1. Exotic Weed Establishment and Movement Through Landscape Corridors. What are we doing about it? John Rademacher

2. Hierarchy Weed Classification Weed Native Exotic Non Invasive Invasive Non Noxious Noxious Federal State

3. Corridor Types

4. Exotic Weed Establishment within Road and Trail Corridors Average viable seeds found on the undercarriage of United Kingdom vehicles (Hodkinson et al 1997) Average viable seeds per car

5. Exotic Weed Establishment within Road and Trail Corridors Seeds are able to survive livestock digestion. On average it takes 2-3 days to completely digest forage. Cattle can walk up to 14km per day. Viability of seeds prior to digestion depends on species. In forested landscapes livestock use road systems as primary travel paths and foraging areas.

6. Exotic Weed Establishment within Road and Trail Corridors Historically invasive grass species were used to stabilize road sides especially on highly stressed or disturbed landscapes. Invasive grass species have been used to increase wildlife forage, hay and residential landscaping.

7. Seed viability Beal (started in 1879, 1 st published in 1911), Michigan State University buried seed of 21 common plant species. 1920, 8 species germinated 1940, 3 species germinated 1980, 2 species germinated Info Source: David Priestley's book on Seed Aging (Comstock Publishers, Cornell Univ. Press), published in 1986. Viable common lambsquarters found in archeological sites, 1700 years old.

8. How patch vegetation effects weed movement Exotic species richness across an area of road influence ARI for three road corridors (Tyser et al 1992) Exotic species richness Distance from road (m)

9. How patch vegetation effects weed movement Exotic species richness across an area of road influence ARI for two closed canopy patch types (Watkins et al 2003) Exotic species richness Distance from road (m)

10. How patch vegetation effects weed movement Closed canopy forest controls perpendicular spread. Open canopy forest allows perpendicular and parallel spread. Potential weed habitat extends 15m into every closed canopy forested patch touching the clear cut

11. Landscape Weed Management Eradicate – Remove all individuals (newly established weed species, small population or high economic damage) Contain – Stop the spread (medium sized population and large populations close to sensitive habitat) Control – Slow the spread (large populations)

12. Eradication Control Contain Time Invader abundance Phases of noxious weed invasion. Ease of treatment declines from left to right (Hobbs et al 1995)

13. Landscape Weed Management Nez perce National Forest, Clearwater Ranger District

14. Noxious weed control and prevention Weed free hay and straw (quarantine livestock for 3 days) Herbicide application Biological control Mechanical control Try to leave at least a 15 meter closed canopy buffer around forested roads Reduce road densities in susceptible areas

15. Questions?