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The relative importance of intrinsic and extrinsic factors in the decline of obligate seeder forests


Bowman, DMJS and Williamson, GJ and Prior, LD and Murphy, BP, The relative importance of intrinsic and extrinsic factors in the decline of obligate seeder forests, Global Ecology and Biogeography, 25, (10) pp. 1166-1172. ISSN 1466-822X (2016) [Refereed Article]


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Copyright 2016 The Authors Licensed under Creative CommonsAttribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0)

DOI: doi:10.1111/geb.12484


Forests that regenerate exclusively from seed following high-severity fire are particularly vulnerable to local extinction if fire frequency leaves insufficient time for regenerating plants to reach sexual maturity. We evaluate the relative importance of extrinsic (such as fire weather and climate cycles) and intrinsic (such as proneness to fire due to stand age and structural development) factors in driving the decline of obligate seeder forests. We illustrate this using obligate seeding alpine ash (Eucalyptus delegatensis) forests in the montane regions of Victoria, Australia, that were burnt by megafires in 2003 (142,256 ha) or 2007 (79,902 ha), including some twice-burnt areas (11,599 ha). Geospatial analyses showed only a small effect of stand age on the remote sensing estimates of crown defoliation, but a substantial effect of forest fire weather, as measured by forest fire danger index (FFDI). Analysis of meteorological data over the last century showed that 5-year increases in FFDI precede cycle major fires in the E. delegatensis forests. Such strong extrinsic climate/weather driving of high-severity fires is consistent with the ‘interval squeeze model’ that postulates the vulnerability of obligate seeder forests to landscape-scale demographic collapse in response to worsening fire weather under climate change.

Item Details

Item Type:Refereed Article
Keywords:alternative stable state, Australia, climate change, disturbance ecology, Eucalyptus, forest regeneration, landscape ecology, wildfire
Research Division:Environmental Sciences
Research Group:Ecological applications
Research Field:Landscape ecology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Ecosystem adaptation to climate change
UTAS Author:Bowman, DMJS (Professor David Bowman)
UTAS Author:Williamson, GJ (Dr Grant Williamson)
UTAS Author:Prior, LD (Dr Lynda Prior)
ID Code:110137
Year Published:2016
Web of Science® Times Cited:43
Deposited By:Plant Science
Deposited On:2016-07-14
Last Modified:2017-11-01
Downloads:207 View Download Statistics

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