Invasive Non-Native Plants in the Lower Elwha Watershed

1. Invasive Non-Native Plants in the Lower Elwha Watershed Elwha Ecosystem Restoration Preparing for the Revegetation of the Reservoirs Olympic National Park In partnership with The Lower Elwha Klallam Tribe

2. Strait of Juan De Fuca Lower Elwha Klallam Reservation Highway 112 Port Angeles Robyn Hill Elwha Dam Highway 101 Olympic National Park Glines Canyon Dam Geyser Valley

3. Strait of Juan De Fuca Lower Elwha Klallam Reservation Highway 112 Port Angeles Robyn Hill Elwha Dam Highway 101 Olympic National Park Glines Canyon Dam Geyser Valley

4. Lake Aldwell Lake Mills Glines Canyon Dam Elwha Dam Critical Ecosystem processes will be severely damaged (erosion, nutrient cycling, hydrology) Natural succession of the middle areas of the reservoirs expected to be slow Expected Conditions

5. Managing Invasive Species in the Lower Elwha • Prioritize species to manage • From 1991-2008, 147 exotic species have been observed in the lower Elwha watershed • Rank species according to invasive potential • Resources: • County and State noxious weed lists • NatureServe.org • Park data • Scientific literature

6. The Top “Species of Concern” known to occur in the Lower Elwha

7. Bromus tectorum (cheatgrass) • Annual grass • Cheatgrass mainly threatens dry, grassland ecosystems • May be common in riparian communities • Can drastically change fire regime • Depletes soil moisture early in growing season Spikelets 15-20mm Pubescent blades and sheaths

8. Cytisus scoparius (Scot’s broom) • Evergreen, perennial shrub • Aggressive invader currently infesting over 2 million acres in CA, WA, and OR • Alters soil nutrient regime by adding nitrogen • Creates monocultures • Can change fire regimes

9. Geranium robertianum (herb Robert, stinky Bob) • Semi-evergreen, semi-perennial forb • Aggressive invader of shady forests and sunny sites • Creates monocultures • Seeds prolifically • Seed dispersed by ejecting out of pods and sticking to travelers

10. Phalaris arundinacea (reed canarygrass) • Perennial, rhizotomous grass • Forms dense single species stands • Inhibits native • Reduces diveristy • Little value to wildlife • Alters hydrology in streams, wetlands Ligules: membranous 4-10 mm

11. Polygonum spp.(the BIG knotweeds) • Includes P. sachalinense, P. cuspidatum, and P. x bohemicum • Displaces streamside vegetation • Causes increased bank erosion and clogs small waterways • Forms thickets up to 12 feet tall and produces allelochemicals • Spreads mainly by rhizomes but also by fragments of root

12. Rubus armeniacus (Himalayan blackberry) • Displaces streamside and upland vegetation • Forms thickets up to 12 feet tall • Vegetatively spreads by rhizomes and by fragments of root • Birds and mammals disperse the seed

13. Managing Invasive Species in the Lower Elwha • Prioritize species to manage • Locate populations of the primary species of concern in the Elwha watershed • 2001 mapping project

14. Roads • ONP Trails • Reveg Project Boundary • 2001 Survey Points

15. Roads • ONP Trails • Reveg Project Boundary • 2001 Survey Points • 2008 Survey Points

16. Managing Invasive Species in the Lower Elwha • Treat priority species in watershed prior to dam removal • Prioritize sites to manage • Areas directly adjacent to reservoirs • Areas we will use as staging sites for revegetation activities • Use model of propagule movements to identify invasive population “hot spots”

18. Managing Invasive Species in the Lower Elwha • Treatments • Herbicides specific for each species/situation • Hand-pull some species • Scot’s broom • Herb Robert • Young seedlings of English holly