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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

A group of fish swim just under the surface of the blue-green water near a red canyon wall

Study Uncovers Migration Patterns of Native Fish in the Colorado River

A study conducted by the USGS provides new insights into the migration patterns of three native fish species in the Colorado River: humpback chub, flannelmouth sucker, and bluehead sucker. This research highlights the importance of understanding native fish population dynamics within the Colorado River ecosystem in Grand Canyon, AZ.
By
Southwest Biological Science Center
Study Uncovers Migration Patterns of Native Fish in the Colorado River

Study Uncovers Migration Patterns of Native Fish in the Colorado River

A study conducted by the USGS provides new insights into the migration patterns of three native fish species in the Colorado River: humpback chub, flannelmouth sucker, and bluehead sucker. This research highlights the importance of understanding native fish population dynamics within the Colorado River ecosystem in Grand Canyon, AZ.
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Smallmouth Bass

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...
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Southwest Biological Science Center
Smallmouth bass expansion downstream of Glen Canyon Dam

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...
Learn More
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

Humpback Chub in the Colorado River, 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.
By
Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Humpback Chub in the Colorado River, Grand Canyon

Humpback Chub in the Colorado River, 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.
Learn More
A rainbow trout swims in aquatic vegetation below the water surface in Colorado River with Glen Canyon Dam in the distance

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...
By
Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Rainbow Trout in the Colorado River, Grand Canyon

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...
Learn More
A boat on the Colorado River in front of a rock outcrop containing a concrete structure.

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...
By
Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Uncovering the Base of the Food Web: Primary Production Dynamics in the Colorado River

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...
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Image Collage of Landsat, pollinator, and volcanologist

Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

State and federal agencies are negotiating long-term water-supply agreements for the Colorado River basin, but current policies prioritize water supply over ecological factors due to limited knowledge about how water storage strategies impact ecosystems. Researchers supported by this Southwest CASC project will develop a tool to evaluate river ecosystem outcomes of various patterns of...
By
Climate Adaptation Science Centers, Colorado River Basin: Actionable and Strategic Integrated Science and Technology
Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

State and federal agencies are negotiating long-term water-supply agreements for the Colorado River basin, but current policies prioritize water supply over ecological factors due to limited knowledge about how water storage strategies impact ecosystems. Researchers supported by this Southwest CASC project will develop a tool to evaluate river ecosystem outcomes of various patterns of water
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Colorado River Near Moab, Utah (small)

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...
By
Climate Adaptation Science Centers
The Impacts of Climate Change and Water Supply Management on Fish in the Colorado River

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
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USGS science for a changing world logo

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...
By
John Wesley Powell Center for Analysis and Synthesis
Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry

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
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Filter Total Items: 30

Catch and mark-recapture data to estimate abundance of humpback chub Gila cypha in western Grand Canyon from 2010-2024 Catch and mark-recapture data to estimate abundance of humpback chub Gila cypha in western Grand Canyon from 2010-2024

This dataset describes the catch of humpback chub (Gila cypha) in baited hoop nets from humpback chub aggregations monitoring trips that occurred 2010-2024. Additionally, this data set includes tables that describe the number of captures and recaptures for repeat visits (i.e., mark-recapture) as well as categorical habitat scores from two experts assigned to the Colorado River in western...
By
Southwest Biological Science Center

Forecasting smallmouth bass invasion under different management scenarios for Lake Powell releases, 2024-2027 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...
By
Southwest Biological Science Center

Dissolved oxygen predictions for releases from Lake Powell under different management scenarios for Lake Powell releases Dissolved 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...
By
Southwest Biological Science Center

Predicted hydropower impacts of different management scenarios for Lake Powell releases Predicted 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...
By
Southwest Biological Science Center

Modelled Lake Powell releases and reservoir elevations under different alternative management scenarios Modelled 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...
By
Southwest Biological Science Center

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 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

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...
By
Southwest Biological Science Center

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 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...
By
Southwest Biological Science Center

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 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

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...
By
Southwest Biological Science Center

Humpback chub (Gila cypha) capture histories and growth data for two areas in the Colorado River network from 2009-2022 and 2017-2022 Humpback 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...
By
Southwest Biological Science Center

Brown trout movement data in Glen and Grand Canyons, Arizona, USA Brown 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...
By
Southwest Biological Science Center

Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona. Proximal 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...
By
Southwest Biological Science Center

Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam Gross 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...
By
Southwest Biological Science Center
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon
A school of humpback chub swimming in Havasu Creek, Grand Canyon
A school of humpback chub swimming in Havasu Creek, Grand Canyon
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

A school of humpback chub swimming in Havasu Creek, Grand Canyon

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. 

