Research

The Conservancy posts research and education papers on its web site for public consumption. The purpose of these papers is to promote better understanding of the biological and scientific issues associated with the implementation of the Natomas Basin Habitat Conservation Plan (NBHCP) and the Metro Air Park Habitat Conservation Plan (MAPHCP). They seek to serve as a resource for students, educators, the media and those interested in wildlife and the creation of habitat in the Natomas Basin of California, which will be published on a periodic basis.

Giant garter snake

A tale of two valleys: Endangered species policy and the fate of the giant gartersnake (.pdf)

Brian J. Halstead, Patricia Valcarcel, Richard Kim, Anna Jordan, Jonathan P. Rose, Shannon Skalos, Gabriel Reyes, Julia Ersan, Michael L. Casazza, Allison Essert, Alexandria M Fulton

July 2021 – U.S. Geological Survey, Western Ecological Research Center
Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community (.pdf)

Julia S.M. Ersan, Brian J. Halstead, Erica L. Wildy, Michael L. Casazza, Glenn D. Wylie

June 2020 – Journal of Fish and Wildlife Management
Giant Gartersnakes (Thamnophis gigas) Exploit Abundant Nonnative Prey While Maintaining Their Appetite for Native Anurans (.pdf)

Julia S.M. Ersan, Brian J. Halstead, Erica L. Wildy, Michael L. Casazza, Glenn D. Wylie

February 2020 – Herpetologica
Conservation reliance of a threatened snake on rice agriculture (.pdf)

Brian J. Halstead, Jonathan P. Rose, Gabriel A. Reyes, Glenn D. Wylie, Michael L. Casazza

May 2019 – Global Ecology and Conservation
Integrating growth and capture–mark–recapture models reveals size-dependent survival in an elusive species (.pdf)

Jonathan P. Rose, Glenn D. Wylie, Michael L. Casazza, and Brian J. Halstead

August 2018 – Ecosphere
Distribution of the Giant gartersnake (Thamnophis gigas) in the Volta Area of the San Joaquin Valley (.pdf)

Eric C. Hansen and Rick Scherer, Ph.D

December 2017 – Eric C. Hansen
Giant gartersnake (Thamnophis gigas) Environmental DNA and trapping surveys at the Natomas Basin Conservancy’s Cummings Tract, Sacramento County, CA (.pdf)

Eric C. Hansen

December 2017 – Eric C. Hansen
Giant gartersnake (Thamnophis gigas) Surveys on the Cosumnes River Ecological Reserve: Sacramento County, California – 2017 Monitoring Report (.pdf)

Eric C. Hansen and Rick Scherer, Ph.D.

October 2017 – Eric C. Hansen
Recovery Plan for the Giant Garter Snake (Thamnophis gigas) (.pdf)

U.S. Fish & Wildlife Service

September 2017 – U.S. Fish & Wildlife Service
An Evaluation of the Efficacy of Using Environmental DNA (eDNA) to Detect Giant Gartersnakes (Thamnophis gigas) (.pdf)

Brian J. Halstead, Dustin A. Wood, Lizabeth Bowen, Shannon C. Waters, Amy G. Vandergast, Julia S. Ersan, Shannon M. Skalos, and Michael L. Casazza

September 2017 – U.S. Geological Survey
Relations between Environmental Attributes and Contemporary Occupancy of Threatened Giant gartersnakes (.pdf)

Eric C. Hansen, Rick D. Scherer, Erica Fleishman, Brett G. Dickson, and Dave Krolick

April 2017 – Journal of Herpetology, 51(2):274-283.
Estimates of Survival Probability from Two Populations of Giant gartersnakes in California’s Great Central Valley (.pdf)

Eric C. Hansen, Rick D. Scherer, Gary C. White, Brett G. Dickson, and Erica Fleishman

December 2015 – Copeia
Defining population structure and genetics signatures of declines in the giant gartersnakes (Thamnophis gigas): implications for conserving threatened species within highly altered landscapes. (.pdf)

Dustin A. Wood, Brian J. Halstead, Michael L. Casazza, Eric C. Hansen, Glenn D. Wylie and Amy G. Vandergast

October 2015 – Conservation Genetics
A Conceptual Model for Site-Level Ecology of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley, California (.pdf)

Brian J. Halstead, Glenn D. Wylie, Michael L. Casazza, Eric C. Hansen, Rick D. Scherer, and Laura C. Patterson

August 2015 – U.S. Geological Survey
Literature Review of Giant Gartersnake (Thamnophis gigas) Biology and Conservation (.pdf)

Brian J. Halstead, Glenn D. Wylie, and Michael L. Casazza

August 2015 – U.S. Geological Survey
Thamnophis Gigas (Giant Gartersnake) Movement (.pdf)

Brian J. Halstead, Glenn D. Wylie, Michael L. Casazza, Eric C. Hansen, and John R. Roberts III

March 2013 – Herpetological Review 44(1)
Giant Garter Snake Monitoring Update (.pdf)

Brian Halstead and Michael Casazza

October 2012 – U.S. Geological Survey, Western Ecological Research Center
Implementation of Priority 1, Priority 2, and Priority 3 Recovery Tasks for Giant Garter Snake (Thamnophis gigas) – Status and distribution of giant garter snakes at the eastern Delta’s White Slough Wildlife Area, San Joaquin County, CA (.pdf)

Eric C. Hansen

March 2011 – Eric C. Hansen
Giant Garter Snake Status Report (.pdf)

Eric Hansen

February 2009 – The Natomas Basin Conservancy
Acute Oral and Dermal Toxicity of Aquatic Herbicides and a Surfactant to Garter Snakes (.pdf)

