A school of humpback chub swimming in Havasu Creek, Grand Canyon. Photo by David Herasimtschuk, Freshwaters Illustrated, paid for and used with permission by USGS Southwest Biological Science Center.
Charles B Yackulic, Ph.D.
Charles Yackulic is a research statistician with the Southwest Biological Science Center.
Dr. Yackulic's research primarily focuses on developing and fitting statistical models that integrate multiple data sources, link environmental drivers and management actions to population and ecosystem processes, and can be used to make near and long-term forecasting of system dynamics under different management alternatives. Areas of particular interest include species distribution dynamics, population dynamics, interspecific interactions, animal movement, food web dynamics and river metabolism.
Professional Experience
2011-present: Research Statistician, USGS Southwest Biological Science Center, Flagstaff, AZ
2010-2011: National Science Foundation (NSF) postdoc in Bioinformatics, USGS Patuxent Wildlife Research Center, MD
2009-2010: Postdoctoral Researcher, Columbia University, NY
Education and Certifications
2009 - Ph.D. in Ecology and Evolutionary Biology, Columbia University, NY
2003 - MSc. in Environmental Change and Management, Oxford University, UK
2001 - B.A. in Biology (major) and Math (minor), Columbia University, NY
Science and Products
Smallmouth bass expansion downstream of Glen Canyon Dam
Population Dynamics of Threatened Humpback Chub in Grand Canyon
The Impacts of Climate Change and Water Supply Management on Fish in the Colorado River
Rainbow Trout Abundance and Movement in the Colorado River in Grand Canyon
Uncovering the Base of the Food Web: Primary Production Dynamics in the Colorado River
Understanding Factors Influencing Rainbow Trout Growth in the Colorado River
Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry
Forecasting smallmouth bass invasion under different management scenarios for Lake Powell releases, 2024-2027
Dissolved oxygen predictions for releases from Lake Powell under different management scenarios for Lake Powell releases
Predicted hydropower impacts of different management scenarios for Lake Powell releases
Modelled Lake Powell releases and reservoir elevations under different alternative management scenarios
Various Lake Powell data used for predicting smallmouth bass entrainment rates and population growth based on thermal suitability below and downstream of Glen Canyon Dam
Discharge and water temperature data, Lake Powell thermal profiles, and Annual Thermal Units used to assess reintroduction feasibility of Colorado pikeminnow (Ptychocheilus lucius) in the Colorado River in Grand Canyon
Mark-recapture and environmental data used to predict flannelmouth sucker (Catostomous latippinis) growth rates within the Colorado River in the Grand Canyon from April 2012 to October 2018
Humpback chub (Gila cypha) capture histories and growth data for two areas in the Colorado River network from 2009-2022 and 2017-2022
Brown trout movement data in Glen and Grand Canyons, Arizona, USA
Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
Rainbow trout diet and invertebrate drift data from 2012-2015 for the Colorado River, Grand Canyon, Arizona
A school of humpback chub swimming in Havasu Creek, Grand Canyon. Photo by David Herasimtschuk, Freshwaters Illustrated, paid for and used with permission by USGS Southwest Biological Science Center.
Modeling the impacts of Glen Canyon Dam operations on Colorado River resources
Fishes move to transient local refuges, not persistent landscape refuges during river drying experiment
Utilizing artificial nesting platforms as a management tool: Enhancing breeding productivity of Western Flycatchers (Empidonax difficilis occidentalis) in southwestern Colorado and southern Arizona, USA
U.S. Geological Survey Grand Canyon Monitoring and Research Center: Proceedings of the fiscal year 2023 annual reporting meeting to the Glen Canyon Dam Adaptive Management Program
Range-wide trends in tiger conservation landscapes, 2001 - 2020
Migration timing and tributary use of spawning flannelmouth sucker (Catostomus latipinnis)
Genetic erosion in an endangered desert fish during a multidecadal megadrought despite long-term supportive breeding
Storms and pH of dam releases affect downstream phosphorus cycling in an arid regulated river
Models of underlying autotrophic biomass dynamics fit to daily river ecosystem productivity estimates improve understanding of ecosystem disturbance and resilience
The Colorado River water crisis: Its origin and the future
Linking ecosystem processes to consumer growth rates: Gross primary productivity as a driver of freshwater fish somatic growth in a resource-limited river
Estimating northern spotted owl (Strix occidentalis caurina) pair detection probabilities based on call-back surveys associated with long-term mark-recapture studies, 1993–2018
Colorado River Basin Projects
The Colorado River Basin Actionable and Strategic Integrated Science and Technology Team has created an interactive map of USGS projects to highlight the integrated science currently conducted within the Colorado River Basin. These projects are not all inclusive of the work conducted by the USGS within the CRB, but highlight the broad range of integrated science currently conducted.
