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Literature review of giant gartersnake (Thamnophis gigas) biology and conservation

Open-File Report 2015-1150
Prepared in cooperation with the California Department of Water Resources
By: , , and 
https://doi.org/10.3133/ofr20151150

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Abstract

This report reviews the available literature on giant gartersnakes (Thamnophis gigas) to compile existing information on this species and identify knowledge gaps that, if addressed, would help to inform conservation efforts for giant gartersnakes.  Giant gartersnakes comprise a species of semi-aquatic snake precinctive to wetlands in the Central Valley of California.  The diversion of surface water and conversion of wetlands to agricultural and other land uses resulted in the loss of more than 90 percent of natural giant gartersnake habitats.  Because of this habitat loss, giant gartersnakes are now listed by the United States and California Endangered Species Acts as Threatened.  Most extant populations occur in the rice-growing regions of the Sacramento Valley, which comprises the northern portion of the giant gartersnake’s former range.  The huge demand for water in California for agriculture, industry, recreation, and other human consumption, combined with periodic severe drought, places remaining giant gartersnake habitats at increased risk of degradation and loss.  This literature review summarizes the available information on giant gartersnake distribution, habitat relations, behavior, demography, and other aspects of its biology relevant to conservation.  This information is then compiled into a graphical conceptual model that indicates the importance of different aspects of giant gartersnake biology for maintaining positive population growth, and identifies those areas for which important information relevant for conservation is lacking.  Directing research efforts toward these aspects of giant gartersnake ecology will likely result in improvements to conserving this unique species while meeting the high demands for water in California.

Suggested Citation

Halstead, B.J., Wylie, G.D., and Casazza, M.L., 2015, Literature review of giant gartersnake (Thamnophis gigas) biology and conservation: U.S. Geological Survey Open-File Report 2015–1150, 38 p., http://dx.doi.org/10.3133/ofr20151150.

ISSN: 2331-1258 (online)

Table of Contents

  • Acknowledgments
  • Identification and Physical Description 
  • Confusing Species
  • Evolutionary History and Fossil Record
  • Distribution
  • Systematics and Geographic Variation
  • Habitat
  • Behavior 
  • Reproduction
  • Growth and Longevity
  • Physiology
  • Food and Feeding
  • Predators and Defense 
  • Population Ecology
  • Community Ecology
  • Conservation Biology
  • Research Methods 
  • Conceptual Model of Giant Gartersnake Ecology at the Population Level 
  • References Cited 
  • Glossary
Publication type Report
Publication Subtype USGS Numbered Series
Title Literature review of giant gartersnake (Thamnophis gigas) biology and conservation
Series title Open-File Report
Series number 2015-1150
DOI 10.3133/ofr20151150
Year Published 2015
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Western Ecological Research Center
Description vi, 38 p.
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details