Conservation genomics reveals low genetic diversity and multiple parentage in the threatened freshwater mussel,<i>Margaritifera hembeli</i>

Garrison, Nicole L.; Whelan, Nathan V.; Johnson, Paul D.

doi:10.1101/2020.03.31.018689

Cited by 3 publications

(3 citation statements)

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“…Such differences can be explained by different availabilities of gravid mussels (in some populations only single individuals in certain years) as well as different infestation, metamorphosis and rearing success. Variable levels of multiple paternity as previously observed in this species 62 , 63 and the Louisiana Pearlshell, Margaritifera hembeli , may also play a role 64 . In any case, the results of this study allow drawing the consistent picture that maintaining rearing activities for specific populations over multiple years is most beneficial since it reduces the risk of genetic bottlenecks, drift and selection effects.…”

Section: Discussionsupporting

confidence: 65%

Securing genetic integrity in freshwater pearl mussel propagation and captive breeding

Geist

Bayerl

Stoeckle

et al. 2021

Sci Rep

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Securing genetic integrity is of key importance in conservation-oriented captive breeding programs releasing juveniles into the wild. This is particularly true for species such as the endangered freshwater pearl mussel (Margaritifera margaritifera) for which a number of captive breeding facilities has been established in Europe. The core objective of this study was to compare the genetic constitution of 29 cohorts of captive-bred freshwater pearl mussels from five different breeding facilities in Austria, France, Luxembourg and Germany, with their original 14 source populations from nine major European drainages, based on microsatellite markers. Captive-bred mussels represented 11 different genetic clusters, suggesting an important contribution of the breeding stations to securing the genetic diversity of the species. In almost all cases, the cultured offspring closely resembled the genetic constitution of the source mussels as revealed from the STRUCTURE analysis and the generally high assignment of offspring to the original source populations. The majority of captive-bred cohorts had an increased inbreeding coefficient and decreased genetic variability compared to their source populations as measured by AR and HO. Highest numbers of deformed juveniles coincided with very low levels of HO < 0.05. Since erosion of genetic diversity in captive breeding was mostly evident in individual year-cohorts, long-term breeding over multiple years can minimize such effects. The systematic selection of priority populations for conservation, effective breeding strategies avoiding effects of in- and outbreeding by genetically informed selection of parent individuals, and a network of collaboration among the different breeding facilities would be very useful to increase resilience and effectiveness.

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Section: Discussionsupporting

confidence: 65%

Securing genetic integrity in freshwater pearl mussel propagation and captive breeding

Geist

Bayerl

Stoeckle

et al. 2021

Sci Rep

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“…For example, persistent inbreeding and genetic bottlenecks may affect some isolated populations and pose a threat to their long-term genetic viability. Gathering these information could also be useful for planning potential future reintroduction efforts, with particular attention to the presence of genetic differentiation among populations (Grobler et al, 2006), following the example of ongoing projects for endangered freshwater mussels in Northern America (Garrison, Johnson & Whelan, 2020). Another potential application of modern genetic approaches to the conservation of Congeria lies in the use of environmental DNA (eDNA) as a proxy to define the exact range of the species.…”

Section: Future Directions For Improved Conservation Effortsmentioning

confidence: 99%

Hidden from Our Sight, but Not from Our Impact: The Conservation Issues of Cave Bivalves

Bilandžija¹,

Puljas²,

Gerdol³

2021

Preprint

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Groundwater habitats in the Dinaric Karst are home to the only known cave-adapted genus of bivalve mollusks, which currently survives as three distinct species with a highly fragmented distribution. Over the past few decades, Congeria populations suffered a steep decline across their range, as a result of human activities. Here, we identify the most pressing issues concerning the current conservation status of Congeria and identify key priorities for its scientific study. The building of dams and other hydrotechnical constructions have led to a significant decrease in the water inputs that used to supply underground systems where Congeria lives, contributing to a reduction of the cave habitats feasible for bivalve settlement. This is relatively well documented in Popovo polje where, as a result of hydrotechnical interventions on Trebisnjica river, water level drop destroyed well over 99 % of Congeria kusceri population in Zira cave and caused their complete disappearance in other caves. Similar factors are likely to have also affected the sister species Congeria jalzici in the Lika region. In addition, the salinization of Neretva river, lack of proper wastewater management, intense agriculture, tourist exploitation, and additional hydrotechnical plans add to the ongoing decline of the quality of Congeria habitats. These threats are expected to least to drastic reductions in population size within the next few decades, and this situation might be further aggravated by the lack of regulations and active measures for Congeria protection, as well by the limited understanding of its biology. Future scientific studies should be aimed at better elucidating microhabitat preference, defining the range of tolerance of environmental parameters, and assessing the size and genetic viability of existing Congeria populations. However, we highlight that these efforts would most certainly require the collaboration of local authorities and the allocation of appropriate financial resources in order to be effective.

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“…Conservation genomics might involve the assessment of genetic diversity, inbreeding and effective population size (e.g., Garrison et al. 2020), identification of management‐relevant conservation units (i.e., genetically distinct populations) and gene flow (e.g., Feutry et al. 2020), and detection of geographic patterns of local adaption (e.g., Brauer et al.…”

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confidence: 99%

Conservation genomics of a critically endangered brown seaweed

Mamo

Wood

Wheeler

et al. 2021

Journal of Phycology

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Seaweeds provide valuable ecosystem services, but many are undergoing global decline due to climate and anthropogenic stressors. The brown macroalga, Nereia lophocladia (hereafter called Nereia), is among only a handful of seaweeds globally to be listed as critically endangered and is only described from two known locations, but there exists little knowledge about this species. Here, we combine field surveys to verify the distribution of Nereia, with cutting‐edge genomics to determine genetic diversity and population structure, and inform ongoing conservation actions. We expand Nereia's known distribution from one to seven locations along a 70‐km long coastal stretch in New South Wales but reveal small population sizes at some sites (as few as 8 individuals despite extensive searching). A total of 1,261 genome‐wide SNPs were retained from 70 individuals after filtering, and 304 outlier loci under putative selection were detected by one of three methods. Populations showed low genetic diversity (mean expected heterozygosity HE = 0.055 ± 0.014) and high levels of inbreeding within populations (mean FIS = 0.721 ± 0.085), along with high genetic differentiation among sites (mean FST = 0.276), which may increase susceptibility to future environmental change and decrease the species' ability to recover after loss. Given these findings, we recommend the consideration of both in situ and ex situ conservation measures for Nereia, as well as further research into the species' ecology and biology. Nereia remains of conservation concern and its listing as critically endangered is justified until further investigation elucidates the full distribution and adaptive capacity of the species.

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Conservation genomics reveals low genetic diversity and multiple parentage in the threatened freshwater mussel,Margaritifera hembeli

Cited by 3 publications

References 69 publications

Securing genetic integrity in freshwater pearl mussel propagation and captive breeding

Securing genetic integrity in freshwater pearl mussel propagation and captive breeding

Hidden from Our Sight, but Not from Our Impact: The Conservation Issues of Cave Bivalves

Conservation genomics of a critically endangered brown seaweed

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