Orchid populations and endophytic fungi change with rainfall and prescribed burning in Pterostylis

Wildfires are common in seasonally dry parts of the world with a Mediterranean climate. Prescribed burning is used to reduce fuel load and fire risk, but information on its effects is often lacking.

The orchid Pterostylis revoluta

Jasinge et al. conduct a survey of the effects of prescribed burns during different seasons on Pterostylis revoluta, an autumn-flowering Australian terrestrial orchid, and its orchid mycorrhizal fungi (OMF) in order to determine the least damaging season for a prescribed burn. They find that P. revoluta quadrupled its numbers, with 90 % of plants becoming vegetative, and the orchid adopted a different mycorrhizal fungus (from Tulasnella to Ceratobasidium). Rainfall, rather than fire effects and timing is likely to have been the main driving factor in the changes observed. Reserve authorities should note these impacts and aim to time prescribed burning from winter to spring to maximise subsequent orchid populations.

Reference List

Jasinge, N. U., Huynh, T., & Lawrie, A. C. (2018). Changes in orchid populations and endophytic fungi with rainfall and prescribed burning in Pterostylis revoluta in Victoria, Australia. Annals of Botany, 121(2), 321–334. https://doi.org/10.1093/aob/mcx164