Using Pedigree Reconstruction to Test Head-Starting Efficiency for Endangered Amphibians: Field Tested in the Houston Toad (Bufo Houstonensis)




Vandewege, Michael W.

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The Houston Toad (Bufo houstonensis) was first described in 1953 and due to habitat loss and severe droughts the species was placed on the endangered species list in 1970. In 2007, a head-starting project was implemented using tadpoles and juveniles that cannot be marked by traditional means. I developed a method to use molecular genotyping arrays and tested four full sibling reconstruction algorithms to estimate the frequency of head-starts on the landscape. The overall allelic retention of the head-starts was 67% of the wild population. The percent retention ranged from 28% to 90% among subpopulations. COLONY was the most accurate family assignment software placing 97% of samples into their appropriate sib groups. Several of these groups (20%) showed evidence of multiple paternity but it is unclear if this is the result of multiple amplexus events, indirect fertilization, or physical cross contamination of egg strands either in captivity or upon collection from the wild. I estimated the over winter survivorship of post-metamorphosed juveniles to be 0.001. Given the low survivorship and low frequency of head-starts on the landscape, this age group is not efficient for head-starting and adult head-starts should be tested for survivorship in the coming years.



Houston Toad, Head-starting, Microsatellites, Conservation genetics, Pedigree reconstruction


Vandewege, M. W. (2011). Using pedigree reconstruction to test head-starting efficiency for endangered amphibians: Field tested in the Houston Toad (Bufo Houstonensis)</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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