Changing Hudson Project Institute of Ecosystem Studies Invasive Species Photo by Kara Goodwin

Changing Hudson Project Institute of Ecosystem Studies Definitions Alien: Non-native, outside its native range –Exotic, introduced, weedy, non-indigenous –Not normally part of ecosystem –Established, self-sustaining population 10% rule –10% survive –10% become invasive Human activities involved What is an invasive species? –one that is aggressive and threatens local biodiversity.

Changing Hudson Project Institute of Ecosystem Studies Why Should you be Concerned? 50,000 introductions to U.S. Cost –$137 billion/ year in damages and pest control costs (Pimentel, 2000) Impacts to native species –Threats to 49% of all endangered and threatened species –Blamed for 68% of fish extinctions in U.S.

Changing Hudson Project Institute of Ecosystem Studies Why are Invasive Species a Problem? No natural enemies –Predators –Competitors –Parasites and diseases Populations increase rapidly Out compete native species for resources

Changing Hudson Project Institute of Ecosystem Studies Mile-a-minute Grows up to 6 inches per day Native to Asia, brought over by mistake in ornamental plants in the 1930s Takes over open spaces, grows over existing vegetation Spikes on the vines make it difficult to remove

Changing Hudson Project Institute of Ecosystem Studies Kudzu “the vine that ate the South” Introduced from Japan in 1800s to control soil erosion on farms Now entering NY Spreads by runners and seeds –60 feet a year, 1 foot/day –6 inch taproot Smothers native species

Changing Hudson Project Institute of Ecosystem Studies Islands Islands often suffer damage-why? -small geographic areas, lack of genetic variability: native species -islands tend to have fewer overall species -rate of introduction is often higher

Changing Hudson Project Institute of Ecosystem Studies Galapagos Islands: Introduced Goats, Pigs, Raspberry bushes, Rats…

Changing Hudson Project Institute of Ecosystem Studies Brown Tree Snake In Guam Native to South Pacific Probably stowaway in ship cargo, 1950 Eats small vertebrates and bird eggs (9 of 11 native forest-dwelling bird species extirpated; 5 extinct) 40 snakes/acre Local extinctions Power outages Source:

Changing Hudson Project Institute of Ecosystem Studies Mongooses on Hawaii Native to South Asia and Africa Introduced as a biological control for rats and snake in sugar cane, late 1800s Mongooses diurnal, rats nocturnal Feed on native wildlife, decimating endemic birds

Changing Hudson Project Institute of Ecosystem Studies Zebra Mussels, Dreissena polymorpha Native to SE Europe and W Asia Live in fresh and brackish water 1985, ballast water from European ship, Lake St. Clair, near Detroit Spread through Great Lakes and Erie Canal

Changing Hudson Project Institute of Ecosystem Studies

Changing Hudson Project Institute of Ecosystem Studies Zebra Mussels, Dreissena polymorpha Life history –Warm water, external fertilization –Larvae, veligers –Settle on hard surfaces –Mature at one year –Live years –Filter feeders, plankton –Eaten by some fish, some ducks, crayfish and crabs

Changing Hudson Project Institute of Ecosystem Studies

Changing Hudson Project Institute of Ecosystem Studies A map showing the distribution of zebra mussels and quagga mussels, another invasive. (USGS, Zebra Mussel Information: U.S. Distribution Maps,

Changing Hudson Project Institute of Ecosystem Studies The dotted line shows the arrival of the zebra mussels in the Hudson. Based only on this data, what can you say about the effects of the invasive mollusk on the Hudson river?

Changing Hudson Project Institute of Ecosystem Studies Zebra Mussels, Dreissena polymorpha Effects of the Mussels: –Less phytoplankton and zooplankton –Plankton-feeders declined, including fish –Water clarity and nutrient increases –Uses lots of oxygen, less fish –Economic Water intakes, boat hulls Toxic antifouling compounds Costs $1000,000 – 1,000,000/yr

Changing Hudson Project Institute of Ecosystem Studies Ecological Effects INCREASE DECREASE

Changing Hudson Project Institute of Ecosystem Studies Characteristics of Successful Invasives High reproductive rate Long lived Good dispersal Adapt well to new place Few predators

Changing Hudson Project Institute of Ecosystem Studies Controlling Invasive Species Often not possible, significant costs National Invasive Species Act of 1996 –For the Hudson River and Great Lakes only –Ballast water must be treated, retained, or released in ocean -Inspection of goods at customs -Global shipping is a problem

Ways to Eradicate Biological Control Chemical Control Mechanical Control Prevention Changing Hudson Project Institute of Ecosystem Studies