Science and Products
- Science
Smallmouth bass expansion downstream of Glen Canyon Dam
In the Upper Colorado River Basin, smallmouth bass ( Micropterus dolomieu ) are considered the greatest threat to native fishes and have been linked to declines in federally protected humpback chub ( Gila cypha ), including one population that was rapidly extirpated in the past. Long-term management efforts have been underway to remove smallmouth bass from rivers in the Upper Basin, but smallmouth...Population Dynamics of Threatened Humpback Chub in Grand Canyon
The federally-listed threatened humpback chub is a native fish of the Colorado River. Despite the environmental changes to the river following the construction of Glen Canyon Dam, humpback chub persists alongside nonnative species, including rainbow trout. The pre-dam Colorado River experienced seasonal variation in temperature and discharge. Seasonal flooding resulted in sediments carried...The Impacts of Climate Change and Water Supply Management on Fish in the Colorado River
The Colorado River and its major tributaries provide a crucial water supply for more than 40 million people in the American Southwest and in California. This water supply is primarily used in irrigated agriculture but also provides essential drinking water to many large metropolitan areas. Hydropower is also produced at many of the large dams on the river. River flows have declined during the pastRainbow Trout Abundance and Movement in the Colorado River in Grand Canyon
Just below Glen Canyon Dam on the Colorado River is a very popular Blue Ribbon trout fishery known for its rainbow trout. However, approximately 78 miles downstream, near were the Little Colorado River flows into the Colorado River, is a population of endangered humpback chub. The introduced rainbow trout can negatively affect native humpback chub by competing with them for food (immature black...Uncovering the Base of the Food Web: Primary Production Dynamics in the Colorado River
Algae, phytoplankton, and rooted macrophytes represent the base of many aquatic food webs and are known as primary producers. Through photosynthesis, these organisms convert sunlight energy into chemical energy (i.e., carbon) that in turn fuels the growth of animals such as macroinvertebrates and fish. This project uses high frequency measurements of dissolved oxygen, which is a by-product of...Understanding Factors Influencing Rainbow Trout Growth in the Colorado River
Rainbow trout is a desirable sport fish that has been introduced in many locations around the world. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying management options that allow rainbow...Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry
Streams and rivers have a limited spatial extent, but are increasingly recognized as key components of regional biogeochemical cycles. The collective metabolic processing of organisms, known as ecosystem metabolism, is centrally important to nutrient cycling and carbon fluxes in these environments, but is poorly integrated into emerging biogeochemical concepts. This line of inquiry lags behind oth - Data
Filter Total Items: 29
Forecasting smallmouth bass invasion under different management scenarios for Lake Powell releases, 2024-2027
These data were compiled for modeling efforts of Bureau of Reclamation National Environmental Policy Act (NEPA) analyses for the Colorado River in Grand Canyon, Arizona. Objective(s) of our study were to forecast water temperature, smallmouth bass population growth rate, and smallmouth bass entrainment rates under different water management scenarios. These data represent forecasted smallmouth basDissolved oxygen predictions for releases from Lake Powell under different management scenarios for Lake Powell releases
Dissolved oxygen estimates were generated to help understand how different alternative management scenarios may affect the likelihood of low dissolved oxygen in Glen Canyon Dam releases. The study aimed to examine the effects of different management alternatives on late summer and early fall dissolved oxygen concentrations in Glen Canyon Dam releases. The estimates represent estimates of dissolvedPredicted hydropower impacts of different management scenarios for Lake Powell releases
These data were compiled to predict hourly Glen Canyon Dam operations and hydropower impacts. The objective of our study was to estimate hydropower impacts under different future LTEMP sEIS alternatives. These data represent hourly outflow in cubic feet per second, generation in megawatt hours, and economic value of hydropower in nominal dollars. These data were created for operations at Glen CanyModelled Lake Powell releases and reservoir elevations under different alternative management scenarios
