Early post‐fire regeneration in subalpine heathland and grassland in the Victorian Alpine National Park, south‐eastern Australia

Abstract

Landscape fire (at the scale of square kilometres or more) is relatively rare in the alpine and subalpine environments of Australia. In early 1998, a major fire (the ‘Caledonia Fire’), burnt approximately 35 000 ha, of which approximately 3000 hectares was subalpine heathland, grassland and wetland within the Victorian Alpine National Park. This fire was one of only three landscape‐scale fires that have occurred anywhere in the treeless vegetation of the Victorian Alps in the past 100 years, the others being in 1939 and 1985. Monitoring of regeneration in subalpine vegetation commenced 3 weeks postfire. Sites were established in burnt grassland at Holmes Plain (1400 m a.s.l.) and burnt grassland and heathland at Wellington Plain (1480 m a.s.l.), and in unburnt grassland at both sites. In burnt grassland and heathland, the fire consumed much of the vegetation, leaving extensive areas of bare ground. The cover of dense vegetation declined from > 70% prefire, to approximately 15% immediately postfire. Bare ground at the Holmes and Wellington Plains sites ranged from 70% to 85% immediately postfire. By May 2000, approximately 2.5 years postfire, dense vegetation cover in grassland had increased to approximately 20%, and bare ground had decreased to an average of approximately 30%. In unburnt grassland, dense vegetation cover was generally > 95%, and the amount of bare ground less than 5%. The tussock‐forming snow grasses resprouted vigorously following fire, and had flowered prolifically after 1 year. In heathland, most of the shrubs were incinerated, leaving close to 100% bare soil. Since then, a number of grasses and some dominant shrubs have resprouted vigorously, with some seedling regeneration. By May 2000, in heathland, bare soil was still > 50% and dense vegetation < 20%. Such ground cover conditions during this early postfire period were well below prefire levels, and well below the levels necessary to protect alpine soils from erosion. The Caledonia Fire has provided a rare opportunity to study ecological processes associated with postfire regeneration in treeless subalpine landscapes.

Post‐fire regeneration in alpine heathland: Does fire severity matter?

“…In Australian alpine and subalpine vegetation, most species re-establish within one or two years after fire (Wahren et al 2001;Walsh & McDougall 2004), suggesting that these heathlands, like many temperate sclerophyllous shrubby vegetation types, follow the 'initial floristic composition' model of Egler (1954) or the 'auto-succession' model of Keeley et al (2005), whereby species diversity and composition is established rapidly post fire. Five years after landscape-scale fire, there were few differences in plant diversity and floristic composition across a strong fire severity gradient.…”

A critical review of the science underpinning fire management in the high altitude ecosystems of south-eastern Australia

“…The cover of grassland in the Victorian Alps increased from 20% to 70% within two and a half years of fire (Wahren et al, 2001). In addition, the growth of inter-tussock herbs and Themeda spp.…”

Advances in Remote Sensing of Post-Fire Vegetation Recovery Monitoring - A Review

“…), or a combination of the above (Pausas et al 1999;Eshel et al 2000;Kazanis and Arianoutsou 2004). In addition, protocols used can be distinguished into two general categories, that of plots Daskalakou and Thanos 1997;Tsitsoni 1997;Martínez-Sánchez et al 1999;De Luis et al 2001;Bailey and Covington 2002;Kennard et al 2002) and that of transects (Ne'eman et al 1999;Pausas et al 1999;Caturla et al 2000;Wahren et al 2001;Gould et al 2002). Pausas et al (1999) investigated the effect of different environmental conditions (climatic zones, aspect, and lithology) on the recovery process.…”

“…spatial organisation of vegetation) (Calvo et al 1994;Ne'eman et al 1999;Mouillet et al 2001) Resprouting vigour (plant's anatomical features, and the characteristics of the individual before disturbance), intensity of disturbance, and the environmental conditions after disturbance (Lloret and Vilà 1997;Díaz-Delgado and Pons 2001) Seed banks and germination -Seed number contained in soil samples -Cone opening and seed dispersal (Thanos and Georghiou 1988;Skordilis and Thanos 1995;Daskalakou and Thanos 1996;Ferrandis et al 1996;Herranz et al 1999;Keeley 2000) Seedling germination, survival and growth in a plot and along a transect on which samples are taken of plant cover, tree cover, tree characteristics or the floristic composition and cover per species Daskalakou and Thanos 1997;Tsitsoni 1997;Martínez-Sánchez et al 1999;Ne'eman et al 1999;Pausas et al 1999;Caturla et al 2000;De Luis et al 2001;Wahren et al 2001;Bailey and Covington 2002;Gould et al 2002;Kennard et al 2002) Post-fire structural dynamics (Calvo et al 1991) Species richness patterns and vegetation diversity -density of seedlings -abundance of different age classes (Pausas et al 2003;Perula et al 2003;Kavgaci et al 2010) Permanent plot collection per plant community type and data reduction -Visual cover of the plant species (Santalla et al 2002;Clemente et al 2009) Non-native species cover correlated with high native species richness (Hunter et al 2006) Field spectrometry (Broge and Leblanc 2000;Thenkabail et al 2000;Thenkabail et al 2002;...…”

“…Seed banks are important in the dynamics of many plant communities as they provide an immediate source of propagules for recruitment after disturbance. Measurements may be focused on the monitoring of seedling germination, survival and growth (height) in a plot (Tsitsoni 1997;Martínez-Sánchez et al 1999;De Luis et al 2001;Bailey and Covington 2002;Kennard et al 2002), or may be along a transect on which samples are taken of plant cover (Caturla et al 2000), tree cover (Ne'eman et al 1999), tree characteristics (Ne'eman et al 1999;Gould et al 2002) or the floristic composition and cover per species (Pausas et al 1999;Wahren et al 2001). …”