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
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
Humpback Chub (Gila cypha) capture history data (2009-2017), and code for mark-recapture analysis and stochastic matrix projections, Colorado River and Little Colorado River, Arizona
Water temperature models, data and code for the Colorado, Green, San Juan, Yampa, and White rivers in the Colorado River basin
Marginalizing Bayesian population models - data for examples in the Grand Canyon region, southeastern Arizona, western Oregon USA - 1990-2015
Bioeconomic model population data, Grand Canyon, Arizona, USA
Northern spotted owl data and analysis code, Cascade Range, Pacific Northwest, USA
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
Assessment of potential recovery viability for Colorado Pikeminnow Ptychocheilus lucius in the Colorado River in Grand Canyon
Insectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Vital rates of a burgeoning population of Humpback Chub in western Grand Canyon
Declines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
Proceedings of the Fiscal Year 2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program
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: 23
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
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 distinctHumpback Chub (Gila cypha) capture history data (2009-2017), and code for mark-recapture analysis and stochastic matrix projections, Colorado River and Little Colorado River, Arizona
These data represent capture histories for humpback chub (Gila cypha) that spawn in the Little Colorado River (LCR) from 2009-2017. Capture histories pertain to size class (250mm TL) and spatial location (the juvenile chub monitoring [JCM] reach in the Colorado River [63.4-65.0 river miles downstream of Lees Ferry], lower LCR [0-13.56 km upstream of Colorado River confluence], and upper LCR [13.5Water temperature models, data and code for the Colorado, Green, San Juan, Yampa, and White rivers in the Colorado River basin
These data were compiled for a manuscript in which 1) we develop a water temperature model for the major river segments and tributaries of the Colorado River basin, including the Colorado, Green, Yampa, White, and San Juan rivers; 2) we link modeled water temperature to fish population data to predict the probability native and nonnative species will be common in the future in a warming climate; aMarginalizing Bayesian population models - data for examples in the Grand Canyon region, southeastern Arizona, western Oregon USA - 1990-2015
These data were compiled here to fit various versions of Bayesian population models and compare their performance, primarily the time required to make inferences using different softwares and versions of code. The humpback chub data were collected by US Geological Survey and US Fish and Wildlife service in the Colorado and Little Colorado Rivers from April 2009 to October 2017. Adult fish were capBioeconomic model population data, Grand Canyon, Arizona, USA
These data were estimated for use in the bioecomomic model simulation of the rainbow trout population in the Colorado River in Marble Canyon. The initial rainbow trout abundance is a vector (RBT_intN) representing the population of rainbow trout within each river segment (151 mile long sergments) along the mainstem of the Colorado River from Lees Ferry to 151 river miles downstream. The movement mNorthern spotted owl data and analysis code, Cascade Range, Pacific Northwest, USA
These data were compiled to allow examination of northern spotted owl territorial occupancy dynamics, especially with regards to the roles played by habitat and competition with barred owl in past and future dynamics. Data are estimates of parameters derived from previous modelling of northern spotted owl territorial occupancy dynamics. These data were collected as part of monitoring of northern s - Multimedia
- Publications
Filter Total Items: 104
Migration 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 WiseAssessment of potential recovery viability for Colorado Pikeminnow Ptychocheilus lucius in the Colorado River in Grand Canyon
Colorado Pikeminnow Ptychocheilus lucius, the Colorado River’s top native predatory fish, was historically distributed from the Gulf of California delta to the upper reaches of the Green, Colorado, and San Juan rivers in the Colorado River basin in the Southwestern US. In recent decades Colorado Pikeminnow population abundance has declined, primarily due to predation by warmwater nonnative fish anAuthorsKimberly L. Dibble, Charles Yackulic, Kevin R. Bestgen, Keith B. Gido, Tildon Jones, Mark McKinstry, Doug Osmundson, Dale Ryden, Robert C. SchellyInsectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian insects uAuthorsAnya Metcalfe, Carol Fritzinger, Theodore J. Weller, Michael Dodrill, Jeffrey Muehlbauer, Charles Yackulic, Brandon P. Holton, Cheyenne Maxime Szydlo, Laura E. Durning, Joel B. Sankey, Theodore KennedyVital rates of a burgeoning population of Humpback Chub in western Grand Canyon
The Colorado River ecosystem has experienced habitat alterations and non-native species invasions, and as a result, many of its native species have experienced extirpations, abundance declines, and range constrictions. Despite these pitfalls, Humpback Chub, Gila cypha, have persisted and, in the last 10-15 years, expanded their range to become abundant in western Grand Canyon, a river segment in wAuthorsMaria C. Dzul, Charles Yackulic, Mariah Aurelia Giardina, David R. Van Haverbeke, Michael D. YardDeclines in prey production during the collapse of a tailwater Rainbow Trout population are associated with changing reservoir conditions
ObjectiveUnderstanding how energy moves through food webs and limits productivity at various trophic levels is a central question in aquatic ecology and can provide insight into drivers of fish population dynamics since many fish populations are food limited. In this study, we seek to better understand what factors drove a decline of >85% in the number of Rainbow TroutOncorhynchus mykiss found inAuthorsMichael D. Yard, Charles Yackulic, Josh Korman, Michael Dodrill, Bridget DeemerProceedings of the Fiscal Year 2022 Annual Reporting Meeting to the Glen Canyon Dam Adaptive Management Program
(Hartwell) This report is prepared primarily to account for work conducted and products delivered in FY 2022 by GCMRC and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the Glen Canyon Dam Adaptive Management Program (GCDAMP). It includes a summary of accomplishments, modifications to work plans, results, and recommendations related to projects iAuthorsDavid Topping, Paul Grams, Emily C. Palmquist, Joel B. Sankey, Helen C. Fairley, Bridget Deemer, Charles Yackulic, Theodore Kennedy, Anya Metcalfe, Maria C. Dzul, David Ward, Mariah Aurelia Giardina, Lucas Bair, Thomas Gushue, Caitlin M. Andrews, Ronald E. Griffiths, David Dean, Keith Kohl, Michael J Moran, Nicholas Voichick, Thomas A. Sabol, Laura A. Tennant, Kimberly Dibble, Michael C. Runge - 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