By
Southwest Biological Science Center
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

A school of humpback chub swimming in Havasu Creek, Grand Canyon

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. 

By
Southwest Biological Science Center
Filter Total Items: 126

Status report on the Long-Term Experimental and Management Plan (LTEMP) Metrics for the Glen Canyon Dam adaptive management program Status report on the Long-Term Experimental and Management Plan (LTEMP) Metrics for the Glen Canyon Dam adaptive management program

No abstract available.
Authors
Helen C. Fairley, Gregory Mark Anderson, Andrew Alan Schultz, Joel B. Sankey, Joshua Caster, Lauren Lynn Tango, Bridget Deemer, Theodore Kennedy, Anya Metcalfe, Emily C. Palmquist, Maria C. Dzul, Kimberly L. Dibble, David Ward, David L. Rogowski, Emily C. Omana Smith, Jeffrey Arnold, Brian D. Healy, Charles Yackulic, Lucas Bair, David J. Topping, Paul Grams, Katherine Anne Chapman, Robert B. Tusso, Dale Fonken, Josh Korman, Lindsay Erika Hansen, Benjamin John Miller, John M. Fennell, Drew Elliot Eppehimer, Claudia James Dimartini, Nathaniel D. Bransky
By
Ecosystems Mission Area, Southwest Biological Science Center

Do bighorn sheep use desert tortoise burrow spoil piles as mineral licks in southern California? Do bighorn sheep use desert tortoise burrow spoil piles as mineral licks in southern California?

In a previous study, bighorn sheep (Ovis canadensis) were periodically photographed by trail cameras when they visited desert tortoise (Gopherus agassizii) burrows in the San Bernardino Mountains near Palm Springs, California, USA. The authors suggested that bighorn sheep may utilize the excavated spoil material from burrows as a mineral lick. To test that supposition, we collected soil...
Authors
Jeffrey E. Lovich, Danielle M. Cleveland, Charles Yackulic, Kristy L. Cummings, Michele R. Puffer, Molly J. Bechtel, Christopher R. Tracy, William J. Hoese, Gerardo Avila, Megan Peukert, Samantha Hubbard
By
Ecosystems Mission Area, Columbia Environmental Research Center, Southwest Biological Science Center

Reservoir operational strategies for sustainable sand management in the Colorado River Reservoir operational strategies for sustainable sand management in the Colorado River

Climate change and increasing societal demands for water pose challenges for the management of dam-regulated rivers. Management decisions impact the environment of these rivers, creating the need to balance societal needs with environmental conservation. Here we present a modeling framework that optimizes resource benefits within imposed water use goals for the Colorado River in Grand...
Authors
Gerard Lewis Salter, David J. Topping, Jianghao Wang, John C. Schmidt, Charles Yackulic, Lucas Bair, Erich R. Mueller, Paul E. Grams
By
Ecosystems Mission Area, Southwest Biological Science Center

Declining reservoir elevations following a two-decade drought increase water temperatures and non-native fish passage facilitating a downstream invasion Declining reservoir elevations following a two-decade drought increase water temperatures and non-native fish passage facilitating a downstream invasion

River ecosystems are threatened by interactions among river regulation, non-native species, and climate change. Water use has exceeded supply in USA’s Colorado River basin draining its two largest storage reservoirs (Lake Powell and Lake Mead). In 2022, Lake Powell began releasing water from its lower epilimnion into the Grand Canyon segment of the Colorado River, which (1) increased...
Authors
Drew Elliot Eppehimer, Charles B. Yackulic, Lindsey Ann Bruckerhoff, Jianghao Wang, Kirk L. Young, Kevin R. Bestgen, Bryce Anthony Mihalevich, John C. Schmidt
By
Ecosystems Mission Area, Cooperative Research Units, Southwest Biological Science Center

