Title

Appraising widespread resprouting but variable levels of postfire seeding in Australian ecosystems: The effect of phylogeny, fire regime and productivity

Publication Name

Australian Journal of Botany

Abstract

Postfire resprouting (R+) and recruitment from seed (S+) are common resilience traits in Australian ecosystems. We classified 2696 woody Australian taxa as R+ or not (R-) and as S+ or not (S-). The proportions of these traits in Australian ecosystems were examined in relation to fire regimes and other ecological correlates, and by trait mapping on a phylogeny scaled to time. Resprouting mapped as an ancestral trait. Postfire reseeding recruitment, while ancient, is more taxonomically restricted and has evolved independently several times. Nevertheless, both R+ and S+ are common in most clades, but negatively correlated at the ecosystem level indicating an evolutionary trade-off related to differences in the severity of fire regimes, determined in part by ecosystem productivity. Thus, R+ was associated with persistence in ecosystems characterised by higher productivity and relatively frequent surface fires of moderate to low severity (fire-productivity hypothesis). S+, the fire-stimulated recruitment by seed, occurred in ecosystems characterised by infrequent but intense crown-fire and topkill, reducing competition between postfire survivors and recruits (fire-resource-competition hypothesis). Consistently large proportions of R+ or S+ imply fire has been a pervasive evolutionary selection pressure resulting in highly fire-adapted and fire-resilient flora in most Australian ecosystems.

Open Access Status

This publication is not available as open access

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Link to publisher version (DOI)

http://dx.doi.org/10.1071/BT21110