Computer-assisted photo identification outperforms visible implant elastomers in an endangered salamander, Eurycea tonkawae
- PMID: 23555669
- PMCID: PMC3605430
- DOI: 10.1371/journal.pone.0059424
Computer-assisted photo identification outperforms visible implant elastomers in an endangered salamander, Eurycea tonkawae
Abstract
Despite recognition that nearly one-third of the 6300 amphibian species are threatened with extinction, our understanding of the general ecology and population status of many amphibians is relatively poor. A widely-used method for monitoring amphibians involves injecting captured individuals with unique combinations of colored visible implant elastomer (VIE). We compared VIE identification to a less-invasive method - computer-assisted photographic identification (photoID) - in endangered Jollyville Plateau salamanders (Eurycea tonkawae), a species with a known range limited to eight stream drainages in central Texas. We based photoID on the unique pigmentation patterns on the dorsal head region of 1215 individual salamanders using identification software Wild-ID. We compared the performance of photoID methods to VIEs using both 'high-quality' and 'low-quality' images, which were taken using two different camera types and technologies. For high-quality images, the photoID method had a false rejection rate of 0.76% compared to 1.90% for VIEs. Using a comparable dataset of lower-quality images, the false rejection rate was much higher (15.9%). Photo matching scores were negatively correlated with time between captures, suggesting that evolving natural marks could increase misidentification rates in longer term capture-recapture studies. Our study demonstrates the utility of large-scale capture-recapture using photo identification methods for Eurycea and other species with stable natural marks that can be reliably photographed.
Conflict of interest statement
Figures




References
-
- Stuart SN, Chanson JS, Cox NA, Young BE, Rodrigues ASL, et al. (2004) Status and trends of amphibian declines and extinctions worldwide. Science 306: 1783–1786 doi:10.1126/science.1103538 - DOI - PubMed
-
- Wake DB, Vredenburg VT (2008) Are we in the midst of the sixth mass extinction? A view from the world of amphibians. Proc Natl Acad Sci U S A 105: 11466–11473 doi:10.1073/pnas.0801921105 - DOI - PMC - PubMed
-
- Amstrup SC, McDonald TL, Manly BFJ (2010) Handbook of Capture-Recapture Analysis. Princeton: Princeton University Press. 335 p.
-
- Bailey LL (2004) Evaluating elastomer marking and photo identification methods for terrestrial salamanders: Marking effects and observer bias. Herpetol Rev 35: 38–41.
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources