Charles Yackulic
Science and Products
Rainbow 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...
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...
Population Dynamics of Endangered Humpback Chub in Grand Canyon
The federally endangered 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...
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...
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...
Assessing the population impacts and cost‐effectiveness of a conservation translocation
Managers often move, or translocate, organisms into habitats that are assumed to be suitable, however the consequences of these translocations are usually not rigorously assessed. Robust assessment of these management experiments should consider impacts to both donor and recipient populations and compare the cost‐effectiveness of translocations to...
Yackulic, Charles B.; Van Haverbeke, David R.; Dzul, Maria C.; Bair, Lucas S.; Young, Kirk L.
The Transformation of dryland rivers: The future of introduced tamarisk in the U.S.
Tamarix spp. (tamarisk or saltcedar), a shrub-like tree, was intentionally introduced to the U.S. from Asia in the mid-1800s. Tamarisk thrives in today’s human-altered streamside (riparian) habitats and can be found along wetlands, rivers, lakes, and streams across the western U.S. In 2001, a biological control agent, Diorhabda spp. (tamarisk leaf...
Nagler, Pamela L.; Hull, Julia B.; van Riper, Charles; Shafroth, Patrick B.; Yackulic, Charles B. Partial migration and spawning movements of humpback chub in the Little Colorado River are better understood using data from autonomous PIT tag antennas
Choosing whether or not to migrate is an important life history decision for many fishes. Here we combine data from physical captures and detections on autonomous passive integrated transponder (PIT) tag antennas to study migration in an endangered fish, the humpback chub (Gila cypha). We develop hidden Markov mark-recapture models with and...
Dzul, Maria C.; Kendall, William Louis; Yackulic, Charles; Winkelman, Dana L.; Van Haverbeke, David Randall; Yard, Mike Movement ecology
(Yackulic) At first glance, the decision to study movement in Galapagos tortoises seems curious. Given the slow speed of tortoises and tendency to forage and rest as they move, it seems implausible that tortoises would string their slow bursts of activity together to accomplish large-scale movements. Nonetheless, as early as 1815 (Porter 1815),...
Blake, Stephen; Yackulic, Charles B.; Cabrera, Freddy; Deem, Sharon L.; Ellis-Soto, Diego; Gibbs, James P.; Kummeth, Franz; Wikelski, Martin; Bastille-Rousseau, Guillaume Water storage decisions will determine the distribution and persistence of imperiled river fishes
Managing the world’s freshwater supply to meet societal and environmental needs in a changing climate is one of the biggest challenges for the 21st century. Dams provide water security, however, the allocation of dwindling water supply among reservoirs could exacerbate or ameliorate the effects of climate change on aquatic communities. Here,...
Dibble, Kimberly L.; Yackulic, Charles; Kennedy, Theodore; Bestgen, Kevin R.; Schmidt, John C. Thinking like a consumer: Linking aquatic basal metabolism and consumer dynamics
The increasing availability of high‐frequency freshwater ecosystem metabolism data provides an opportunity to identify links between metabolic regimes, as gross primary production and ecosystem respiration patterns, and consumer energetics with the potential to improve our current understanding of consumer dynamics (e.g., population dynamics,...
Rüegg, Janine; Conn, Caitlin C; Anderson, Elizabeth P; Battin, Tom J; Bernhardt, Emily S.; Canadell, Marta Boix; Bonjour, Sophia M; Hosen, Jacob D.; Marzolf, Nicholas S; Yackulic, Charles Net-spinning caddisfly distribution in large regulated rivers
Most of the world's large rivers are dammed for the purposes of water storage, flood control, and power production. Damming rivers fundamentally alters water temperature and flows in tailwater ecosystems, which in turn affects the presence and abundance of downstream biota.We collaborated with more than 200 citizen scientists to collect 2,194...
Metcalfe, Anya; Muehlbauer, Jeffrey; Kennedy, Theodore; Yackulic, Charles; Dibble, Kimberly L.; Marks, Jane C. Water temperature controls for regulated canyon-bound rivers
Many canyon‐bound rivers have been dammed and downstream flow and water temperatures modified. Climate change is expected to cause lower storage in reservoirs and warmer release temperatures, which may further alter downstream flow and thermal regimes. To anticipate potential future changes, we first need to understand the dominant heat transfer...
Mihalevich, Bryce A.; Neilson, Bethany; Buahin, Caleb A.; Yackulic, Charles; Schmidt, John C. Changes in prey, turbidity, and competition reduce somatic growth and cause the collapse of a fish population
Somatic growth exerts strong control on patterns in the abundance of animal populations via effects on maturation, fecundity, and survival rates of juveniles and adults. In this paper, we quantify abiotic and biotic drivers of rainbow trout growth in the Colorado River, AZ, and the resulting impact on spatial and temporal variation in abundance....
Korman, Josh; Yard, Mike; Dzul, Maria C.; Yackulic, Charles; Dodrill, Michael; Deemer, Bridget; Kennedy, Theodore Brackish tidal marsh management and the ecology of a declining freshwater turtle
Water management practices in tidal marshes of the San Francisco Bay Estuary, California are often aimed at increasing suitable habitat for threatened fish species and sport fishes. However, little is known about how best to manage habitat for other sensitive status species like the semiaquatic freshwater Western Pond Turtle (Actinemys marmorata)...
Agha, Mickey; Yackulic, Charles; Riley, Melissa K.; Peterson, Blair; Todd, Brian D A need for speed in Bayesian population models: A practical guide to marginalizing and recovering discrete latent states
Bayesian population models can be exceedingly slow due, in part, to the choice to simulate discrete latent states. Here, we discuss an alternative approach to discrete latent states, marginalization, that forms the basis of maximum likelihood population models and is much faster. Our manuscript has two goals: 1) to introduce readers unfamiliar...
Yackulic, Charles B.; Dodrill, Michael J.; Dzul, Maria C.; Sanderlin, Jamie S.; Reid, Janice A. Is your ad hoc model selection strategy affecting your multimodel inference?
(Yackulic) 1. Ecologists routinely fit complex models with multiple parameters of interest, where hundreds or more competing models are plausible. To limit the number of fitted models, ecologists often define a model selection strategy composed of a series of stages in which certain features of a model are compared while other features are held...
Morin, Dana J.; Yackulic, Charles B.; Diffendorfer, James; Lesmeister, Damon B.; Nielsen, Clayton K.; Reid, Janice; Schauber, Eric M.
SBSC Research on Barred and Spotted Owls Covered by Ecological Society of America
The Ecological Society of America put out a press release on a paper that investigated the relative importance of barred owl competition and habitat on northern spotted owls in an effort to assist managers. The lead author of the paper is Charles Yackulic of the USGS Southwest Biological Science Center.
Barred Owls Ousting Spotted Owls in the Pacific Northwest
An increase in the barred owl population is contributing to the decline of threatened Northern spotted owls, according to models developed by U.S. Geological Survey and U.S. Forest Service scientists.