Resilience and recovery of plant communities facing increasing fire severity

Extreme events such as megafires are becoming more frequent with changing climate. Changes in fire regimes like increasing fire severity, threaten the survival and recovery of plants through lack of adaptation to these extreme occurrences. Beyond impacts on individuals this can shift the composition, structure and functioning of communities. To fully understand the extent of these changes, community-wide studies need to be employed but are rarely focused on changing fire severity. In this thesis I holistically focused on the recovery of a threatened plant community following fire. Recovery after disturbance often occurs through multiple pathways, and I explored three: persistence, recruitment and dispersal, across four studies. I focused on threatened wet sclerophyll forest (WSF), a mesic forest susceptible to changing fire regimes given its composition contains both fire-prone and fire-sensitive species. The first study used a functional diversity approach, collecting field data to analyse how changing fire severity impacted extant vegetation of WSF one- and three-years following fire. I found increasing fire severity reduced diversity, which was most apparent in the shrub layer three years following fire. The second study delved further into recovery through persistence namely resprouting. I undertook a literature review of post-fire resprouting, revealing how increasing fire severity can reduce resprouting ability. Critically, interactions between fire severity and resprouting success were different across species and varied between studies. My third study focused on recovery through recruitment from the soil seed bank. By establishing a greenhouse experiment, I observed how increasing fire severity reduced diversity in the soil seed bank. My fourth study examined post-fire recovery through seed dispersal. I monitored seed rain through collection from seed traps, finding post-fire dispersal to be primarily local, reflecting a lower diversity at higher fire severity sites. These studies give a holistic understanding of how WSF recovers as a community to changing fire regimes. The theory examined in these studies is comprehensively outlined in an introduction and the management implications are explored in an in-depth discussion. Fire-sensitive species are at risk of loss from extreme fire severity sites, and management needs to consider functional diversity and impacts on differing recovery pathways to fully understand the impact of changing fire regimes.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2025

Author dc:creator

• Paroissien, Ruby

• Ecology
• Fire ecology
• Community ecology
• Seed ecology
• Threatened ecological community
• Soil seed bank
• Seed rain
• Resprouting
• anzsrc-for: 31 BIOLOGICAL SCIENCES

Statement dc:rights

• open access
• CC BY 4.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by/4.0/

Language dc:language

en

Identifier

https://doi.org/10.26190/unsworks/31908

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/106673