Provisonal Report Rare Plant and Vegetation Survey of Riverside State Park Pacific Biodiversity Institute 2 Provisonal Report Rare Plant and Vegetation Survey of Riverside State Park Peter H. Morrison [email protected] George Wooten [email protected] Juliet Rhodes [email protected] Robin O’Quinn, Ph.D. [email protected] Hans M. Smith IV [email protected] January 2009 Pacific Biodiversity Institute P.O. Box 298 Winthrop, Washington 98862 509-996-2490 Recommended Citation Morrison, P.H., G. Wooten, J. Rhodes, R. O’Quinn and H.M. Smith IV, 2008. Provisional Report: Rare Plant and Vegetation Survey of Riverside State Park. Pacific Biodiversity Institute, Winthrop, Washington. 433 p. Acknowledgements Diana Hackenburg and Alexis Monetta assisted with entering and checking the data we collected into databases. The photographs in this report were taken by Peter Morrison, Robin O’Quinn, Geroge Wooten, and Diana Hackenburg. Project Funding This project was funded by the Washington State Parks and Recreation Commission. 3 Executive Summary Pacific Biodiversity Institute (PBI) conducted a rare plant and vegetation survey of Riverside State Park (RSP) for the Washington State Parks and Recreation Commission (WSPRC). RSP is located in Spokane County, Washington. A large portion of the park is located within the City of Spokane. RSP extends along both sides of the Spokane River and includes upland areas on the basalt plateau above the river terraces. The park also includes the lower portion of the Little Spokane River and adjacent uplands. The park contains numerous trails, campgrounds and other recreational facilities. The park receives a tremendous amount of recreational use from the nearby population. The ownership of the park in the updated GIS layer provide by WSPRC in June was 8821 acres. Substantial acreage was added to the park ownership layer in this updated ownership layer. The total area of both the updated and the prior ownership layers combined is 9393 acres. The new boundary deleted 572 acres from the old ownership layer. The size of the original mapped ownership was 7272 acres. For reasons detailed in Appendix A of this report, the significant change in size of the park and ownership boundaries during the survey period has required us to issue a provisional report. Significant work needs to be completed by the WSPRC resolving the ownership boundary issues we discuss before a comprehensive rare plant and vegetation survey can be finished for this park. We mapped 352 vegetation community polygons within RSP. These polygons were categorized into 32 specific plant associations or one of approximately 8 generalized land cover types. We found three rare plant species at Riverside SP, prairie cordgrass (Spartina pectinata Bosc ex Link), gray stickseed (Hackelia cinerea (Piper) I.M. Johnst.) and small-leaf pussytoes (Antennaria parvifolia Nutt.). All of these are state-listed sensitive plants. All of these species have been sighted before at RSP, but our surveys located significant new populations within the park. Descriptions of the sightings and recommendations are given in this report. We identified 410 vascular plant taxa to the rank species at RSP. Of these, 120 were non-native species (29%). RSP has more noxious weeds than any other State Park we have surveyed since 2004. We found 18 Class B weeds and 10 Class C weeds. Recommendations are given to survey for Class A and B noxious weeds on a regular basis. The ecological condition of RSP varies from developed and poor to excellent. There are many restoration opportunities in the park. The most urgent restoration need is to reintroduce a natural fire regime (through use of prescribed fire) to the ponderosa pine forests of the park, which are currently choked with many small seedlings and saplings. Also, a key restoration objective will be to continue an aggressive noxious weed monitoring and management plan. Our primary management recommendation for the park is to resolve ownership boundary issues for the park. This will require a concerted effort. Some of this work can be done through GIS, remote sensing and cooperation with assessors’ offices at the City of Spokane and Spokane Country. A proper survey is needed for the entire property. 4 Table of Contents Introduction.................................................................................................................................6 Survey Conditions, Survey Routes and Property Boundary Issues ......................................6 Vegetation Communities............................................................................................................8 Methods......................................................................................................................................................8 Historical Vegetation .................................................................................................................................9 Results......................................................................................................................................................10 Vegetation Community Mapping........................................................................................................ 10 Common Vegetation Community and Land Cover Types at RSP...................................................... 15 Coniferous Forest Communities ......................................................................................................... 15 Deciduous forests, mesic shrub and wetland communities................................................................. 23 Dry shrublands and grasslands............................................................................................................ 29 Other Land Cover Types..................................................................................................................... 29 Rare Plant Surveys...................................................................................................................31 Methods....................................................................................................................................................31 Results......................................................................................................................................................31 Antennaria parvifolia .......................................................................................................................... 32 Hackelia cinerea.................................................................................................................................. 34 Spartina pectinata................................................................................................................................ 37 Overall Botanical Survey Results ....................................................................................................... 39 Discussion and Recommendations ........................................................................................49 Noxious Weeds ........................................................................................................................................49 Ecological Condition................................................................................................................................51 Restoration Opportunities ........................................................................................................................53 Other Recommendations..........................................................................................................................53 GIS Products Produced ...........................................................................................................53 References ................................................................................................................................54 Appendix A - Property Boundary Issues ................................................................................57 Comparison of original and new park ownership layers..................................................................... 57 Impact of ownership boundary changes on PBI’s rare plant and vegetation survey .......................... 70 Appendix B – Ecological Condition Ranking System ...........................................................72 Appendix C – Definitions of Vegetation Community Ranks .................................................73 Appendix D – Vegetation Survey Codes and Instructions....................................................74 Appendix E – Vegetation Survey Polygon Data.....................................................................76 Appendix F – Washington Natural Heritage Program Rare Plant Sighting Forms............428 5 Introduction RSP was surveyed for rare plant occurrences, vegetation communities and characteristics, noxious weeds and ecological condition by PBI under contract with WSPRC. This report summarizes the activities and findings of the contracted work. This park is located in Spokane County, Washington. A large amount of the park is located within the City of Spokane. RSP extends along both sides of the Spokane River and includes upland areas on the basalt plateau above the river terraces. The park also includes the lower portion of the Little Spokane River and adjacent uplands. The park contains numerous trails, campgrounds and other recreational facilities. Since the park is in Spokane, it receives a tremendous amount of