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Burning for savanna biodiversity�Management lessons from a long-term fire experiment

Alan Andersen

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Stefan Maier

TWP fire experiment

2004 - ongoing

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Fire effects on vegetation

Woody cover

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Biodiversity: the variety of life

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Biodiversity: the variety of life

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Biodiversity: the variety of life

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Insect responses to fire

Ants

Dung beetles

Butterflies

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Ant diversity declines with increasing woody cover

Brassard et al. 2023

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Vertical stratification of ant communities

Arboreal

Cryptobiotic

Epigaeic

Photos from AntWeb

Hypogaeic

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Vertical stratification of ant communities

Like frequent fire

Photos from AntWeb

Brassard et al. 2024

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Vertical stratification of ant communities

Photos from AntWeb

Like frequent fire

Brassard et al. 2024

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Vertical stratification of ant communities

Don’t like frequent fire

Photos from AntWeb

Brassard et al. 2024

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Vertical stratification of ant communities

Don’t care

Photos from AntWeb

Brassard et al. 2024

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Vertical stratification of ant communities

Likely to apply to a range of animal groups

Don’t care

Photos from AntWeb

Don’t like frequent fire

Like frequent fire

Like frequent fire

Brassard et al. 2024

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Overall, ants prefer frequent burning

  • Almost all (82 of 86) species occurred in plots burned every 2 yrs

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  • Frequently burnt plots contain patches with higher vegetation cover

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  • Long-unburned plots have lowest ant diversity and no unique species – they do not contribute to ant biodiversity

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Abundance of dung beetles declines with increasing woody cover

Carvalho et al. 2020

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Fire promotes butterfly abundance and species richness

No. butterflies

No. species

Early

Unburnt

Late

Early

Unburnt

Late

Leone et al. 2023

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Fire promotes butterflies by promoting floral resources, which are promoted by fire

Leone et al. 2023

No. butterflies

No. species

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Fire and insect diversity

Lessons for management

  • Frequent fire promotes diversity
    • maintains the open habitats that most species prefer
    • increases herbaceous plant diversity and nectar resources

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Fire and insect diversity

Lessons for management

  • Frequent fire promotes diversity
    • maintains the open habitats that most species prefer
    • increases herbaceous plant diversity and nectar resources

​

  • Long-term fire exclusion reduces diversity
    • favours non-savanna species that are already common in the broader landscape

​

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Fire and insect diversity

Lessons for management

  • Frequent fire promotes diversity
    • maintains the open habitats that most species prefer
    • increases herbaceous plant diversity and nectar resources

​

  • Long-term fire exclusion reduces diversity
    • favours non-savanna species that are already common in the broader landscape

​

  • Responses of small mammals do not reflect biodiversity