What Invasive Species What Invasive Species are affecting Forest are affecting Forest

Ecosystems and Ecosystems and Waterfowl?Waterfowl?

By Jay RendallBy Jay Rendall

Minnesota Department of Natural ResourcesMinnesota Department of Natural Resources

What are What are “Nonnative Invasive “Nonnative Invasive

Species”?Species”?

Definitions

Exotic, alien, introduced, nonnative, nonindigenous species -

a species that is not a native species (Minn. Stat. 84D)

the condition of a species being beyond its natural range or natural zone of potential dispersal (OTA 1993)

Definitions

“Nonnative”

“Invasive”

“Naturalized”

Invasive Species Concepts

“We are in a period of the worlds history when the mingling of thousands of kinds of organisms is setting up terrific dislocations in nature."

- Charles Elton, The Ecology of Invasions

Local Spread

Increase in purple loosestrife biomass in a USFWS refuge.

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20

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1962 1966 1970 1974 1978

“Invasive Species”Invasive Species”affecting affecting

Forest EcosystemsForest Ecosystems

“Invasive Species”Invasive Species”affecting Waterfowl affecting Waterfowl

and Wetlandsand Wetlands

Waterfowl and Invasive Species Interactions:Waterfowl and Invasive Species Interactions:

• Eurasian Milfoil increase leads to native aquatic plant decrease (Knapton and Petrie 1999, Madsen 1991)

• Curly-leaf pondweed and common carp populations can lead to turbid conditions rather than clear-water, macrophyte dominated conditions in shallow lakes.

Waterfowl and Invasive Species Interactions:Waterfowl and Invasive Species Interactions:

• Several studies have documented the negative impacts of common carp on shallow water ecosystems such as reduction of wild celery and increased cycling of nutrients.

• Zebra mussels filter water leads to increase of native aquatic plants including wild celery and may contribute to decline of Eurasian milfoil (Knapton and Petrie 1999)

Invasive Species and Invasive Species and Climate Change InteractionsClimate Change Interactions

• If tree composition of forests begin to change due to climate change, invasive species may have an advantage in the transition period — and may become more dominant than without climate change.

• Kudzu and many other species currently limited by climate to southern states may extend their range northward into the northern latitudes.

Invasive Species and Invasive Species and Climate Change InteractionsClimate Change Interactions

• Incidences of diseases and parasites could increase under climate change (Leach 1999).

• If climate change leads to ecological disruption, the task of predicting the probability of successful invasions will be more difficult (Leach 1999).