The bull trout is an ESA-listed species that relies on cold stream environments across the Northwest and is expected to decline with climate change. Resource managers are charged with maintaining bull trout across their range, but monitoring this species is difficult and many populations have rarely or never been sampled. To reduce this uncertainty (and regulatory gridlock), we propose to coordinate a crowd-sourced field assessment of the distribution of bull trout in the U.S. by using inexpensive, reliable environmental DNA (eDNA) sampling. Samples collected by this multi-partner effort can be used to evaluate many other species (e.g., a biodiversity assessment) with no additional field costs and can serve as a multi-species baseline for future assessments.
FY2015and FY2016 Objectives:We will build on previous work by pairing predictions of bull trout habitat occupancy from the Climate Shield model with an optimized eDNA protocol to survey all juvenile bull trout habitats throughout two 4th-code river basins, the Upper Clark Fork River in Montana and the St. Joe River in Idaho.
In 2016, we propose to extend this sampling to the entire range of bull trout in the U.S., with expected completion in 2018. Locations to be sampled will include those predicted to be suitable by the Climate Shield model but rarely or never sampled, and those with historical observations of juvenile or spawning bull trout for which there are no recent surveys. The refined estimates of habitat occupancy will be used to build a more robust and precise Climate Shield model for bull trout to more accurately project suitable habitats under climate change. And the comprehensive sampling of eDNA from throughout the Columbia River basin will provide an archive for analyses of the distribution and habitat suitability of any other freshwater species of concern e.g., Pacific lamprey, steelhead/redband trout, westslope cutthroat trout, western pearlshell mussel, or North American river otter.