Low water levels interact with reservoir aging to increase the severity of summertime metalimnion dissolved oxygen minima in Lake Powell, desert Southwest, USA Low water levels interact with reservoir aging to increase the severity of summertime metalimnion dissolved oxygen minima in Lake Powell, desert Southwest, USA

Water level drawdowns are common in reservoirs and can affect dissolved oxygen (DO) dynamics via several pathways. In large storage reservoirs, inflow deltas are often important sites for sediment deposition, with some sediment laden rivers forming highly dynamic delta regions as they enter the reservoir. As water levels change, deposited sediment may be remobilized and affect pelagic DO...
Authors
Bridget Deemer, Caitlin M. Andrews, Robin H. Reibold, Bryce A. Mihalevich, Thomas A. Sabol, Jeremiah Drewel, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Estimating drivers and identifying uncertainties in smallmouth bass population dynamics in an invaded river network Estimating drivers and identifying uncertainties in smallmouth bass population dynamics in an invaded river network

Smallmouth bass (Micropterus dolomieu) is an important recreational sportfish and destructive non-native species when introduced into freshwater habitats. There is therefore a need to understand the drivers of, and uncertainties in, smallmouth bass population dynamics for various management objectives. We combined long-term smallmouth bass catch-effort and early life history data from a...
Authors
Lindsey A. Bruckerhoff, Charles Yackulic, Drew Elliot Eppehimer, Kevin R. Bestgen, M. Tildon Jones, Chris Michaud
By
Ecosystems Mission Area, Southwest Biological Science Center

Genetic structure of an expanding population of Humpback Chub in Grand Canyon Genetic structure of an expanding population of Humpback Chub in Grand Canyon

Objective Humpback Chub (HBC) Gila cypha in Grand Canyon declined in abundance and distribution over the latter part of the 20th century but have substantially increased in abundance and distribution over the past two decades. Although previous genetic work suggested that HBC in Grand Canyon belong to one genetic group, here we evaluate the genetic structure of HBC in Grand Canyon to...
Authors
Maria C. Dzul, Robert Massatti, Charles Yackulic, Emily Omana-Smith, Kirk Young
By
Ecosystems Mission Area, Southwest Biological Science Center

The importance of sampling design for unbiased estimation of survival using joint live-recapture and live resight models The importance of sampling design for unbiased estimation of survival using joint live-recapture and live resight models

Survival is a key life history parameter that can inform management decisions and basic life history research. Because true survival is often confounded with emigration from the study area, many studies are forced to estimate apparent survival (i.e., probability of surviving and remaining inside the study area), which can be much lower than true survival for highly mobile species. One...
Authors
Maria C. Dzul, Charles Yackulic, William L. Kendall
By
Ecosystems Mission Area, Cooperative Research Units, Southwest Biological Science Center

Before the fire: Predicting burn severity and potential post-fire debris-flow hazards to Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus) conservation populations Before the fire: Predicting burn severity and potential post-fire debris-flow hazards to Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus) conservation populations

Background Colorado River Cutthroat Trout (CRCT; Oncorhynchus clarkii pleuriticus) conservation populations may be at risk from wildfire and post-fire debris flows hazards. Aim To predict burn severity and potential post-fire debris flow hazard classifications to CRCT conservation populations before wildfires occur. Methods We used remote sensing, spatial analyses, and machine learning...
Authors
Adam Gerhard Wells, Charles Yackulic, Jaime Kostelnik, Andrew R. Bock, Robert E. Zuellig, Daren M. Carlisle, James Roberts, Kevin B. Rogers, Seth M. Munson
By
Natural Hazards Mission Area, Ecosystems Mission Area, Central Plains Water Science Center, Colorado Water Science Center, Geologic Hazards Science Center, Great Lakes Science Center, Southwest Biological Science Center

