UNPRECEDENTED WILDFIRE SEASON LEAVES LASTING IMPACT ON CAVE RESOURCES: A CASE STUDY FROM LAVA BEDS NATIONAL MONUMENT

Disaster struck Lava Beds National Monument during the summer of 2020 as the Caldwell Fire burned approximately 70% of the park. Lava Beds National Monument is home to a unique geologic environment of volcanic upheaval, both on and below the surface. Due to the lack of documentation regarding wildfire impact on cave resources located in a volcanic landscape, we conduct ongoing cave monitoring protocols in order to guide future wildfire management response efforts in cave-rich areas. In this study, we focus on cave invertebrates and how changes in their presence may be an indicator of the cave environment’s response to wildfire activity.

Since 2014, thirty-three caves located within the boundary of the park have been randomly selected for biennial invertebrate monitoring. During the months May-August, invertebrates are monitored in established entrance, middle, and deep zones of these caves. Following an established protocol, we placed three bait stations throughout each zone. After 14-16 days our team quantifies and classifies invertebrates at each station. We performed statistical analysis of taxa present in burned and unburned caves. Statistically significant changes in taxa indicate that a shift occurred post-fire, while no change indicates that there is continued stabilization of cave conditions.

Preliminary data suggest that based upon the presence or absence of different cave invertebrate species in comparison to previous years, following the Caldwell Fire environmental changes in caves have been recorded. The loss of vegetation on the surface has led to changes in groundwater, cave temperature, and cave humidity. The impact of these changes extend beyond cave invertebrates. For example, changes to cave resources impact bats who rely on the specific conditions of the caves to raise their young and to hibernate, while other wildlife rely on the caves for shelter and predation. In addition, the caves house important cultural resources from the prehistoric Modoc people who once inhabited the land and also contain artifacts from the Modoc War of 1872. While it cannot yet be determined what the maximum impact will be, Lava Beds National Monument is already seeing subtle and dramatic changes to cave ecosystems.