Reptile Biodiversity in the Pacific Basin Islands

Science Center Objects

Dr. Robert Fisher and his colleagues have teamed up with the U.S. Fish and Wildlife, The Nature Conservancy and multiple universities to conduct several types of studies that will address high priority issues related to reptiles in the Pacific Basin Islands. These studies will provide new information about species diversity, endemicity, biology and demography of reptile fauna and will lay the groundwork to provide a relatively easy and efficient method for detecting future, non-natural ecosystem disturbances.

USGS and San Diego Zoo scientists study iguana
Photo of USGS scientist Robert Fisher and a researcher from San Diego Zoo Global studying a Fijian crested iguana on Monuriki Island, Fiji. Used with permission from San Diego Zoo Global.

The Pacific Basin is comprised of many island groups. Some of these are U.S. Territories such as Guam, American Samoa, and Palmyra Atoll. A few are former U.S. Trust Territories such as Federated States of Micronesia, Marshall Islands, and Palau. Most are foreign nations and USGS works directly with their ministries of environment, these include Fiji, Samoa, Tonga, Nauru, Vanuatu, Tuvalu, Kiribati, Solomons, Papua New Guinea, and the Cook Islands.

Across the Pacific Basin, there have been a number of inventory and monitoring programs conducted on several major vertebrate groups, including, birds, fish and mammals. However, one integral component of the vertebrate fauna that has not received much attention is the reptiles. Their important role as top predators within the ecosystem warrant the attention as populations vary from highly abundant to rare. Habitat disturbance, presence of non-native species, and the perpetual risk of additional non-native introductions via commercial shipping operations and various U.S. military activities continue to threaten the native reptile populations, but limited knowledge of species diversity, biology and demography is preventing adequate assessment of their conservation status. Baseline data are lacking for most island groups and quantitative data are lacking for almost all of these island groups. Thus the current knowledge is insufficient to inform recovery action if or when it is needed.  Particular examples of this lack of data include American Samoa where the herpetofauna have not been inventoried since 1976, prior to establishment of any protected lands on the islands. Thus, there are no current data that can be used to characterize the conservation status of this ecologically important taxonomic group, nor is there reliable data on existing or potential threats to their existence. This lack of information is preventing the development of specific monitoring and management goals, including the design of biosecurity measures that will assist in preventing the further spread of invasive species and possible extinction of rare or endemic taxa.

With the development of genetic sampling, it is possible to screen and develop several nuclear and mitochondrial genetic markers to assess their utility for phylogenetic analysis in taxonomic groups (i.e. geckos of the genus Gehyra; skinks of the genus Emoia). Collecting molecular data for several focal taxonomic groups will help to investigate colonization and dispersal patterns, identify cryptic species, and assess cause of declines in biodiversity of these species groups in particular species listed by the USFWS under the ESA, by CITES, and by IUCN Red List (i.e. iguanas of the genus Brachylophus).

Another facet of this research is to investigate how plant and animal communities, as well as specific target species, respond to landscape alteration caused by increasing human development, invasive species, sea level rise, and increasing intensity of storm surges. The communities represented in this research include both invertebrates (selected terrestrial macro-invertebrates, and ants), and vertebrates (amphibians, reptiles, small mammals, birds, bats, and carnivores (invasive mongoose, cats)), as well as the associated plant communities. The research involves numerous individual projects, a variety of study areas, and many complex questions. Overall, the primary objectives include, (1) determining baseline species richness, distribution, and abundance within study sites, (2) obtaining data essential to proper conservation and management of target species (i.e. habitat affinities and environmental variables influencing distribution), and (3) monitoring ecological communities and/or focal species over time to assess long-term trends. However, the ultimate goal is development of guidelines and protocols for future monitoring and preservation of wildlife species, as well as, comprehensive datasets to inform land management and recovery decisions across the Pacific Basin. The majority of this research is done to support National Park Service (NPS), U.S. Fish and Wildlife Service (USFWS), the Department of Defense (DOD), Department of State Regional Environmental Office (Suva), BINGO’s (including IUCN, CI, WCS, TNC, WWF), and many small island nation governments (ie Fiji, Nauru, Samoa, Tonga, Tuvalu, etc.), in the monitoring and recovery of threatened and endangered (T & E) species in addition to assessing biosecurity risks.

Our main goals are to:

1. Provide the scientific foundation for the conservation of terrestrial plants, wildlife, and habitats

2. Provide tools and techniques for science based management

3. Identify factors that contribute or limit conservation and recovery for terrestrial plant and wildlife species at risk

4. Institute and adaptive science approach to support the adaptive management of terrestrial plants and wildlife and provide technical assistance to natural resource managers

5 Enhance USGS wildlife research to meet emerging and future issues