Aspects of the demography of a relict population of southwestern pond turtles (Actinemys pallida) in a West Mojave Desert stream in California Aspects of the demography of a relict population of southwestern pond turtles (Actinemys pallida) in a West Mojave Desert stream in California

We studied Actinemys pallida (Southwestern Pond Turtle) in Amargosa Creek, near Palmdale, CA, from 1997 to 2023. The population in the upper creek was the focus of a mark–recapture study from 1997 to 2003 during monitoring required by a road-construction project. An estimated 193 (95% CI = 142–256) turtles were present in 1997 or recruited to the upper creek population between 1997 and...
Authors
David Muth, Jeffrey E. Lovich, Rodrigo Macip-Rios, Doug Gomez, Kristy L. Cummings, Michele R. Puffer, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Dynamic occupancy modelling of Asian elephants (Elephas maximus) reveals increasing landscape use in Nepal Dynamic occupancy modelling of Asian elephants (Elephas maximus) reveals increasing landscape use in Nepal

Large mammals with general habitat needs can persist throughout mixed used landscapes, however, human-wildlife conflict frequently leads to their restriction to protected areas. Conservation efforts, especially for reducing conflicts with humans, can enhance tolerance of humans towards species like Asian elephants (Elephas maximus) in human-dominated landscapes. Here, we examine how...
Authors
Ashok Kumar Ram, Babu Ram Lamichhane, Naresh Subedi, Nabin Kumar Yadav, Ajay Karki, Bivash Pandav, Cory Brown, Top B. Khatri, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

eZ flow metrics: Using z-scores to estimate deviations from natural flow in the Colorado River below Glen Canyon Dam eZ flow metrics: Using z-scores to estimate deviations from natural flow in the Colorado River below Glen Canyon Dam

River flow patterns are primary drivers of lotic ecosystems, and hundreds of metrics have been developed to quantify flow attributes. Although existing metrics have been a powerful tool in designing environmental flows, they are often developed with specific resources in mind and are rarely directly comparable with each other (i.e., units are often different). Here, we focus on natural...
Authors
Emily C. Palmquist, Bridget Deemer, Anya Metcalfe, Theodore Kennedy, Lucas Bair, Helen C. Fairley, Paul E. Grams, Joel B. Sankey, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Colorado River Basin Projects 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.
JOB ALERT! Post-doc position open for highly motivated algal or macrophyte ecologist to study diatom community dynamics and ecosystem metabolism in a regulated river

JOB ALERT! Post-doc position open for highly motivated algal or macrophyte ecologist to study diatom community dynamics and ecosystem metabolism in a regulated river

The U.S. Geological Survey is hiring a post-doc with experience in algal and macrophyte taxonomic ID, stream or lake metabolism modeling...

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A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

An integrated framework has been developed in order to resolve mismatches and provide continuity during transitions to different monitoring procedures...

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A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

An integrated framework has been developed in order to resolve mismatches and provide continuity during transitions to different monitoring procedures...

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Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

USGS and Grand Canyon National Park Service researchers investigated the increased dispersal of brown trout (Salmo trutta) into the Colorado River...

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Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

USGS and Grand Canyon National Park Service researchers investigated the increased dispersal of brown trout (Salmo trutta) into the Colorado River...

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Northern Spotted Owl Still Fights for Survival

Northern Spotted Owl Still Fights for Survival

Three studies highlight how the interactions between northern spotted owl and the invasive barred owl are intertwined. 

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Invader Removal Halts Long-term Population Declines of Northern Spotted Owls

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...

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SBSC Research on Barred and Spotted Owls Covered by Ecological Society of America

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...

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Barred Owls Ousting Spotted Owls in the Pacific Northwest

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...

