Population Genetics and Impact Threat Assessment of Invasive Jackson's Chameleons in Hawaii

Several dozen Jackson’s chameleons (Chamaeleo jacksonii xantholopholus) were introduced to Oahu from Africa by a pet importer in 1973. A recent study demonstrated that Jackson’s chameleons prey on native invertebrates, including critically endangered tree snails, in pristine Hawaiian forests. The University of Hawaii Tree Snail Conservation Laboratory has begun a series of investigations to determine the level of threat posed by this invasive reptile, including molecular studies to evaluate genetic diversity of chameleon populations in Hawaii. Population genetics theory predicts that introduced species with low genetic diversity will not thrive in novel habitats due to an inability to adapt, however, chameleons are established and thriving on all major islands of Hawaii. We hypothesize that chameleons have done well in the Hawaiian Islands despite low genetic diversity, contrary to theoretical predictions. Current molecular research involves the collection of Jackson’s chameleons by hand from native Hawaiian forests and generation of mtDNA sequences (ND4-Leu). In collaboration with researchers in Eastern Africa and Australia, African haplotypes collected from the natural range in Kenya were compared to those of Hawaiian chameleons using phylogenetic trees and haplotype networks. Preliminary data show low genetic variance within Hawaiian chameleons; only four haplotypes were found among 52 Hawaiian chameleons with Kenyan sequences differing by just a few basepairs. Our hypothesis is supported by preliminary results, and sampling is ongoing. Threat assessment and population genetic studies of predators such as Jackson’s chameleons contribute to the efforts to conserve and maintain the integrity of Hawaiian forests and associated endemic biodiversity.