Urban Ecology Research Lab

Current Projects

Understanding the hydrologic consequences of urban gardening during COVID-19. NSF supplement, Pataki (PI), Litvak
Environmental impacts of the COVID-19 pandemic are beginning to be reported. There appear to be significant reductions in traffic, industrial activity, atmospheric pollution, and greenhouse gas emissions associated with changing travel, employment, and recreational patterns in cities around the country. In addition, it now appears likely that the pandemic is also changing irrigation patterns in residential yards, due to changes in gardening practices associated with increased time spent at home, rising unemployment, fears of food insecurity, and changes in the supply chain of horticultural plants. Horticultural suppliers and professionals are reporting a dramatic increase in interest in food gardening, and many seed and plant sources have been sold out this spring. This 'panic buying' is likely changing planting and yard management practices in many households, some of which are planting intensive gardens for the first time. Many urban gardens, particularly food gardens, are associated with intensive irrigation, with potential consequences for water resources, hydrologic cycles and local and regional climate. To evaluate impacts of the pandemic on urban vegetation and hydrology, we will study changes in vegetation cover, hydrologic fluxes, gardening, and irrigation practices in response to pandemic conditions in three contrasting cities: Salt Lake City, Los Angeles, and Tallahassee. These cities differ in hydrologic context and water management practices, with varying rates of irrigation and water conservation policies. In each city, we will use satellite remote sensing to quantify changes in vegetation cover and greenness, and validate the land surface temperature and evapotranspiration products of ECOSTRESS, a sensor mounted on the International Space Station. We will combine these measurements with household surveys of gardening and watering practices in response to COVID-19. This will allow us to better understand how urban ecohydrology intersects with work and leisure patterns in cities across the United States.

Can green infrastructure maximize ecosystem processes related to nitrogen? NSF DEB, Smith (PI), Goel, Pataki, Shah
Nitrogen pollution causes many environmental and human health problems. These include harmful algal blooms, acid rain and smog. In cities, fossil fuel burning and fertilizer application add large amounts of nitrogen to stormwater. City infrastructure carries stormwater downstream, which may pollute downstream ecosystems with excess nitrogen. Nature-based designs that use ecological processes to remove nitrogen from stormwater may provide a solution. These green infrastructure designs are popular in cities globally. Questions remain, however, about their effectiveness. Should green infrastructure design mimic natural ecosystems as closely as possible? Or can new combinations of soils and species more effectively mitigate pollution? This research will seek answers to these questions by studying several types of stormwater management facilities in Salt Lake City, UT. Results from this research will provide useful guidance to the design of stormwater management systems. It also has the potential to advance fundamental understanding of the nitrogen cycle. Researchers will also conduct extensive public outreach and educational activities to highlight the importance of ecological processes in urban spaces.

Understanding the hydrologic consequences of urban irrigation across the U.S. NSF EAR,  Pataki (PI), Litvak, Jenerette
All components of the water cycle are altered by human activities in cities, and the impacts of these changes on urban water and climate are still poorly understood. Urbanization affects climate, the amount of water in soil (soil moisture), and the type and amount of vegetation across the landscape. All of these factors strongly impact evapotranspiration (ET): the flux of water from land to the atmosphere. Urban ET is poorly predicted by hydrologic models that do not adequately represent human actions, such as irrigation. Yet, urban irrigation can have large effects on climate, soil moisture, and plant growth and survival. This study addresses the extent to which ET is limited by soil moisture, atmospheric water demand (a function of humidity and air temperature), or the density and distribution of vegetation within and across U.S. cities. Measurements will be made in three urban regions: Los Angeles, CA (a semi-arid city where irrigation has been declining due to drought response policy), Salt Lake City, UT (semi-arid but still heavily irrigated), and Tallahassee, FL (high rainfall and very high urban tree cover). These cities represent urban settings with different water cycle components. This project will advance knowledge and understanding of urban ET, improve basic climate and water cycle models, and to contribute to efficient water management in cities and urban landscapes.

Toward a theory of trees as living infrastructure. Subcontract from the University of California, Riverside, Pataki (PI)
Trees are now ubiquitous components of urban landscapes in the United States. Increasingly urban trees are called upon as a form of living (i.e., green) infrastructure that is used to meet a variety of municipal goals to provide ecosystem services and combat the effects of climate change that, for many cities in the US and abroad, is causing an increase in the urban heat island effect. However, using trees as a form of infrastructure raises new challenges compared to traditional gray infrastructure typically managed by cities. This research addresses major knowledge gaps in our understanding of the effectiveness and capacity of urban trees to provide the services expected within the structure of municipal tree planting, stewardship and decision making and community interaction. Living infrastructure is a socio-environmental-technological system of feedbacks between organisms, the environment, societal desires, and governance capacity. In the case of urban trees, their capacity to meet municipal goals is uncertain and likely varies among cities. Part of this uncertainty exists because the ability to adequately model the effect of urban trees on their local environment suffers from a lack of quantitative information and scientific study. At the same time, the capacity of institutional managers to successfully steward urban trees is also unclear. Taken together, cities may have goals for tree-derived functions that are disconnected from both the biophysical realities of what trees can do and realities and limitations of community management practices. Broader impacts of the work include student and postdoc training in convergent research, providing data and findings to inform municipal decision making, and informing the public and other stakeholders of the role of living infrastructure in cities via social media and other outreach mechanisms.

Alternative futures for the American residential macrosystem. NSF Macrosystems, Groffman (PI), Grove, Lerman, Hall, Larson, Pataki, Hobbie, Cavendar-Bares, Nelson, Morse, Chowdhury, Heffernan, Neill, Trammell, Avolio
An apparent, but untested result of changes to the urban landscape is the homogenization of cities, such that neighborhoods in very different parts of the country increasingly exhibit similar patterns in their road systems, residential lots, commercial sites, and aquatic areas; cities have now become more similar to each other than to the native ecosystems that they replaced. This research builds on the team's prior NSF funded research on the "ecological homogenization of the American Residential Macrosystem (ARM)" and specifically investigates factors that contribute to stability and/or changes in the ARM. The aim is to determine how factors that effect change such as shifts in human demographics, desires for biodiversity and water conservation, regulations that govern water use and quality, and dispersal of organisms?will interact with factors that contribute to stability such as social norms, property values, neighborhood and city covenants and laws, and commercial interests. The project will determine ecological implications of alternative futures of the ARM for the assembly of ecological communities, ecosystem function, and responses to environmental change and disturbance at parcel (ecosystem), landscape (city), regional (Metropolitan Statistical Area) and continental scales. Five types of residential parcels as well as embedded semi-natural interstitial ecosystems will be studied, across six U.S. cities (Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, and Los Angeles). Education and outreach work will focus on K-12 teachers and students and on collaborative policy efforts with city, county, and state environmental managers.