Explaining the distribution of Pinus spp. in a Canadian boreal insular landscape

Authors

  • Yves Bergeron,

    1. Groupe de recherche en écologie forestière, Université du Québec à Montréal, CP 8888 Succ. A, Montréal, Canada H3C 3P8; Tel. +1 514 9874872; Fax +1 514 9874648; E-mail: yves.bergeron@uqam.ca
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  • Alain Leduc,

    1. Groupe de recherche en écologie forestière, Université du Québec à Montréal, CP 8888 Succ. A, Montréal, Canada H3C 3P8; Tel. +1 514 9874872; Fax +1 514 9874648; E-mail: yves.bergeron@uqam.ca
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  • Ting-Xian Li

    1. Groupe de recherche en écologie forestière, Université du Québec à Montréal, CP 8888 Succ. A, Montréal, Canada H3C 3P8; Tel. +1 514 9874872; Fax +1 514 9874648; E-mail: yves.bergeron@uqam.ca
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    • 1

      Ministère de l'Environnement et de la Faune, Division de la cartographie écologique, 2360 Chemin Sainte-Foy, ler étage, Sainte-Foy, Québec G1V 4H2, Canada


Abstract

Abstract. To evaluate the respective contributions of habitat, fire regime and colonization-extinction processes to the distribution of northern Pinus species, we investigated the distribution of P. banksiana (jack pine), P. resinosa (red pine) and P. strobus (white pine) on 117 islands of Lake Duparquet in northwestern Québec. Stepwise logistic regressions indicated that the extent of xeric areas on the islands was the sole factor predicting jack pine distribution. The distribution of white pine was predicted primarily by the combined effects of distance to the shoreline and elevation, with a smaller effect of area of xeric habitat. The distribution of red pine was predicted by other populations of red pine nearby, with a slightly smaller effect of the combined effects of distance to shoreline and elevation. None of the species completely saturates all available islands nor is any restricted to specific, very exposed aspects. The results suggest that pine is more frequent on islands with characteristics that promote lightning strikes and thus higher fire occurrence. However, absence of pine in several islands may not be explained by abiotic characteristics or recent fire history. The presence of very small populations, together with low invasion potential, suggests that the observed distribution is mainly driven by the process of random extinction. A disequilibrium between present and past fire regimes may explain why northern pines have discontinuous distributions inside their range limits.

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