2018 Galápagos Pink Iguana Report

Tracking the Galápagos Pink Iguana: Conservation of a Critically Endangered Flagship Species

Gabriele Gentile, University of Rome

Galapagos Pink Iguana
A Pink Iguana male (Photo G. Gentile)

                                                                                          Overview and Objectives. 

  •  Installation of GPS devices on Conolophus martha and Conolophus subcristatus on Wolf Volcano.
  • Data collection: GPS devices collect data on iguana positions for approximately one year.
  • On-site dissemination activities with the Galapagos National Park Directorate
  • Location of nesting sites for C. marthae and C. subcristatus in Wolf volcano and habitat suitability maps (due to delay in activities these objectives were not able to be completed)                                                                                                                                                                                                            Outcomes and Impact

Installation of GPS devices on C. marthae and C. subcristatus on Wolf Volcano

 As soon as the logistics allowed (a helicopter became available), we organized a trip to Wolf Volcano (Isabela Island). GPS devices were successfully installed on 15 pink iguanas (C. marthae, 8 males and 7 females) and 5 yellow iguanas (C. subcristatus, 2 males and 3 females) from the Wolf Volcano area between 20-26 September 2019. A very good result, even if it required a strong search effort, considering that during that time of year iguanas are expected to be dispersed along the slopes of the volcano and the population size of the C. marthae is very small. Captures were performed according to a protocol approved by the GNPD and park rangers participated in the captures. Devices were attached to iguanas using a combination of gluing and dermal microsurgery. Proper disinfection of skin and local anesthesia were performed before suturing. By using this approach, GPSs are expected to remain attached for at least a year. Accidentally detached devices cause negligible habitat alteration. In fact, the GPS devices were developed and built pursuing a “green engineering” approach to the design of the device by using processes and products to minimize potential hazards and toxicity (e.g. using micro solar panels and supercapacitors instead of Li-Ion batteries). Additionally, we installed 5 data-logging weather stations in different areas of the volcano.

Galapagos Pink Iguana
A Pink Iguana with a GPS device installed (Photo G. Colosimo)
The satellite gateway and one the weather stations installed on the top of Wolf Volcano, Isabela Island (Photo G. Colosimo)

Data collection: GPS devices collect data on iguana positions for approximately one year. 

Since their installation, in September 2019, GPSs have started collecting data. The satellite gateway had been already transported and tested in Galápagos in November 2018, but we could lift it up to the top of the volcano only when the helicopter became available. This occurred in September 2019. Now it has been assembled on the top of Wolf Volcano, where it works properly and regularly transmits data to the Galápagos National Park Directorate and the Tor Vergata University, in Rome, Italy.           

We provided the devices with a software algorithm that can evaluate the goodness and reliability of the points collected, allowing to filter bad data out. Filtered data are immediately plotted on a geographic map of the area. We are also working at an alternative way to retrieve data from the devices in case of poor communication between devices and the gateway or interruption of satellite connection. In fact, under those circumstances, collected data will not get lost, because they will remain stored in the memory of the device. We are working at the possibility retrieve them via a radio-receiving device installed on a drone overflying the area.

On-site dissemination activities with the Galapagos National Park Directorate

We took advantage of our trips to Galapagos to organize meetings (November 2018, and September 2019) with the local community, Municipality of Puerto Ayora (Santa Cruz Island), Park rangers, and Park guides to illustrate the activities and objectives of the project. In coordination with the Communication Department of the Galápagos National Park we provided material to be popularized by local press and the Park’s website.

Future

Even though the system works efficiently, the number of pink and yellow iguanas equipped with GPS units is still too low. By June 2020, that is before the laying season starts, more pink iguana females should be equipped with GPS units, to increase the opportunity to monitor gravid females migrating to nesting sites. Based on the sample size, sex ratio, and gravid/non-gravid ratio observed in previous mark/recapture sessions we estimate that at least 30 pink iguana females should be equipped with GPS units before the laying season starts. Usually, by late July most gravid pink iguana females have laid their eggs. We have to go there again and install more GPSs to maximize our chances of locating nest sites.

Galapagos Pink Iguana
Researchers in action. Weighing a Galapagos Pink Iguana (C. marthae) male. (Photo G. Colosimo)
Measuring iguanas -G cossimo