The invasive weed Lantana camara increases fire risk in dry rainforest by altering fuel beds

The invasive weed, Lantana camara, dominates numerous tropical and sub-tropical ecosystems and affects many aspects of ecosystem functioning, one of them being susceptibility to fire intrusion. The process by which L. camara might alter fire regimes in dry rainforest was examined by considering two potential mechanisms: (i) by being more ignitable than native species or (ii) by altering the structure and distribution of biomass to facilitate fire spread. We hypothesised that L. camara might alter fire regimes by both mechanisms. Measurements of leaf dry matter content, twig dry matter content and burn durations in laboratory trials implied that L. camara was less ignitable than native dry rainforest species. Fuel bed depths, leaf litter depths, percentage cover by fuels and amount of medium-size class fuels were higher in dry rainforest invaded by L. camara than in non-invaded forests. This suggests that the mechanism by which L. camara alters the fire regime in dry rainforest is by shifting the distribution of available fuels closer to the ground and providing a more continuous fuel layer in the understory. Management should focus on targeting L. camara removal around forest edges adjacent to frequently burned savannas and in areas of high conservation value.