INVASIVE SPECIES

1. INVASIVE SPECIES ppws.vt.edu

2. ‘The Homogecene’ Invasive species constitute the second greatest threat to biological diversity. E.O. Wilson Global damage estimated at $400 billion IUCN (U.S. spending estimated at $130 billion)

3. What does it mean to be invasive? news.uns.purdue.edu “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.”

4. Defining invasive “Non-native organisms that cause economic or environmental harm and are capable of spreading to new areas of the state. Invasive species do not include domestic livestock, intentionally planted agronomic crops, or harmless exotic organisms.” -Washington Invasive Species Council

5. It’s all relative… • Kentucky bluegrass • Rocky Mountain National Park in Colorado • 60 miles away at a golf course in Denver • English ivy • Good ground cover in Great Plains and Midwest • Highly invasive in PNW and Eastern U.S. forests

6. First mention of invasive species? “Many European productions cover the ground in La Plata, and in a lesser degree in Australia, and have to a certain extent beaten the natives.” “We may infer from the these facts, what havoc the introduction of any new beast of prey must cause in a country, before the instincts of the aborigines become adapted to the stranger’s craft or power.” Charles Darwin Voyage of the Beagle

8. WorldConservation Union • Created a list of world’s most destructive species. • Of 10 worst, the PNW has 4 • Feral pigs • Dutch elm disease • Gray squirrel • Japanese knotweed Gray squirrel in Bellingham, NSJ

9. IMPACTS • Threaten native species: Reduce biodiversity • Outcompete natives • Predators • Create hybrids • Remove/impair key species or habitats • Degrade landscapes/obstruct natural processes • Fire regimes, floods, water purifying, water temp, O2 • Economic costs • Health risks

10. Hybridization: new species can result Helianthus annus + H. debilia = H. annus texacanus Spartinaalternifolia + S. maritima = S. anglica

11. Getting here • Natural Migration (ocean currents, wind patterns, migratory birds) • Legal importation of seeds, plants, fruits, and vegetables. • Research organisms accidentally released. • Biocontrol(species here to control another becomes invasive itself ) • Pet releases (exotic fish and snakes) • Internet sales. • Ballast water discharged from ships. • Soil brought in with nursery stock. • Hulls of boats, car tires. • Traveler’s clothes or shoes. • Soil dumped as fill into wetlands. • Ecosystem disturbance (logging, prescribed burning) • Garbage (landfill and transport of garbage)

12. Dispersal isn’t unnatural. • 10,000 years ago: ice sheet covered the PNW forests. So 99% of organisms here now are relative newcomers. • The scale and the rateof dispersal is accelerated. • Still… only about 1% of introduced species actually become invasive.

13. The great release… Universaltimer.com

14. What makes them so invasive? • Freed from limitations in natural range • All organisms face ecological pressures • Resource allocation • Response to environmental change • Climate, weather

15. What makes them so invasive? • Released from native predators/herbivores • Had lived in a hostile/competitive environment, so they had gotten really good at what they do. • Dispersing in barren environments • Foraging • Growing fast • Growing in poor soils

16. What makes them so invasive? • Novel weapons hypothesis • Physiology • Allelopathy

17. Physical weapons * Glycosides • Polymers (tannins, resins, rubbers), chemicals, and calcium oxolate crystals * Storage locations - Cell vacuoles, heartwood, aerenchyma tissue, ducts, glandular hairs (trichomes) Raphide crystals in Tradescantia

18. Trichomes in Pelargonium, NSJ

19. Root Exudates = 30% photosynthate • Release of compounds alters the soil environment. • Increase/decrease ability of other plants to take up nutrients and water. • Changes the types and amounts of soil microorganisms.

20. Germination inhibition • Plant-specific • Positive/negative roles simultaneously

21. Role of allelopathicchemicals: Knapweed

22. What should we do? • We know invasive species are a major threat to biological diversity. • We know that they are difficult to extirpate. • We know the incidence of invasive-species movement is only likely to increase.

23. What’s in our toolkit? • Prevention • Physical/biological control • Incentives • Regulations McClatchy

24. Even better… Current actions • Public awareness • Regulatory efforts • Treating ballast water • Quarantines • Creation of local and state control boards • Improved coordination • Online clearinghouse • Hub of information including listings of known invasives, funding sources, Web sites, risk assessments, control methods • White-list quarantines • Global GIS system

25. Hemlock woolly adelgid • Application of insecticides • Horticultural oil • Predatory beetles are commercially available • Varied success • Released beetles can fly and many leave

26. Spartina • If state and federal agencies had begun treating Spartinain the 1970s when the grass covered a mere 75 acres of Willapa Bay, the cost of eradication would have been destroyed in a few weeks. • Instead, it took 10 years and about $14 million.