Get access

Strong founder effects and low genetic diversity in introduced populations of Coqui frogs

Authors


  • Mary Peacock's research focuses on addressing population viability questions. She also uses phytogeographic and phylogenetic approaches to address species conservation issues. Associate Professor Karen Beard's research focuses on invasive species, in particular E. coqui, and the conservation implications of their impacts. Eric O'Neill studied E. coqui colour patterns as part of his dissertation and is now a postdoctoral researcher using molecular techniques to investigate evolutionary questions. Veronica Kirchoff conducted the DNA sequencing for this study. Maureen Peters developed the microsatellites while working as a research technician at SREL.

Karen H. Beard, Fax: +1 435 797 3796; E-mail: karen.beard@usu.edu

Abstract

The success of non-native species may depend on the genetic resources maintained through the invasion process. The Coqui (Eleutherodactylus coqui), a frog endemic to Puerto Rico, was introduced to Hawaii in the late 1980s via the horticulture trade, and has become an aggressive invader. To explore whether genetic diversity and population structure changed with the introduction, we assessed individuals from 15 populations across the Hawaiian Islands and 13 populations across Puerto Rico using six to nine polymorphic microsatellite loci and five dorsolateral colour patterns. Allelic richness (RT) and gene diversity were significantly higher in Puerto Rico than in Hawaii populations. Hawaii also had fewer colour patterns (two versus three to five per population) than Puerto Rico. We found no isolation by distance in the introduced range, even though it exists in the native range. Results suggest extensive mixing among frog populations across Hawaii, and that their spread has been facilitated by humans. Like previous research, our results suggest that Hawaiian Coquis were founded by individuals from sites around San Juan, but unlike previous research the colour pattern and molecular genetic data (nuclear and mtDNA) support two separate introductions, one on the island of Hawaii and one on Maui. Coquis are successful invaders in Hawaii despite the loss of genetic variation. Future introductions may increase genetic variation and potentially its range.

Ancillary