These data were compiled for/to modeling efforts for U.S. Bureau of Reclamation National Environmental Policy Act (NEPA) analyses for the Colorado River in Grand Canyon, Arizona. Objective(s) of our study were to create revised monthly Lake Powell elevations and outflows from Bureau of Reclamation Colorado River Mid-term Modeling System (CRMMS) traces that incorporate the alternatives in the sEISVarious Lake Powell data used for predicting smallmouth bass entrainment rates and population growth based on thermal suitability below and downstream of Glen Canyon Dam
These data were compiled to create models that estimate entrainment rates and population growth rates of smallmouth bass below Glen Canyon Dam. Objective(s) of our study were to predict smallmouth bass entrainment rates and population growth under different future scenarios of Lake Powell elevations and management. These data represent parameters needed for associated models and data needed to proDischarge and water temperature data, Lake Powell thermal profiles, and Annual Thermal Units used to assess reintroduction feasibility of Colorado pikeminnow (Ptychocheilus lucius) in the Colorado River in Grand Canyon
These data were compiled to assess the physical attributes of the Colorado River and its tributaries in Grand Canyon, including discharge, water temperature, Annual Thermal Units, and the potential future thermal regime of the river due to climate change. The objective of our study was to assess whether this river reach could support various life stages of Colorado pikeminnow (Ptychocheilus luciusMark-recapture and environmental data used to predict flannelmouth sucker (Catostomous latippinis) growth rates within the Colorado River in the Grand Canyon from April 2012 to October 2018
These data were compiled to fit Bayesian state-space growth in length models to estimate the environmental variables that influence flannelmouth sucker growth rates in the Grand Canyon. Objective(s) of our study were to quantify monthly intervals of growth of flannelmouth suckers in four river reaches, and test if novel high frequency gross primary productivity data would be a significant predictoHumpback chub (Gila cypha) capture histories and growth data for two areas in the Colorado River network from 2009-2022 and 2017-2022
These data were compiled for a manuscript entitled 'Vital rates of a burgeoning population of Humpback Chub in western Grand Canyon. Objective(s) of our study were to compare survival and growth of humpback chub in western Grand Canyon to that from the more established metapopulation in eastern Grand Canyon that spawns in the Little Colorado River (LCR). These data represent capture histories of fBrown trout movement data in Glen and Grand Canyons, Arizona, USA
These data were compiled to test hypotheses regarding drivers of movement of brown trout. Objectives of our study were to test whether the degree of movement varied in response to placement of a weir in Bright Angel Creek, fall timed flooding events, or simply seasonal changes. These data represent summarized capture histories of brown trout in terms of states based on physical locations, data onProximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona.
Using a bioenergetic model, demographic data for the Rainbow Trout (Oncorhynchus mykiss) population were compiled and used to estimate total prey consumption in the Colorado River, Glen Canyon , AZ. Additionally, other data including invertebrate diet, drift, and benthic measurements were used to make generalized estimates of daily production rates for the most common benthic invertebrate taxa. ThGross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam
These data were compiled to model the effects of flow regime and bed grain size distributions on rates of gross primary production (GPP) in the Colorado River below Glen Canyon Dam, AZ, USA. The objectives of our study were to quantify daily and weekly scale effects of an experimental flow regime on GPP in the Colorado River. The experimental flow was conducted at Glen Canyon Dam from May-August iRainbow trout diet and invertebrate drift data from 2012-2015 for the Colorado River, Grand Canyon, Arizona
These data were compiled to explore the foraging ecology of Rainbow Trout (Oncorhynchus mykiss) in the Colorado River, Grand Canyon, Arizona. These data represent samples characterizing the availability of drifting invertebrate prey (hereafter, drift) and use of these invertebrate prey by rainbow trout determined by gut samples (hereafter, diets). Drift and diet sampling occurred in five distinct - Multimedia
A school of humpback chub swimming in Havasu Creek, Grand CanyonA school of humpback chub swimming in Havasu Creek, Grand Canyon
A school of humpback chub swimming in Havasu Creek, Grand Canyon. Photo by David Herasimtschuk, Freshwaters Illustrated, paid for and used with permission by USGS Southwest Biological Science Center.
A school of humpback chub swimming in Havasu Creek, Grand Canyon. Photo by David Herasimtschuk, Freshwaters Illustrated, paid for and used with permission by USGS Southwest Biological Science Center.
