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Pavlova A, Schneller NM, Lintermans M, Beitzel M, Robledo‐Ruiz DA, Sunnucks P. Planning and implementing genetic rescue of an endangered freshwater fish population in a regulated river, where low flow reduces breeding opportunities and may trigger inbreeding depression. Evol Appl 2024; 17:e13679. [PMID: 38617824 PMCID: PMC11009430 DOI: 10.1111/eva.13679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 02/11/2024] [Accepted: 02/26/2024] [Indexed: 04/16/2024] Open
Abstract
Augmenting depleted genetic diversity can improve the fitness and evolutionary potential of wildlife populations, but developing effective management approaches requires genetically monitored test cases. One such case is the small, isolated and inbred Cotter River population of an endangered Australian freshwater fish, the Macquarie perch Macquaria australasica, which over 3 years (2017-2019) received 71 translocated migrants from a closely related, genetically more diverse population. We used genetic monitoring to test whether immigrants bred, interbred with local fish and augmented population genetic diversity. We also investigated whether levels of river flow affected recruitment, inbreeding depression and juvenile dispersal. Fish length was used to estimate the age, birth year cohort and growth of 524 individuals born between 2016 and 2020 under variable flow conditions. DArT genome-wide genotypes were used to assess individual ancestry, heterozygosity, short-term effective population size and identify parent-offspring and full-sibling families. Of 442 individuals born after translocations commenced, only two (0.45%) were of mixed ancestry; these were half-sibs with one translocated parent in common. Numbers of breeders and genetic diversity for five birth year cohorts of the Cotter River fish were low, especially in low-flow years. Additionally, individuals born in the year of lowest flow evidently suffered from inbreeding depression for juvenile growth. The year of highest flow was associated with the largest number of breeders, lowest inbreeding in the offspring and greatest juvenile dispersal distances. Genetic diversity decreased in the upstream direction, flagging restricted access of breeders to the most upstream breeding sites, exacerbated by low river flow. Our results suggest that the effectiveness of translocations could be increased by focussing on upstream sites and moving more individuals per year; using riverine sources should be considered. Our results indicate that river flow sufficient to facilitate fish movement through the system would increase the number of breeders, promote individuals' growth, reduce inbreeding depression and promote genetic rescue.
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Affiliation(s)
- Alexandra Pavlova
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Nadja M. Schneller
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Mark Lintermans
- Centre for Applied Water ScienceInstitute for Applied Ecology, University of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Matt Beitzel
- Environment, Planning & Sustainable Development Directorate (ACT Government)CanberraAustralian Capital TerritoryAustralia
| | | | - Paul Sunnucks
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
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Buono V, Burgio S, Macrì N, Catania G, Hauffe HC, Mucci N, Davoli F. Microsatellite Characterization and Panel Selection for Brown Bear ( Ursus arctos) Population Assessment. Genes (Basel) 2022; 13:2164. [PMID: 36421838 PMCID: PMC9690282 DOI: 10.3390/genes13112164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 10/28/2023] Open
Abstract
An assessment of the genetic diversity and structure of a population is essential for designing recovery plans for threatened species. Italy hosts two brown bear populations, Ursus arctos marsicanus (Uam), endemic to the Apennines of central Italy, and Ursus arctos arctos (Uaa), in the Italian Alps. Both populations are endangered and occasionally involved in human-wildlife conflict; thus, detailed management plans have been in place for several decades, including genetic monitoring. Here, we propose a simple cost-effective microsatellite-based protocol for the management of populations with low genetic variation. We sampled 22 Uam and 22 Uaa individuals and analyzed a total of 32 microsatellite loci in order to evaluate their applicability in individual identification. Based on genetic variability estimates, we compared data from four different STR marker sets, to evaluate the optimal settings in long-term monitoring projects. Allelic richness and gene diversity were the highest for the Uaa population, whereas depleted genetic variability was noted for the Uam population, which should be regarded as a conservation priority. Our results identified the most effective STR sets for the estimation of genetic diversity and individual discrimination in Uam (9 loci, PIC 0.45; PID 2.0 × 10-5), and Uaa (12 loci, PIC 0.64; PID 6.9 × 10-11) populations, which can easily be utilized by smaller laboratories to support local governments in regular population monitoring. The method we proposed to select the most variable markers could be adopted for the genetic characterization of other small and isolated populations.
