Impacts of climate and land-use/land-cover (LULC) changes on vegetation productivity
Over the past two centuries, the southeastern US region has experienced a remarkable disturbance history characterized by widespread clearcutting and then reforestation under active land management that affects both forest cover and species composition. While the potential for carbon sequestration could be further and severely impacted by climate changes, the increased frequency and intensity of extreme weather conditions create disturbances that may have very long legacy effect. This project is to examine what has been the total gain (or loss) in regional GPP/NPP attributable to management-driven reforestation and species composition shifts, and to more recent patterns of forest loss related to urbanization. This project is supported by NASA Carbon Science program from 2017 to 2020. The total amount for this grant is $919,212, with $436,669 allotted for IU. The lead-PI is Dr. Conghe Song at University of North Carolina at Chapel Hill and Dr. Kim Novick at Indiana University.
Vulnerability of freshwater resources due to climate and land-use/land-cover (LULC) changes
Human disturbances are also altering the dominant hydrologic regimes with concomitant changes in ecosystem structure and function, and regional hydrological cycles. Recent drought experience in the southeastern US indicates that even small changes drought severity and frequency will have a major impact on water supply systems. The overall hypothesis for this project is that LCLU and climate changes will have profound consequences in both carbon storage and fresh water availability in the US Southeast, particularly under extreme drought conditions. This work has been in collaboration with USDA Forest Service (Drs. James Vose and David Wear), and North Carolina State University (Dr. Katie Martin) since 2014. This project was funded by the USDA Forest Service (2014-2019) for a total of $100,000 to IU so far, serving myself as a Principal Investigator.
Impacts of invasive species on sustainability of freshwater resources
Southern Appalachian forests have experienced significant forest composition changes by invasive species over several centuries including chestnut blight, hemlock woolly adelgid (HWA; Adelges tsugae), and Princess tree (Paulownia tomentosa) etc. HWA is an invasive species that has functionally extirpated eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) from southern Appalachians to New England, and has led to near-complete mortality over the past decades in many forests. Invasive P. tomentosa seedlings have rapidly recruited and are impacting the oak-pine communities in particular, following wildfires. These invasive species may alter seasonal streamflow and stormflow regimes due to changes in leaf phenology, plant water use, and subsequent freshwater yield. This proposal was supported by NSF LTER (Long-Term Ecological Research) and Grand Challenge Initiatives This work has been in collaboration with the Dr. Crystal Schaaf at Boston University and University of Massachusetts Boston, Dr. Chelcy Miniat at USDA Forest Service, and Dr. David Orwig at Harvard Forest LTER site.