Introduced species

1. Introduced species

2. Introduced Species: should we give up? Homogenization of the World

3. Feral Animals: Cats http://www.sibleyguides.com/ A study in 2013 estimated that cats kill from 1 to 4 billion birds in the U.S. each year

4. Stephens Island Wren, New Zealand

5. Introduced Species • Introduction of exotic species to new areas can be the result of: • Deliberate actions, ignorance of consequences, or for control of other species • Accidental, unknown carriers bring species to new area • Natural, rarer, species naturally disperse to new areas • Invasive species—an introduced species that establishes itself and spreads beyond point of introduction

6. Deliberate: Kudzu -- Kudzu vine introduced to U.S. in 1876 at the Philadelphia Centennial Exposition -- Plantings in southeast encouraged to prevent soil erosion, as a forage plant, and ornamental until listed as pest species in 1953 -- Rapid growth: 60 feet/season or ~1 foot/day www.firehow.com

7. Deliberate: Reindeer to sub-Antarctic Island, South Georgia http://english.ohmynews.com • Introduced in early 1900’s by Norwegian whalers • Reindeer adapted well to climate, new food, and reproduced • 1st of 3 introductions in 1909, by 1958: 3,000 animals • Arctic density 5-7/km2, South Georgia approaches 40-85/km2 • Severe overgrazing: soil erosion, loss of plant biodiversity, loss of • nesting habitat for birds

8. Reindeer exclusion pen, South Georgia Island http://www.sgisland.gs/index.php/%28h%29South_Georgia_Newsletter,_January_2013

9. Only place in the world where you could see penguins intermixed with reindeer

10. Intense eradication efforts have been successful at South Georgia

11. Accidental: Whitefly ‘superbug’ • Introduced in Florida in 1980s on poinsettias • Attack 500+ crop plants; killing stunting growth • Deposit sticky residue that allows mold to grow • Spread viruses among crops • Congregate under leaves, out of harm from pesticides

12. Spotted Knapweed in western U.S and Canada --arrived from Europe to British Columbia in 1883 as an accidental introduction --takes over large areas of open grassland --except for sheep, most grazing animals avoid it --produces an allelopathy to prevent other plants from growing around it

13. Natural introduction: Cattle egret, only species to have reached all 7 continents From Africa, reached Brazil in 1930s, Florida in 1940s, now widespread in Southeast

14. Keystone exotics • Species that change entire community structure • In Southeast, Honeysuckle and Kudzu smother native forests http://www.treehugger.com/renewable-energy/biofuel-feedstocks-gain-a-new-candidate-kudzu.html http://www.ppws.vt.edu/scott/weed_id/lonja.htm

15. Keystone exotics Hyacinths in Everglades Given away at 1884 New Orleans at Worlds Fair, one visitor from Florida brought one home, grew in outdoor pond, then threw extras into St. Johns River. One cattle rancher spread them to Kissimmee River thinking that cows would eat them, but they lack nutrition and cows didn’t like them.

16. Keystone exotics Livestock—grazing in western US • once desert grassland, now gone • shifting baseline again

17. Erosion in New Mexico from 100+ yrs of overgrazing

18. Loss of cultural remains ~800 yrs old

19. Most introductions fail • Wrong ecological conditions for survival, can’t compete with natives (niches full) • Egrets reached Antarctica, couldn’t survive there • Warming trend may change conditions and some introductions could succeed

20. Antarctic Peninsula is becoming more susceptible to successful introductions Poa annua bluegrass on King George Island is spreading from the Polish station where it first appeared It also has independently arrived at three other stations along the western AP http://www.antarctica.gov.au/

21. Two other vascular plants from South America have invaded Deception Island, as well as two springtail species As climate warms, especially in the Antarctic Peninsula, the risk of additional invasive species increases http://antarcticsun.usap.gov/

22. What factors allow for successful invasions? • Small organisms do best. • Rapid generations and r-selected reproduction • Evolve and adapt to new conditions quickly 2) Easily transported, or not detected • Small insects on plants, fungi • 40% crop pests in US are insects • Seeds on shoes can be carried long distances • Ballast tanks on ships

23. What factors allow for successful invasions? 3)Favorable habitats present in new area • May have fewer or no predators • Acts as release from counteradaptations • Islands particularly susceptible as often have more open niches, lower species diversity then mainland e.g., cats, goats, pigs, rats

24. Eradication • Once a species becomes established, can be very difficult to eradicate 0 % population remaining 100 Cost/effort to eradicate

25. Rats were introduced on South Georgia Island with whaling ships Devastating to ground nesting birds, including an endemic song bird (South Georgia Pipit), petrels, and penguins Rat eradication began in 2011 by spreading poison pellets over the entire island where rats were know to occur Largest island eradication ever attempted for this South Georgia rat eradication

26. South Georgia Pipit Most southerly nesting songbird First nesting record in living memory in 2015, after rats eradicated http://www.independent.co.uk/

27. Eradication: Biological controls • Use natural predators from invaders home community • Sometimes successful • Australia introduced dung beetle to solve livestock dung and fly problem

28. Eradication with Genomics • Genetic engineering: a new weapon • Rabbits introduced in Australia being controlled by a manufactured virus, causes sterility • Lots of experiments prior to release • Unintended consequences—will virus mutate and spread to other native species?

29. New ways of dealing with invaders: Asian Carp Locals method… 'Unified' method

30. Introduced Species examples: From Cane Toad film, know: 1) Why/how they were introduced 2) Why they are so successful 3) Why are they difficult to eradicate 4) Problems caused? Solutions? Cane Toads: an unnatural history whitefly ‘superbug’ kudzu, honeysuckle, hyacinth, and knapweed as keystone exotics reindeer, rats, cats on islands Asian carp in streams, threat to Great Lakes domestic animals in western U.S., Australia rabbits, cane toads in Australia

31. The Infamous Cane Toad • Native to South America • Introduced to Australia in 1930s for biological control of cane grub • Became part of local culture • No natural predators, spread rapidly • Impacts native wildlife with poison glands

32. Quiz • What are three ways in which an exotic species is introduced to a new area? • When does an introduced species become an invasive species and what factors are most important for a successful invasion? • Graph and explain the relationship between cost/effort vs complete eradicate of an exotic species. • Why are islands more susceptible to species invasions than mainlands? • What new methods and tools are being employed now to stop and/or eradicate invasive species?