Data: Aridity modulates post-fire succession of plant communities and plant function groups in two vegetation types.

Aims

Understanding how plant communities change during post-fire succession is essential for effective fire management that seeks to ensure both human safety and biodiversity conservation. We investigated post-fire succession of plant communities along an environmental gradient in semi-arid southern Australia and compared fire responses for two vegetation types in each of two climate zones.

Location

Two conservation reserve systems in Victoria, south-eastern Australia: Little Desert National Park (132,000 ha; ‘less-arid zone’) and Big Desert Wilderness Area/Wyperfeld National Park (744,850 ha; ‘more-arid zone’).

Methods

We conducted floristic surveys at 251 sites, stratified by climate zone, vegetation type, and time since last fire (across a 75-year chrono-sequence).

Results

Time since fire had a significant influence on floristic composition, species richness and species diversity in each vegetation type and across both climate zones. Floristic composition between sites within early successional age-classes tended to be more similar than composition within late successional age-classes. There were distinct patterns of post-fire succession between climate zones, with time-since-fire having a stronger influence in the more-arid environment. Above-ground species richness and species diversity declined with increasing time since fire. Species diversity of several functional trait groups exhibited divergent time-since-fire responses between climate zones; notably, resprouter diversity was lower and declined more rapidly in the more-arid zone.

Conclusions

Time-since-fire had a strong influence on post-fire vegetation succession, with such patterns also influenced by climate for a given vegetation type or fire-response trait group. We highlight the need for context-specific fire management, particularly when applying guidelines across environmental gradients, to ensure the provision of diverse age-classes across the landscape that meet the needs of both plants and animals. This is particularly relevant in the light of a mega-fire (>90,000 ha) in Jan 2025, that reduced >65% of the less-arid study zone to a single age-class.