Recreation and firearms use as an emerging wildfire risk on western United States National Conservation Lands

Public lands are sources of valuable ecological, social, cultural, economic, scientific, and recreational resources in the United States. Wildfires may threaten the continued provision of some of these benefits. Fire management on public lands is increasingly challenging due to the growing array of human activities responsible for fires, including recreational target shooting. We used detailed information in agency fire reports from 1992 to 2020 to advance our understanding of contemporary wildfire ignition sources and patterns on a subset of public lands managed by the Bureau of Land Management (BLM): the National Conservation Lands (NCL) system. We used a multi-scale approach, first exploring patterns of wildfire causes across 17 NCLs. Natural ignitions were dominant within 71 % of NCLs and accounted for 73 % of all ignitions. Although less frequent, human-caused ignitions have increased since 1992 across all NCLs, indicative of a potential departure from regional patterns. Second, we focused on a case study site, the Morley Nelson Snake River Birds of Prey (MONE) National Conservation Area. MONE represents an exception among and potential future state for other NCLs. We found that 25 % of all BLM NCL ignitions from 1992 through 2020 were within MONE and furthermore, 68 % of ignitions at MONE were attributed to human activities, predominantly firearms and explosives use (34 %). Previous work exploring national patterns in ignitions has shown that the non-coastal western US has more natural ignitions, but we found that MONE, with its high rate of human-caused ignitions, serves as an example of ignition patterns in a conservation area with intense recreational use and diverse human impacts. Ultimately, we emphasize the need for targeted outreach and regulatory approaches to reduce recreational shooting ignitions and advocate for increased use of improved reporting standards for fire cause data. • Natural ignitions caused most fires in NCLs and were more frequent than human ignitions. • Human-caused ignitions have increased across all NCLs since 1992. • Morley Nelson Snake River Birds of Prey (MONE) NCA is a hotspot of recreation-related ignitions. • Human-caused ignition prevalence at MONE may portend future conditions on other NCLs. • New fire cause data standards should expand our understanding of ignition sources.