Wildfire season in Pantanal wetland on track for record ecosystem damage

By the 9th of June, the number of fires burning in the Pantanal wetland are almost an order of magnitude larger (935% higher) than for the same period last year.  Between the 1st of January and the 9th of June this year, 3,400 km² has burned, which is the highest on record for the period.  The peak period for such wildfires is still far off, as they mostly occur in August and September, but the wetlands are dry due to the lack of rain and vulnerable to the outbreak of fire. At the current rate, the fires are on track to surpass the extent of the damage that occurred in 2020.  

In 2020, fires resulted in unprecedented damage to the world’s largest wetland and its associated ecosystems: studies based on images from the Sentinel 2 satellites taken between June and October showed that 35% of the biome has been burnt.

The fires are the result of weak rains which have disrupted the seasonal flooding patterns of the rivers: usually the rains last from October to March and floodwaters fill the Pantanal wetlands, which store the water and release it slowly over the months from April to September. Now however, areas that are normally flooded during the rainy season are lying bare and exposed to the elements, and the dry reeds and grasses are creating conditions for the ignition and expansion of fires. In the state of Mato Grosso do Sul in Brazil, which contains 60% of the biome of the Parana-Paraguay wetland system, researchers identified 698 fires which took place between January and the first week of June. Currently, the Parana and Paraguay rivers have low flow levels, which is also affecting the transportation capacity of ships serving the area.

The Pantanal system is the world’s largest tropical wetland, covering an area of 187,000 km² across Bolivia, Paraguay and Brazil. It is a complex tapestry of wetlands and grasslands which are crossed by waterways and alternate with dense forest. The Pantanal system therefore contains a variety of different habitats, which in total are estimated to be home to some 2,000 species of plants, 580 bird species, 271 fish species, 174 mammals – famously including the Jaguar and the giant anteater – and 57 amphibians.  In the year 2000, the Pantanal was declared a World Heritage Site. Brazil, Bolivia and Paraguay have signed and ratified the Convention on Biological diversity, and a goal has been set in the past to protect 10% of the Pantanal’s territory by creating or expanding conservation units. Currently, however, just over 5% of the territory is formally protected.   

Recent research has shown that there is a close relationship between climate change and fire activity. For South America as a whole, an increasing trend in fire risk and extent is predicted across a range of different climate scenarios. The number of heatwaves associated with record-breaking temperatures have also been increasing over Pantanal, and the 2020 Pantanal fires resulted from a combination of extremely hot and dry conditions and the negligent use of fire. However, climate change is not the only factor driving the fires: there is a relatively recent history of expansion of ranching and farming in the area, as well as the expansion of infrastructure projects. Research has found that 60% of the fire outbreaks was concentrated at distances less than 5 km from roads, waterways, and railways and that 80% was concentrated at distances less than 10 km from areas with human activities. Therefore, fires are closely associated with human expansion in the area, and research into fire hotspots can help to protect the environment and establish measures for fire control.