Is realised connectivity among populations of aquatic fauna predictable from potential connectivity?

Hughes, Jane; Huey, Joel A.; Schmidt, Daniel J.

doi:10.1111/fwb.12099

Cited by 60 publications

(79 citation statements)

References 115 publications

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“…However, genetic subdivision in MRTs is spatially identical to the pattern seen in co-distributed freshwater taxa. A turtle that engages in overland dispersal should be less susceptible to a barrier of this nature (Hughes, Huey, & Schmidt, 2013), but overland dispersal is unlikely in MRTs, which are a strongly stream-dependent species, not recorded from peripheral water bodies (Limpus, 2012). Salinity levels above the confluence of these streams may be a significant barrier that impedes gene flow between Tinana and Mary populations of freshwater taxa.…”

Section: Discussionmentioning

confidence: 99%

Conservation genetics of the Mary River turtle (Elusor macrurus) in natural and captive populations

Schmidt

Espinoza²,

Connell³

et al. 2017

Aquatic Conservation

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1. Many thousands of Mary River turtle eggs were harvested for the pet trade in the 1960s and 1970s before it was recognized as a new species in a unique genus. Pet turtles and their descendants still survive in captive collections. Elusor macrurus is now an endangered species after suffering dramatic population declines along the single Australian river that constitutes its entire range. 2. A conservation genetic assessment was conducted to evaluate population subdivision within the remaining wild population of the Mary River turtle; to compare diversity of the wild population with a captive sample derived from the pet trade; and to establish a baseline estimate of effective population size (N e ) to assist with future monitoring and recovery. 3. Microsatellite analysis indicated panmixia throughout most of the Mary River catchment with the exception of one downstream tributary -Tinana Creek (pop. Specific F ST = 0.154). Subdivision between Tinana Creek and Mary River is a feature common to multiple co-distributed freshwater taxa including the threatened Australian lungfish and Mary River cod. Microsatellite diversity of the wild adult population was low (average H S = 0.554) and not significantly different from that of a sample of captive turtles from the pet tradeindicating genetic diversity may be well represented in captive stocks. Mitochondrial DNA diversity was extremely limited, with only two haplotypes found in the wild and a single shared haplotype in captive turtles.4. Estimates of N e applicable to the entire species in the wild were~136 and~158 using two independent methods. A reasonable management objective should be retention of N e levels >100 during recovery of the species. Additional recommendations include that Mary River turtles be listed as Critically Endangered, and that a recovery plan be developed that considers 'headstarting'using captive bred stocks to supplement the wild population.

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Section: Discussionmentioning

confidence: 99%

Conservation genetics of the Mary River turtle (Elusor macrurus) in natural and captive populations

Schmidt

Espinoza²,

Connell³

et al. 2017

Aquatic Conservation

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“…It is therefore important for conservation management to consider how species biology may alter the way that connectivity is affected by processes such as habitat fragmentation [74], [75]. Nannoperca obscura is known to possess limited dispersal potential at all life stages.…”

Section: Discussionmentioning

confidence: 99%

Catchment-Scale Conservation Units Identified for the Threatened Yarra Pygmy Perch (Nannoperca obscura) in Highly Modified River Systems

et al. 2013

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Habitat fragmentation caused by human activities alters metapopulation dynamics and decreases biological connectivity through reduced migration and gene flow, leading to lowered levels of population genetic diversity and to local extinctions. The threatened Yarra pygmy perch, Nannoperca obscura, is a poor disperser found in small, isolated populations in wetlands and streams of southeastern Australia. Modifications to natural flow regimes in anthropogenically-impacted river systems have recently reduced the amount of habitat for this species and likely further limited its opportunity to disperse. We employed highly resolving microsatellite DNA markers to assess genetic variation, population structure and the spatial scale that dispersal takes place across the distribution of this freshwater fish and used this information to identify conservation units for management. The levels of genetic variation found for N. obscura are amongst the lowest reported for a fish species (mean heterozygosity of 0.318 and mean allelic richness of 1.92). We identified very strong population genetic structure, nil to little evidence of recent migration among demes and a minimum of 11 units for conservation management, hierarchically nested within four major genetic lineages. A combination of spatial analytical methods revealed hierarchical genetic structure corresponding with catchment boundaries and also demonstrated significant isolation by riverine distance. Our findings have implications for the national recovery plan of this species by demonstrating that N. obscura populations should be managed at a catchment level and highlighting the need to restore habitat and avoid further alteration of the natural hydrology.

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“…Since ecology of the species and characteristics of the environment strongly influence the distribution of genetic diversity within and between populations, sympatric and ecologically similar species can be expected to exhibit similar genetic patterns (Whiteley et al 2006, Dawson 2012, Hughes et al 2013. On the other hand, increasing ecological similarity of species can be expected to increase interactions between them, and can therefore create differences between their genetic structures .…”

Section: Study Questionsmentioning

confidence: 99%

Interspecific interactions influence contrasting spatial genetic structures in two closely related damselfly species

et al. 2014

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The similarities in the theories of community ecology and population genetics suggest that species diversity within and between communities and genetic diversity within and between populations are driven by the same four general mechanisms: (1) drift, (2) dispersal, (3) selection, and (4) the formation of new variants (i.e. speciation and mutation). Since, for both species diversity and genetic diversity, the relative significances of each of the first three mechanisms are very much influenced by characteristics of the environment, correlations between species diversity and genetic diversity, i.e. species-genetic diversity correlations (SGDCs), are expected. Considering that practical conservation most often focuses on species diversity (or surrogates thereof), SGDCs could provide information on how conservation and management decisions influence genetic diversities of populations, and thus also their viabilities. Furthermore, teasing apart the drivers of the SGDCs can offer mechanistic explanations for diversity and therefore suggest a process-based approach to conservation. I studied the generalizability of SGDC and the role of environmental characteristics by means of a literary review and empirical studies on natural dragonfly and damselfly communities. I then conducted individual-based simulations to assess how inbreeding depression due to loss of genetic diversity can influence extinction rates in neutral multispecies metacommunities. My results suggest that SGDCs are highly variable in natural systems and that interactions between ecologically similar species can influence their genetic structures. Therefore, the results question the utility of using species diversity or genetic structures of ecologically similar species as surrogates for genetic diversity of species of conservation concern. Furthermore, my results suggest that if intraspecific genetic diversity is not explicitly considered, the extinction rates in multispecies metacommunities might be underestimated.

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Is realised connectivity among populations of aquatic fauna predictable from potential connectivity?

Cited by 60 publications

References 115 publications

Conservation genetics of the Mary River turtle (Elusor macrurus) in natural and captive populations

Conservation genetics of the Mary River turtle (Elusor macrurus) in natural and captive populations

Catchment-Scale Conservation Units Identified for the Threatened Yarra Pygmy Perch (Nannoperca obscura) in Highly Modified River Systems

Interspecific interactions influence contrasting spatial genetic structures in two closely related damselfly species

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