Debra A Willard, Ph.D.
I am a palynologist (pollen and spores) with expertise in paleoecology and biostratigraphy. My biostratigraphic expertise extends from the Carboniferous to the Holocene, with an emphasis on Euramerica (Paleozoic) and the Northern Hemisphere. My paleoecological expertise includes the late Paleozoic and the Paleogene to Holocene intervals.
Editorial Boards
- Global and Planetary Change
- Frontiers in Ecology and Evolution – Paleoecology section Review Editor
- Quaternary
- Review of Palaeobotany and Palynology
Professional Experience
2021-Present Research Geologist, US Geological Survey, Reston, Virginia
2011-2021 Coordinator, USGS Land Change Science Program
1991-2011 Research Geologist, US Geological Survey, Reston, Virginia
1990-1991 Postdoctoral Researcher, National Museum of Natural History, Smithsonian Institution, Washington, DC
Education and Certifications
University of Illinois at Urbana-Champaign - Ph.D., Botany 1990
University of Illinois at Urbana-Champaign - M.S., Botany 1985
The Pennsylvania State University - B.S., Botany 1982
Stephens College - A.A., Geology 1980
Affiliations and Memberships*
American Geophysical Union
Geological Society of America
The Palynological Society
Science and Products
Filter Total Items: 105
Foreword: Wetland carbon and environmental management Foreword: Wetland carbon and environmental management
No abstract available.
Authors
Scott Covington, Debra A. Willard
Tidal erosion and upstream sediment trapping modulate records of land-use change in a formerly glaciated New England estuary Tidal erosion and upstream sediment trapping modulate records of land-use change in a formerly glaciated New England estuary
Land clearing, river impoundments, and other human modifications to the upland landscape and within estuarine systems can drive coastal change at local to regional scales. However, as compared with mid-latitude coasts, the impacts of human modifications along sediment-starved formerly glaciated coastal landscapes are relatively understudied. To address this gap, we present a late...
Authors
Justin L. Shawler, Christopher J. Hein, Elizabeth A Canuel, James M Kaste, Gregory G Fitzsimons, Ioannis Y. Georgiou, Debra A. Willard
Application of a regional climate model to assess changes in the climatology of the Eastern US and Cuba associated with historic landcover change Application of a regional climate model to assess changes in the climatology of the Eastern US and Cuba associated with historic landcover change
We examine the annual, seasonal, monthly, and diurnal climate responses to the land use change (LUC) in eastern United States and Cuba during four epochs (1650, 1850, 1920, and 1992) with ensemble simulations conducted with the RegCM4 regional climate model that includes the Biosphere Atmosphere Transfer Scheme (BATS1e) surface physics package (Dickinson et al., 1993). We derived the...
Authors
Steven W. Hostetler, R Reker, Jay R. Alder, Thomas Loveland, Debra A. Willard, Christopher E. Bernhardt, Eric T. Sundquist, Renee L. Thompson
Paleoclimate of the subtropical Andes during the latest Miocene, Lauca Basin, Chile Paleoclimate of the subtropical Andes during the latest Miocene, Lauca Basin, Chile
Uplift of the Andean Cordillera during the Miocene and Pliocene produced large-scale changes in regional atmospheric circulation that impacted local ecosystems. The Lauca Basin (northern Chilean Altiplano) contains variably fluvial and lacustrine sedimentary sequences spanning the interval from 8.7 to 2.3 Ma. Field samples were collected from paleo-lacustrine sediments in the basin...
Authors
Melina Feitl, Andrea Kern, Amanda Jones, Sherilyn Fritz, Paul E. Baker, Joeckel . R.M., Wout Salenbien, Debra A. Willard
Rapid inundation of the southern Florida coastline despite low relative sea-level rise rates during the late-Holocene Rapid inundation of the southern Florida coastline despite low relative sea-level rise rates during the late-Holocene
Sediment cores from Florida Bay, Everglades National Park were examined to determine ecosystem response to relative sea-level rise (RSLR) over the Holocene. High-resolution multiproxy analysis from four sites show freshwater wetlands transitioned to mangrove environments 4–3.6 ka, followed by estuarine environments 3.4–2.8 ka, during a period of enhanced climate variability. We calculate...
