Ecological Research

, Volume 27, Issue 4, pp 715–724 | Cite as

Drought-induced mortality affects understory vegetation: release after death

  • M. L. SuarezEmail author
  • Y. Sasal
Original Article


In recent decades, severe droughts have become an important cause of canopy disturbance in forests, and have shown potential to cause rapid and pronounced vegetation shifts. Under dead canopy, undamaged understory could influence the nature of resource limitation for seedling growth and survival, limiting forest regeneration. We assessed the release response of understory vegetation after a severe drought event in temperate forests of northern Patagonia. Growth trends of dominant tree saplings, and changes in vegetation biodiversity and cover were compared between drought-dead and unaffected canopy. Nothofagus dombeyi undergo growth release after the climatic event in affected forests, and the response was evidenced immediately after the disturbance. For Austrocedrus chilensis, the growth release response was less evident, due mainly to a difference in age structure. In the understory the release response was barely discernable for some components. There was a tendency towards higher cover of the shrub layer in the understory of drought-affected forests, and an important presence of the exotic shrub Rosa rubiginosa. However, the clearest biotic response following drought mortality was the release in growth of understory dominant tree component. Those results strongly suggest that the environment under drought-dead canopy, and the die-off in woody sapling cohorts in a self-thinning process, could favor crown expansion and growth release of understory species that could help predict future forest trajectories in the context of the influence of climatic extreme events.


Drought-dead canopy Temperate forest Sapling growth release Understory vegetation cover Understory vegetation diversity 



We are grateful to Idea Wild (Fort Collins, CO) for providing fundamental equipment for this study; the personnel from the Nahuel Huapi National Park for logistic support; and M. Bastidas and C. Ziperovich for their volunteer field assistance. This research was developed with the support from CONICET doctoral fellowships received by both authors.


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Copyright information

© The Ecological Society of Japan 2012

Authors and Affiliations

  1. 1.Laboratorio Ecotono, INIBIOMA-CONICETUniversidad Nacional del ComahueSan Carlos de BarilocheArgentina

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