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...
Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon
A common impact on riparian ecosystem function following river regulation is the expansion and encroachment of riparian plant species in the active river channels and floodplain, which reduces flow of water and suspended sediment between the river, riparian area, and upland ecosystems. We characterized riparian plant species occurrence and...
Durning, Laura E.; Sankey, Joel B.; Yackulic, Charles; Grams, Paul; Butterfield, Bradley J.; Sankey, Temuulen T. Incorporating antenna detections into abundance estimates of fish
Autonomous passive integrated transponder (PIT) tag antennas are commonly used to detect fish marked with PIT tags but cannot detect unmarked fish, creating challenges for abundance estimation. Here we describe an approach to estimate abundance from paired physical capture and antenna detection data in closed and open mark-recapture models....
Dzul, Maria C.; Yackulic, Charles; Kendall, William L.; Winkelman, Dana L.; Conner, Mary M; Yard, Mike Invader removal triggers competitive release in a threatened avian predator
Invasive species can cause extinctions of native species and widespread biodiversity loss. Invader removal is a common management response, but the use of long-term field experiments to characterize effectiveness of removals in benefitting impacted native species is rare. We used a large-scale removal experiment to investigate the demographic...
Wiens, David; Dugger, Catherine M.; Higley, J. Mark; Lesmeister, Damon B.; Franklin, Alan B.; Hamm, Keith A.; White, Gary C.; Dilione, Krista E.; Simon, David C.; Bown, Robin R.; Carlson, Peter C.; Yackulic, Charles; Nichols, James D.; Hines, James E.; Davis, Raymond J.; Lamphear, David W.; McCafferty, Christopher; McDonald, Trent L.; Sovern, Stan G. Simulating the effort necessary to detect changes in northern spotted owl (Strix occidentalis caurina) populations using passive acoustic monitoring
Passive acoustic monitoring is a promising method for monitoring rare and nocturnal species, and for tracking changes in forest wildlife biodiversity. We conducted simulations to compare and evaluate various passive acoustic sampling designs effectiveness for monitoring spotted owl (Strix occidentalis caurina) population trends. We found that each...
Lesmeister, Damon B.; Appel, Cara L.; Davis, Raymond J.; Yackulic, Charles; Ruff, Zachary J. Ontogenetic trait shifts: Seedlings display high trait variability during early stages of development
Characterizing variation in plant functional traits is often key to understanding community-level processes and predicting ecosystem responses to environmental change. Trait-based ecology has focused on interspecific trait variation, but sources and consequences of within-species ontogenetic trait variation, particularly during early stages of...
Havrilla, Caroline Ann; Munson, Seth M.; Yackulic, Charles; Butterfield, Bradley J. As the prey thickens: Rainbow trout select prey based upon width not length
Drift-feeding fish are typically considered size-selective predators. Yet, few studies have explicitly tested which aspect of prey “size” best explains size selection by drift-foraging fish. Here, we develop a Bayesian discrete choice model to evaluate how attributes of both prey and predator simultaneously influence size-selective foraging. We...
Dodrill, Michael; Yackulic, Charles; Kennedy, Theodore; Yard, Mike; Josh Korman Range-wide declines of northern spotted owl populations in the Pacific Northwest: A meta-analysis
The northern spotted owl (Strix occidentalis caurina) inhabits older coniferous forests in the Pacific Northwest and has been at the center of forest management issues in this region. The immediate threats to this federally listed species include habitat loss and competition with barred owls (Strix varia), which invaded from...
Franklin, Alan B.; Dugger, Katie M.; Lesmeister, Damon B.; Davis, Raymond J.; Wiens, J. David; White, Gary C.; Nichols, James D.; Hines, James E.; Yackulic, Charles B.; Schwarz, Carl J.; Ackers, Steven H.; Stevens, Andrew L.; Bailey, Larissa L.; Brown, Robin G.; Burgher, Jesse; Burnham, Kenneth P.; Carlson, Peter C.; Chestnut, Tara; Conner, Mary M; Dilione, Krista E.; Forsman, Eric D.; Glenn, Elizabeth M.; Gremel, Scott A.; Hamm, Keith A.; Herter, Dale R.; Higley, J. Mark; Horn, Rob B.; Jenkins, Julianna M.; Kendall, William L.; Lamphear, David W; McCafferty, Christopher; McDonald, Trent L.; Reid, Janice A; Rockweit, Jeremy T.; Simon, David C.; Sovern, Stan G.; Swingle, James; Wise, Heather 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.
Invader Removal Halts Long-term Population Declines of Northern Spotted Owls
Invasive species can cause extinctions of native species and widespread biodiversity loss. Invader removal is a common management response, but the use of long-term field experiments to test the effectiveness of removals in benefitting impacted native species is rare.
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.