Download “Invasive” Plants - MSU Department of Geography

What Invasive Species are
affecting Forest Ecosystems
and Waterfowl?
By Jay Rendall
Minnesota Department of Natural Resources
What are
“Nonnative Invasive
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”
“Naturalized”
“Invasive”
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
100
80
60
40
20
0
1962
1966
1970
1974
Increase in purple loosestrife biomass in a USFWS refuge.
1978
“Invasive Species”
affecting
Forest Ecosystems
“Invasive Species”
affecting Waterfowl
and Wetlands
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:
• 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
Climate 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
Climate 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).