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Affiliation(s)
- Vincenzo Buono
- Unit for Conservation Genetics (BIO-CGE), Department for the Monitoring and Protection of the Environment and for Biodiversity Conservation, Italian Institute for Environmental Protection and Research (ISPRA), Ozzano dell’Emilia, 40064 Bologna, Italy
| | - Salvatore Burgio
- Department of Biological, Geological and Environmental Sciences (BiGeA), University of Bologna, 40100 Bologna, Italy
| | - Nicole Macrì
- Unit for Conservation Genetics (BIO-CGE), Department for the Monitoring and Protection of the Environment and for Biodiversity Conservation, Italian Institute for Environmental Protection and Research (ISPRA), Ozzano dell’Emilia, 40064 Bologna, Italy
| | - Giovanni Catania
- Department of Biological, Geological and Environmental Sciences (BiGeA), University of Bologna, 40100 Bologna, Italy
| | - Heidi C. Hauffe
- Conservation Genomics Research Unit, Research and Innovation Centre, Fondazione E. Mach, San Michele all’Adige, 38098 Trento, Italy
| | - Nadia Mucci
- Unit for Conservation Genetics (BIO-CGE), Department for the Monitoring and Protection of the Environment and for Biodiversity Conservation, Italian Institute for Environmental Protection and Research (ISPRA), Ozzano dell’Emilia, 40064 Bologna, Italy
| | - Francesca Davoli
- Unit for Conservation Genetics (BIO-CGE), Department for the Monitoring and Protection of the Environment and for Biodiversity Conservation, Italian Institute for Environmental Protection and Research (ISPRA), Ozzano dell’Emilia, 40064 Bologna, Italy
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Nabutanyi P, Wittmann MJ. Modeling minimum viable population size with multiple genetic problems of small populations. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13940. [PMID: 35674090 DOI: 10.1111/cobi.13940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 06/15/2023]
Abstract
An important goal for conservation is to define minimum viable population (MVP) sizes for long-term persistence of a species. There is increasing evidence of the role of genetics in population extinction; thus, conservation practitioners are starting to consider the effects of deleterious mutations (DM), in particular the effects of inbreeding depression on fitness. We sought to develop methods to account for genetic problems other than inbreeding depression in MVP estimates, quantify the effect of the interaction of multiple genetic problems on MVP sizes, and find ways to reduce the arbitrariness of time and persistence probability thresholds in MVP analyses. To do so, we developed ecoevolutionary quantitative models to track population size and levels of genetic diversity. We assumed a biallelic multilocus genome with loci under single or multiple, interacting genetic forces. We included mutation-selection-drift balance (for loci with DM) and 3 forms of balancing selection for loci for which variation is lost through genetic drift. We defined MVP size as the lowest population size that avoids an ecoevolutionary extinction vortex. For populations affected by only balancing selection, MVP size decreased rapidly as mutation rates increased. For populations affected by mutation-selection-drift balance, the MVP size increased rapidly. In addition, MVP sizes increased rapidly as the number of loci increased under the same or different selection mechanisms until even arbitrarily large populations could not survive. In the case of fixed number of loci under selection, interaction of genetic problems did not always increase MVP sizes. To further enhance understanding about interaction of genetic problems, there is need for more empirical studies to reveal how different genetic processes interact in the genome.
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Affiliation(s)
- Peter Nabutanyi
- Department of Theoretical Biology, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Meike J Wittmann
- Department of Theoretical Biology, Faculty of Biology, Bielefeld University, Bielefeld, Germany
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Steventon C, Harley D, Wicker L, Legione AR, Devlin JM, Hufschmid J. An assessment of ectoparasites across highland and lowland populations of Leadbeater's possum (Gymnobelideus leadbeateri): Implications for genetic rescue translocations. Int J Parasitol Parasites Wildl 2022; 18:152-156. [PMID: 35586791 PMCID: PMC9108725 DOI: 10.1016/j.ijppaw.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/30/2022] [Accepted: 05/01/2022] [Indexed: 11/28/2022]
Abstract
Leadbeater's possum (Gymnobelideus leadbeateri) is a nocturnal arboreal marsupial with a restricted range centered on the Victorian Central Highlands, south-eastern Australia. Most populations inhabit wet montane ash forest and subalpine woodland, with one notable exception - a small, outlying and genetically-distinct lowland population inhabiting swamp forest at Yellingbo, Victoria. The species has been listed as critically endangered since 2015. Translocations are the mainstay of critical genetic rescue and this study explores the ectoparasites that are ‘along for the ride’ during translocation activities. Ectoparasites (133 fleas, 15 ticks and 76 mites) were collected opportunistically from 24 Leadbeater's possum colonies during population monitoring and genetic sampling across the lowland and highland populations. The composition of the flea assemblage varied by habitat type. Significantly greater numbers of the general marsupial fleas Acanthopsylla r. rothschildii. and Choristopsylla tristis (as a proportion of total flea numbers) were detected in lowland habitats, compared to highland habitats (Fishers exact test, P < 0.0001). Two host-specific flea species, Stephanocircus domrowi and Wurunjerria warnekei were detected only on possums in highland habitats. As a proportion of total fleas this was significantly different to possums in lowland habitats (Fisher's exact test, P = 0.0042 and P < 0.0001, respectively). Wurunjerria warnekei was suspected to be extinct prior to this study. Ticks (Ixodes tasmanii, n = 15) and mites (Haemdoelaps cleptus, n = 47 and H. anticlea, n = 29) have been identified in Leadbeater's possums historically. The possible causes of the different flea assemblages may be environmental/climatic, or due to the historic geographic division between highland and lowland animals. The planned translocations of highland individuals to lowland habitats will expose lowland individuals to novel species of previously exclusively highland fleas with unknown indirect consequences, thus careful monitoring will be required to manage any potential risks. Ectoparasites were examined in critically endangered Leadbeater's possum populations. . Differences were seen between the lowland and the highland populations. The fleas Wurunjerria warnekei and Stephanocircus domrowi were found in the highlands. The fleas Choristopsylla tristis and Acanthopsylla rothschildii sp were found in the lowlands. Wurrenjerria warnekei, thought to be extinct prior to this study, was found.
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Affiliation(s)
- Chloe Steventon
- Australian Wildlife Health Centre, Healesville Sanctuary, Glen Eadie Avenue, Healesville, VIC, 3777, Australia
- Asia Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
- Corresponding author. Australian Wildlife Health Centre, Healesville Sanctuary, Glen Eadie Avenue, Healesville, VIC, 3777, Australia.
| | - Dan Harley
- Wildlife Conservation & Science, Zoos Victoria, Healesville, Victoria, 3777, Australia
| | - Leanne Wicker
- Australian Wildlife Health Centre, Healesville Sanctuary, Glen Eadie Avenue, Healesville, VIC, 3777, Australia
| | - Alistair R. Legione
- Asia Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Joanne M. Devlin
- Asia Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jasmin Hufschmid
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, VIC, 3030, Australia
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