<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Worldwide, large areas of forest are being transformed to other land cover types and the resulting fragmented populations may suffer from restricted gene flow leading to genetic pauperization and increased inbreeding. To assess the genetic constitution of fragmented <italic>Polylepis australis</italic> mountain forests of central Argentina, analyses of the structure and diversity of ISSR markers were carried out for 90 trees distributed throughout five river basins with differing degrees of fragmentation. Overall, average polymorphism (<italic>P</italic>) ranged between 87.2 and 94.9% (95% criterion) while marker diversity index (<italic>M</italic>) varied between 0.35 and 0.39; values which are comparable with other wind-pollinated tree species. Analysis of molecular variance (AMOVA) revealed that most genetic variation occurred within river basins (97.8%), with only a little occurring between river basins (2.2%; Φ<italic><sub>ST</sub></italic> = 0.02). In addition, Mantel’s test indicated that <italic>P. australis</italic> does not follow the usual pattern of isolation by distance; instead the UPGMA method showed that trees from the two most degraded river basins formed a group while trees from the three better preserved basins formed another. As such, either effective pollen flow has maintained high levels of genetic diversity, or present day genetic variability is a remnant of a recently fragmented ancestral panmictic population. We conclude that, at present, genetic degradation in <italic>P. australis</italic> populations of central Argentina is not as important as ecological degradation – such as soil loss, intensive browsing by livestock or increased frequencies of wildfires, and that genetic variability is still fully available for forest restoration.</p></abstract>

Worldwide, large areas of forest are being transformed to other land cover types and the resulting fragmented populations may suffer from restricted gene flow leading to genetic pauperization and increased inbreeding. To assess the genetic constitution of fragmented Polylepis australis mountain forests of central Argentina, analyses of the structure and diversity of ISSR markers were carried out for 90 trees distributed throughout five river basins with differing degrees of fragmentation. Overall, average polymorphism (P) ranged between 87.2 and 94.9% (95% criterion) while marker diversity index (M) varied between 0.35 and 0.39; values which are comparable with other wind-pollinated tree species. Analysis of molecular variance (AMOVA) revealed that most genetic variation occurred within river basins (97.8%), with only a little occurring between river basins (2.2%; ΦST = 0.02). In addition, Mantel’s test indicated that P. australis does not follow the usual pattern of isolation by distance; instead the UPGMA method showed that trees from the two most degraded river basins formed a group while trees from the three better preserved basins formed another. As such, either effective pollen flow has maintained high levels of genetic diversity, or present day genetic variability is a remnant of a recently fragmented ancestral panmictic population. We conclude that, at present, genetic degradation in P. australis populations of central Argentina is not as important as ecological degradation – such as soil loss, intensive browsing by livestock or increased frequencies of wildfires, and that genetic variability is still fully available for forest restoration.

Genetic structure and diversity of <italic>Polylepis australis</italic> (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Cátedra de Genética de Poblaciones y Evolución

Centro de Ecología y Recursos Naturales Renovables – Dr. Ricardo Luti (CERNAR)

Institute of Biology, Geobotany and Botanical Garden

Martin-Luther-University Halle-Wittenberg

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Genetic structure and diversity of  (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Worldwide, large areas of forest are being transformed to other land cover types and the resulting fragmented populations may suffer from restricted gene flow...

Genetic structure and diversity of Polylepis australis (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Published Online: Aug 05, 2017

Page range: 55 - 61

Received: Sep 04, 2009

DOI: https://doi.org/10.1515/sg-2011-0007

Keywords
fragmentation, genetic diversity, Argentina, conservation, ISSR

© 2011 N. B. Julio et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Genetic structure and diversity of Polylepis australis (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Published Online: Aug 05, 2017

Page range: 55 - 61

Received: Sep 04, 2009

DOI: https://doi.org/10.1515/sg-2011-0007

Keywordsfragmentation, genetic diversity, Argentina, conservation, ISSR

© 2011 N. B. Julio et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
fragmentation, genetic diversity, Argentina, conservation, ISSR