Patrick Shafroth, PhD
Patrick B. Shafroth is a Research Ecologist at the Fort Collins Science Center.
Since 1991, Dr. Shafroth has conducted research on riparian ecosystems, primarily in arid and semi-arid regions of western U.S. He and his colleagues from the USGS and other institutions have focused their work on understanding relationships between surface and ground-water hydrology, fluvial processes, and the dynamics of native and introduced riparian vegetation. This research has often been conducted in the applied context of riparian ecosystem restoration with the goal of providing solid, objective scientific information that can be used to inform riparian restoration efforts. More specific restoration-related research areas include studies of large-scale flow experiments, dam removal, effects of invasive species control and associated restoration actions, and potential interactions with climate change.
Some of Dr. Shafroth’s current research includes studies of: vegetation and geomorphic responses to experimental flow releases downstream of dams on the Bill Williams River, Arizona; the Colorado River delta in Mexico and the U.S.; and the the Colorado River in Grand Canyon; vegetation and geomorphic responses to dam removal on the Elwha River, Washington, where the world's largest dam removals occurred recently; dynamics of non-native riparian plants along western rivers, including patterns of riparian vegetation recovery associated with biological control of Tamarix.
Education and Certifications
Ph.D. in Plant Biology, Arizona State University, 1999
M.S. in Forest Ecology, Colorado State University, 1993
B.A. in Environmental Studies and Geography, University of California, Santa Barbara, 1989
Science and Products
Combined effects of biological control of an invasive shrub and fluvial processes on riparian vegetation dynamics
Effect of an environmental flow on vegetation growth and health using ground and remote sensing metrics
Short-term geomorphological and riparian vegetation responses to a 40-year flood on a braided, dryland river
Projected warming disrupts the synchrony of riparian seed dispersal and snowmelt streamflow
Conceptualizing ecological responses to dam removal: If you remove it, what's to come?
Vegetative and geomorphic complexity at tributary junctions on the Colorado and Dolores Rivers: a blueprint for riparian restoration
The role of a non-native tree in riparian vegetation expansion and channel narrowing along a dryland river
Regeneration of Salicaceae riparian forests in the Northern Hemisphere: A new framework and management tool
Divergent effects of land-use, propagule pressure, and climate on woody riparian invasion
Landscape-scale processes influence riparian plant composition along a regulated river
Riparian plant composition along hydrologic gradients in a dryland river basin and implications for a warming climate
Secondary invasions of noxious weeds associated with control of invasive Tamarix are frequent, idiosyncratic and persistent
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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Combined effects of biological control of an invasive shrub and fluvial processes on riparian vegetation dynamics
Plant community responses to biocontrol of invasive plants are understudied, despite the strong influence of the composition of replacement vegetation on ecosystem functions and services. We studied the vegetation response to a folivore beetle (Diorhabda genus, Coleoptera) that has been introduced along southwestern US river valleys to control the invasion of non-native shrubs in the genus TamarixAuthorsEduardo Gonzalez, Patrick B. Shafroth, Steven R. Lee, Steven M. Ostoja, Matthew L. BrooksEffect of an environmental flow on vegetation growth and health using ground and remote sensing metrics
Understanding the effectiveness of environmental flow deliveries along rivers requires monitoring vegetation. Monitoring data are often collected at multiple spatial scales. For riparian vegetation, optical remote sensing methods can estimate growth responses at the riparian corridor scale, and field‐based measures can quantify species composition; however, the extent to which these different measAuthorsMartha M. Gomez-Sapiens, Christopher Jarchow, Karl W. Flessa, Patrick B. Shafroth, Edward P. Glenn, Pamela L. NaglerShort-term geomorphological and riparian vegetation responses to a 40-year flood on a braided, dryland river
In December 2010, a 40-yr flood occurred in the lower Virgin River (SE Nevada, southwestern U.S.), a braided river segment with riparian vegetation largely dominated by invasive shrubs in the genus Tamarix. We assessed geomorphological and vegetation responses to this large magnitude disturbance event by comparing pre- and post-flood remote sensing and field survey data in four river reaches. AnalAuthorsEduardo Gozalez, Patrick B. Shafroth, Steven R. Lee, Glen T. Leverich, Rafael Real de Asua, Rebecca A. Sherry, Steven M. Ostoja, Bruce K. OrrProjected warming disrupts the synchrony of riparian seed dispersal and snowmelt streamflow
• Globally, spring phenology and abiotic processes are shifting earlier with warming. Differences in the magnitudes of these shifts may decouple the timing of plant resource requirements from resource availability. In riparian forests across the northern hemisphere, warming could decouple seed dispersal from snowmelt peak streamflow, thus reducing moisture and safe-sites for dominant tree recruitmAuthorsLaura G. Perry, Patrick B. Shafroth, Lauren Hay, Steven L. Markstrom, Andrew R. BockConceptualizing ecological responses to dam removal: If you remove it, what's to come?
