Invasive Species “the second greatest threat to global diversity—after the loss of habitat”

What is a native species? Native species are those that normally live and thrive in a particular community. They occupy specific habitats and have specific niches in their native environment. They have natural predators that help to keep their populations in check. Leopard Frog Three Ridge Mussel

What is a non-native species? Purple loosestrife (Lythrum salicaria), were brought N. America accidentally in ballast water, as medicinal herb seeds, and as an ornamental plant A species one that is not native to an ecosystem. It’s outside its native distributional range Arrived there by human activity, either deliberate or accidental.  AKA: “Exotic” “Alien” Non-native species are not necessarily invasive. Example stocking sport fish in a lake Pheasants—native of China Zebra mussels (Dreissena polymorpha), were accidentally introduced to North America in ballast water of ships

Examples: Plants— Leafy Spurge, Canada Thistle, Absinth Wormwood Aquatic—Eurasian water milfoil, purple loosestrife, zebra mussels Soils– Earthworms!!!!! Wildlife—European starling, nutria Microorganisms—Avian Influenza, West Nile Virus Invertebrates—Emerald Ash Borer, Rusty Crayfish

Environmental Impacts Decreases biodiversity—changes landscapes, outcompetes native species for habitat and food, introduces diseases Outcompetes native species, sometimes to near extinction Hybridizes and displaces native populations Decreases food sources and impacts food webs

Economic Impacts Reduces productivity in forestry, agriculture and fisheries Causes export and import trade restrictions Reduces property values Costs associated with prevention and management Impacts on recreation and tourism

Pathways of Introduction and Spread Raw Wood and forest products—including campfire wood Transportation of animals and animal by-products Transportation of topsoil Recreational and commercial boating and fishing Releases of live fish and bait Gardening and landscaping Canals and changes to waterways Ballast water of ships Aquariums, water gardens and pet trade ATV’s Intentional stocking—as biocontrol Illegal release—cultural release Construction equipment Hiking boots

Why are invasive species so successful? Tolerate a variety of habitat conditions Grow and reproduce rapidly Compete aggressively for resources Food, water, habitat Lack of natural enemies or predators in the new ecosystem Low susceptibility to disease “Generalists” – can adapt to different environments

Invasives: Plant Animal Invertebrates Fungi Microorganisms

Aquatic Nuisance Species---ANS Aquatic and terrestrial organisms, that produce harmful impacts on aquatic natural resources in these ecosystems and on the human use of these resources.

Aquatic Nuisance Species---ANS ANS Task Force: http://www.anstaskforce.gov/default.php North Dakota Game and Fish Department: http://gf.nd.gov/ans Minnesota Sea Grant: http://www.seagrant.umn.edu/ais/

Zebra Mussel Native to the Caspian Sea region of Asia. Clog water-intake systems of power plants and water treatment facilities Clog cooling systems of boat engines Female zebra mussels can produce as many as 1 million eggs per year Develop into microscopic, free-swimming larvae (called veligers)

Larvae settle and attach to any firm surface

Rusty Crayfish Native to streams in the Ohio, Kentucky, and Tennessee region. Spread by anglers who use them as bait Prolific, severely reduce lake and stream vegetation, depriving native fish and their prey of cover and food. Reduce native crayfish populations. Likely means of spread: Accidental release by anglers Aquarium hobbyists, Commercial harvesters Teachers and students who buy them from biological supply houses and then release them when their study is completed.

Eurasian Watermilfoil feathery submerged aquatic plant that can quickly form thick mats in shallow areas of lakes and rivers mats interfere with swimming and entangles in propellers spreads when plant pieces break off and float on water currents or clings to boat motors and trailers

Curly Leaf Pondweed rooted submerged plant that quickly forms dense mats at the water surface of lakes and rivers in late spring and early summer Shades out other native plants As they die and decay, oxygen levels are depleted leading to fish kills and eutrophication mats interfere with swimming and entangles in propellers

Take Home Point Invasive Species are not native and don’t belong in the ecosystem they’re brought to Humans are responsible for their introduction Humans can prevent their spread by following preventative measures Invasive species can affect our lives and livelihood

ACTIVITIES Challenge students to think about how invasive species are spread through human activities How they can reduce the spread of these organisms “Around the World: The Invasive Species Challenge” (page 45) “No big deal, it’s just a weed” or “A rampaging, alien invader here to wreak havoc on our landscape” “Zebra Mussel Baseball” (page 68)