Authors
Miriam Jones, G. Lynn Wingard, Bethany Stackhouse, Katherine Keller, Debra A. Willard, Marci E. Marot, Bryan D. Landacre, Christopher E. Bernhardt
Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events
Early Eocene global climate was warmer than much of the Cenozoic and was punctuated by a series of transient warming events or ‘hyperthermals’ associated with carbon isotope excursions when temperature increased by 4–8° C. The Paleocene-Eocene Thermal Maximum (PETM, ~55 Ma) and Eocene Thermal Maximum 2 (ETM2, 53.5 Ma) hyperthermals were of short duration ( 200 kyr) and dramatically...
Authors
Debra A. Willard, Timme H Donders, Tammo Reichgelt, David R Greenwood, Francien Peterse, Francesca Sangiorgi, Appy Sluijs, Stefan Schouten
The mighty Susquehanna—extreme floods in Eastern North America during the past two millennia The mighty Susquehanna—extreme floods in Eastern North America during the past two millennia
The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high‐flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99‐2209, a sediment core recovered in 26 m of water...
Authors
Michael Toomey, Meagan Cantwell, Steven Colman, Thomas M. Cronin, Jeffrey P. Donnelly, Liviu Giosan, Clifford Heil, Robert L. Korty, Marci E. Marot, Debra A. Willard
Geographic attribution of soils using probabilistic modeling of GIS data for forensic search efforts Geographic attribution of soils using probabilistic modeling of GIS data for forensic search efforts
Examinations of soil traces associated with forensic evidence can be used to narrow potential source area(s) by characterizing features of the trace soil assemblage, some of which are limited to specific regions. Soil characteristics may be used to infer the likelihoods of the soil trace being derived from distinct areas within digital maps, including both maps of discrete classes such...
Authors
Libby A Stern, Jodi B Webb, Debra A. Willard, Christopher E. Bernhardt, David Korejwo, Maureen Bottrell, Garrett McMahon, nancy McMillan, Jared Schuetter, Patrick Wheatley, Jack Hieptas
A North American Hydroclimate Synthesis (NAHS) of the Common Era A North American Hydroclimate Synthesis (NAHS) of the Common Era
This study presents a synthesis of century-scale hydroclimate variations in North America for the Common Era (last 2000 years) using new age models of previously published multiple proxy-based paleoclimate data. This North American Hydroclimate Synthesis (NAHS) examines regional hydroclimate patterns and related environmental indicators, including vegetation, lake water elevation, stream...
Authors
Jessica R. Rodysill, Lesleigh Anderson, Thomas M. Cronin, Miriam C. Jones, Robert S. Thompson, David B. Wahl, Debra A. Willard, Jason A. Addison, Jay R. Alder, Katherine H. Anderson, Lysanna Anderson, John A. Barron, Christopher E. Bernhardt, Steven W. Hostetler, Natalie M. Kehrwald, Nicole Khan, Julie N. Richey, Scott W. Starratt, Laura E. Strickland, Michael Toomey, Claire C. Treat, G. Lynn Wingard
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Florence Bascom Geoscience Center, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center, St. Petersburg Coastal and Marine Science Center
The ACER pollen and charcoal database: A global resource to document vegetation and fire response to abrupt climate changes during the last glacial period The ACER pollen and charcoal database: A global resource to document vegetation and fire response to abrupt climate changes during the last glacial period
Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were
Authors
