(RTE) Plant Species Inventory Final Report
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Boundary Hydroelectric Project (FERC No. 2144) Study No. 17 Rare, Threatened, and Endangered (RTE) Plant Species Inventory Final Report Prepared for Seattle City Light Prepared by Kathryn Beck Beck Botanical Services and Mary Clare Schroeder Tetra Tech March 2009 Correction page to Study 17, RTE Plant Species Inventory, as provided by SCL on February 12, 2009 1) p. 2, third bullet, The Boundary Wildlife Preserve (BWP) (155 acres) and adjoining SCL-owned property (85 acres). Subsequent to completion of the final report, SCL discovered a discrepancy between the description of the study area for the “adjoining SCL-owned parcel” and the area that was surveyed during field studies. The BWP was mapped accurately in the study reports and the entire BWP was surveyed as planned; this discrepancy relates only to the "adjoining SCL-owned property." Terrestrial field crews were working from an incorrect map of the parcel and thus, detailed field surveys took place on only 42 acres of the parcel. Regardless of this error, SCL believes that the conclusions presented in the final study report are still valid. Additionally, the size of the “adjoining SCL-owned parcel” is 88 acres, not 85 acres. FINAL REPORT STUDY NO. 17 – RTE PLANT SPECIES INVENTORY TABLE OF CONTENTS 1 Introduction..............................................................................................................................1 2 Study Objectives.......................................................................................................................1 3 Study Area ................................................................................................................................2 4 Methods.....................................................................................................................................5 4.1. Information Update and Pre-Field Review..........................................................................5 4.2. RTE Plant Survey ................................................................................................................6 4.3. Documentation and Effects Assessment..............................................................................7 4.4. Resolution of Outstanding Issues.........................................................................................8 5 Results .......................................................................................................................................9 5.1. Information Update and Pre-Field Review..........................................................................9 5.2. RTE Plant Surveys.............................................................................................................17 5.2.1 Least Bladdery Milk-vetch (Astragalus microcystis) ........................................ 23 5.2.2 Hair-like Sedge (Carex capillaris)..................................................................... 24 5.2.3 Yellow Sedge (Carex flava)............................................................................... 25 5.2.4 Porsild’s Sedge (Carex krausei ssp. porsildiana).............................................. 25 5.2.5 Steller’s Rock-brake (Cryptogramma stelleri) .................................................. 26 5.2.6 Yellow Mountain-avens (Dryas drummondii)................................................... 27 5.2.7 Common Northern Sweetgrass (Hierochloe odorata)....................................... 27 5.2.8 Canadian St. John’s-wort (Hypericum majus)................................................... 28 5.2.9 Orange Balsam (Impatiens aurella)................................................................... 28 5.2.10 Wirestem Muhly (Muhlenbergia mexicana var. mexicana) .............................. 29 5.2.11 Adder’s-tongue (Ophioglossum pusillum)......................................................... 30 5.2.12 Black Snake-root (Sanicula marilandica) ......................................................... 30 5.2.13 Northern Blue-eyed Grass (Sisyrinchium septentrionale) ................................. 31 5.2.14 Purple Meadowrue (Thalictrum dasycarpum)................................................... 31 5.2.15 Kidney-leaved Violet (Viola renifolia).............................................................. 32 5.3. Effects Assessment ............................................................................................................33 5.3.1 Project Effects.................................................................................................... 33 5.3.2 Non-Project Effects............................................................................................ 40 5.3.3 Project and Non-Project Effects to RTE Plant Populations by Species............. 42 6 Conclusions.............................................................................................................................46 6.1. Summary............................................................................................................................46 6.2. Conclusions........................................................................................................................47 7 Variances from FERC-Approved Study Plan and Proposed Modifications....................48 Boundary Hydroelectric Project Seattle City Light FERC No. 2144 i March 2009 FINAL REPORT STUDY NO. 17 – RTE PLANT SPECIES INVENTORY 8 References...............................................................................................................................49 Appendices Appendix 1: Complete List of Vascular Plant Species Observed in the Boundary Hydroelectric Project Study Area, 2007 Appendix 2: RTE Location Information Including 2007 Status, Sighting Form Names, and Subpopulations Mapped in the Boundary Hydroelectric Project Study Area, 2007 – Privileged Appendix 3: WNHP Rare Plant Sighting Forms for RTE Populations on Non-USFS Land, Boundary Hydroelectric Project Study Area, 2007– Privileged Appendix 4: USFS Element Occurrence Field Forms for RTE Populations on USFS Land, Boundary Hydroelectric Project Study Area, 2007 – Privileged Appendix 5: Maps of RTE Plant Polygons Located in the Boundary Hydroelectric Project Study Area, 2007 – Privileged Appendix 6: RTE Plant Polygons and Potential Impacts, Boundary Hydroelectric Project Appendix 7: Erosion Effects on RTE Plant Polygons, Boundary Hydroelectric Project, 2007 – Privileged Boundary Hydroelectric Project Seattle City Light FERC No. 2144 ii March 2009 FINAL REPORT STUDY NO. 17 – RTE PLANT SPECIES INVENTORY List of Tables Table 5.1-1. RTE plant species documented or suspected to occur in the study area. ................ 10 Table 5.2-1. RTE plant populations and polygons (subpopulations) delineated during 2007 surveys. ................................................................................................................................. 17 Table 5.3-1. Summary of potential and existing Project effects on subpopulations of RTE plant species in the study area........................................................................................................ 34 Table 5.3-2. Number of erosion/RTE plant polygon intersections by erosion group.................. 38 List of Figures Figure 3.0-1. Study area for RTE plant species inventory............................................................. 4 Figure 5.2-1. General locations of RTE plant species found in the study area............................ 19 Figure 5.2-2. General locations of RTE plant species Dryas drummondii and Thalictrum dasycarpum found in the study area. .................................................................................... 21 Boundary Hydroelectric Project Seattle City Light FERC No. 2144 iii March 2009 FINAL REPORT STUDY NO. 17 – RTE PLANT SPECIES INVENTORY This page intentionally left blank. Boundary Hydroelectric Project Seattle City Light FERC No. 2144 iv March 2009 Study No. 17: Rare, Threatened, and Endangered (RTE) Plant Species Inventory Final Report Boundary Hydroelectric Project (FERC No. 2144) 1 INTRODUCTION Study No. 17, the Rare, Threatened, and Endangered (RTE) Plant Species Inventory (RTE Plant Study), was conducted in support of the relicensing of the Boundary Hydroelectric Project (Project), Federal Energy Regulatory Commission (FERC) No. 2144, as identified in the Revised Study Plan (RSP; SCL 2007) submitted by Seattle City Light (SCL) on February 14, 2007, and approved by the FERC in its Study Plan Determination letter dated March 15, 2007. This report describes the field efforts, analyses, and determination of Project effects and represents the completion of the study. 2 STUDY OBJECTIVES The goals of the RTE Plant Study were to determine the presence of RTE plants in the Project area, assess Project effects on these species, and direct management decisions related to RTE plant species. Specific objectives of this study were as follows: • Survey for and identify the RTE plant species occurring in the Project area. • Map the location, distribution, and extent of RTE plant populations. • Identify any threats to existing RTE plant populations (e.g., nearby infestations of invasive non-native species, erosion, herbivory) and their habitats, including potential Project effects. The RTE Plant Study built on a 2005 reconnaissance level survey of RTE plants that was conducted in the Project vicinity to provide baseline information for the Pre-Application Document (PAD). The primary goal of the 2005 RTE survey was to confirm locations of historic and relatively