Assessing the status of a threatened island endemic, Ctenosaura oedirhina, on Roatán, Honduras
A. B. C. Goode
A B E , S. A. Pasachnik C and T. L. Maple D
+ Author Affiliations
- Author Affiliations
A College of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
B USDA-ARS Invasive Plant Research Laboratory, 3225 College Avenue, Davie, FL 33314, USA.
C Fort Worth Zoo, 1989 Colonial Parkway, Fort Worth, TX 76110, USA.
D Jacksonville Zoo, 370 Zoo Parkway, Jacksonville, FL 32218, USA.
E Corresponding author. Email: acampbellgoode@gmail.com
Wildlife Research 47(2) 137-145 https://doi.org/10.1071/WR18195
Submitted: 22 August 2017 Accepted: 23 September 2019 Published: 21 February 2020
Abstract
Context: Organisms living in small, isolated populations with very restricted ranges are at high risk of extirpation due to various direct and indirect forces than mainland populations. Roatán spiny-tailed iguanas (Ctenosaura oedirhina) are endemic to the 146-km2 island of Roatán, Honduras. Harvesting for consumption, fragmentation of habitat and predation by domestic animals threaten the existence of this lizard. This species is federally protected in Honduras; however, enforcement is rare. These iguanas are also listed as Endangered by the International Union for Conservation of Nature (IUCN) and are on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This species is geographically and genetically isolated into small subpopulations that are declining in density.
Aims: To estimate the population size of Roatán spiny-tailed iguanas (Ctenosaura oedirhina) on the island of Roatán, Honduras.
Methods: Distance sampling surveys have been used to monitor this species since 2012, and have been used to determine population density at five study sites. Estimates of density at those sites and across the island were used to calculate the population size of this species.
Key results: The present study elucidates that the high-density populations remaining are declining. The current population size is estimated to be 3759 (95% CI = 1406–12 616) individuals within the study sites, with 730 additional iguanas potentially outside of the study sites.
Conclusions: If the current level of decline continues, this species may become extirpated from some locations on Roatán, and go extinct in the wild. Although Honduras does have laws protecting this species and other wildlife, enforcement must be enhanced.
Implications: Lack of enforced protection for this species allows poaching for consumption to continue, which has been shown to alter its distribution and cause increased adult mortality. Local customs value the consumption of this species, creating a delicate management situation. Recommendations include strategies that mitigate the threat posed by consumption and increase enforcement of the current laws, while acknowledging cultural traditions.
Additional keywords: distance sampling, population density, Spiny-tailed Iguana.
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