M.F. Sanchez-Goni, S. Desprat, A.-L. Daniau, F. Bassinot, J.M. Polanco-Martinez, S.P. Harrison, J.R.M. Allen, R. S. Anderson, H. Behling, R. Bonnefille, F. Burjachs, J.S. Carrion, R. Cheddadi, J.S. Clark, N. Combourieu-Nebout, C.J. Courtney Mustaphi, G.H. Debusk, L. Dupont, J. Finch, W.J. Fletcher, M. Giardini, C. González, W.D. Gosling, L.D. Grigg, E.C. Grimm, R. Hayashi, K. Helmens, Heusser. L.E., T. Hill, G. Hope, B. Huntley, Y. Igarashi, T. Irino, B. F. Jacobs, G. Jiménez-Moreno, S. Kawai, P. Kershaw, F. Kumon, I. Lawson, M.-P. Ledru, A.-M. Lézine, P.-M. Liew, D. Magri, R. Marchant, V. Margari, F. Mayle, M. McKenzie, P. Moss, U.C. Muller, F. Naughton, R.M. Newnham, T. Oba, R. Perez-Obiol, R. Pini, C. Ravazzi, K.H. Roucoux, S. Rucina, L. Scott, H. Takahara, P.C. Tzedakis, D.H. Urrego, Debra A. Willard, B. Van Geel, B.G. Valencia, M.J. Vandergoes, A. Vincens, C.L. Whitlock, Debra A. Willard, M. Yamamoto
Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA
The Paleocene-Eocene Thermal Maximum (PETM) was an interval of extreme warmth that caused disruption of marine and terrestrial ecosystems on a global scale. Here we examine the sediments, flora, and fauna from an expanded section at Mattawoman Creek-Billingsley Road (MCBR) in Maryland and explore the impact of warming at a nearshore shallow marine (30–100 m water depth) site in the...
Authors
Jean Self-Trail, Marci M. Robinson, Timothy J. Bralower, Jocelyn A. Sessa, Elizabeth A. Hajek, Lee R. Kump, Sheila M. Trampush, Debra A. Willard, Lucy E. Edwards, David S. Powars, Gregory A. Wandless
Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics
This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate...
Authors
P.A. Baker, S.C. Fritz, C.G. Silva, C.A. Rigsby, M.L. Absy, R.P. Almeida, Maria C. Caputo, C.M. Chiessi, F.W. Cruz, C.W. Dick, S.J. Feakins, J. Figueiredo, K.H. Freeman, C. Hoorn, C.A. Jaramillo, A. Kern, E.M. Latrubesse, M.P. Ledru, A. Marzoli, A. Myrbo, A. Noren, W.E. Piller, M.I.F. Ramos, C.C. Ribas, R. Trinadade, A.J. West, I. Wahnfried, Debra A. Willard
Science and Products
Filter Total Items: 105
Foreword: Wetland carbon and environmental management Foreword: Wetland carbon and environmental management
No abstract available.
Authors
Scott Covington, Debra A. Willard
Tidal erosion and upstream sediment trapping modulate records of land-use change in a formerly glaciated New England estuary Tidal erosion and upstream sediment trapping modulate records of land-use change in a formerly glaciated New England estuary
Land clearing, river impoundments, and other human modifications to the upland landscape and within estuarine systems can drive coastal change at local to regional scales. However, as compared with mid-latitude coasts, the impacts of human modifications along sediment-starved formerly glaciated coastal landscapes are relatively understudied. To address this gap, we present a late...
Authors
Justin L. Shawler, Christopher J. Hein, Elizabeth A Canuel, James M Kaste, Gregory G Fitzsimons, Ioannis Y. Georgiou, Debra A. Willard
Application of a regional climate model to assess changes in the climatology of the Eastern US and Cuba associated with historic landcover change Application of a regional climate model to assess changes in the climatology of the Eastern US and Cuba associated with historic landcover change
We examine the annual, seasonal, monthly, and diurnal climate responses to the land use change (LUC) in eastern United States and Cuba during four epochs (1650, 1850, 1920, and 1992) with ensemble simulations conducted with the RegCM4 regional climate model that includes the Biosphere Atmosphere Transfer Scheme (BATS1e) surface physics package (Dickinson et al., 1993). We derived the...
