Get access

Influence of fire severity on the regeneration, recruitment and distribution of eucalypts in the Cotter River Catchment, Australian Capital Territory

Authors

  • LYNDSEY M. VIVIAN,

    1. The Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia (Email: lyndsey.vivian@anu.edu.au),
    2. Bushfire Cooperative Research Centre, East Melbourne Victoria, and
    Search for more papers by this author
  • GEOFFREY J. CARY,

    1. The Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia (Email: lyndsey.vivian@anu.edu.au),
    2. Bushfire Cooperative Research Centre, East Melbourne Victoria, and
    Search for more papers by this author
  • ROSS A. BRADSTOCK,

    1. Bushfire Cooperative Research Centre, East Melbourne Victoria, and
    2. Biodiversity Research and Management Division, NSW National Parks and Wildlife Service, Hurstville, New South Wales, Australia
    Search for more papers by this author
    • Present address: Centre for Environmental Risk Management of Bushfires, University of Wollongong, 2522, Australia.

  • A. MALCOLM GILL

    1. The Fenner School of Environment and Society, Australian National University, Canberra, ACT 0200, Australia (Email: lyndsey.vivian@anu.edu.au),
    2. Bushfire Cooperative Research Centre, East Melbourne Victoria, and
    Search for more papers by this author

Abstract

Abstract  Plant responses to fire are variable between and within species and are influenced by numerous factors including fire severity. This study investigated the effects of fire severity on the regeneration and recruitment of forest eucalypts in the Cotter River Catchment, Australian Capital Territory (ACT). This study also examined the potential for the obligate seeder Eucalyptus delegatensis R.T. Baker (Myrtaceae) to expand into adjacent stands dominated by the facultative resprouter Eucalyptus fastigata H. Deane & Maiden (Myrtaceae) by seed shed and seedling establishment beyond the pre-fire boundary. Sites were located in areas of either higher or lower fire severity, and transects were placed across the boundary of stands of E. delegatensis and E. fastigata. Species distributions, tree survival and seedling densities and heights were recorded, and the location of each boundary was determined as the region of maximum change in species composition along the transects. Eucalyptus delegatensis was the only eucalypt killed by higher severity fire. However, E. delegatensis seedling density was greater at higher severity sites than lower severity sites. Eucalyptus fastigata seedling density was low across all sites, with other eucalypts producing few, if any, seedlings. There was no evidence that E. delegatensis had increased its range into downslope stands dominated by E. fastigata. Patterns of vegetative recovery and seedling recruitment may be related to a number of factors, including differences in allocation patterns between seeders and sprouters, and the effects of overstory and understory competition. It is unclear what processes impede E. delegatensis seedling establishment beyond the stand boundary, but may involve an inability of E. delegatensis to shed seed sufficiently far downslope; unsuitable conditions for germination beyond the boundary; or, competition from a retained or resprouting overstory, despite the potential for increased dispersal distance soon after fire.

Ancillary