The Road to Recovery of the Monito Gecko (Sphaerodactylus micropithecus)
Jan P. Zegarra-Vila1,*, Miguel A. García-Bermúdez2, Cielo E. Figuerola-Hernández3,Iván Llerandi-Román1, Nicole Angeli4, Ricardo López-Ortiz5, José A. Cruz-Burgos1, and Omar A. Monsegur-Rivera1
1US Fish and Wildlife Service (USFWS) Caribbean Ecological Services Field Office, PO Box 491, Boquerón, PR 00622, USA. 2USFWS, Science Application, 1201 Ceiba Street, San Juan, PR 00926, USA. 3Island Conservation, 2100 Delaware Avenue, Suite 1, Santa Cruz, CA 95060, USA. 4US Virgin Islands Department of Planning and Natural Resources, Division of Fish and Wildlife, 45 Mars Hill, Frederiksted, VI 00840, USA. 5Puerto Rico Department of Natural and Environmental Resources, Division of Commercial Fisheries Research and Management. PO Box 366147, San Juan, PR 00936, USA. *Corresponding author.
Caribbean Naturalist, No. 87 (2022)
Sphaerodactylus micropithecus (Monito Gecko) is an endemic species restricted to Monito Island, an island ~75 km west of mainland Puerto Rico that consist of ~14.7 ha of protected habitat. This species was listed as endangered in October 1982 under the Endangered Species Act (ESA) based on the best available science, which indicated that the species had 1 small population where suspected predation by Rattus rattus (Black Rat) was limiting population growth. Between 1982 and 1994, diurnal visual surveys resulted in a direct maximum count of 21 individuals. Furthermore, 3 capture–mark–recapture surveys conducted in 1993, 1994, and 1997 indicated population densities of 4100, 6000, and 3500 geckos, respectively, based on Petersen-method estimation. A rat eradication campaign was conducted in 1992–1993 and 1998–1999. After the last rat eradication event and gecko survey in 1997, neither formal rat searches nor gecko population estimates were conducted until 2014. When we re-surveyed Monito Island in 2014, no rats were found, and 23 geckos were directly counted in the first nocturnal survey on the island. The discovery of nocturnal activity led to the development of the first nocturnal systematic survey for the gecko in 2016 within 40 randomly distributed plots across the island. Survey and estimation results indicated an occupancy of 27.8% (50% CI: 11.3–68.6%) and a population estimate of 7661 geckos (50% CI: 5344–10,590). Based on these results and alleviation of rat predation, the Monito Gecko was removed from the ESA list in October 2019. Here, we describe the history of conservation efforts for the Monito Gecko, highlight the collaborative efforts between governmental and non-governmental entities for the recovery of the species, and describe the foundation for systematic surveys for this gecko that may work for other threatened species throughout the region.