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Project Descriptions

Each research area in the 2021 Cary REU program is mentored by a team of 2 or more scientists from Cary Institute or collaborating institutions. Each team of mentors will select two REU students to join their team. Students will design and carry out individual research projects, in collaboration with the other members of their research team.

Research will take place during the 9 week period between the kick-off and wrap-up meetings in New York. For the 2021 program, most projects (A-F) will involve modeling, analysis and synthesis of existing datasets from the mentors or other sources. For one project (G), the two students will be in residence at the Hubbard Brook Experimental Forest in New Hampshire for a portion of their research period. Field work may be arranged for projects D, E and F. In all cases, field work will only take place if allowable in accordance with local and Institute heath guidelines.

In the Cary REU 2021 Application, you will indicate your preference for research projects. This is a very important step in the process, since you are most likely to be considered for your top choice project(s). You may find it helpful to learn more about the mentors and their work by clicking on their names to go to their websites.

Project Descriptions for 2021

Project A. How ecosystems influence arthropod vector populations and potential transmission risk

Mentors: Shannon LaDeau (Cary Institute), Barbara Han (Cary Institute) and Sarah A. Batterman (Cary Institute)

Mosquitos and other arthropods are important vectors of many emerging diseases. Local biological and abiotic conditions of vector habitats can directly influence the composition and fitness of biting populations, with implications for potential disease transmission risk. Students will use mechanistic and statistical models to investigate how differences in local vegetation and abiotic drivers can influence vector population growth and potential pathogen transmission. Datasets from urban-to-rural gradients will allow the students to explore the impact of human structures and behavior on disease risk, including questions about the equitable or inequitable distribution of risk across metropolitan regions.

Project B. Understanding the intersection of global change, conservation, and disease risk

Mentors: Barbara Han (Cary Institute), Ilya Fischhoff (Cary Institute) and Adrian Castellanos (Cary Institute)

Deforestation, wildlife trade, and other global changes bring people close to wildlife that may harbor pathogens dangerous for people, like the virus causing COVID-19. To safeguard public health and mitigate the species extinction crisis, we need to understand how global changes and conservation actions influence pathogens that people may pick up from wildlife and those that may threaten wildlife directly. Students will have the opportunity to learn and apply statistical and machine learning methods to discover how wildlife responses to global changes interact with conservation actions to shape disease risk and conservation outcomes.

Project C. Projecting future treelines in Alaska

Mentors: Winslow Hansen (Cary Institute) and Sarah A. Batterman (Cary Institute)

Treeline is the upper limit of forest distributions where cold temperatures constrain the establishment and survival of trees. Yet despite the assumption that human-induced warming should cause trees to expand north and up in elevation, it is not clear why decades of climate change have not changed the global treeline. This project will examine which demographic processes -- including seed production and dispersal, seedling establishment, and tree growth -- constrain forest expansion and the importance of soils and disturbance in mediating treeline expansion. Students will use existing datasets and a state-of-the-art individual-based forest process model to develop 21st-century projections of white spruce expansion beyond current treeline in interior Alaska and identify the mechanisms that most constrain or facilitate treeline expansion.

Project D. Environmental history of an urban-suburban watershed in Dutchess County, NY

Mentors: Steward T.A. Pickett (Cary Institute) and Alan R. Berkowitz (Cary Institute)

The Fallkill Creek is a tributary of the Hudson River that runs through the north side of the City of Poughkeepsie, with headwaters in suburban and rural territories beyond. The creek is currently the centerpiece of a community revitalization effort in the northern, minority neighborhoods of the city and parts of the downtown. Although there are various documents and reports about the creek, including some spot samples of water quality and condition of the banks, a fuller environmental history of the creek is lacking. In addition, summarizing key aspects of the history of the creek and opportunities for improvement would be useful for engaging the residents of the watershed in the restoration and re-envisioning of the creek and seeing it as an amenity for their neighborhoods. Students will have the chance to design research projects using data from past and current programs, documents and other historical sources and interviews with diverse stakeholders in Poughkeepsie.

Project E. Are symbiotic nitrogen-fixing trees in the Anthropocene shifting functions?

Mentors: Sarah A. Batterman (Cary Institute) and Michelle Wong (Cary Institute)

Temperate forests have undergone a changed nutrient environment due to chronic nitrogen deposition and climate change, raising the question of whether nitrogen-fixing trees will continue to fulfill their biogeochemical function as the dominant source of new nitrogen to these ecosystems. Students will use existing datasets, or a greenhouse experiment or field work at the Cary Institute if possible, to test the hypothesis that the dominant nitrogen fixer Robinia pseudoacacia has switched niches and now is successful because of an ability to acquire newly-limiting soil phosphorus. Students may alternatively examine how herbivore pests govern symbiotic nitrogen fixation by gathering data from leaf scans and analyzing existing datasets gathered from around the world.

Project F. Vertical dimension of microbial community assembly and function in forests

Mentors: Jane Lucas (Cary Institute) and Evan Gora (Smithsonian Tropical Research Institute)

Microbial communities are the “invisible” components of ecosystems that regulate ecological interactions and ecosystem processes, but we know little about microbial community assembly and activity from the forest floor to the canopy. Students will take an experimental approach in a temperate forest at the Hubbard Brook or the Pymatuning field stations if possible, or an analytical approach using existing datasets from a tropical forest in Panama to examine how vertical differences in microclimate, nutrient availability, and dispersal distance influence microbially-mediated ecosystem processes across this vertical gradient.

Project G. Examining the effects of global change on streams of the Northeastern US

Mentors: Audrey Thellman (Duke University), Emma Rosi (Cary Institute) and Emily Bernhardt (Duke University)

Global change is manifested in various ways.  In the Northeastern US, climate change is leading to earlier and more prolonged springs, warmer water temperatures and more frequent summer storms. In addition, the legacy of acid deposition has left some streams of the Northeastern US extremely dilute, with stream water that is nearly equivalent to deionized water.  At the Hubbard Brook LTER, we are collecting long-term data on stream invertebrates, algae and bryophytes to investigate the influence of climate-associated changes coupled with the influence of stream water chemistry across an array of experimental watersheds.  The Cary REU students will have the opportunity to spend the summer program at the Hubbard Brook Experimental Forest, located in the White Mountains of NH, investigating how stream ecosystems are responding to long-term changes associated with global change. Students will have access to previously collected samples of aquatic insects and long-term water chemistry records, and also will have the opportunity to conduct field studies for their research into the causes and consequences of these changes.

Project H: Urban forest ecology in New York City

Timon McPhearson (Cary Institute and The New College), Elizabeth Cook (Barnard College), Steward T.A. Pickett (Cary Institute)

The MillionTreesNYC Afforestation Study is a long-term experiment tracking the growth, survival, and other ecological effects of tree planting in New York City parks initiated with partners at Columbia University and NYC Dept. of Parks and Recreation. With nearly 40 long-term subplots in Brooklyn, Queens, Bronx, and Staten Island, this experiment offers a unique opportunity to understand the effectiveness and ecological effects of urban afforestation efforts and their impacts on climate. The REU students will conduct independent research related to trees’ roles in urban ecosystem functions and implications for designing sustainable urban environments. Research areas may include: 1) estimating carbon sequestration rates of trees and soil following afforestation to address the contributions of urban tree plantings to mitigating cities’ contributions to climate change, 2) analyzing the response of native and invasive plants to afforestation and different tree diversity treatments, or 3) measuring plant trait and functional diversity responses to different soil conditions.