Fire in Feces: Bats Reliably Record Fire History in Their Guano

Abstract

Abstract New approaches are needed to resolve persistent geographic gaps and biases in paleofire research. Most sedimentary paleofire research relies on lake and peat sediments. We present an unconventional sedimentary charcoal record preserved in a modern, post‐bomb bat guano deposit and compare its accumulation to historical fire data. We find strong correlations between charcoal accumulation rates (CHAR) and non‐winter prescribed burns. CHAR in bat guano is more strongly correlated with prescribed fire than wildfire or total area burned, likely due to bats seeking out areas burned by prescribed fire for better foraging opportunities and/or bats avoiding wildfire. We attribute the CHAR in guano being a better recorder of area burned during non‐winter months to winter bat hibernation. Our analyses show that charcoal preserved in bat guano is a reliable paleofire proxy system, which has important implications for the paleofire field and encourages future research using bat guano as a viable archive.

Keywords

• paleofire
• proxy calibration
• charcoal accumulation rate
• human caused fire
• prescribed fire