Patrick Shafroth, Ph.D.
Biography
Patrick B. Shafroth is a research ecologist with the U.S. Geological Survey, 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
- 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
USGS science supporting the Elwha River Restoration Project
The Elwha River Restoration Project...
... has reconnected the water, salmon, and sediment of a pristine river and coast of the Olympic Peninsula of Washington. Coordinated by the National Park Service, restoration of the Elwha River included the removal of two large dams that had blocked salmon and sediment passage for almost 100 years. The largest dam removal in U.S. history began in...
Ecological Drought in Riparian Ecosystems
Drought is killing riparian trees along many rivers in the western United States. The cause can be increasing temperature or decreasing precipitation, flow or water-table elevation. At multiple locations we are relating water availability to physiological measurements of tree survival and water stress, such as ring width, carbon stable isotope ratio and branch hydraulic conductivity. These...
Ecology and Management of Invasive Riparian Plants
Due to high rates of disturbance and human activity, streamside or “riparian” areas are prone to colonization and spread of invasive plants. In the western United States, hundreds of thousands of riparian acres are occupied by the invasive shrubs/trees tamarisk and Russian olive, as well as numerous exotic herbaceous plants. Our work focuses on understanding the factors driving the...
Erosion and Invasive Saltcedar
Formation of arroyos in the late 1800s greatly increased erosion across the southwestern United States. Since the 1930s, however, this erosion has decreased, partly because of bank stabilization by introduced saltcedar. With Isleta Pueblo Indian Nation, the Aquatic Systems Branch developed a new sediment dating method using saltcedar tree rings. We applied the method in a landmark study of...
Riparian Ecology
Riparian ecologists in the AS Branch study interactions among flow, channel change, and vegetation along rivers across the western United States and worldwide. Our work focuses on issues relevant to the management of water and public lands, including dam operation, climate change, invasive species, and ecological restoration. Investigations take place on a range of scales. For example,...
Riparian Vegetation Response to Dam Removal
Dam removal is an approach to river restoration that is becoming increasingly common. In most cases, dam removal is driven by considerations other than river restoration like dam safety, but how dam removal affects aquatic and riparian systems is of great interest in many dam removals. My work in this area has had two areas of focus thus far: 1) studies of vegetation and geomorphic change...
Science to Inform Riparian Ecosystem Restoration and Management
Throughout the world, riparian habitats have been dramatically modified from their natural condition. Dams, non-native species and climate change are often principal drivers of these changes, via their alteration of water and sediment regimes that determine key resources for riparian plants.
Large-scale streamflow experiments
Because the underlying cause of riparian system alteration is often attributed to the effects of dams on flow regime, managing flow releases, particularly high flows, from dams is an often-advocated approach to river and riparian restoration. Our work has focused on understanding effects of managed high flow releases (a.k.a., pulse flows, controlled floods) from dams along rivers in the lower...
Biological Invasions of Riparian Ecosystems
Beginning in the early twentieth century, non-native trees and shrubs, including tamarisk (also commonly known as saltcedar) and Russian-olive, were introduced to the United States for use as ornamental plants and in erosion-control plantings. These plants spread extensively, becoming the third and fourth most frequently occurring woody riparian plants in the American West.
Streamflow-fluvial Geomorphology-riparian Vegetation Interactions
The foundation for applying science to river and riparian restoration contexts lies in a basic understanding of the factors that drive riparian vegetation dynamics. Much of our research is focused on clarifying relationships between streamflow, fluvial geomorphology, and riparian vegetation, including various feedbacks.
Dam removal: synthesis of ecological and physical responses
Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular,...
Projecting Future Climate Effects on Cottonwood and Willow Seed Dispersal and Tree Regeneration in Western Riparian Forests
Throughout western North America, warming associated with climate change is leading to both earlier spring peak streamflows and earlier seed dispersal, potentially reducing seedling establishment and in turn reducing the quality of riparian (near-river) forests, which provide critical habitat for diverse birds, mammals, reptiles, amphibians, and insects, and food and shade for fish and other...
Ecological interfaces between land and flowing water: Themes and trends in riparian research and management
This paper provides an overview of past, present and future themes for research and management of riparian zones, often relating to papers within this Wetlands Special Feature. Riparian research expanded in the United States around 1980 with themes that recognized (1) damage from excessive livestock, or (2) damage from river damming and...
Rood, Stewart B.; Scott, Michael L; Dixon, Mark; Gonzalez, Eduardo; Marks, Christian O; Shafroth, Patrick B.; Volk, MartinRiparian plant communities remain stable in response to a second cycle of Tamarix biocontrol defoliation
Reduced abundance of non-native Tamarix shrubs in western U.S. riparian systems following biological control by a defoliating beetle has led to concerns that replacement plant communities could be dominated by other invasive species and/or not provide some of the ecosystem services that Tamarix was providing. In previous...
Eduardo Gonzalez; Shafroth, Patrick B.; Lee, Steven R.; Reed, Sasha; Belnap, JayneFlow‐ecology modelling to inform reservoir releases for riparian restoration and management
Linked hydrologic, hydraulic, and ecological models can facilitate planning and implementing water releases from reservoirs to achieve ecological objectives along rivers. We applied a flow‐ecology model, the Ecosystem Functions Model (HEC‐EFM), to the Bill Williams River in southwestern USA to estimate areas suitable for recruitment of riparian...
Hickey, John T; Shafroth, Patrick B.; Fields, Woodrow LCombined 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...
Gonzalez, Eduardo; Shafroth, Patrick B.; Lee, Steven R.; Ostoja, Steven M.; Brooks, Matthew L.Effect 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...
Gomez-Sapiens, Martha M.; Jarchow, Christopher; Flessa, Karl W.; Shafroth, Patrick B.; Glenn, Edward P.; Nagler, Pamela L.Short-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...
Gozalez, Eduardo; Shafroth, Patrick B.; Lee, Steven R.; Leverich, Glen T.; Real de Asua, Rafael; Sherry, Rebecca A.; Ostoja, Steven M.; Orr, Bruce K.Projected 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...
Perry, Laura G.; Shafroth, Patrick B.; Hay, Lauren; Markstrom, Steven L.; Bock, Andrew R.Conceptualizing 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...
Bellmore, J. Ryan; Pess, George R.; Duda, Jeffrey J.; O'Connor, Jim E.; East, Amy E.; Foley, Melissa M.; Wilcox, Andrew C.; Major, Jon J.; Shafroth, Patrick B.; Morley, Sarah A.; Magirl, Christopher S.; Anderson, Chauncey W.; Evans, James E.; Torgersen, Christian E.; Craig, Laura S.Vegetative 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...
White, Margaret S.; Tavernia, Brian G.; Shafroth, Patrick B.; Chapman, Teresa B.; Sanderson, John S.The 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...
Scott, Michael L.; Reynolds, Lindsay V.; Shafroth, Patrick B.; Spencer, John R.Regeneration 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....
Gonzalez, Eduardo; Martinez-Fernandez, Vanesa; Shafroth, Patrick B.; Sher, Anna A.; Henry, Annie L.; Garofano-Gomez, Virginia; Corenblit, DovDivergent 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...
Perry, Laura G; Reynolds, Lindsay V.; Shafroth, Patrick B.