The Nilgiri Biosphere Reserve (NBR) in the Western Ghats, India, contains a mosaic of savannas and forests. This landscape experiences wildfires regularly, but we lack an understanding of factors driving fire regimes in the region.

To examine the effects of climate, vegetation and human activity on wildfires in the NBR.

Using remotely sensed datasets, we examine how mean annual rainfall (MAR), topographic complexity and human activity influence fires in savannas and forests of the NBR across a wet (2001–2010) and dry decade (2011–2020).

Across both decades, savannas burned more frequently and over larger areas than forests. Burnt area and fire frequency in both habitats were higher in the wet decade. Human modification was the major driver of fire occurrence in the wet decade, but MAR took on greater importance in the dry decade.

Savannas and forests in the NBR have differing fire regimes. During dry periods, these systems are fuel limited and MAR best describes the occurrence of fires. During wet periods when fuel is not limiting, proxies for anthropogenic ignitions best explain fire occurrence.

Climate, vegetation and humans collectively determine fire regimes in the NBR. Fire management must integrate across all these factors at the landscape scale to be effective.