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

Abstract

Fire severity is thought to be an important determinant of landscape patterns of post-fire regeneration, yet there have been few studies of the effects of variation in fire severity at landscape scales on floristic diversity and composition, and none within alpine vegetation. Understanding how fire severity affects alpine vegetation is important because fire is relatively infrequent in alpine environments. Globally, alpine ecosystems are at risk from climate change, which, in addition to warming, is likely to increase the severity and frequency of fire in southeastern Australia. Here we examine the effects of variation in fire severity on plant diversity and vegetation composition, 5 years after the widespread fires of 2003. We used floristic data from two wide-spread vegetation types on the Bogong High Plains: open heathland and closed heathland. Three alternative models were tested relating variation in plant community attributes (e.g. diversity, ground cover of dominant species, amount of bare ground) to variation in fire severity. The models were (i) 'linear', attributes vary linearly with fire severity; (ii) 'intermediate disturbance', attributes are highest at intermediate fire severity and lowest at both low-and highseverity; and (iii) 'null', attributes are unaffected by fire severity. In both heathlands, there were few differences in floristic diversity, cover of dominant species and community composition, across the strong fire severity gradient. The null model was most supported in the vast majority of cases, with only limited support for either the linear and intermediate disturbance models. Our data indicate that in both heathlands, vegetation attributes in burnt vegetation were converging towards that of the unburnt state. We conclude that fire severity had little impact on post-fire regeneration, and that both closed and open alpine heathlands are resilient to variation in fire severity during landscape scale fires.

Mapping and exploring variation in post‐fire vegetation recovery following mixed severity wildfire using airborne LiDAR

“…It can be measured in the field or from remote sensing using multi-spectral indices that describe blackening (Hammill and Bradstock 2006). Also, studies have found that high-severity fires often have minimal effects on vegetation diversity, including in North American pine forests and west coast shrublands (Turner et al 1999, Purdon et al 2004, Keeley et al 2008, Fornwalt and Kaufmann 2014 and Australian eucalypt forests (Bradstock 2009, Knox and Clarke 2012, Camac et al 2013, Clarke et al 2014. However, there is increasing evidence that some floristic elements are favored by high-severity fires because these fires are required to trigger seed germination (Ooi et al 2006, Liyanage andOoi 2015).…”

“…However, there is increasing evidence that some floristic elements are favored by high-severity fires because these fires are required to trigger seed germination (Ooi et al 2006, Liyanage andOoi 2015). Also, studies have found that high-severity fires often have minimal effects on vegetation diversity, including in North American pine forests and west coast shrublands (Turner et al 1999, Purdon et al 2004, Keeley et al 2008, Fornwalt and Kaufmann 2014 and Australian eucalypt forests (Bradstock 2009, Knox and Clarke 2012, Camac et al 2013, Clarke et al 2014.…”

Local lithological drivers of post‐fire vegetation recovery and implications for fire‐prone regions

“…Small black dots represent important species. by promoting supervised natural succession (Maguire and Menges 2011;Camac et al 2013). Thus, on substrates that are unfavourable for rapid vegetation recovery after fire (like schist-derived soils in our test region), post-fire management of burnt areas may have to include active protection of soil against erosion as well as active plantation or seeding (e.g.…”

Post‐fire vegetation recovery at forest sites is affected by permafrost degradation in the Da Xing'an Mountains of northern China

“…Previous studies of post‐fire succession have primarily concentrated on the direct impacts of fire on forest recovery and linked those impacts to factors such as disturbance history, the regional species pool and species life histories (Girard, De Grandpré, & Ruel, ; Schoennagel, Veblen, & Romme, ). However, the specific role of biotic and abiotic factors in post‐fire regeneration can differ substantially among fires (Ackerly, ; Camac, Williams, Wahren, Morris, & Morgan, ; Nuñez & Raffaele, ), depending on the context provided by the characteristics of the local environment. Under certain unique geographical conditions, succession cannot be completely described by a general pattern of community development, but rather is the result of a variety of dynamic site‐specific factors that change the trajectory from the typical chronosequence (Conway & Johnstone, ; Yuan et al., ).…”

“…Previous studies of post-fire succession have primarily concentrated on the direct impacts of fire on forest recovery and linked those impacts to factors such as disturbance history, the regional species pool and species life histories (Girard, De Grandpré, & Ruel, 2014;Schoennagel, Veblen, & Romme, 2004). However, the specific role of biotic and abiotic factors in post-fire regeneration can differ substantially among fires (Ackerly, 2004;Camac, Williams, Wahren, Morris, & Morgan, 2013;Nuñez & Raffaele, 2007), depending on the context provided by the characteristics of the local environment.…”