Leucaena leucocephala (Fabaceae) Invasion: The Opposite Effects of Fire and Flood

Leucaena leucocephala (hereafter L. leucocephala ) is considered one of the 100 most invasive plant species in the world and has been found in areas subject to wildfire events and flooding. Its rapid L. leucocephala invasion capacity can lead to decrease in local diversity due to the exclusion of native plant species. In this way, the L. leucocephala proliferation has advanced across the Pantanal. Here, we assess the effects of the fire, flooding and distance to the source population on the invasion of L. leucocephala , and whether this dynamic negatively affects the richness of native plant species in the Brazilian Pantanal. Our results showed that fire recurrence and flood level were the opposite under L. leucocephala invasion. Areas with low flood level and greater fire occurrence tend to have more L. leucocephala regenerants while the distance of the source population had no effect. L. leucocephala and native plants occupy sites with different abiotic conditions. In an expected scenario for the Pantanal islonger droughts and more frequent wildfire, this could mean a pronounced increase in L. leucocephala invasion over time. Therefore, the use of fire as a management action for L. leucocephala control is not recommended, and it is necessary to find methods to extract or eliminate the seed banks.