2018 Roatán Monitoring

Monitoring an endangered iguana and cultivating the next generation of researchers and managers, 2018 report

IIF Grant report submitted by Stesha Pasachnik (Fort Worth Zoo), Daisy Maryon (University of South Wales), and Ashley Goode (USDA)

Ctenosaura oedirhina
A recaptured Roatán Spiny-tailed Iguana that was first marked in 2010. Photo by Daisy Maryon.

Ctenosaura oedirhina
2018 workshop participants at one of our long-term field sites. This site has been supportive of our work since 2010 and has even made iguana informational signs. Photo by Stesha Pasachnik.
Ctenosaura oedirhina
Daisy Maryon instructing two participants on processing techniques. Photo by Stesha Pasachnik.

Our standard workshop included five participants from five different countries. Our sixth participant had to cancel due to yellow fever-related travel issues. One participant was an undergraduate student (Guatemala), two were conservation technicians (Nicaragua and Jamaica), one was a conservation program volunteer (Bahamas), and one was a museum curator (Cuba). After assessing the varied backgrounds and interests of the participants, we designed the field and lecture components of the workshop to cater to their interests and needs. By training participants, we help to build capacity in the region for those just beginning their research careers and those already involved in iguana projects and management. The undergraduate student was able to get hands-on experience that will help them as they move forward in their academic career: “I enjoyed a lot the group interactions and also the field work. My favorite part was the processing because I learned a lot and also because I have never done some of these things”. While one of the technicians had “the opportunity to work with a different species of iguanas,” the other technician was excited to work on a capture/recapture survey, they said, “me gusto mucho la captura y recaptura de los species”. The participants came with diverse backgrounds in fieldwork, education, and career paths, but all were able to practice common field techniques and surveys they may not have had experience with in their current projects.

Ctenosaura oedirhina
Ultrasound exams were performed on captured female iguanas to look for eggs. Photo by Daisy Maryon.

Due to weather conditions we were not able to continue our ongoing dietary study but instead focused on an IUCN Red List assessment for Ctenosaura quinquecarinata. This assessment is one that has needed to be completed for some time, making this activity a great help to the IUCN SSC Iguana Specialist Group. At the same time the participants gained valuable insight into the decision-making process of listing a species and will get a publication out of the experience. The Houston high school workshop was a less intensive program but still provided hands-on experience.

The data collected during these workshops marks our eighth year of mark-recapture research. In total, 151 new iguanas were captured and 45 were recaptured across our sites, including a new privately-owned site. The new site is small but has a high density of iguanas. Over the course of this study from 2010 onward, we have seen fluctuations in population size, so continued monitoring of demographic trends is vital to proper management of this species. In addition, maintaining a presence on the island helps to reinforce protection for iguanas, especially at study sites where hunting intrusions occur. The captured and tagged iguanas provide important data points for growth and survival analyses. The recaptured individuals in the last workshop show some of the originally captured iguanas from 2010 and 2011 are still alive, providing longevity information. These demographic data provide the first long-term monitoring effort for this genus and can be used as a model for other species within the genus.

Ctenosaura oedirhina
Long-time field assistant Mikel Belcaries working with an upcoming assistant to release an iguana. Photo by Daisy Maryon.

Unfortunately, this year also marks the discovery of an invasive population of Útila Spiny-tailed Iguana, Ctenosaura bakeri, the neighboring island endemic from Útila, Honduras. The cay where the population occurs was briefly surveyed and several invasive iguanas were documented. We worked closely with the federal government of Honduras, discussed what actions to take, and have begun moving forward with our joint decision, recognizing that it is ultimately the responsibility of the government agency to take action.


Future. We plan to continue these workshops to ensure that monitoring of this species persists, while building capacity in iguana range countries. In future years, we will continue to complete IUCN Red List assessments and would like to include additional smaller projects, similar to our ongoing dietary study. This will allow participants to experience managing data collection, analyzing data, and give them the opportunity to publish short articles. We are also beginning a collaboration with Dr. Susannah French (Utah State University) to study stress physiology of iguanas across the sites. In addition to stress-related data, we will work together to better understand the reproductive cycle and behavior of this species, something that has been lacking in our research to date. Lastly, due to our discovery of an invasive Ctenosaura bakeri population on a small cay off Roatán we will focus monitoring and management efforts on this population to reduce risk of hybridization and genetic swamping.

Ctenosaura palearis
El Arenal elementary school children (Cabañas, Zacapa) wearing their environmental awareness t-shirts during the field workshop at the HNR. Photo by Gilberto Salazar.

Because of the great success we had with schools that were initially part of the education program, we have had many requests from school principals in towns that were not encompassed by the project to consider them for 2017. The Local Coordinator of the Education Ministry said that the program has changed the lives of many children in those impoverished rural communities. For us, there is nothing more soul-fulfilling than the smiles of children that gave their best efforts in drawing the iguana friends they learned to protect.

Camera trap monitoring. Beginning in the last week of April, we implemented a camera trapping program to follow shelter activity of four iguanas that were radiotracked in 2015. These iguanas were monitored with eight Stealth Cam camera traps. This video data was shared in the school workshops and allowed the children to learn about iguana behavior in the wild. With the camera traps we also documented that adult Ctenosaura palearis actively search and hunt for ants (Formicidae) and velvet ants (Mutillidae). The daily activity patterns obtained to date show that Ctenosaura palearis usually emerges from their shelters at approximately 9:00 AM and returns to them at 4:00 PM. We now have a better understanding of Ctenosaura palearis wild behavior and ecology by documenting daily activity, shelter use, and behavior. We also documented other species visiting iguana shelters, such as the Southern Spotted Skunk Spilogale angustifrons, Margay Leopardus wiedii, and the Central American Lyre Snake Trimorphodon quadruplex.

Future. In response to requests from school principals in neighboring towns, we intend to expand the conservation education program in 2017. We will next visit the elementary schools in San Luis, Cerco Piedra, Quebrada Honda, and Puente. We also need to continue camera trap monitoring of iguana daily activity patterns and continue microchip marking for long-term population monitoring. We also need research to determine the genetic structure of the population and identify possible evolutionary significant units throughout the valley. Additionally, we intend to assess basic health parameters such as hemogram and parasite testing, and also determine the gut microbiota that may affect germination of gut-passed seeds. Finally, we need to radiotrack iguanas in the dry season (January through June) to get a better understanding of mating behavior and complement our data from the wet season (July–December 2015).

We will seek additional IIF funding to achieve these goals, which will cover lab reagents, transportation costs, education materials, microchips, and an education program coordinator’s salary.