A preliminary report on research concerning the lizards of Redonda, Antigua, and Great Bird Island Prepared for: The Government of Antigua and Barbuda Ministry of Health and the Environment March 10, 2017 Prepared by: Dr. Colin Donihue In collaboration with Dr. Anthony Herrel and Geoffrey Giller Contact: [email protected] Harvard University, Museum of Comparative Zoology 26 Oxford St. Cambridge, MA 02140. USA. Components Report Introduction and aims .......................................................................................................2 Data collected ....................................................................................................................2 Summary of findings ........................................................................................................3 Next steps ..........................................................................................................................4 Additional Information Research picture captions .................................................................................................4 Description of field notes ..................................................................................................6 Description of databases ...................................................................................................6 C. M. Donihue Preliminary report on the status of lizards in Antigua and Barbuda Introduction and Aims The Redonda Restoration Program is a unique opportunity to study the ramifications of goat relocation and rat eradication on the ecology of small islands and particularly on the evolutionary ecology of the three endemic lizard species living on Redonda. We set out to gather diverse baseline data that will allow comparisons with future data sets to determine how the removal of goats and rats from Redonda may change the evolutionary trajectory of Anolis nubilus, Pholidoscelis atrata, and Sphaerodactylus sp. In so doing, we have also gathered unique data on the demography, morphology, performance, population density, behavior, habitat use, and diet of A. nubilus and P. atrata. As Redonda is restored, these lizard populations will no doubt change, and quantifying these changes through time will provide invaluable insight informing other conservation efforts locally and globally. Data Collected Redonda: Anolis nubilus: Demography Morphology, including toe pad and dewlap pictures Bite force Stomach contents of 49 A. nubilus Dewlap color analysis with spectrophotometer Density estimates: survey of the island on set tracks, mark recapture study Behavior: 24 x 30 minute videos of A. nubilus to assess their time budget Habitat use and thermal environment of 60 A. nubilus Fleeing behavior of 50 A. nubilus Pholidoscelis atrata: Demography Morphology Bite force Stomach contents of 17 P. atrata individuals Density estimates: survey of the island on a set track Behavior: 20 x 5 minute videos of P. atrata Fleeing behavior of 50 P. atrata Sphaerodactylus sp. Demography Morphology via pictures of 10 individuals Density estimates: searched under 1200 rocks in organized search Antigua (near Jolly Harbor): Anolis watsii: Demography Morphology of 17 A. watsii individuals 2 C. M. Donihue Preliminary report on the status of lizards in Antigua and Barbuda Bite force Anolis leachii: Demography Morphology of 21 A. leachii individuals Bite force Great Bird Island: Anolis watsii: Demography Morphology of 22 A. watsii individuals Habitat use and thermal environment of 21 individuals Anolis leachii: Demography Morphology of 14 A. leachii individuals Habitat use and thermal environment of 8 individuals Summary of Findings Redonda: During our week on the island, we found large populations of lizards on Redonda. Both A. nubilus and P. atrata are widespread across Redonda. We also found higher than anticipated densities of the dwarf gecko, Sphaerodactylus sp. Finally, we found incidences of an exotic gecko, presumed to be Hemidactylus mabouia though additional efforts to confirm that identification are needed. The tree lizards (A. nubilus) on Redonda are large, particularly compared to similar Anoles found in the West Indies. Males averaged 78 mm in body length whereas females averaged 55 mm in body length. The ground lizard (P. atrata) males averaged 95 mm in length while females averaged 77 mm in length. Of the 31 female Anoles caught as part of the study, 20 were gravid (with eggs). Of the 11 ground lizards captured, 5 had eggs. To survey the dwarf gecko we each flipped 100 rocks on four consecutive nights at four different sites on the island. On average, we each found 6 geckos under those 100 rocks (range: 0 to 10). We avoided capturing most of these lizards to avoid risk of accidental harm, and so confidently