Wildfires are a natural feature of the Earth system, necessary for the functioning of many ecosystems. Interactions between vegetation and climate over extended periods establish a particular pattern of wildfire recurrence in a defined ecosystem, known as its fire regime. Deviations from the prevailing fire regime – the timing, frequency, size and intensity of wildfires – can drive significant ecological changes in both fire-dependent ecosystems that need fires to thrive and fire-sensitive ecosystems where fires bring more negative than positive effects.