Journal of Plant Ecology Advance Access originally published online on August 13, 2009
Journal of Plant Ecology 2009 2(3):143-151; doi:10.1093/jpe/rtp016
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Assessing genetic diversity and structure of fragmented populations of eastern white pine (Pinus strobus) and western white pine (P. monticola) for conservation management
Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6
* Correspondence address. Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6. Tel: +1-705-675-1151 ext. 2307; Fax: +1-705-675-4859; E-mail: knkongolo{at}laurentian.ca
Aims: Many pine populations in Canada have fragmented distributions resulting from the effects of glaciations, overharvesting and white pine blister rust infections. Forest fragmentation can modify gene flow and reduce genetic diversity. Selective logging can reduce the density of trees, thereby altering mating patterns and increasing inbreeding. The hypothesis of the present study is that forest fragmentation will not increase inbreeding and will have no effect on genetic diversity parameters in the Canadian Pinus moniticola and P. strobus populations targeted because of (i) the long life span of the pine species, (ii) outbreeding and self-incompatibility of P. monticola and P. strobus and (iii) wind pollination resulting in high gene flow among populations. We studied the genetic diversity of P. strobus across its range in Canada, and we completed a detailed analysis of the genetic structure of P. monticola populations from western Canada using microsatellites genetic markers.
Methods: Seed samples from 10 P. monticola populations and 10 P. strobus populations were collected from western and eastern Canada, respectively. The mother trees included in seed lots were representative of each stand. Genomic DNA extracted from each sample was amplified with microsatellite primers. The intra- and interpopulation genetic diversity parameters were assessed using Popgene and Genepop softwares and the genetic distances among populations within each species using the PowerMarker software.
Important findings: Pinus monticola and P. strobus exhibited moderate to high genetic diversity. Also, both species showed low levels of inbreeding despite the geographic isolation and small stand size. Gene flow estimates were high and population differentiation values were relatively low for these fragmented forest sites.
Keywords: Pinus strobus • Pinus monticola • microsatellite • genetic diversity • forest fragmentation