TY - JOUR
T1 - Severe consequences of habitat fragmentation on genetic diversity of an endangered Australian freshwater fish
T2 - A call for assisted gene flow
AU - Pavlova, Alexandra
AU - Beheregaray, Luciano B.
AU - Coleman, Rhys
AU - Gilligan, Dean M.
AU - Harrisson, Katherine A.
AU - Ingram, Brett A.
AU - Kearns, Joanne
AU - Lamb, Annika M.
AU - Lintermans, Mark
AU - Lyon, Jarod
AU - Nguyen, Thuy
AU - Sasaki, Minami
AU - Tonkin, Zeb
AU - Yen, Jian D. L.
AU - Sunnucks, Paul
N1 - Funding Information:
This work was supported by ARC Grant LP110200017 to Monash University, Flinders University of South Australia and the University of Canberra, with Partner Organization University of Montana. Funding and other support were contributed by industry Partner Organizations Icon Water (formerly ACTEW Corporation), Melbourne Water, Department of Sustainability and Environment (Victoria) and Fisheries Victoria (now within DEDJTR - Department of Economic Development, Jobs, Transport and Resources). Goulburn Broken Catchment Management Authority (GBCMA) provided the funds to undertake fish surveys and collect genetic material. Additional funding was provided to AP and PS by the Fisheries Victoria Recreational Fishing Grants programme (DEDJTR) and to DG by NSW DPI?Fisheries. Computationally intensive analyses were performed on a Monash computer cluster. We thank M. Asmus, R. Ayres, P. Boyd, B. Broadhurst, A. Bruce, T. Cable, R. Clear, J. Doyle, B. Ebner, L. Farrington, L. Faulks, D. Hartwell, P. Heath, J. Knight, J. Mahoney, A. McDonald, T. McGarry, J. O'Mahony, A. Pickworth, K. Pitman, S. Raymond, M. Rodgers, J. Stanger, D. Stoessel, B. Talbot, M. Timmins and P. Unmack for sample collection, M. Roitman, A. Sunnucks, R. Albury for laboratory assistance, D. Tallmon for provision of the locally installable version of OneSamp, L. Faulks for curatorial assistance of earlier samples and J. Thomson for statistical advice. We are grateful to the Chief Editor Prof. Louis Bernatchez, Associate Editor Prof. Craig Primmer and three anonymous reviewers, whose comments helped us to improve the manuscript.
Publisher Copyright:
© 2017 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Genetic diversity underpins the ability of populations to persist and adapt to environmental changes. Substantial empirical data show that genetic diversity rapidly deteriorates in small and isolated populations due to genetic drift, leading to reduction in adaptive potential and fitness and increase in inbreeding. Assisted gene flow (e.g. via translocations) can reverse these trends, but lack of data on fitness loss and fear of impairing population “uniqueness” often prevents managers from acting. Here, we use population genetic and riverscape genetic analyses and simulations to explore the consequences of extensive habitat loss and fragmentation on population genetic diversity and future population trajectories of an endangered Australian freshwater fish, Macquarie perch Macquaria australasica. Using guidelines to assess the risk of outbreeding depression under admixture, we develop recommendations for population management, identify populations requiring genetic rescue and/or genetic restoration and potential donor sources. We found that most remaining populations of Macquarie perch have low genetic diversity, and effective population sizes below the threshold required to retain adaptive potential. Our simulations showed that under management inaction, smaller populations of Macquarie perch will face inbreeding depression within a few decades, but regular small-scale translocations will rapidly rescue populations from inbreeding depression and increase adaptive potential through genetic restoration. Despite the lack of data on fitness loss, based on our genetic data for Macquarie perch populations, simulations and empirical results from other systems, we recommend regular and frequent translocations among remnant populations within catchments. These translocations will emulate the effect of historical gene flow and improve population persistence through decrease in demographic and genetic stochasticity. Increasing population genetic connectivity within each catchment will help to maintain large effective population sizes and maximize species adaptive potential. The approach proposed here could be readily applicable to genetic management of other threatened species to improve their adaptive potential.
AB - Genetic diversity underpins the ability of populations to persist and adapt to environmental changes. Substantial empirical data show that genetic diversity rapidly deteriorates in small and isolated populations due to genetic drift, leading to reduction in adaptive potential and fitness and increase in inbreeding. Assisted gene flow (e.g. via translocations) can reverse these trends, but lack of data on fitness loss and fear of impairing population “uniqueness” often prevents managers from acting. Here, we use population genetic and riverscape genetic analyses and simulations to explore the consequences of extensive habitat loss and fragmentation on population genetic diversity and future population trajectories of an endangered Australian freshwater fish, Macquarie perch Macquaria australasica. Using guidelines to assess the risk of outbreeding depression under admixture, we develop recommendations for population management, identify populations requiring genetic rescue and/or genetic restoration and potential donor sources. We found that most remaining populations of Macquarie perch have low genetic diversity, and effective population sizes below the threshold required to retain adaptive potential. Our simulations showed that under management inaction, smaller populations of Macquarie perch will face inbreeding depression within a few decades, but regular small-scale translocations will rapidly rescue populations from inbreeding depression and increase adaptive potential through genetic restoration. Despite the lack of data on fitness loss, based on our genetic data for Macquarie perch populations, simulations and empirical results from other systems, we recommend regular and frequent translocations among remnant populations within catchments. These translocations will emulate the effect of historical gene flow and improve population persistence through decrease in demographic and genetic stochasticity. Increasing population genetic connectivity within each catchment will help to maintain large effective population sizes and maximize species adaptive potential. The approach proposed here could be readily applicable to genetic management of other threatened species to improve their adaptive potential.
KW - adaptive potential
KW - effective population size
KW - genetic rescue
KW - genetic restoration
KW - inbreeding depression
KW - Macquarie perch Macquaria australasica
KW - management
KW - population persistence
UR - http://www.scopus.com/inward/record.url?scp=85017382865&partnerID=8YFLogxK
UR - http://www.mendeley.com/research/severe-consequences-habitat-fragmentation-genetic-diversity-endangered-australian-freshwater-fish-ca
U2 - 10.1111/eva.12484
DO - 10.1111/eva.12484
M3 - Article
AN - SCOPUS:85017382865
SN - 1752-4563
VL - 10
SP - 531
EP - 550
JO - Evolutionary Applications
JF - Evolutionary Applications
IS - 6
ER -