Conversion and fragmentation of wildlife habitat often leads to smaller and isolated populations and can reduce a species’ ability to disperse across the landscape. As a consequence, genetic drift can quickly lower genetic variation and increase vulnerability to extirpation. For species of conservation concern, quantification of population size and connectivity can clarify the influence of genetic drift in local populations and provides important information for conservation management and recovery strategies. Here, we used genome-wide single nucleotide polymorphism (SNP) data and capture-mark-recapture methods to evaluate the population structure, genetic diversity and abundance of seven focal sites of the endangered San Francisco gartersnake (Thamnophis sirtalis tetrataenia), a species affected by alteration and isolation of wetland habitats throughout its distribution. We also used temporally sampled datasets to examine the magnitude of genetic change over time.

We used genome-wide single nucleotide polymorphism (SNP) data and capture-mark-recapture methods to evaluate the genetic diversity and demography within seven focal sites of the endangered San Francisco gartersnake (Thamnophis sirtalis tetrataenia). As Thamnophis sirtalis tetrataenia is listed as endangered by the U.S. Fish and Wildlife Service (USFWS), sensitive location information can be made available upon request by contacting Brian J. Halstead and/or Amy G. Vandergast.

We used genome-wide single nucleotide polymorphism (SNP) data and capture-mark-recapture methods to evaluate the genetic diversity and demography within seven focal sites of the endangered San Francisco gartersnake (Thamnophis sirtalis tetrataenia). As Thamnophis sirtalis tetrataenia is listed as endangered by the U.S. Fish and Wildlife Service (USFWS), sensitive location information can be made available upon request by contacting Brian J. Halstead and/or Amy G. Vandergast.

A study comparing reintroduction scenarios for the San Francisco gartersnake (Thamnophis sirtalis tetrataenia), an endangered subspecies native to San Mateo County and Santa Cruz County in northern California. Models for snake survival, growth, fecundity, and reproductive status were used to construct a demographic population model. Data are posterior distributions for demographic parameters from Markov Chain Monte Carlo sampling in hierarchical Bayesian models.

A study comparing reintroduction scenarios for the San Francisco gartersnake (Thamnophis sirtalis tetrataenia), an endangered subspecies native to San Mateo County and Santa Cruz County in northern California. Models for snake survival, growth, fecundity, and reproductive status were used to construct a demographic population model. Data are posterior distributions for demographic parameters from Markov Chain Monte Carlo sampling in hierarchical Bayesian models.

This dataset includes records of captures of San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) collected at five sites from 2007 to 2020. The data include measurements of snake snout-vent length to estimate growth patterns, snake sex, and the record of all captures of individual snakes for estimating capture probability, availability for capture, and survival.

Capture-mark-recapture data from San Francisco Gartersnakes at five sites in San Mateo County, California in 2018. These data include capture histories, snout-vent lengths, and sex for individual snakes. R files included with the data fit closed capture-mark-recapture models to estimate the abundance of adult snakes at each site in 2018.

Adult female San Francisco gartersnakes (Thamnophis sirtalis tetrataenia) were captured and examined using an ultrasound device to determine if they were gravid and count the number of embryos in those that were. Morphological data including length and mass were collected for each snake, along with the date of capture and a study site identifier.

The sea-cliff bedstraw (Galium buxifolium) data set contains two types of information, formatted as CSV worksheets: 1) Spatial coordinates (WGS 84) of known population occurrences on Santa Cruz and San Miguel Islands, California, as of 2006 (sensitive locality information); 2) Demographic data measured at four populations growing on Santa Cruz Island. Three of the populations were measured in 2005 and 2006, the fourth was measured in 2005, 2006, 2008, 2010, 2011, and 2014.

These data support the following publication: Rose, J.P., Ersan, J.S., Wylie, G.D., Casazza, M.L. and Halstead, B.J., 2019. Demographic factors affecting population growth in giant gartersnakes. The Journal of Wildlife Management, 83(7), pp.1540-1551.