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Science and Products

A group of fish swim just under the surface of the blue-green water near a red canyon wall

Study Uncovers Migration Patterns of Native Fish in the Colorado River

A study conducted by the USGS provides new insights into the migration patterns of three native fish species in the Colorado River: humpback chub, flannelmouth sucker, and bluehead sucker. This research highlights the importance of understanding native fish population dynamics within the Colorado River ecosystem in Grand Canyon, AZ.
By
Southwest Biological Science Center
Study Uncovers Migration Patterns of Native Fish in the Colorado River

Study Uncovers Migration Patterns of Native Fish in the Colorado River

A study conducted by the USGS provides new insights into the migration patterns of three native fish species in the Colorado River: humpback chub, flannelmouth sucker, and bluehead sucker. This research highlights the importance of understanding native fish population dynamics within the Colorado River ecosystem in Grand Canyon, AZ.
Learn More
Smallmouth Bass

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...
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Southwest Biological Science Center
Smallmouth bass expansion downstream of Glen Canyon Dam

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...
Learn More
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

Humpback Chub in the Colorado River, 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.
By
Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Humpback Chub in the Colorado River, Grand Canyon

Humpback Chub in the Colorado River, 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.
Learn More
A rainbow trout swims in aquatic vegetation below the water surface in Colorado River with Glen Canyon Dam in the distance

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...
By
Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Rainbow Trout in the Colorado River, Grand Canyon

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...
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A boat on the Colorado River in front of a rock outcrop containing a concrete structure.

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...
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Ecosystems Mission Area, Species Management Research Program, Southwest Biological Science Center
Uncovering the Base of the Food Web: Primary Production Dynamics in the Colorado River

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...
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Image Collage of Landsat, pollinator, and volcanologist

Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

State and federal agencies are negotiating long-term water-supply agreements for the Colorado River basin, but current policies prioritize water supply over ecological factors due to limited knowledge about how water storage strategies impact ecosystems. Researchers supported by this Southwest CASC project will develop a tool to evaluate river ecosystem outcomes of various patterns of...
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Climate Adaptation Science Centers, Colorado River Basin: Actionable and Strategic Integrated Science and Technology
Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

Future of the Colorado River (Phase 2): Reservoir Operation to Balance Water Supply and River Ecosystems in the Grand Canyon

State and federal agencies are negotiating long-term water-supply agreements for the Colorado River basin, but current policies prioritize water supply over ecological factors due to limited knowledge about how water storage strategies impact ecosystems. Researchers supported by this Southwest CASC project will develop a tool to evaluate river ecosystem outcomes of various patterns of water
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Colorado River Near Moab, Utah (small)

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...
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Climate Adaptation Science Centers
The Impacts of Climate Change and Water Supply Management on Fish in the Colorado River

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
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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...
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John Wesley Powell Center for Analysis and Synthesis
Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry

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
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Catch and mark-recapture data to estimate abundance of humpback chub Gila cypha in western Grand Canyon from 2010-2024 Catch and mark-recapture data to estimate abundance of humpback chub Gila cypha in western Grand Canyon from 2010-2024

This dataset describes the catch of humpback chub (Gila cypha) in baited hoop nets from humpback chub aggregations monitoring trips that occurred 2010-2024. Additionally, this data set includes tables that describe the number of captures and recaptures for repeat visits (i.e., mark-recapture) as well as categorical habitat scores from two experts assigned to the Colorado River in western...
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Southwest Biological Science Center

Forecasting smallmouth bass invasion under different management scenarios for Lake Powell releases, 2024-2027 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...
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Southwest Biological Science Center

Dissolved oxygen predictions for releases from Lake Powell under different management scenarios for Lake Powell releases Dissolved 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...
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Southwest Biological Science Center

Predicted hydropower impacts of different management scenarios for Lake Powell releases Predicted 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...
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Southwest Biological Science Center

Modelled Lake Powell releases and reservoir elevations under different alternative management scenarios Modelled 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...
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Southwest Biological Science Center

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 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

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...
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Southwest Biological Science Center

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 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...
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Southwest Biological Science Center

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 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

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...
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Southwest Biological Science Center

Humpback chub (Gila cypha) capture histories and growth data for two areas in the Colorado River network from 2009-2022 and 2017-2022 Humpback 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...
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Southwest Biological Science Center

Brown trout movement data in Glen and Grand Canyons, Arizona, USA Brown 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...
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Southwest Biological Science Center

Proximal and distal factors associated with the decline in secondary invertebrate prey production in the Colorado River, Glen Canyon, Arizona. Proximal 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...
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Southwest Biological Science Center

Gross primary production estimates and associated light, sediment, and water quality data from the Colorado River below Glen Canyon Dam Gross 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...
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Southwest Biological Science Center
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon
A school of humpback chub swimming in Havasu Creek, Grand Canyon
A school of humpback chub swimming in Havasu Creek, Grand Canyon
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

A school of humpback chub swimming in Havasu Creek, Grand Canyon

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. 

