Determinants of growth of the flammable grass, Triodia scariosa: Consequences for fuel dynamics under climate change in the Mediterranean region of South Eastern Australia

Abstract

Environmental conditions may influence the presence and strength of competitive interactions between different life forms, thereby shaping community composition and structure, and corresponding fuel dynamics. Woodland and shrubland communities of the Mediterranean climate region of South Eastern Australia contain a varied mixture of herbaceous and woody plants. The ratio of herbaceous to woody plants changes along gradients of temperature, moisture and soil fertility. This study aimed to experimentally examine the relative importance of, and interactions between environmental controls (moisture and soil fertility) on the balance of dominant herbaceous (Triodia scariosa) and woody plants (e.g. Acacia ligulata and Leptospermum coriaceum) and their ultimate effects on fuel and fire regimes. The results suggest that environmental determinants of the growth of T. scariosa are likely to be more important than interactions with shrubs in controlling the distribution of T. scariosa. The growth of T. scariosa was consistently higher under hot temperatures and on the less fertile yellow sands, which dominate the south of the region. The results suggest that there is strong potential for the distribution and abundance of T. scariosa to be altered in the future with changes in temperature associated with climate change. The distribution of soil types across the Mediterranean climate region of South Eastern Australia may be predisposed to favour the southerly expansion of T. scariosa-dominated communities in the future under a warmer climate.

Time‐since‐fire and climate interact to affect the structural recovery of an Australian semi‐arid plant community

“…Cover was greater in drier environments where there was lower rainfall, greater evaporation and greater rainfall variability, and higher temperature (Gibson et al . ). Mean hummock height decreased with increasing time‐since‐fire and mean annual rainfall but fluctuated with annual rainfall variability.…”

“…It also ensures its return to reproductive maturity earlier than those plants germinating from seed and highlights its increased growth under higher temperatures (Gibson et al . ).…”

Interactions between rainfall, fire and herbivory drive resprouter vital rates in a semi‐arid ecosystem

“…No pre-fire survey occurred at sites burnt by wildfire, therefore at these sites A it used data on the total number of live and fire-killed hummocks at the first post-fire census. Although variation in post-fire rainfall and temperature are expected to influence seedling germination and establishment (Gibson et al 2016), these variables were not retained in the final model for germination because they were strongly correlated with fire type. The relatively short time frames relevant to germination (3-6 months) meant that potential trends in rainfall and temperature were masked by seasonal differences between summer and autumn.…”