There is strong evidence that taylors checkerspot butterfly (TCB) population numbers are dramatically declining across many sites, particularly in the center of its range

While this decline may be due in part to direct impacts of extreme weather events (extended spring-summer drought, late winter freeze events, the 2021 heat dome, etc.), IT is also hypothesized that a large contributing factor is a concurrent decline in oviposition and larval host plant abundance in occupied sites due to the same extreme weather events. Very little information exists around the microsite conditions needed to support the primary host plant species throughout the different life stages of the butterfly. With the projected increase in the frequency of extreme weather events, including extensive and intensive spring-summer droughts throughout the PNW, IT is imperative to understand the conditions that support climate-resilient populations of taylors checkerspot host plants to meet recovery goals for this endangered butterfly species. In addition to identifying and creating supportive microsite conditions, we also need to select the genetics that will thrive in the range of conditions expected in the future. Testing seeds sourced from different local and regional sites will provide the information needed to create resilient populations of host plants going forward. This project will focus on four objectives: 1) identify the microsite conditions that lead to p. Lanceolata and castilleja SP. Patch persistence and density that meet taylors checkerspot butterfly oviposition habitat requirements, 2) evaluate the effects of microsite conditions on the phenology of castilleja SP. And p. Lanceolata that maximize both pre- and post-diapause larval food resources, 3) evaluate the effects of seed provenance on p. Lanceolata establishment, growth and reproduction within different microsites, and 4) communicate project progress and outcomes to local and regional partners, researchers and practitioners through reports, regional and national conferences and peer-reviewed publications. These objectives will be addressed through a combination of monitoring of long-term plots, instrumentation of occupied microsites with soil moisture and temperature dataloggers along with phenological monitoring of host plants, and a common garden trial crossing seed source by microsite. Activities will take place at three sites occupied by host plants (and in most cases, TCB) in each of three regions that span the U.S. Distribution of TCB: the north and south puget sound in washington, and the willamette valley in oregon.