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Southwest Biological Science Center
A school of humpback chub (Gila cypha) swimming in Havasu Creek, Grand Canyon

A school of humpback chub swimming in Havasu Creek, Grand Canyon

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. 

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Southwest Biological Science Center
Filter Total Items: 126

Status report on the Long-Term Experimental and Management Plan (LTEMP) Metrics for the Glen Canyon Dam adaptive management program Status report on the Long-Term Experimental and Management Plan (LTEMP) Metrics for the Glen Canyon Dam adaptive management program

No abstract available.
Authors
Helen C. Fairley, Gregory Mark Anderson, Andrew Alan Schultz, Joel B. Sankey, Joshua Caster, Lauren Lynn Tango, Bridget Deemer, Theodore Kennedy, Anya Metcalfe, Emily C. Palmquist, Maria C. Dzul, Kimberly L. Dibble, David Ward, David L. Rogowski, Emily C. Omana Smith, Jeffrey Arnold, Brian D. Healy, Charles Yackulic, Lucas Bair, David J. Topping, Paul Grams, Katherine Anne Chapman, Robert B. Tusso, Dale Fonken, Josh Korman, Lindsay Erika Hansen, Benjamin John Miller, John M. Fennell, Drew Elliot Eppehimer, Claudia James Dimartini, Nathaniel D. Bransky
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Ecosystems Mission Area, Southwest Biological Science Center

Do bighorn sheep use desert tortoise burrow spoil piles as mineral licks in southern California? Do bighorn sheep use desert tortoise burrow spoil piles as mineral licks in southern California?

In a previous study, bighorn sheep (Ovis canadensis) were periodically photographed by trail cameras when they visited desert tortoise (Gopherus agassizii) burrows in the San Bernardino Mountains near Palm Springs, California, USA. The authors suggested that bighorn sheep may utilize the excavated spoil material from burrows as a mineral lick. To test that supposition, we collected soil...
Authors
Jeffrey E. Lovich, Danielle M. Cleveland, Charles Yackulic, Kristy L. Cummings, Michele R. Puffer, Molly J. Bechtel, Christopher R. Tracy, William J. Hoese, Gerardo Avila, Megan Peukert, Samantha Hubbard
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Ecosystems Mission Area, Columbia Environmental Research Center, Southwest Biological Science Center

Reservoir operational strategies for sustainable sand management in the Colorado River Reservoir operational strategies for sustainable sand management in the Colorado River

Climate change and increasing societal demands for water pose challenges for the management of dam-regulated rivers. Management decisions impact the environment of these rivers, creating the need to balance societal needs with environmental conservation. Here we present a modeling framework that optimizes resource benefits within imposed water use goals for the Colorado River in Grand...
Authors
Gerard Lewis Salter, David J. Topping, Jianghao Wang, John C. Schmidt, Charles Yackulic, Lucas Bair, Erich R. Mueller, Paul E. Grams
By
Ecosystems Mission Area, Southwest Biological Science Center

Declining reservoir elevations following a two-decade drought increase water temperatures and non-native fish passage facilitating a downstream invasion Declining reservoir elevations following a two-decade drought increase water temperatures and non-native fish passage facilitating a downstream invasion