Authors
Steven W. Hostetler, R Reker, Jay R. Alder, Thomas Loveland, Debra A. Willard, Christopher E. Bernhardt, Eric T. Sundquist, Renee L. Thompson
Paleoclimate of the subtropical Andes during the latest Miocene, Lauca Basin, Chile Paleoclimate of the subtropical Andes during the latest Miocene, Lauca Basin, Chile
Uplift of the Andean Cordillera during the Miocene and Pliocene produced large-scale changes in regional atmospheric circulation that impacted local ecosystems. The Lauca Basin (northern Chilean Altiplano) contains variably fluvial and lacustrine sedimentary sequences spanning the interval from 8.7 to 2.3 Ma. Field samples were collected from paleo-lacustrine sediments in the basin...
Authors
Melina Feitl, Andrea Kern, Amanda Jones, Sherilyn Fritz, Paul E. Baker, Joeckel . R.M., Wout Salenbien, Debra A. Willard
Rapid inundation of the southern Florida coastline despite low relative sea-level rise rates during the late-Holocene Rapid inundation of the southern Florida coastline despite low relative sea-level rise rates during the late-Holocene
Sediment cores from Florida Bay, Everglades National Park were examined to determine ecosystem response to relative sea-level rise (RSLR) over the Holocene. High-resolution multiproxy analysis from four sites show freshwater wetlands transitioned to mangrove environments 4–3.6 ka, followed by estuarine environments 3.4–2.8 ka, during a period of enhanced climate variability. We calculate...
Authors
Miriam Jones, G. Lynn Wingard, Bethany Stackhouse, Katherine Keller, Debra A. Willard, Marci E. Marot, Bryan D. Landacre, Christopher E. Bernhardt
Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events Arctic vegetation, temperature, and hydrology during Early Eocene transient global warming events
Early Eocene global climate was warmer than much of the Cenozoic and was punctuated by a series of transient warming events or ‘hyperthermals’ associated with carbon isotope excursions when temperature increased by 4–8° C. The Paleocene-Eocene Thermal Maximum (PETM, ~55 Ma) and Eocene Thermal Maximum 2 (ETM2, 53.5 Ma) hyperthermals were of short duration ( 200 kyr) and dramatically...
Authors
Debra A. Willard, Timme H Donders, Tammo Reichgelt, David R Greenwood, Francien Peterse, Francesca Sangiorgi, Appy Sluijs, Stefan Schouten
The mighty Susquehanna—extreme floods in Eastern North America during the past two millennia The mighty Susquehanna—extreme floods in Eastern North America during the past two millennia
The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high‐flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99‐2209, a sediment core recovered in 26 m of water...
Authors
Michael Toomey, Meagan Cantwell, Steven Colman, Thomas M. Cronin, Jeffrey P. Donnelly, Liviu Giosan, Clifford Heil, Robert L. Korty, Marci E. Marot, Debra A. Willard
Geographic attribution of soils using probabilistic modeling of GIS data for forensic search efforts Geographic attribution of soils using probabilistic modeling of GIS data for forensic search efforts
Examinations of soil traces associated with forensic evidence can be used to narrow potential source area(s) by characterizing features of the trace soil assemblage, some of which are limited to specific regions. Soil characteristics may be used to infer the likelihoods of the soil trace being derived from distinct areas within digital maps, including both maps of discrete classes such...
Authors
Libby A Stern, Jodi B Webb, Debra A. Willard, Christopher E. Bernhardt, David Korejwo, Maureen Bottrell, Garrett McMahon, nancy McMillan, Jared Schuetter, Patrick Wheatley, Jack Hieptas
A North American Hydroclimate Synthesis (NAHS) of the Common Era A North American Hydroclimate Synthesis (NAHS) of the Common Era
This study presents a synthesis of century-scale hydroclimate variations in North America for the Common Era (last 2000 years) using new age models of previously published multiple proxy-based paleoclimate data. This North American Hydroclimate Synthesis (NAHS) examines regional hydroclimate patterns and related environmental indicators, including vegetation, lake water elevation, stream...