- Publications
Filter Total Items: 109
Modeling the impacts of Glen Canyon Dam operations on Colorado River resources
At the time of this report, the Bureau of Reclamation (Reclamation) is writing two supplemental Environmental Impact Statements (sEIS ) and a new Environmental Impact Statement (EIS) that will analyze the effects of changing water flow out of Glen Canyon Dam (GCD) (U.S. Department of Interior, 2024). These actions have the potential to affect downstream resources, including threatened and endangerAuthorsCharles Yackulic, Lucas Bair, Drew Elliot Eppehimer, Gerard Lewis Salter, Bridget Deemer, Bradley J. Butterfield, Alan Kasprak, Joshua Caster, Helen C. Fairley, Paul Grams, Bryce Anthony Mihalevich, Emily C. Palmquist, Joel B. SankeyFishes move to transient local refuges, not persistent landscape refuges during river drying experiment
Anthropogenically driven flow intermittency is increasing in freshwater streams, with important implications for the management and conservation of aquatic ecosystems. Because most freshwater fishes are mobile, they are expected to emigrate from intermittent reaches, but this may not be true in streams transitioning from perennial to intermittent. Here, we attempt to determine if riverine fishes vAuthorsThomas P Archdeacon, Eric J. Gonzales, Charles YackulicUtilizing artificial nesting platforms as a management tool: Enhancing breeding productivity of Western Flycatchers (Empidonax difficilis occidentalis) in southwestern Colorado and southern Arizona, USA
Artificial nesting substrates have been added around the world for many cavity-nesting bird species, but this has not been undertaken as extensively for crevice-nesting birds. The Western Cordilleran Flycatcher (Empidonax difficilis occidentalis) is a migratory, crevice-nesting flycatcher that is nest-site limited, breeding in higher elevation riparian habitats throughout intermountain western NorAuthorsCharles van Riper, Harold F. Greeney, Abigail J. Darrah, Andrew J. Boyce, Drew F. van Riper, Charles YackulicU.S. Geological Survey Grand Canyon Monitoring and Research Center: Proceedings of the fiscal year 2023 annual reporting meeting to the Glen Canyon Dam Adaptive Management Program
This proceedings is prepared for the USBR and Glen Canyon Dam Adaptive Management Program (GCDAMP) to account for work conducted and products delivered in FY 2023 by SBSC's Grand Canyon Monitoring and Research Center (GCMRC) and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the GCDAMP. It includes a summary of accomplishments, modifications to wAuthorsAndrew Alan Schultz, Gregory Mark Anderson, David Topping, Ronald E. Griffiths, David Dean, Paul Grams, Keith Kohl, Gerard Lewis Salter, Matthew A. Kaplinski, Katherine Chapman, Erich R. Mueller, Emily C. Palmquist, Bradley J. Butterfield, Joel B. Sankey, Bridget Deemer, Charles Yackulic, Lindsay Erika Hansen, Drew Elliot Eppehimer, Theodore Kennedy, Anya Metcalfe, Jeffrey Muehlbauer, Morgan Ford, Michael Dodrill, Maria C. Dzul, Pilar Rinker, Michael J. Pillow, David Ward, Josh Korman, Molly A.H. Webb, James A. Crossman, Eric J Frye, David L. Rogowski, Kimberley Dibble, Lucas Bair, Joshua Abbott, Thomas Gushue, Erica Paige Byerley, Joseph E Thomas, Thomas A. Sabol, Bryce Anthony MihalevichRange-wide trends in tiger conservation landscapes, 2001 - 2020
Of all the ways human beings have modified the planet over the last 10,000 years, habitat loss is the most important for other species. To address this most critical threat to biodiversity, governments, non-governmental actors, and the public need to know, in near real-time, where and when habitat loss is occurring. Here we present an integrated habitat modelling system at the range-wide scale forAuthorsEric W. Sanderson, Dale G. Miquelle, Kim Fisher, Abishek Harihar, Chris Clark, Jesse Moy, Peter V. Potapov, Nathaniel P. Robinson, Lucinda Royte, Dustin Sampson, Jamie S Sanderlin, Charles Yackulic, Michael Belecky, Urs Breitenmoser, Christine Breitenmoser-Würsten, Pranav Chanchani, Stuart Chapman, Arpit Deomurari, Somphot Duangchantrasiri, Elisa Facchini, Thomas N.E. Gray, John Goodrich, Luke Hunter, Matthew Linkie, Willy Marthy, Akchousanh Rasphone, Sogoto Roy, Detrit Sittibal, Tshering Tempa, Mayuree Umponjan, Karen WoodMigration timing and tributary use of spawning flannelmouth sucker (Catostomus latipinnis)
Spawning phenology and associated migrations of fishes are often regulated by factors such as temperature and stream discharge, but flow regulation of mainstem rivers coupled with climate change might disrupt these cues and affect fitness. Flannelmouth sucker (Catostomus latipinnis) persisting in heavily modified river networks are known to spawn in tributaries that might provide better spawning hAuthorsSophia M. Bonjour, Keith B. Gido, Mark C. McKinstry, Charles N. Cathcart, Matthew R. Bogaard, Maria C. Dzul, Brian Daniel Healy, Zachary E. Hooley-Underwood, David L. Rogowski, Charles YackulicGenetic erosion in an endangered desert fish during a multidecadal megadrought despite long-term supportive breeding