assigning sex was difficult. However, we did see many geckos with eggs (visible through the skin). In total we found 62 geckos during the four-night survey. Antigua (near Jolly Harbor): For comparison, we caught a small number of the two Antiguan Anoles, A. watsii and A. leachii. After taking morphological measurements and bite force, all were released without harm. We measured 10 males of each species, 7 watsii females and 11 leachii females. We found that the leachii were particularly sexually dimorphic in bodysize – the average body length of females was 55 mm whereas for males it was nearly 90 mm. The 3 C. M. Donihue Preliminary report on the status of lizards in Antigua and Barbuda watsii males and females were more similar in body size – 50 mm and 42 mm on average, respectively. Both species were very common on the palm trees around Jolly Harbor. Great Bird Island: On Great Bird we caught 14 A. leachii (6 females and 8 males) and 22 A. watsii (9 females and 13 males). The strong sexual dimorphism in leachii found on Antigua was mirrored with female body size slightly larger at an average of 57 mm and male body size averaging 93 mm. Anolis watsii body sizes were nearly identical to those found on Antigua: male average length was 50 mm and female average was 42 mm. Whereas on Antigua the majority of the watsii females were gravid (6 of 7) we found only 1 gravid female among the 9 we captured on Great Bird Island. By and large, on both islands female leachii were unlikely to be gravid – 1 gravid in 6 on Great Bird, 2 gravid in 11 on Antigua. Next Steps: 1) Identify the stomach contents taken from lizards on Redonda. This process will be taking place at the Natural History Museum in Paris under the supervision of Dr. Anthony Herrel. Goal: completion by June 2017. 2) Analyze behavior videos from the lizards on Redonda. This analysis will take place at the Natural History Museum in Paris under the supervision of Dr. Anthony Herrel. Goal: completion by June 2017. 3) Write brief natural history manuscripts aimed at the journal “Breviora” a publication of the Natural History Museum at Harvard. Goal: completion by August 2017. 4) Write a detailed report for the Government of Antigua and Barbuda, Ministry of Health and the Environment presenting our key findings. Completion by August 2017. 5) Apply for permits to the Government of Antigua and Barbuda for a 1-year revisit to Redonda in 2018. Completion by October 2017. Research Picture Captions (all photos by Geoffrey Giller): IMG_00_Giller.jpg: A large ficus tree on Redonda provides ideal habitat for Anolis nubilus. This was the site of one of our mark-recapture surveys to determine A. nubilus abundance. At this tree alone we found 26 lizards. IMG_01_Giller.jpg: Dr. Donihue and Dr. Herrel capturing a lizard and taking data in more typical A. nubilus habitat on Redonda – a large boulder field. IMG_02_Giller.jpg: A large A. nubilus male displaying with his dewlap and head crest at another male (not pictured) in his tree. These displays are common, particularly in the morning. 4 C. M. Donihue Preliminary report on the status of lizards in Antigua and Barbuda IMG_03_Giller.jpg: Most lizards in the study were noosed with a simple slipknot at the end of a long pole. This method is a well-established means of capturing skittish animals and does them no harm. In the background is the thermocouple used to take the lizards’ temperature immediately after capture to better understand their thermal ecology. IMG_04_Giller.jpg: Dr. Herrel measuring a particularly long Pholidoscelis atrata tail. IMG_05_Giller.jpg: Dr. Herrel taking head morphometrics on a P. atrata head. Twenty different morphometrics were taken for each lizard in this way. IMG_06_Giller.jpg: Dr. Donihue and Dr. Herrel at a workstation on Redonda stomach flushing the Anoles. IMG_07_Giller.jpg: A detail shot of the process of stomach flushing the lizards. Water was slowly squeezed into the stomachs of a lizard with a ball-tipped syringe and subsequently, the water and stomach contents would flow out into a waiting mesh strainer. IMG_08_Giller.jpg: A detail shot of an anole being massed. Lizards were kept in this bag and then weighed using a spring scale. IMG_09_Giller.jpg: Lizard bite force is an important functional trait involved in determining what a lizard can eat and how effectively it can defend a territory. Lizard bite forces were measured using this purpose-built bite force meter. Lizards would bite on the bite plates, inducing a current in a force transducer which can be read by an instrument (not shown). IMG_10_Giller.jpg: Dewlap color is an important signaling trait in Anoles. Here we use a spectrophotometer to assess the wavelength of light reflected by these dewlaps. While most Anolis nubilus