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Wildfires pose threat to important night-time pollinators

Posted on 12 July 2019

Researchers have shown how wildfires have a detrimental impact on moths and the plants they pollinate at night.


Elephant Hawkmoth with Greater Butterfly Orchid pollen on its eyes. Image credit: John Bebbington

The study, by an international team of experts including researchers at the universities of York and Newcastle, studied the impact of a large wildfire in Portugal on moths and flowering plants.

The results of the study showed that moths dropped significantly in numbers and were transporting five times less pollen at burned sites, making it harder for the ecosystem to recover.

Extinction threat

In recent years wildfires have been increasing in frequency and duration in areas including parts of Europe and the US.

Previous studies have shown that fires can benefit day-time pollinators such as bees and butterflies due to the flush of pollen-producing wildflowers that spring up in the aftermath. In contrast, the team found that fires had a detrimental effect on moths and the ecological benefits they provide as important but often overlooked night-time pollinators.

The team found that, depending on the time of year, up to 95% of moths were transporting pollen from over 80% of flowering plant species in the study area. However at burned sites, the total amount of pollen transported by moths was five times lower suggesting that more frequent wildfires may disrupt night-time pollination and increase the risk of extinction of these key species.

The researchers, from Newcastle University, the University of York, A Rocha Portugal and Universidade de Évora, Portugal, working with collaborators from the Centre for Ecology & Hydrology and Butterfly Conservation, also found that the moth community was significantly reduced at burned sites, likely due to the moths’ inability to breed in burned areas if host plants are destroyed by fire.

Night-flying pollinators

Lead author Dr Callum Macgregor from the Department of Biology, University of York, said: “Day-time pollinators, such as bees, have previously been shown to respond positively to the post-fire increase in resources of pollen and nectar, but it was not known whether night-flying pollinators, such as moths, benefit in the same way.

“By comparing sites within the burned area to unburned sites nearby, we found that after the fire, flowers were more abundant and represented more species, which was mainly due to increases of flowers in winter and spring. By contrast, we found that moths were much less abundant and less species rich after the fire, across all seasons.”

Co-lead author Paula Banza, from A Rocha Portugal and Universidade de Évora, said: “By analysing the networks of interactions between moths and plants, we showed that plant-insect communities at burned sites were less able to resist the effects of any further disturbances without suffering species extinctions.”

Co-supervisor of the study, Dr Darren Evans from Newcastle University, said: “Given the increasing frequency of devastating wildfires we are witnessing in places such as Portugal, the United States and even British moorlands, this is a cause for concern as ecosystems may be becoming less resilient and unable to return to a functioning state.”

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About this research

Wildfire alters the structure and seasonal dynamics of nocturnal pollen-transport networks is published in the journal Functional Ecology.

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