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.
Science and Products
Rainbow Trout in the Colorado River, Grand Canyon
Rainbow trout are a desirable sport fish that have been introduced in many locations around the world, including the Colorado River. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they can also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying...
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
Threatened humpback chub are a native fish found only in the Colorado River Basin. Once found in warm-water canyons in the Basin, the largest population now persists in the Colorado River in Grand Canyon National Park, downstream of Glen Canyon Dam and Lake Powell, the reservoir upstream, created by the dam.
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 past
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...
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
A 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.
Science and Products
Rainbow Trout in the Colorado River, Grand Canyon
Rainbow trout are a desirable sport fish that have been introduced in many locations around the world, including the Colorado River. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they can also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying...
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
Threatened humpback chub are a native fish found only in the Colorado River Basin. Once found in warm-water canyons in the Basin, the largest population now persists in the Colorado River in Grand Canyon National Park, downstream of Glen Canyon Dam and Lake Powell, the reservoir upstream, created by the dam.
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 past
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...
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
A 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.