Conservation genetics of an endangered orchid in eastern Canada

Paul, Jennifer; Budd, Cara; Freeland, Joanna R.

doi:10.1007/s10592-012-0443-x

Cited by 7 publications

(10 citation statements)

References 61 publications

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“…Prior to this colonization, the Southern Appalachians provided potential glacial refugia for numerous species that now inhabit the Great Lakes region, although the numbers and locations of refugia, the recolonization routes, and hence the dispersal of genetic diversity into this region, are generally not well known (Austin et al 2002;Waldron 1993;Flannery 2003;Church et al 2003;Hewitt 2004;Loehle 2007). Genetic diversity of peripheral plant populations around the Great Lakes has been assessed in a small number of species, and in some cases was found to be low relative to core populations (Hamilton and Eckert 2007;Row et al 2011;Paul et al 2013), although this is not inevitable (Freeland et al 2010). In addition, the evolutionary novelty of disjunct or peripheral populations around the Great Lakes has been quantified for a few species on the basis of putatively neutral markers, and although some studies have found little evidence of genetic novelty (Hamilton and Eckert 2007;Row et al 2011), at least one study has challenged the assumption that disjunct populations around the Great Lakes are genetically similar to core populations (Ciotir et al 2013).…”

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confidence: 99%

Conservation genetics of Magnolia acuminata, an endangered species in Canada: Can genetic diversity be maintained in fragmented, peripheral populations?

2015

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The genetic diversity of peripheral populations is potentially important to the future adaptive capacity of species, although may be difficult to predict. A large number of species-at-risk in Canada are at the northern edge of their distribution, and many of these live in fragmented habitat. We used nuclear and chloroplast markers to assess patterns of genetic diversity and differentiation within and among populations of Canadian Magnolia acuminata (Cucumber tree), an endangered species in Canada that extends as far north as the fragmented Carolinian forest in southern Ontario. We also compared the genetic composition of Canadian M. acuminata to populations sampled throughout its central distribution in the USA. We found a high proportion of shared microsatellite alleles, plus a single cpDNA haplotype, distributed throughout the entire M. acuminata range. We also found that despite occupying fragmented habitat at their range periphery, Canadian populations showed little reduction in genetic diversity relative to the USA populations, and we attribute this to effective historical dispersal in a longlived, polyploid species. However, a combination of private alleles, genetic substructuring, and lower levels of genetic diversity in seedlings compared to mature trees, suggests that current levels of gene flow are relatively low among Canadian populations. Therefore, despite high levels of genetic diversity in Canadian M. acuminata, managers should be aware that without intervention, populations will likely become increasingly isolated and experience a reduction in genetic diversity which in turn may threaten their long-term survival in Canada.

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Conservation genetics of Magnolia acuminata, an endangered species in Canada: Can genetic diversity be maintained in fragmented, peripheral populations?

2015

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“…Population genetic studies of both the western (Ross and Travers 2015; Tennefos unpublished data) and the eastern prairie fringed orchid (Paul, Budd and Freeland 2013) support the conclusion that inbreeding is common in these species. Analyses of population patterns of molecular markers in both species found relatively high degrees of homozygosity regardless of population size (P. Outbreeding depression is a concern in a species with the potential for long distance pollen dispersal by hawkmoths.…”

Section: Pollinator Behavior and Self-pollinationmentioning

confidence: 90%

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Travers

Anderson

Vitt

et al. 2018

Botany

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An important consequence of self-compatibility in plants is that self-pollination can have deleterious effects on plant fitness due to inbreeding. We conducted a hand pollination experiment under field conditions to measure the magnitude of inbreeding depression associated with self-pollination in the rare western prairie fringed-orchid Platanthera praeclara Sheviak and Bowles. By comparing capsules and seeds resulting from cross versus self-pollination treatments, we determined that self-pollination reduces seed quality while having no detectable effect on capsule production or seed numbers. A smaller percentage of seeds resulting from self-pollination contained an embryo (18%) relative to seeds from cross-pollination (46%). Seeds that had an embryo were scored for the size of the embryo, small or large. A smaller proportion of seeds from self-pollination contained a large embryo (75%) relative to seeds from cross-pollination (92%).These results suggest that sexual reproduction and recruitment in this rare plant are dependent on the frequency of pollinator visitations that result in outcrossing.

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“…However, once mating occurs and offspring are produced, a relatively large proportion of these are dispersed to ‘Far’ distances off the fragment, leaving behind a small number of surviving individuals. The repetition of this process over time apparently leads to the creation of increasingly smaller and isolated subpopulations, which are more susceptible to increased inbreeding levels [ 70 , 23 ]. The reverse of this gene dispersal condition (‘Near’ offspring and ‘Far’ pollen dispersal) does not, in this study, lead to such an increase in F it values, suggesting the latter conditions are more effective in facilitating gene flow.…”

Section: Discussionmentioning

confidence: 99%

Variable Gene Dispersal Conditions and Spatial Deforestation Patterns Can Interact to Affect Tropical Tree Conservation Outcomes

2015

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Tropical lowland rain forest (TLRF) biodiversity is under threat from anthropogenic factors including deforestation which creates forest fragments of different sizes that can further undergo various internal patterns of logging. Such interventions can modify previous equilibrium abundance and spatial distribution patterns of offspring recruitment and/or pollen dispersal. Little is known about how these aspects of deforestation and fragmentation might synergistically affect TLRF tree recovery demographics and population genetics in newly formed forest fragments. To investigate these TLRF anthropogenic disturbance processes we used the computer program NEWGARDEN (NG), which models spatially-explicit, individual-based plant populations, to simulate 10% deforestation in six different spatial logging patterns for the plant functional type of a long-lived TLRF canopy tree species. Further, each logging pattern was analyzed under nine varying patterns of offspring versus pollen dispersal distances that could have arisen post-fragmentation. Results indicated that gene dispersal condition (especially via offspring) had a greater effect on population growth and genetic diversity retention (explaining 98.5% and 88.8% of the variance respectively) than spatial logging pattern (0.2% and 4.7% respectively), with ‘Near’ distance dispersal maximizing population growth and genetic diversity relative to distant dispersal. Within logged regions of the fragment, deforestation patterns closer to fragment borders more often exhibited lower population recovery rates and founding genetic diversity retention relative to more centrally located logging. These results suggest newly isolated fragments have populations that are more sensitive to the way in which their offspring and pollen dispersers are affected than the spatial pattern in which subsequent logging occurs, and that large variation in the recovery rates of different TLRF tree species attributable to altered gene dispersal regimens will be a likely outcome of fragmentation. Conservation implications include possible manual interventions (manual manipulations of offspring dispersers and/or pollinators) in forest fragments to increase population recovery and genetic diversity retention.

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Conservation genetics of an endangered orchid in eastern Canada

Cited by 7 publications

References 61 publications

Conservation genetics of Magnolia acuminata, an endangered species in Canada: Can genetic diversity be maintained in fragmented, peripheral populations?

Conservation genetics of Magnolia acuminata, an endangered species in Canada: Can genetic diversity be maintained in fragmented, peripheral populations?

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Variable Gene Dispersal Conditions and Spatial Deforestation Patterns Can Interact to Affect Tropical Tree Conservation Outcomes

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