Photo of Erin Hanan, Extension

Erin Hanan

Assistant Professor

Summary

I study interactions among plant, soil, and hydrologic processes in terrestrial systems. Disturbances such as wildfire, insect outbreaks, and forest clearing, play an important role in these dynamics, and in many ecosystems, disturbance events are becoming more frequent and severe in response to climate change and growing human populations. I use process-based models, remote sensing, and empirical analysis to answer questions about how climate change will affect future disturbance regimes, how these shifts will alter biogeochemical and ecohydrologic processes, and how we can mitigate the effects of climate change through management.

Education

B.S. University of Southern California, 2004
M.S. Florida International University, 2008
Ph.D. University of California, Santa Barbara, 2015

News & Journal Articles, Fact Sheets, Reports...

Journals
Simulating the role of biogeochemical hotspots in driving nitrogen export from dryland watersheds
Climate change and nitrogen (N) pollution are altering biogeochemical and ecohydrological processes in dryland watersheds, increasing N export, and threatening water quality. To better project future N export, we developed a framework for representing hotspots using the ecohydrological model RHESSys.
Ren J., Hanan E.J., Greene A., Tague C., Krichels A.H., Burke W.D., Schimel J.P., Homyak P.M. 2024, Water Resources Research, 60(3): e2023WR036008
Antecedent Snowpack Cold Content Alters the Hydrologic Response to Extreme Rain-on-Snow Events Katz, L., G. Lewis, S. Krogh, S. Drake, E. Hanan, B. Hatchett, and A. Harpold 2023, J. Hydrometeor., 24, 1825–1846
Effects of experimental nitrogen deposition on soil organic carbon storage in Southern California drylands Püspök, J. F., Zhao, S., Calma, A. D., Vourlitis, G. L., Allison, S. D., Aronson, E. L., Schimel, J. P., Hanan, E. J., & Homyak, P. M. 2023, Global Change Biology, 29(6), 1660-1679
Bark Beetle Effects on Fire Regimes Depend on Underlying Fuel Modifications in Semiarid Systems Ren, J., Hanan, E. J., Hicke, J. A., Kolden, C. A., Abatzoglou, J. T., Tague, L., Bart, R. R., Kennedy, M. C., Liu, M., & Adam, J. C. 2023, Journal of Advances in Modeling Earth Systems, 15(1), e2022MS003073
Missing Climate Feedbacks in Fire Models: Limitations and Uncertainties in Fuel Loadings and the Role of Decomposition in Fine Fuel Accumulation E.J. Hanan, M. Kennedy, J. Ren, M. Johnson, A. Smith 2022, Journal of Advances in Modeling Earth Systems, Volume14, Issue3 March 2022 e2021MS002818
Reimagine fire science for the anthropocene J. Shuman, et. al. 2022, PNAS Nexus, Volume 1, Issue 3, July 2022, pgac115
How interactions between wildfire and seasonal soil moisture fluxes drive nitrogen cycling in Northern Sierra Nevada forests M.K. Brady, E.J. Hanan, D.B. Matthew, M.R. Jessica, J. Greenberg 2022, International Journal of Wildland Fire 31(8) 786-798
Projecting Future Fire Regimes in a Semiarid Watershed of the Inland Northwestern United States: Interactions Among Climate Change, Vegetation Productivity, and Fuel Dynamics Ren J, Hanan EJ, Abatzoglou JT, Kolden CA, Tague C, Kennedy M, Liu M, Adam J 2022, Earth’s Future 10(3): e2021EF002518
Bark Beetle Effects on Fire Regimes Depend on Underlying Fuel Modifications in Semiarid Systems Ren J, Hanan EJ, Hicke JA, Abatzoglou JT, Kolden CA, Tague C, Bart R, Liu M, Adam J 2022, Journal of Advances in Modeling Earth Systems (JAMES). 15(1): e2022MS003073
How climate change and fire exclusion drive wildfire regimes at actionable scales E. J Hanan, J. Ren, C. L. Tague, et.al. 2021, Environmental Research Letters 16(2)
From burned slopes to streams: how wildfire affects nitrogen cycling and retention in forests and fire-prone watersheds. Gustine, R. N., Hanan, E. J., Robichaud, P. R., & Elliot, W. J. 2021, Biogeochemistry, 157(1), 51–68
How does water yield respond to mountain pine beetle infestation in a semiarid forest? Ren, J., Adam, J. C., Hicke, J. A., Hanan, E. J., Tague, C. L., Liu, M., … Abatzoglou, J. T. 2021, Hydrology and Earth System Sciences (HESS), 25(8), 4681–4699
Responses and recovery of a chaparral watershed following wildfire. Goodridge, B., Hanan, E., Wetherley, E., Aquilera, R., Chen, H., D'Antonio, C., Melack, J. 2018, Ecosystems, 21(8), 1608-1622
Accounting for disturbance history in models: using remote sensing to constrain carbon and nitrogen pool spin-up. Hanan EJ, Tague CL, Choate J, Liu M, Kolden C, Adam J 2018, Ecological Applications. https://doi.org/10.1002/eap.1718.
Nitrogen cycling and export in California chaparral: the role of climate in shaping ecosystem responses to fire. Hanan EJ, Tague C, Schimel JP 2017, Ecological Monographs. 87(1):76-90.
Factors regulating nitrogen retention during the early stages of recovery from fire in coastal chaparral ecosystems. Hanan EJ, D’Antonio CM, Roberts DA, Schimel JP 2016, Ecosystems 19(5): 910-926
Effects of substrate supply, pH, and char on net nitrogen mineralization and nitrification along a wildfire-structured age gradient in chaparral. Hanan EJ, Schimel JP, Dowdy K, D’Antonio CM 2016, Soil Biology and Biochemistry 95: 87-99
Multi-scaled grassland-woody plant dynamics in the heterogeneous marl prairies of the southern Everglades. Hanan EJ, Ross MS, Ruiz PL, Sah JP 2010, Ecosystems 13(8): 1256-1274
Across-scale patterning of plant-soil-water interactions surrounding tree islands in southern Everglades landscapes. Hanan EJ, Ross MS 2009, Landscape Ecology 25(3): 463-476
Lay or Popular Publications
Megafires: Climate change or land management? Hanan, E, 2020, Niskanen Center, Sept. 15, 2020
Reviews
The Changing Water Cycle: The ecohydrologic impacts of forest density reduction in Mediterranean (seasonally dry) regions. Tague CL, Moritz M, Hanan EJ 2019, WIREs Water. 6(4)