Authors
Jessica R. Rodysill, Lesleigh Anderson, Thomas M. Cronin, Miriam C. Jones, Robert S. Thompson, David B. Wahl, Debra A. Willard, Jason A. Addison, Jay R. Alder, Katherine H. Anderson, Lysanna Anderson, John A. Barron, Christopher E. Bernhardt, Steven W. Hostetler, Natalie M. Kehrwald, Nicole Khan, Julie N. Richey, Scott W. Starratt, Laura E. Strickland, Michael Toomey, Claire C. Treat, G. Lynn Wingard
By
Water Resources Mission Area, Ecosystems Land Change Science Program, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Florence Bascom Geoscience Center, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center, St. Petersburg Coastal and Marine Science Center
The ACER pollen and charcoal database: A global resource to document vegetation and fire response to abrupt climate changes during the last glacial period The ACER pollen and charcoal database: A global resource to document vegetation and fire response to abrupt climate changes during the last glacial period
Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were
Authors
M.F. Sanchez-Goni, S. Desprat, A.-L. Daniau, F. Bassinot, J.M. Polanco-Martinez, S.P. Harrison, J.R.M. Allen, R. S. Anderson, H. Behling, R. Bonnefille, F. Burjachs, J.S. Carrion, R. Cheddadi, J.S. Clark, N. Combourieu-Nebout, C.J. Courtney Mustaphi, G.H. Debusk, L. Dupont, J. Finch, W.J. Fletcher, M. Giardini, C. González, W.D. Gosling, L.D. Grigg, E.C. Grimm, R. Hayashi, K. Helmens, Heusser. L.E., T. Hill, G. Hope, B. Huntley, Y. Igarashi, T. Irino, B. F. Jacobs, G. Jiménez-Moreno, S. Kawai, P. Kershaw, F. Kumon, I. Lawson, M.-P. Ledru, A.-M. Lézine, P.-M. Liew, D. Magri, R. Marchant, V. Margari, F. Mayle, M. McKenzie, P. Moss, U.C. Muller, F. Naughton, R.M. Newnham, T. Oba, R. Perez-Obiol, R. Pini, C. Ravazzi, K.H. Roucoux, S. Rucina, L. Scott, H. Takahara, P.C. Tzedakis, D.H. Urrego, Debra A. Willard, B. Van Geel, B.G. Valencia, M.J. Vandergoes, A. Vincens, C.L. Whitlock, Debra A. Willard, M. Yamamoto
Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA Shallow marine response to global climate change during the Paleocene-Eocene Thermal Maximum, Salisbury Embayment, USA
The Paleocene-Eocene Thermal Maximum (PETM) was an interval of extreme warmth that caused disruption of marine and terrestrial ecosystems on a global scale. Here we examine the sediments, flora, and fauna from an expanded section at Mattawoman Creek-Billingsley Road (MCBR) in Maryland and explore the impact of warming at a nearshore shallow marine (30–100 m water depth) site in the...
Authors
Jean Self-Trail, Marci M. Robinson, Timothy J. Bralower, Jocelyn A. Sessa, Elizabeth A. Hajek, Lee R. Kump, Sheila M. Trampush, Debra A. Willard, Lucy E. Edwards, David S. Powars, Gregory A. Wandless
Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics Trans-Amazon Drilling Project (TADP): origins and evolution of the forests, climate, and hydrology of the South American tropics
This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate...
Authors
P.A. Baker, S.C. Fritz, C.G. Silva, C.A. Rigsby, M.L. Absy, R.P. Almeida, Maria C. Caputo, C.M. Chiessi, F.W. Cruz, C.W. Dick, S.J. Feakins, J. Figueiredo, K.H. Freeman, C. Hoorn, C.A. Jaramillo, A. Kern, E.M. Latrubesse, M.P. Ledru, A. Marzoli, A. Myrbo, A. Noren, W.E. Piller, M.I.F. Ramos, C.C. Ribas, R. Trinadade, A.J. West, I. Wahnfried, Debra A. Willard
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government