Institute of Ecosystem Studies

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. Alien species are organisms that are not normally part of the ecosystem They have been introduced from some place else Now occur outside their native range in established, breeding populations Also called exotic, introduced, weedy, non-indigenous Not all alien species survive EPA estimates only 10% of introduced species survive and of these, only 10% become invasive No/few predators, competitors or diseases in new environment Populations may grow very rapidly Take over habitats, out compete native species Introductions involve human activities, either accidental or deliberate Changing Hudson Project Institute of Ecosystem Studies

Why Should you be Concerned?
50,000 alien 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. Experts estimate that 50,000 alien species have been introduced to the U.S. These introductions cost you money Pimentel ‘s study estimated $137K/year to “fix” what they mess up or control them What kinds of damage do they do? 49% of all threats to species that are already rare Typically as predators or competitors for food or habitat Alien species implicated in 68% of all fish extinctions that occurred between 1900 and 2000 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 In addition to being predators and competitors also include parasites and diseases Native species have no ability to resist Smallpox introduced by European devastated native American Indians Without natural enemies populations grow rapidly Out compete native species for resources Lets look at some examples: Terrestrial plant 2 terrestrial animals 2 Hudson River examples One plant, one animals Changing Hudson Project Institute of Ecosystem Studies

Mile-a-minute Native to Asia, introduced through nurseries in the 1930s Lots of seeds Grows rapidly, crowding out native species 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 Kudzu, a vine Introduced from Japan, 1830s to control soil erosion of farms First in the SE US, moving N and entering NY Spreads by runners and seeds Grows very fast, 60 ft/year Has a huge taproot so difficult to control Taproot stores food, even herbicides don’t work. Smothers native plants Changing Hudson Project Institute of Ecosystem Studies

Islands Islands often suffer extraordinary damage-why? -small geographic areas, lack of genetic variability: endemic species -islands tend to have fewer overall species - “ecological release” -rate of introduction is often higher Introduced mammals, including rats, cats and pigs, have caused 64% of frogs and lizard extinctions and 75% of known bird extinctions on New Zealand. In Hawaii, around 45% of the flora is now exotic. Ecological release: when the species in its new environment finds itself free of parasites, diseases, predators or herbivores. Changing Hudson Project Institute of Ecosystem Studies

Galapagos Islands: Introduced Goats, Pigs, Raspberry bushes, Rats…
Even on the ‘pristine’ Galapagos Islands, invasives are wreaking havoc. Goats are especially damaging. The photo on the left is before and after goats. Goats have now been hunted out on Isabela Island to allow the native vegetation to regrow, but dozens of other islands face intense pressure from invasive plants and animals. In a recent survey of introduced plants growing in Puerto Villamil, Isabela Island, the third largest town in Galapagos. 261 species were recorded, 39 of which were found growing wild. 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 Introduced to Guam after WWII U.S. colony, lots of boat traffic Native to the S Pacific Probably stowaway in cargo Diet: small vertebrates, frogs, lizards, birds, eggs, small mammals Depleted birds on Guam Reported scavenging garbage, even hamburgers from grills Highly prolific—12 eggs/clutch, 2 clutches/year Densities reached 100 snakes/ha, 40/acre Bite and eat small pets Caused thousands of power outages climbing transmission lines 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 Mongooses on islands Native to S Asia and Africa Introduced to Caribbean islands to control rats, also introduced, and snakes in sugar cane Late 1800s Rats nocturnal, mongoose diurnal Didn’t work Highly prolific 36 young/4years of life Changing Hudson Project Institute of Ecosystem Studies

Invasive Species in the Hudson River
What are they? Where did they come from? When did they arrive? Freshwater parts more than 113 species Beginning around 1800 Continues at about 7species/10 years Switch to closer to home—Hudson River Data from Mills studies on the Hudson River He estimates at least 113 species introduced to the FW parts of the river since 1800 Maps shows river—FW part from Poughkeepsie N. Commerce and ships Introductions continue today at the rate of about 7 species every 10 years Changing Hudson Project Institute of Ecosystem Studies Source:

Invasive Species in the Hudson River
2 major sources Plants from Europe Ballast, solid and water of ships Agricultural escapes Deliberate introductions Animals from U.S. interior basin; Great Lake and Mississippi Erie Canal, 1825 Where do they come from? Plants are mostly from Europe Ballast-used to stabilize ships at sea, dumped once close to shore Solid at first, later water—had things in them Also settlers brought things with them—moving, bring your favorite fruit tree or houseplant, things in the soil Deliberate introductions—nice plants in Europe, good for gardens in US—but no enemies Nursery industry still introduces new varieties—now regulated Animals come from U.S. interior basin, Great Lakes and Mississippi Canal system is main route—Erie Canal opened in 1825—dug a trench and locks to connect the Hudson and Mohawk Rivers to Lake Erie Also deliberate introductions—fish especially, farmed and released for sportsmen Changing Hudson Project Institute of Ecosystem Studies

Water Chestnut, Trapa natans
Native to Eurasia Deliberately introduced by botanists, late 1800s Collins Lake, Schenectady 1884 First appearance in Hudson Valley 1920s Mohawk River Hudson River 1930s Quiet waters Plant example from the Hudson River Native to Eurasia Introduced by botanists to Collins Lake in 1884 in Schenectady Found in Mohawk River 1920s and spread Habitat is quiet waters This is what it looks like today Here being removed by a machine Fouls propellers of boats Photo: Kara Goodwin Changing Hudson Project Institute of Ecosystem Studies