Robert C. Hosea, Kalen Z. Bjurstrom, Edward E. Littrell

February 2004 – California Department of Fish and Game

Swainson’s hawk

Rapid growth of the Swainson’s Hawk population in California since 2005 (.pdf)

Brett J. Furnas, David H. Wright, Erin N. Tennant, Reagen M. O’Leary, Michael J. Kuehn, Peter H. Bloom, and Carie L. Battistone

February 2022 – American Ornithological Society
Clinal variation in morph frequency in Swainson’s hawk across North America: no support for Gloger’s ecogeographical rule (.pdf)

Arjun Amar, Chevonne Reynolds, Julia van Velden, and Christopher W. Briggs

February 2019 – The Linnean Society of London
Space Use by Swainson’s Hawk (Buteo swainsoni) in the Natomas Basin, California (.pdf)

E. Fleishman, J. Anderson, B. G. Dickson, D. Krolick, J. A. Estep, R. L. Anderson, C. S. Elphick, D. S. Dobkin and D. A. Bell

April 2016 – Collabra
Swainson’s Hawk Status Report (.pdf)

Jim Estep

November 2012 – The Natomas Basin Conservancy
Swainson’s Hawk Status Report (.pdf)

Jim Estep

December 2010 – The Natomas Basin Conservancy
Swainson’s Hawk Status Report (.pdf)

Jim Estep

February 2009 – The Natomas Basin Conservancy

Other Reports

Evaluation of Wetland Hydrology in Formerly Irrigated Areas (.pdf)

Jackob F. Berkowitz, Jason P. Pietroski, and Steven J. Currie

July 2017 – US Army Corps of Engineers® Engineer Research and Development Center
Trees of the Natomas Basin Conservancy (.pdf)

Sacramento Tree Foundation

June 2011 – The Natomas Basin Conservancy
Fish Sampling on Constructed Wetland on the Natomas Basin Conservancy’s BKS Tract (.pdf)

Doug Leslie and Marin Greenwood

June 2009 – The Natomas Basin Conservancy
Monitoring Avian Productivity and Survivorship (MAPS) in the North Basin Reserve (.pdf)

Julia Camp and Doug Leslie

April 2008 – The Natomas Basin Conservancy

Research

Giant garter snake

A tale of two valleys: Endangered species policy and the fate of the giant gartersnake (.pdf)

Intrinsic Prey Preference and Selection of the Giant Gartersnake: A Threatened Predator in a Nonnative Prey-Dominated Community (.pdf)

Giant Gartersnakes (Thamnophis gigas) Exploit Abundant Nonnative Prey While Maintaining Their Appetite for Native Anurans (.pdf)

Conservation reliance of a threatened snake on rice agriculture (.pdf)

Integrating growth and capture–mark–recapture models reveals size-dependent survival in an elusive species (.pdf)

Distribution of the Giant gartersnake (Thamnophis gigas) in the Volta Area of the San Joaquin Valley (.pdf)

Giant gartersnake (Thamnophis gigas) Environmental DNA and trapping surveys at the Natomas Basin Conservancy’s Cummings Tract, Sacramento County, CA (.pdf)

Giant gartersnake (Thamnophis gigas) Surveys on the Cosumnes River Ecological Reserve: Sacramento County, California – 2017 Monitoring Report (.pdf)

Recovery Plan for the Giant Garter Snake (Thamnophis gigas) (.pdf)

An Evaluation of the Efficacy of Using Environmental DNA (eDNA) to Detect Giant Gartersnakes (Thamnophis gigas) (.pdf)

Relations between Environmental Attributes and Contemporary Occupancy of Threatened Giant gartersnakes (.pdf)

Estimates of Survival Probability from Two Populations of Giant gartersnakes in California’s Great Central Valley (.pdf)

Defining population structure and genetics signatures of declines in the giant gartersnakes (Thamnophis gigas): implications for conserving threatened species within highly altered landscapes. (.pdf)

A Conceptual Model for Site-Level Ecology of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley, California (.pdf)

Literature Review of Giant Gartersnake (Thamnophis gigas) Biology and Conservation (.pdf)

Thamnophis Gigas (Giant Gartersnake) Movement (.pdf)

Giant Garter Snake Monitoring Update (.pdf)

Implementation of Priority 1, Priority 2, and Priority 3 Recovery Tasks for Giant Garter Snake (Thamnophis gigas) – Status and distribution of giant garter snakes at the eastern Delta’s White Slough Wildlife Area, San Joaquin County, CA (.pdf)

Giant Garter Snake Status Report (.pdf)

Acute Oral and Dermal Toxicity of Aquatic Herbicides and a Surfactant to Garter Snakes (.pdf)

Swainson’s hawk

Rapid growth of the Swainson’s Hawk population in California since 2005 (.pdf)

Clinal variation in morph frequency in Swainson’s hawk across North America: no support for Gloger’s ecogeographical rule (.pdf)

Space Use by Swainson’s Hawk (Buteo swainsoni) in the Natomas Basin, California (.pdf)

Swainson’s Hawk Status Report (.pdf)

Swainson’s Hawk Status Report (.pdf)

Swainson’s Hawk Status Report (.pdf)

Other Reports

Evaluation of Wetland Hydrology in Formerly Irrigated Areas (.pdf)

Trees of the Natomas Basin Conservancy (.pdf)

Fish Sampling on Constructed Wetland on the Natomas Basin Conservancy’s BKS Tract (.pdf)

Monitoring Avian Productivity and Survivorship (MAPS) in the North Basin Reserve (.pdf)