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Abrupt fire regime change may cause landscape‐wide loss of mature obligate seeder forests
Author(s) -
Bowman David M. J. S.,
Murphy Brett P.,
Neyland Dominic L. J.,
Williamson Grant J.,
Prior Lynda D.
Publication year - 2014
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12433
Subject(s) - environmental science , population , ecological succession , biomass (ecology) , chronosequence , ecology , agroforestry , biology , demography , sociology
Obligate seeder trees requiring high‐severity fires to regenerate may be vulnerable to population collapse if fire frequency increases abruptly. We tested this proposition using a long‐lived obligate seeding forest tree, alpine ash ( Eucalyptus delegatensis ), in the Australian Alps. Since 2002, 85% of the Alps bioregion has been burnt by several very large fires, tracking the regional trend of more frequent extreme fire weather. High‐severity fires removed 25% of aboveground tree biomass, and switched fuel arrays from low loads of herbaceous and litter fuels to high loads of flammable shrubs and juvenile trees, priming regenerating stands for subsequent fires. Single high‐severity fires caused adult mortality and triggered mass regeneration, but a second fire in quick succession killed 97% of the regenerating alpine ash. Our results indicate that without interventions to reduce fire severity, interactions between flammability of regenerating stands and increased extreme fire weather will eliminate much of the remaining mature alpine ash forest.