Floating leaves, air bladders Found on surface Blocks lights Spiny nuts Plant floats on surface because of air bladders Reproduces by spiny nuts Forms thick mats and blocks light Changing Hudson Project Institute of Ecosystem Studies

Inbocht Bay, south of Catskill on the Hudson River Photos courtesy of IES Changing Hudson Project Institute of Ecosystem Studies

Inbocht Bay 1995 1997 2002 Changing Hudson Project Institute of Ecosystem Studies

Changing Hudson Project Institute of Ecosystem Studies

Trapa natans, water chestnut

Nuisance by 1950s Recreation Nuts Habitat change Eradication attempts Herbicides Cutting/pulling by hand By 1950s a serious nuisance for boaters Nuts hurt feet of swimmers Effects on aquatic ecosystem Native shoreline plants Oxygen produced from PS goes into air, not water Less available for fish and other animals that live in the water Less light available for PS by phytoplankton in water Attempts to eradicated with herbicides largely unsuccessful Cutting okay for local control but must be repeated annually Changing Hudson Project Institute of Ecosystem Studies

Native submerged plant in the Hudson Water celery: Vallisneria americana Changing Hudson Project Institute of Ecosystem Studies

Why does the dissolved oxygen change so much?
Caraco et.al., 2006 Changing Hudson Project Institute of Ecosystem Studies

Common reed Changing Hudson Project Institute of Ecosystem Studies

Percentage of the most common 11 marsh dependant bird species surveyed at each marsh in 2005 Red Winged Blackbird Marsh Wren Swamp Sparrow Yellow Warbler Virginia Rail Common Yellowthroat Canada Goose Least Bittern American Goldfinch Wood Duck Song Sparrow Iona 77.12 0.98 0.33 2.94 0.65 4.58 5.23 1.63 1.31 Constitution 46.88 20.13 5.19 3.12 8.57 4.29 0.91 2.73 1.17 1.82 1.43 Tivoli 23.4 42.4 12.6 3.7 3.8 4.2 0.64 1.28 0.32 0.16 Stockport 33.6 27.1 11.2 8.9 6.8 0.93 1.87 2.34 - 2.57 Changing Hudson Project Institute of Ecosystem Studies

NITROGEN SEQUESTRATION
30 kg N/ha Changing Hudson Project Institute of Ecosystem Studies

POREWATER AMMMONIUM 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 Alien animal in Hudson River Zebra mussel native to SE Europe and W Asia Lives in FW and brackish water Introduced from Europe in Lake St Claire in ballast water, spread through Great Lakes, Erie Canal to HR One of the most dramatic examples of a successful invasion by an introduced species is the zebra mussel, Dreissena polymorpha. This native to southern Russia was introduced to the Great Lakes in 1985 or 1986 via ballast water from foreign ships. Since then, it has spread rapidly throughout the Great Lakes, into the Hudson River in NY state, and into many other freshwater habitats in the eastern U.S. (Figure 1a). Changing Hudson Project Institute of Ecosystem Studies

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 Filter feeders – strain phytoplankton and zooplankton from water Gamete shed into water, immature form, veiliger, settles on hard surfaces Mature quickly and live 6-7 years Prey item for few species in HR Changing Hudson Project Institute of Ecosystem Studies

Photo of zebra-mussel encrusted crayfish and clogging a pipe. Shows some of the impacts of these invaders on native species and humans. 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 consumed resources (food)

Catskill 1991, now widespread Filter % of water in freshwater estuary daily Changes Less phytoplankton and zooplankton Plankton-feeders declined, including fish Water clarity and nutrient increases Dissolved oxygen used for respiration Economic Water intakes, boat hulls Toxic antifouling compounds Costs $1000,000 – 1,000,000/yr Found near Catskill in 1991, now widespread Ecological changes – filters volume of HR daily Less phytoplankton and zooplankton for native species Clearer water as a result but more N from waste Uses oxygen in water for respiration, less for fish and other animals, native mussels Economic impacts: water intakes, pollution from antifouling compounds, costs Changing Hudson Project Institute of Ecosystem Studies

Ecological Effects INCREASE DECREASE Changing Hudson Project Institute of Ecosystem Studies

“Abundance” is mean riverwide number of fish over standard period of time “Distribution” is ratio of number of fish above RKM 100 (Newburgh) and number of fish below RKM 100 for each species “Growth” is apparent growth, based on field measurements of length Covariates include year (time-trends), freshwater flow, water temperature Technique is multiple regression, using model-averaging Changing Hudson Project Institute of Ecosystem Studies

Characteristics of Successful Invasives
High reproductive rate Long lived Good dispersal Generalists Pioneer species Few predators What characteristics are shared by all these alien species that have become invasive? See slide 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 What can we do to control invasive alien species? No much once they are here. Law now provides some protection for HR and Great Lakes—prevents untreated ballast water release Voluntary elsewhere Customs inspections—this is why we have them. Why you shouldn’t bring stuff in from other countries. Changing Hudson Project Institute of Ecosystem Studies

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