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Medina-Macedo L.,Federal University of Parana | Medina-Macedo L.,Technical Federal University of Parana | Sebbenn A.M.,University of Sao Paulo | Lacerda A.E.B.,EMBRAPA Forestry Brazilian Agriculture Research Corporation | And 3 more authors.
Tree Genetics and Genomes | Year: 2014

In this study, genetic diversity, inbreeding, spatial genetic structure (SGS), and pollen dispersal are analyzed using ten microsatellite loci from two populations of the dioecious, wind-pollinated, coniferous tree Araucaria angustifolia in Southern Brazil. The study populations include an undisturbed 7 ha A. angustifolia cluster, where all adult trees were mapped and sampled, and an adjacent, long-abandoned, open agricultural area with an aggregated A. angustifolia population. Seeds were collected from 13 seed trees inside the forest cluster and from eight seed trees in the open forest. Our results showed that the adults present high levels of heterozygosity (Ho = 0.91) and an absence of inbreeding. However, significant SGS was detected up to 90 m in the forest cluster suggesting that near-neighbor trees are related. The estimate of effective population size was lower than the total number of trees in the cluster (Ne/N = 0.19), which can be explained by the presence of SGS in the stand. Substantial external pollen flow was detected in the forest cluster (26 %) and open forest (20 %), indicating that the reproductive population size is greater than the sampled populations, explaining the high genetic diversity in this population. Our results indicate that this site has potential for in and ex situ conservation due to high levels of genetic diversity and gene immigration resulting from pollen flow. Conservation strategies for A. angustifolia should focus not only on forest fragments but should also include the preservation of isolated trees throughout the landscape. © 2014, Springer-Verlag Berlin Heidelberg. Source


Medina-Macedo L.,Federal University of Technology of Parana | de Lacerda A.E.B.,EMBRAPA Forestry Brazilian Agriculture Research Corporation | Sebbenn A.M.,University of Sao Paulo | Ribeiro J.Z.,Federal University of Parana | And 2 more authors.
Conservation Genetics | Year: 2016

In order to understand the impacts of forest fragmentation on Araucaria angustifolia populations, we evaluated the genetic diversity and mating system using SSR markers and open-pollinated seeds from four populations of varying sizes and spatial isolation, in and around one of the best-conserved Araucaria Forest remnants in Southern Brazil. The four population types of A. angustifolia include: (1) a continuous forest; (2) a physically isolated cluster located 2 km from the continuous forest; (3) an open population in a field located between the cluster and continuous forest; and (4) a fragment on a private property located 5 km from the cluster. Approximately 28 seeds were collected from ten reproductive trees in each population. We found higher amounts of alleles (113) and exclusive alleles (25) in the continuous forest than in the other populations. The multilocus paternity correlation was significantly higher and effective number of pollen donors was significantly lower in the private population, decreasing the diversity and consequently the variance effective size of families sampled from that population. However, despite its isolation from the other studied fragments, the private population had the second highest number of alleles as well as unique alleles from the other populations. Therefore, strategies for A. angustifolia conservation should focus not only on larger populations, such as those found in protected areas, but also include smaller and isolated fragments on private properties as these populations are able to maintain high levels of genetic diversity and functional connectivity between isolated stands across a landscape. © 2015, Springer Science+Business Media Dordrecht. Source

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