Population genetic structure of Banksia spinulosa

Carthew, Susan M.

doi:10.1038/hdy.1993.83

Cited by 23 publications

(12 citation statements)

References 43 publications

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“…2009). However, the level of genetic structuring that we detected ( F ST = 0.03) in assessing variation among our five quadrats within the Kioloa population of B. spinulosa was identical to that reported from an allozyme survey that compared slightly larger quadrats within another population of this species (Carthew 1993b). This relative genetic homogeneity probably reflects the greater seed dispersal afforded by winged seed that are released after fire (Whelan 1995) as is implied by our finding of significant spatial autocorrelation to 25 m in B. spinulosa as compared with approximately 5 m in most of the above studies.…”

Section: Discussionsupporting

confidence: 82%

The accumulation of genetic diversity within a canopy‐stored seed bank

et al. 2010

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Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

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Section: Discussionsupporting

confidence: 82%

The accumulation of genetic diversity within a canopy‐stored seed bank

et al. 2010

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“…Banksia oligantha and B. ilicifolia were also lower at the species level, while values for B. cuneata were more comparable (A, 2.22; P, 65.0%; H e , 0.177; Hamrick et al 1992). The low levels observed, however, appear to be consistent with estimates for species from various proteaceous genera such as Banksia (Coates and Sokolowski 1992;Carthew 1993;Sampson et al 1994), Grevillea (Ayre et al 1994), Persoonia (Krauss 1997) and Lambertia (Coates and Hamley 1999).…”

Section: Discussionsupporting

confidence: 74%

Genetic divergence among and diversity within two rare Banksia species and their common close relative in the subgenusIsostylis R.Br. (Proteaceae)

Broadhurst¹,

Coates²

2004

Conservation Genetics

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The Banskia subgenus Isostylis complex is comprised of two rare and restricted species, B. cuneata and B. oligantha, and the widespread B. ilicifolia. Population genetic structure and genetic diversity were examined within and among the three species using 10 allozyme loci across 21 populations. Levels of genetic diversity did not appear to correspond with either population size or geographic distribution. The restricted species B. cuneata exhibited the highest levels of gene diversity (H es , 0.13) followed by the widespread B. ilicifolia (H es , 0.10) and the other restricted species B. oligantha (H es , 0.08). Similarly, there was no relationship between genetic structure and geographical distribution with the rare B. cuneata being highly structured (h ¼ 0.370) compared with B. ilicifolia (h ¼ 0.164) and B. oligantha (h ¼ 0.221). The relatively low but similar levels of diversity present in the subgenus concur with those observed in other proteaceous genera and probably reflect historical events rather than a genetic effects associated with a recently fragmented landscape.

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“…, 1992 ), is similar to or moderately higher than other members of the Proteaceae. Allozyme studies on species from a number of genera within the Proteaceae such as Banksia ( Coates & Sokolowski, 1992; Carthew, 1993; Sampson et al. , 1994 ), Grevillea ( Ayre et al.…”

Section: Discussionmentioning

confidence: 99%

Genetic divergence and the mating system in the endangered and geographically restricted species, Lambertia orbifolia Gardner (Proteaceae)

Coates¹,

Hamley²

1999

Heredity

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6983Population genetic structure and the mating system were investigated in the endangered plant Lambertia orbifolia. This species is geographically restricted with two disjunct groups of populations. Twelve out of 19 allozyme loci were polymorphic and four were suitable for mating system studies. Levels of genetic variation within populations were comparable to other long-lived woody shrub endemics. Genetic divergence between population groups was very high (D 0.252) and the F ST over all populations was 0.441. Gene¯ow estimates within population groups were low even though the maximum geographical distance between any pair of populations is 15 km and could be attributed to the localized movement of bird pollinators. Mating system studies on four populations showed consistently low levels of outcrossing, compared with other Proteaceae. Correlations of outcrossed paternity were moderately high and all were signi®cantly greater than zero. Values ranged from r p 0.33, in the two largest and very dense populations, to the highest value of r p 0.54 in a smaller low-density population. The current population genetic structure in L. orbifolia is probably the result of local extinction of intervening populations because of Pleistocene climatic change and increased aridity, and extended isolation of the two remnants. It is proposed that the phylogenetically distinct Narrikup population group be recognized as a separate conservation unit and be given high priority for conservation action.Keywords: conservation units, endangered species, gene¯ow, genetic structure, habitat fragmentation, mating system. IntroductionNaturally fragmented and disjunct population systems are a feature of the rich and diverse¯ora in south-west Australia. A signi®cant proportion of the plant species is likely to be relictual and probably had wider, more continuous distributions during favourable climatic regimes up to the early Pleistocene. Increased aridity and climatic instability during the Pleistocene are considered to be major factors in the localized extinction and fragmentation of many plant species in this region (Hopper et al., 1996).The level of geographical separation between population groups within these fragmented species suggests that recent gene¯ow, either by long-distance seed dispersal or pollen movement, has been limited or absent for a long period. Reduction or absence of genē ow, and¯uctuations in population size caused by climatic instability, are likely to lead to signi®cant interpopulation divergence. Studies to date on rare and geographically restricted species from south-west Australia support this view. Signi®cant genetic divergence among populations associated with clear geographical separation is a feature of a range of species in a number of¯owering plant families such as Mimosaceae , Myrtaceae (Moran & Hopper, 1983, 1987Sampson et al., 1988), Proteaceae (Coates & Sokolowski, 1992) and Stylidiaceae (Coates, 1992).A major confounding factor in assessing the evolutionary patterns observed in the south-west¯ora are th...

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Population genetic structure of Banksia spinulosa

Cited by 23 publications

References 43 publications

The accumulation of genetic diversity within a canopy‐stored seed bank

The accumulation of genetic diversity within a canopy‐stored seed bank

Genetic divergence among and diversity within two rare Banksia species and their common close relative in the subgenusIsostylis R.Br. (Proteaceae)

Genetic divergence and the mating system in the endangered and geographically restricted species, Lambertia orbifolia Gardner (Proteaceae)

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