Environmental and Phylogenetic Variations in Plant Rooting Strategies
Recent research has made it clear that plants exhibit varied rooting strategies for accessing water stored in soils. Some trees naturally access deeper soil water when shallow soils become too dry. In other settings we observe trees changing their rooting patterns in response to competition with neighboring species. Researchers have clearly shown that a plant's local environment can influence rooting strategies, but we don't yet understand if this behavior emerges from a larger genetic signal that shows up across the evolutionary history of plants. Our research combines field measurement of stable isotopes in water (2H, 18O) with physically-based ecohydrological modeling and data analytics to better understand plant water uptake strategies and the impact on the hydrologic cycle. We hope this research will ultimately support data-driven methods of parameterizing hydrologic models.
Collaborators: Jaivime Evaristo (Universiteit Utrecht), Evan Fricke (SESYNC), Kanishka Singh (Cornell University)
How will Changing Forest Composition Influence Streamflow Regimes?
Trees mediate the amount of water stored in watersheds and runoff responses to periods of heavy rainfall via transpiration. Given that trees employ varied strategies for root water uptake, have canopies that intercept different volumes of rainfall, and different phenologies (e.g. the timing of leaf on/off in response to air temperatures), shifts in the composition and density of Northeastern US forests will likely have some effect on regional streamflow regimes, and possibly flooding risk. Our research examines the ecohydrological processes influenced by trees that control extreme surface runoff and flooding. We are currently focused on measurement of tree xylem, soil water, and streamflow isotopic compositions at long term research watersheds to refine projections of future hydrologic conditions. We hope this research will support sustainable forest management in the NE.
Collaborators: Varsha Vijay (SESYNC), Margaret Palmer (SESYNC)
How do Social Demographics Shape Our Relationship with Flooding Risk?
Societal flooding "risk" is a complex function of hazards (high water elevations), our exposure and vulnerability to those hazards, and our resilience (how well we recover and learn from past floods). Our group is currently studying how participation in the US National Flood Insurance Program (NFIP) varies along both hydrologic (e.g. stream flashiness) and social dimensions (e.g. poverty, race, age of housing stock) in US metropolitan areas. We are coupling hydrologic datasets to models of social dynamics calibrated to open-access NFIP records. Our preliminary findings suggest that US metropolitan areas fall into two broad categories: 1) risk-averse cities with a short-term "memory" of past floods, and 2) risk-taking cities with a longer memory of flooding. The strongest determinants of these contrasting behaviors are local streamflow dynamics, poverty, and race. We hope that our research will support the development of more equitable policy for disaster mitigation and recovery programs.
Collaborators: Rebecca Elliott (London School of Economics), Kelly Hondula (SESYNC)
Designing Drought Resilient Agricultural Practices with Ecohydrological Modeling
Recent isotopic evidence suggests that water percolating through the rooting zone (to groundwater and ultimately streamflow) may be hydraulically disconnected from matrix-bound soil water (the water predominantly used by plants). Our research aims to understand the implications of these observations for nutrient fate and transport in agricultural settings, specifically when fertilizers are surface applied. Through our research we are developing sustainable agricultural practices that improve crop yields while limiting eutrophication of nearby of receiving streams, lakes, and estuaries.