River ecosystems are threatened by interactions among river regulation, non-native species, and climate change. Water use has exceeded supply in USA’s Colorado River basin draining its two largest storage reservoirs (Lake Powell and Lake Mead). In 2022, Lake Powell began releasing water from its lower epilimnion into the Grand Canyon segment of the Colorado River, which (1) increased...
Authors
Drew Elliot Eppehimer, Charles B. Yackulic, Lindsey Ann Bruckerhoff, Jianghao Wang, Kirk L. Young, Kevin R. Bestgen, Bryce Anthony Mihalevich, John C. Schmidt
By
Ecosystems Mission Area, Cooperative Research Units, Southwest Biological Science Center

Low water levels interact with reservoir aging to increase the severity of summertime metalimnion dissolved oxygen minima in Lake Powell, desert Southwest, USA Low water levels interact with reservoir aging to increase the severity of summertime metalimnion dissolved oxygen minima in Lake Powell, desert Southwest, USA

Water level drawdowns are common in reservoirs and can affect dissolved oxygen (DO) dynamics via several pathways. In large storage reservoirs, inflow deltas are often important sites for sediment deposition, with some sediment laden rivers forming highly dynamic delta regions as they enter the reservoir. As water levels change, deposited sediment may be remobilized and affect pelagic DO...
Authors
Bridget Deemer, Caitlin M. Andrews, Robin H. Reibold, Bryce A. Mihalevich, Thomas A. Sabol, Jeremiah Drewel, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Estimating drivers and identifying uncertainties in smallmouth bass population dynamics in an invaded river network Estimating drivers and identifying uncertainties in smallmouth bass population dynamics in an invaded river network

Smallmouth bass (Micropterus dolomieu) is an important recreational sportfish and destructive non-native species when introduced into freshwater habitats. There is therefore a need to understand the drivers of, and uncertainties in, smallmouth bass population dynamics for various management objectives. We combined long-term smallmouth bass catch-effort and early life history data from a...
Authors
Lindsey A. Bruckerhoff, Charles Yackulic, Drew Elliot Eppehimer, Kevin R. Bestgen, M. Tildon Jones, Chris Michaud
By
Ecosystems Mission Area, Southwest Biological Science Center

Genetic structure of an expanding population of Humpback Chub in Grand Canyon Genetic structure of an expanding population of Humpback Chub in Grand Canyon

Objective Humpback Chub (HBC) Gila cypha in Grand Canyon declined in abundance and distribution over the latter part of the 20th century but have substantially increased in abundance and distribution over the past two decades. Although previous genetic work suggested that HBC in Grand Canyon belong to one genetic group, here we evaluate the genetic structure of HBC in Grand Canyon to...
Authors
Maria C. Dzul, Robert Massatti, Charles Yackulic, Emily Omana-Smith, Kirk Young
By
Ecosystems Mission Area, Southwest Biological Science Center

The importance of sampling design for unbiased estimation of survival using joint live-recapture and live resight models The importance of sampling design for unbiased estimation of survival using joint live-recapture and live resight models

Survival is a key life history parameter that can inform management decisions and basic life history research. Because true survival is often confounded with emigration from the study area, many studies are forced to estimate apparent survival (i.e., probability of surviving and remaining inside the study area), which can be much lower than true survival for highly mobile species. One...
Authors
Maria C. Dzul, Charles Yackulic, William L. Kendall
By
Ecosystems Mission Area, Cooperative Research Units, Southwest Biological Science Center

Before the fire: Predicting burn severity and potential post-fire debris-flow hazards to Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus) conservation populations Before the fire: Predicting burn severity and potential post-fire debris-flow hazards to Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus) conservation populations

Background Colorado River Cutthroat Trout (CRCT; Oncorhynchus clarkii pleuriticus) conservation populations may be at risk from wildfire and post-fire debris flows hazards. Aim To predict burn severity and potential post-fire debris flow hazard classifications to CRCT conservation populations before wildfires occur. Methods We used remote sensing, spatial analyses, and machine learning...
Authors
Adam Gerhard Wells, Charles Yackulic, Jaime Kostelnik, Andrew R. Bock, Robert E. Zuellig, Daren M. Carlisle, James Roberts, Kevin B. Rogers, Seth M. Munson
By
Natural Hazards Mission Area, Ecosystems Mission Area, Central Plains Water Science Center, Colorado Water Science Center, Geologic Hazards Science Center, Great Lakes Science Center, Southwest Biological Science Center