Human water use combined with a recent megadrought have reduced river and stream flow through the Southwestern United States and led to periodic drying of formerly perennial river segments. Reductions in snowmelt runoff and increased extent of drying collectively threaten short-lived, obligate aquatic species, including the endangered Rio Grande silvery minnow. This species experiences ‘boom-and-bAuthorsMegan J. Osborne, Thomas P. Archdeacon, Charles Yackulic, Robert K. Dudley, Guilherme Caeiro-Dias, Thomas F. TurnerStorms and pH of dam releases affect downstream phosphorus cycling in an arid regulated river
Reservoirs often bury phosphorus (P), leading to seasonal or persistent reductions in P supply to downstream rivers. Here we ask if observed variation in the chemistry of dam release waters stimulates downstream sediment P release and biological activity in an arid, oligotrophic system, the Colorado River below Lake Powell, Arizona, USA. We use bottle incubations to simulate a range of observed pHAuthorsBridget Deemer, Robin H. Reibold, Anna Fatta, Jessica R. Corman, Charles Yackulic, Sasha C. ReedModels of underlying autotrophic biomass dynamics fit to daily river ecosystem productivity estimates improve understanding of ecosystem disturbance and resilience
Directly observing autotrophic biomass at ecologically relevant frequencies is difficult in many ecosystems, hampering our ability to predict productivity through time. Since disturbances can impart distinct reductions in river productivity through time by modifying underlying standing stocks of biomass, mechanistic models fit to productivity time series can infer underlying biomass dynamics. We iAuthorsJoanna R. Blaszczak, Charles Yackulic, Robert K. Shriver, Jr. HallThe Colorado River water crisis: Its origin and the future
During much of the 21st century, natural runoff in the Colorado River basin has declined, while consumption has remained relatively constant, leading to historically low reservoir storage. Between January 2000 and April 2023, the amount of water stored in Lake Mead and Lake Powell, the two largest reservoirs in the United States, declined by 33.5 million acre feet (41.3 billion cubic meters). As oAuthorsJohn C. Schmidt, Charles Yackulic, Eric KuhnLinking ecosystem processes to consumer growth rates: Gross primary productivity as a driver of freshwater fish somatic growth in a resource-limited river
Individual growth can exert strong controls on population dynamics and be constrained by resource acquisition rates. Difficulty in accurately quantifying resource availability over large spatial extents and at high temporal frequency often limits attempts to understand the extent that resources limit individual growth. Daily estimates of stream metabolism, including gross primary productivity (GPPAuthorsLindsay Erika Hansen, Charles Yackulic, Brett G. Dickson, Bridget Deemer, Rebecca J. BestEstimating northern spotted owl (Strix occidentalis caurina) pair detection probabilities based on call-back surveys associated with long-term mark-recapture studies, 1993–2018
The northern spotted owl (Strix occidentalis caurina; hereinafter NSO) was listed as “threatened” under the Endangered Species Act in 1990 and population declines have continued since that listing. Given the species’ protected status, any proposed activities on Federal lands that might impact NSO require consultation with U.S. Fish and Wildlife Service and part of that consultation often includesAuthorsKatie M. Dugger, Alan B. Franklin, Damon B. Lesmeister, Raymond J. Davis, J. David Wiens, Gary C. White, James D. Nichols, James E. Hines, Charles B. Yackulic, Carl J. Schwarz, Steven H. Ackers, L. Steven Andrews, Larissa L. Bailey, Robin Bown, Jesse Burgher, Kenneth P. Burnham, Peter C. Carlson, Tara Chestnut, Mary M Conner, Krista E. Dilione, Eric D. Forsman, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, Julianna M Jenkins, William L. Kendall, David W Lamphear, Christopher McCafferty, Trent L. McDonald, Janice A Reid, Jeremy T. Rockweit, David C. Simon, Stan G Sovern, James K. Swingle, Heather Wise - Web Tools
Colorado River Basin Projects
The Colorado River Basin Actionable and Strategic Integrated Science and Technology Team has created an interactive map of USGS projects to highlight the integrated science currently conducted within the Colorado River Basin. These projects are not all inclusive of the work conducted by the USGS within the CRB, but highlight the broad range of integrated science currently conducted.
- News