Microsatellite variation and rare alleles in a bottlenecked Hawaiian Islands endemic: implications for reintroductions

MH Reynolds,KN Courtot,JM Pearce,P Lavretsky,PP Seixas

doi:10.3354/esr00681

Abstract

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 28:117-122 (2015) - DOI: https://doi.org/10.3354/esr00681 NOTE Microsatellite variation and rare alleles in a bottlenecked Hawaiian Islands endemic: implications for reintroductions Michelle H. Reynolds1,*, John M. Pearce2, Philip Lavretsky3, Pedro P. Seixas4, Karen N. Courtot1 1US Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44, Hawai‘i National Park, Hawai‘i 96718, USA 2US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA 3Wright State University, 3640 Colonel Glenn Hwy, Dayton, Ohio 45435, USA 4Centro de Reprodução Anatideos, Rua Mário Pais da Costa, no. 53, 3515-174 Viseu, Portugal *Corresponding author: mreynolds@usgs.gov ABSTRACT: Conservation of genetic biodiversity in endangered wildlife populations is an important challenge to address since the loss of alleles and genetic drift may influence future adaptability. Reintroduction aims to re-establish species to restored or protected ecosystems; however, moving a subset of individuals may result in loss of gene variants during the management-induced bottleneck (i.e. translocation). The endangered Laysan teal Anas laysanensis was once widespread across the Hawaiian archipelago, but became isolated on Laysan Island (415 ha) from the mid-1800s until 2004 when a translocation to Midway Atoll (596 ha) was undertaken to reduce extinction risks. We compared genetic diversity and quantified variation at microsatellite loci sampled from 230 individuals from the wild populations at Laysan (1999 to 2009) and Midway (2007 to 2010; n = 133 Laysan, n = 96 Midway birds). We identified polymorphic markers by screening nuclear microsatellites (N = 83). Low nuclear variation was detected, consistent with the species’ insular isolation and historical bottleneck. Six of 83 microsatellites were polymorphic. We found limited but similar estimates of allelic richness (2.58 alleles per locus) and heterozygosity within populations. However, 2 rare alleles found in the Laysan source population were not present in Midway’s reintroduced population, and a unique allele was discovered in an individual on Midway. Differentiation between island populations was low (FST = 0.6%), but statistically significant. Our results indicate that genetic drift had little effect on offspring generations 3 to 6 yr post-release and demonstrate the utility of using known founder events to help quantify genetic capture during translocations and to inform management decisions. KEY WORDS: Anas laysanensis · Island endemic · Genetic diversity · Laysan duck · Reintroduction biology Full text in pdf format PreviousNextCite this article as: Reynolds MH, Pearce JM, Lavretsky P, Seixas PP, Courtot KN (2015) Microsatellite variation and rare alleles in a bottlenecked Hawaiian Islands endemic: implications for reintroductions. Endang Species Res 28:117-122. https://doi.org/10.3354/esr00681 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 28, No. 2. Online publication date: July 14, 2015 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2015 Inter-Research.

Highlights

A fundamental aspect of management for species conservation should be preservation of genetic variation so that natural selection and other processes have the potential to respond to environmentalPublisher: Inter-Research · www.int-res.comEndang Species Res 28: 117–122, 2015 or other biotic and abiotic environmental changes)
If endangered species recovery strategies include reintroduction, translocations with small numbers of founders and no immigration can lead to loss of genetic variation over time via genetic drift or low initial genetic capture (Weeks et al 2011) and can potentially reduce the reintroduced population’s long-term persistence or its potential to serve as a suitable source for future translocations (Tarr et al 1998, Groombridge et al 2012, Weiser et al 2013)
The low genetic variation at these loci for Laysan teal is consistent with historical accounts of a population bottleneck and a genome-wide loss of variation

Summary

Introduction

A fundamental aspect of management for species conservation should be preservation of genetic variation so that natural selection and other processes have the potential to respond to environmentalPublisher: Inter-Research · www.int-res.comEndang Species Res 28: 117–122, 2015 or other biotic and abiotic environmental changes). The last remaining Laysan teal population grew to the island’s carrying capacity of about 400 to 600 (Seavy et al 2009) in the decades after rabbits were eliminated from Laysan Island in 1924. Since Laysan teal do not migrate or immigrate between distant Northwestern Hawaiian atolls, the establishment of 4 additional populations is a recovery criterion to reduce the inherently high extinction risk associated with a single small population (USFWS 2004, 2009). An experimental translocation (wild to wild) was implemented in 2004 and 2005, moving 20 and 22 juvenile birds, respectively (< 4% of the total post-fledgling population at Laysan Island; Reynolds et al 2008, 2015). The translocated population grew rapidly to 471−535 post-fledglings by 2008 (Reynolds et al 2012, 2013)

Methods

Results

Conclusion