Modelling fire frequency in a Cerrado savanna protected area

Area of Science:

• Ecology
• Environmental Science
• Remote Sensing

Background:

• The Cerrado, Brazil's savanna, is highly biodiverse but threatened by altered fire regimes due to land use changes.
• Fire is a natural and crucial ecological process in the Cerrado ecosystem.
• Current land use practices are disrupting natural fire patterns, impacting biodiversity preservation.

Purpose of the Study:

• To model fire frequency and fire return intervals in Jalapão State Park, a protected Cerrado area.
• To analyze fire data over a 12-year period (1997-2008) using satellite imagery.
• To understand fire dynamics across different land cover types within the park.

Main Methods:

• Utilized Landsat imagery to create burned area maps from 1997-2008.
• Employed object-based image analysis for classifying burned areas.
• Applied the discrete lognormal model to estimate fire intervals, survival, and hazard rates.

Main Results:

• An area four times the size of the park burned during the study period, with a mean annual burn rate of 34%.
• Median fire intervals were short, ranging from 3 to 6 years, with shrub savannas experiencing the shortest intervals and dense woodlands the longest.
• Fire response to fuel age was significant in the first 3-4 years post-fire.

Conclusions:

• Fire intervals in Jalapão State Park are generally short, varying by land cover type.
• Management strategies, such as early dry season patch mosaic burning, could help reduce fire extent and severity.
• Understanding fire dynamics is critical for conserving the Cerrado's unique biodiversity.