hinder urban growth in Quito, Ecuador’s second largest city. Specifically, she focused on understanding the influence of these variables in three peri-urban communities located in two important watersheds southeast of the city. The three communities represent a gradient of urban development defined by presence of formal infrastructure. In order to understand historical growth trends in these areas, Brenna conducted interviews with community leaders as well as with regional urban planning and environmental departments. She also used community surveys and an informal GIS analysis to observe changing demographies and associated land covers in order to gauge the importance of biophysical variables on urban growth. Overall, she found that the contribution of each variable to urban growth varies across the three communities. In addition, land cover changes are often influenced by the effectiveness of planning policies, the attraction of markets, opportunities for livelihoods and resource availability.

2006 Urban Fellows Research Papers

Manja P. Holland: "Echinostome infection in green frogs (Rana clamitans) is stage and age dependent"

The increasing threat of emerging infectious diseases in both wildlife and humans has spurred interest in the causes of disease emergence, including the role of anthropogenic change. A prior field study of infection patterns in amphibians suggests that echinostome infection may be an emerging disease of green frogs, Rana clamitans, living in urbanized environments. We examined the impact of echinostome infection on green frog tadpoles at a wide range of developmental stages (Gosner stage 25–39). Echinostome infection was associated with green frog mortality rates of up to 40% in an early developmental stage, and none in later developmental stages. Tadpoles exposed to higher echinostome doses exhibited higher edema rates, a potential sign of compromised renal function. Histopathological analysis further supported the hypothesis that echinostome-induced tadpole mortality resulted from compromised renal function. Given that the timing of highest cercarial shedding can coincide with the most vulnerable stages of green frog tadpole development, echinostomes could significantly impact green frog survival in nature.

Katrina Jessoe: "Does Public Information Disclosure Reduce Drinking Water Violations?"

James McConaghie: "Evaluation of the behavior of caffeine in fresh watersheds and as a tracer of sewage contamination"

It has been suggested that reductions in nitrogen loading to estuaries should be accomplished by implementing watershed specific programs that target the dominant nitrogen sources. The area surrounding Long Island Sound has been intensively developed and the watersheds contributing water and nutrients to the Sound are subject to a variety of density in urbanization. The loading of nutrients due to urban development to the Sound is influenced by urban infrastructure and the density of human populations and their associated activities. Efficient management of water quality in urban systems requires the identification of elements that contribute most to the loading of various pollutants. Caffeine is unique to sewage sources in the Northern Hemisphere, and could be used as a tracer for sewage contamination and evaluation of landscape elements which contribute to nitrogen loading via sewage effluent. I measured caffeine concentration in a fresh watershed along an urban-rural gradient which exhibited a variety in development intensity and infrastructure connection. Caffeine was detected and resolved a pattern that increased with urban density and correlated to other water quality parameters. The evaluation of caffeine as a tracer for sewage contamination as well as a tool for understanding how urban landscapes contribute nutrients to the environment is promising but requires further study.

Kate Neville: "Beyond Ideology: "Public or Private" is Not the Question"

Urban water management has specific institutional challenges that must be addressed in order to improve freshwater access in developing countries. This paper uses case studies from the Philippines to address the political and regulatory barriers that hinder improvements to water services. The central aim is to move past the typical public versus private debate that has dominated international discussions about investment and management of water utilities over the last two decades. The paper describes the scope of the water access problems, examines the need to move past ideology in water management decisions, provides case study examples to illustrate relevant issues, suggests context-specific factors that must be considered, and develops suggestions for policy approaches to reform. The main conclusions are that decision makers need to consult with a broader spectrum of stakeholders when undertaking water sector reform, better understand the local context and existing water provision systems before enacting new regulations and structures, draw on theories and experiences of institutional organization to find context-appropriate systems for water resources, and increase transparency, accountability, and flexibility in governance.

2005 Urban Fellows Research Papers

Mohamad A. Chakaki: "Can Tears and Blood Sprout Olive Trees?"

Mohamad A. Chakaki (MEM ’06) traveled to Syria where he worked in "Neirab Camp," a Palestinian refugee camp. Mohamad went to Neirab to help introduce sustainability to the camps, which were designed as temporary refuges but have evolved into more permanent homes. Mohamad worked for the UNRWA, the United Nations Agency for Palestinian Refugees. He discovered that developing greenspaces in such a complex environment was a challenge. Questions of "home," ownership and identity are not clearly answered in Neirab, whose residents have always thought of themselves as visitors and yearn for their home in Palestine. Mohamad attempted to untangle how to speak with the refugees about environmental sustainability when there are so many other priorities.

