Wenatchee mountains checker mallow (SIORC) is a federally endangered species found in washington state.competition with encroaching woody shrubs and nonnative grasses is a key threat to the five known…

The Department of the Interior Fish and Wildlife Service Region 1 awarded a $102,194 Cooperative Agreement to the University of Washington under the Endangered Species Recovery Implementation program (CFDA 15.657) to investigate methods for managing woody shrub and non-native grass competition that threatens the endangered Wenatchee Mountains checker-mallow (Sidalcea oregana var. calva, SIORC) in Washington state.

The key products and services to be delivered under this 3-year award include: 1) testing repeated vegetation management treatments on established plots to evaluate the effects on tagged SIORC individuals, recruitment, and competing vegetation; 2) evaluating the use of small slash pile burning as a tool to reduce shrub encroachment and non-native grass competition while stimulating SIORC seed germination; and 3) developing site-specific management recommendations for existing SIORC populations and for introducing new populations to aid in the recovery of this endangered species.

Wenatchee mountains checker mallow (SIORC) is a federally endangered species found in washington state.competition with encroaching woody shrubs and nonnative grasses is a key threat to the five known populations ofsiorc (USFWS 2004, fertig 2022). This species sensitivity to competition affects efforts to expand currentpopulations and establish new ones to meet recovery criteria. Reconnaissance surveys in 2022 of 18 potentialout planting sites identified by an advisory team found that about one third of the sites had high shrub ornonnative grass cover that reduced the sites suitability for out plantings. Learning the best methods to thinshrubs and manage nonnative grass competitors will improve efforts to create and maintain habitat for new siorcpopulations and aid population recovery. We propose to build on the findings of our previous study that investigated the efficacy of woody shrub andnonnative grass management techniques and their impact on wenatchee mountain checker-mallow by testing repeatedvegetation treatments on established vegetation plots. After applying the repeated treatments, we will evaluatethe treatment combinations effect on tagged checker-mallow individuals, checker-mallow recruitment and competingvegetation. Information gathered from these experiments will be used to develop site-specific managementrecommendations for mountain home and general recommendations for use at other native and introduction sites. We will also test small slash pile burning as a tool to reduce woody shrub encroachment and nonnative grasscompetition while increasing checker-mallow seedling recruitment at multiple sites. During our existing work, welearned that SIORC seed germination is stimulated by exposure to 150C heat for 1 minute. Prescribed burns inthis species habitat, including the one conducted for our study and one at camas lands in 2022, have likelyfailed to achieve 150C (zimmerman and reichard 2005, D. Wilderman, pers. Comm.). However, SIORC seedlings havebeen observed around the perimeter of slash burn piles (fertig 2022). Determining a burning practice that reducesshrub competition and breaks SIORC seed dormancy will inform management practices for existing and introducedpopulations.