One of the desired outcomes of dam decommissioning and removal is the recovery of aquatic and riparian ecosystems. To investigate this common objective, we synthesized information from empirical studies and ecological theory into conceptual models that depict key physical and biological links driving ecological responses to removing dams. We define models for three distinct spatial domains: upstreAuthorsJ. Ryan Bellmore, George R. Pess, Jeffrey J. Duda, Jim E. O'Connor, Amy E. East, Melissa M. Foley, Andrew C. Wilcox, Jon J. Major, Patrick B. Shafroth, Sarah A. Morley, Christopher S. Magirl, Chauncey W. Anderson, James E. Evans, Christian E. Torgersen, Laura S. CraigByEcosystems Mission Area, Coastal and Marine Hazards and Resources Program, Species Management Research Program, Arizona Water Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Geology, Minerals, Energy, and Geophysics Science Center, John Wesley Powell Center for Analysis and Synthesis, Oregon Water Science Center, Pacific Coastal and Marine Science Center, Western Fisheries Research CenterVegetative and geomorphic complexity at tributary junctions on the Colorado and Dolores Rivers: a blueprint for riparian restoration
ContextHabitat complexity in rivers is linked to dynamic fluvial conditions acting at various spatial scales. On regulated rivers in the western United States, tributaries are regions of high energy and disturbance, providing important resource inputs for riparian ecosystems.ObjectivesThis study investigated spatial patterns and extents of tributary influence on riparian habitat complexity in theAuthorsMargaret S. White, Brian G. Tavernia, Patrick B. Shafroth, Teresa B. Chapman, John S. SandersonThe role of a non-native tree in riparian vegetation expansion and channel narrowing along a dryland river
Along rivers, native and invasive species may establish and persist on active channel bedforms as part of channel narrowing. Using historical aerial photography and dendrochronology, we quantified spatial and temporal patterns of narrowing and vegetation expansion, including native Fremont cottonwood (Populus fremontii) and non‐native Russian olive (Elaeagnus angustifolia), along the largely unregAuthorsMichael L. Scott, Lindsay V. Reynolds, Patrick B. Shafroth, John R. SpencerRegeneration of Salicaceae riparian forests in the Northern Hemisphere: A new framework and management tool
Human activities on floodplains have severely disrupted the regeneration of foundation riparian shrub and tree species of the Salicaceae family (Populus and Salix spp.) throughout the Northern Hemisphere. Restoration ecologists initially tackled this problem from a terrestrial perspective that emphasized planting. More recently, floodplain restoration activities have embraced an aquatic perspectivAuthorsEduardo Gonzalez, Vanesa Martinez-Fernandez, Patrick B. Shafroth, Anna A. Sher, Annie L. Henry, Virginia Garofano-Gomez, Dov CorenblitDivergent effects of land-use, propagule pressure, and climate on woody riparian invasion
Landscape-scale analyses of biological invasion are needed to understand the relative importance of environmental drivers that vary at larger scales, such as climate, propagule pressure, resource availability, and human disturbance. One poorly understood landscape-scale question is, how does human land-use influence riparian plant invasion? To evaluate the relative importance of land-use, climate,AuthorsLaura G Perry, Lindsay V. Reynolds, Patrick B. ShafrothLandscape-scale processes influence riparian plant composition along a regulated river
Hierarchical frameworks are useful constructs when exploring landscape- and local-scale factors affecting patterns of vegetation in riparian areas. In drylands, which have steep environmental gradients and high habitat heterogeneity, landscape-scale variables, such as climate, can change rapidly along a river's course, affecting the relative influence of environmental variables at different scalesAuthorsEmily C. Palmquist, Barbara Ralston, David M. Merritt, Patrick B. ShafrothRiparian plant composition along hydrologic gradients in a dryland river basin and implications for a warming climate
Droughts in dryland regions on all continents are expected to increase in severity and duration under future climate projections. In dryland regions, it is likely that minimum streamflow will decrease with some perennial streams shifting to intermittent flow under climate-driven changes in precipitation and runoff and increases in temperature. Decreasing base flow and shifting flow regimes from peAuthorsLindsay Reynolds, Patrick B. ShafrothSecondary invasions of noxious weeds associated with control of invasive Tamarix are frequent, idiosyncratic and persistent
Control of invasive species within ecosystems may induce secondary invasions of non-target invaders replacing the first alien. We used four plant species listed as noxious by local authorities in riparian systems to discern whether 1) the severity of these secondary invasions was related to the control method applied to the first alien; and 2) which species that were secondary invaders persisted oAuthorsEduardo González, Anna A. Sher, Robert M. Anderson, Robin F. Bay, Daniel W. Bean, Gabriel J. Bissonnete, David J. Cooper, Kara Dohrenwend, Kim D. Eichhorst, Hisham El Waer, Deborah K. Kennard, Rebecca Harms-Weissinger, Annie L. Henry, Lori J. Makarick, Steven M. Ostoja, Lindsay V. Reynolds, W. Wright Robinson, Patrick B. Shafroth, Erich TabacchiNon-USGS Publications**
Shafroth, P.B., J.C. Stromberg, D.T. Patten, A.E. Springer, and J.M. Wright. 1996. Ground-water recharge and riparian habitat enhancement from water discharged from New Waddell Dam into the Agua Fria River: Phase I--Planning and feasibility. Final Report to Arizona Dept. of Water Resources - Phoenix Active Management Area. Phoenix, AZ78+ap p.Shafroth, P.B., J.M. Friedman, and L.S. Ischinger. 1994. River salinity has little influence on establishment of cottonwood and saltcedar. Research Information Bulletin 94-95. NBS Information Bulletin.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.