Aspects of the demography of a relict population of southwestern pond turtles (Actinemys pallida) in a West Mojave Desert stream in California Aspects of the demography of a relict population of southwestern pond turtles (Actinemys pallida) in a West Mojave Desert stream in California

We studied Actinemys pallida (Southwestern Pond Turtle) in Amargosa Creek, near Palmdale, CA, from 1997 to 2023. The population in the upper creek was the focus of a mark–recapture study from 1997 to 2003 during monitoring required by a road-construction project. An estimated 193 (95% CI = 142–256) turtles were present in 1997 or recruited to the upper creek population between 1997 and...
Authors
David Muth, Jeffrey E. Lovich, Rodrigo Macip-Rios, Doug Gomez, Kristy L. Cummings, Michele R. Puffer, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Dynamic occupancy modelling of Asian elephants (Elephas maximus) reveals increasing landscape use in Nepal Dynamic occupancy modelling of Asian elephants (Elephas maximus) reveals increasing landscape use in Nepal

Large mammals with general habitat needs can persist throughout mixed used landscapes, however, human-wildlife conflict frequently leads to their restriction to protected areas. Conservation efforts, especially for reducing conflicts with humans, can enhance tolerance of humans towards species like Asian elephants (Elephas maximus) in human-dominated landscapes. Here, we examine how...
Authors
Ashok Kumar Ram, Babu Ram Lamichhane, Naresh Subedi, Nabin Kumar Yadav, Ajay Karki, Bivash Pandav, Cory Brown, Top B. Khatri, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

eZ flow metrics: Using z-scores to estimate deviations from natural flow in the Colorado River below Glen Canyon Dam eZ flow metrics: Using z-scores to estimate deviations from natural flow in the Colorado River below Glen Canyon Dam

River flow patterns are primary drivers of lotic ecosystems, and hundreds of metrics have been developed to quantify flow attributes. Although existing metrics have been a powerful tool in designing environmental flows, they are often developed with specific resources in mind and are rarely directly comparable with each other (i.e., units are often different). Here, we focus on natural...
Authors
Emily C. Palmquist, Bridget Deemer, Anya Metcalfe, Theodore Kennedy, Lucas Bair, Helen C. Fairley, Paul E. Grams, Joel B. Sankey, Charles Yackulic
By
Ecosystems Mission Area, Southwest Biological Science Center

Colorado River Basin Projects 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.
JOB ALERT! Post-doc position open for highly motivated algal or macrophyte ecologist to study diatom community dynamics and ecosystem metabolism in a regulated river

JOB ALERT! Post-doc position open for highly motivated algal or macrophyte ecologist to study diatom community dynamics and ecosystem metabolism in a regulated river

The U.S. Geological Survey is hiring a post-doc with experience in algal and macrophyte taxonomic ID, stream or lake metabolism modeling...

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A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

An integrated framework has been developed in order to resolve mismatches and provide continuity during transitions to different monitoring procedures...

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A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

A new framework to resolve mismatches during transitions to different monitoring methods for northern spotted owls

An integrated framework has been developed in order to resolve mismatches and provide continuity during transitions to different monitoring procedures...

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Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

USGS and Grand Canyon National Park Service researchers investigated the increased dispersal of brown trout (Salmo trutta) into the Colorado River...

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Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

Restricting access to Bright Angel Creek and releasing experimental fall-timed floods increases brown trout immigration into Glen Canyon Dam’s tailwater

USGS and Grand Canyon National Park Service researchers investigated the increased dispersal of brown trout (Salmo trutta) into the Colorado River...

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Northern Spotted Owl Still Fights for Survival

Northern Spotted Owl Still Fights for Survival

Three studies highlight how the interactions between northern spotted owl and the invasive barred owl are intertwined. 

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Invader Removal Halts Long-term Population Declines of Northern Spotted Owls

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...

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SBSC Research on Barred and Spotted Owls Covered by Ecological Society of America

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...

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Barred Owls Ousting Spotted Owls in the Pacific Northwest

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...

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