Joel Creswell: "Mercury Concentrations in an Urbanized Watershed"

Joel Creswell (MESc ’06) analyzed water samples from four streams in the three main watersheds of the City of New Haven for mercury content. By analyzing streams in both forested and urbanized landscapes, Joel hoped to determine whether different land uses affected mercury concentrations in streams. Preliminary results show that mercury is inversely correlated with watershed urbanization under dry conditions. Joel expects storm data to show the opposite relationship. Joel’s research will help urban planners and stormwater managers understand the impacts of urban land use on the levels of mercury—a harmful pollutant—in streams.

Tomas Delgado: "Is a Sustainable Urbanism Possible In 21st Century America?"

Tomas Delgado (MEM ’06) focused his internship on improving the understanding of sustainable urban building. The low density "sprawling" neighborhoods that dominated building in the last decades of the 20th century are undesirable in terms of energy, land use, material use, and also in terms of less tangible factors like the lack of "sense of place" they promote among their inhabitants. By studying new designs, like that of downtown Mansfield, Connecticut, Tomas attempted to understand how rating systems like LEED® (Leadership in Energy and Environmental Design) can be used to evaluate the sustainability of urban design. By working on a new rating system, the "LAND code," being developed at Yale, Tomas worked to incorporate important aspects of land use not thoroughly considered using LEED®.

Rachel Gruzen: "Shrimp Aquaculture and Urban Growth in Madagascar: Sustaining Societies and Conserving Coasts?"

Rachel Gruzen (MEM’06) explored the complicated challenge of sustainable shrimp farming in Madagascar. Armed with a video camera, Rachel explored how the growing global demand for shrimp is affecting the diverse, pristine mangrove shorelines of the East African country. In her research, Rachel traced how the government and aquaculture companies are addressing the social wellbeing of their employees. She was especially interested in determining which factors—community development programming, town planning, partnership-building, and policy frameworks—are tending to encourage socially and environmentally sustainable shrimp farming in Madagascar. The result of Rachel’s work is a documentary.

Manja P. Holland: "Urbanization and the Impact of Emerging Disease on Amphibians"

Manja Holland (PhD Candidate) spent her summer investigating emerging disease in amphibians in Northeastern Connecticut. Emerging wildlife diseases are of concern both from conservation and human health perspectives, as many can be transferred between wildlife and people. Urbanization and other forms of anthropogenic change have been linked with increased emergence of wildlife disease, but the mechanisms underlying these patterns remain poorly understood. By understanding how echinostomes, a widespread amphibian macroparasite, impact green frogs (Rana clamitans), Manja hopes to contribute to the understanding of the mechanisms by which diseases, especially those that can be transferred to humans, can emerge as a result of urbanization.

Rita Lohani: "Institutionalizing Eco-Industrial Development Concepts for Philippine Economic Zones"

Robyn Meeks: "Water Governance Programme"

Robyn Meeks (MEM ’05) worked at the United Nations Development Programme (UNDP) Headquarters in New York City with the Water Governance Sub-Practice. The Water Governance Sub-Practice promotes sound and effective governance of water resources. In this capacity, Robyn assisted in activities pertaining to transboundary waters and integrated water resources management (IWRM). Studying IWRM, she researched the outcomes, lessons learned, and achievements of UNDP’s transboundary rivers initiative. Robyn participated in the planning of community stakeholder dialogues to empower and involve historically marginalized groups in decision-making proriver basin organizations. Each year the Hixon Center for Urban Ecology sponsors summer internships designed to encourage students at Yale School of Forestry and Environmental Studies to pursue projects that focus on increasing the understanding of urban ecosystems. During the summer of 2005, seven Hixon Fellows worked all over the world, from the streams of Connecticut to the refugee camps of Syria and the mangroves of Madagascar. Fellows studied topics as far ranging as amphibian disease, water governance and green building.

2004 Urban Fellows Research Papers

Amy Kimball: " If They Don’t Count, You Don’t Count"

Amy Kimball (MF ’05) worked with the Trust for Public Land in Washington, D.C. to conduct nationwide research on the user profile of urban park visitors. After speaking with park managers from around the country, she compiled a list of best practices for enumerating and understanding park users. Her findings concluded that surprisingly few urban park systems have a reliable and consistent method for assessing how many people frequent these public amenities. However, in the case of parks that count and communicate with their users, the data indicate the importance of these public spaces to cities. Amy’s findings will be incorporated into a larger Trust for Public Land project to assess the economic value of urban parks.

Emily Levin: "Water Wisdom"

Emily Levin (MEM '05) traveled to New Delhi, India to work with the Centre for Science and Environment.


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