Fire severity mediates seedling recruitment patterns in slender mulga (Acacia aptaneura), a fire-sensitive Australian desert shrub with heat-stimulated germination

Speculations on the application of foliar <sup>13</sup>C discrimination to reveal groundwater dependency of vegetation, provide estimates of root depth and rates of groundwater use

“…Finally, rates of water use and changes in midday water potential between the end of the wet-season and the end of the dry-season were minimal for E. camaldulensis and C. opaca but were very large for Acacia aptaneura (which was previously classified as Acacia aneura; Maslin and Reid, 2012;Nolan et al, 2017). A. aneura and A. aptaneura often intermix with other members of the large Mulga complex of closely related Acacia species (Wright et al, 2016), thus we will refer Acacia spp. in the Mulga complex by the primary type, A. aneura.…”

Advances in understanding the influence of fire on the ecology and evolution of plants: a tribute to Peter J. Clarke

“…Wright et al (2016;this issue) investigated the variability in post-fire recruitment of mulga (a fire-killed shrub with soil seed bank) in relation to fire severity and soil heating during fire. Maximum germinability of mulga seeds occurred when soil was heated to between 80 and 100°C, and these temperatures were achieved only in high-severity fires.…”

“…Less severe fires produced lower post-fire recruitment, but the response was highly variable among sites. Wright et al (2016) propose that this variable pattern in post-fire seedling recruitment may be a risk-spreading strategy to unpredictable fire severity, with high recruitment levels offsetting high adult mortality following high-severity fire.…”

Fire after a mast year triggers mass recruitment of slender mulga (Acacia aptaneura), a desert shrub with heat‐stimulated germination

“…Its recruitment is typically enhanced by fire, as mulga seeds are stimulated to germinate by temperatures between 80 and 100°C, and such temperatures are often achieved in upper soil layers during fire (Fox, 1985; Hodgkinson and Oxley, 1990). In addition, recruitment patterns can be influenced by fire severity, as high‐severity fires with high levels of soil heating usually trigger increased recruitment compared to low‐severity fires that only partially combust dense understory litter layers (Hodgkinson, 1991; Wright et al, 2015).…”

“…Presumably as a result of the seeds being favored by granivores, previous seedbank studies have found mulga seedbanks to be very sparse (Page, 2009; Wright and Clarke, 2009), or nonexistent (Hodgkinson et al, 1980). However, short‐lived seedbank pulses in upper soil layers do occur following mast years, apparently because seed predators are satiated during such periods, which allows a fraction of the seed crop to disseminate into the soil (Wright and Zuur, 2014; Wright et al, 2015).…”