which of the following are “exotic species”? wheat in kansas steelhead trout in lake michigan...
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Which of the following are “exotic species”?
Wheat in Kansas
Steelhead trout in Lake Michigan
Bluegrass in Kentucky
Zebra mussels in Lake Erie
Steps to become an invasive species…..
Disperse from native range to somewhere else
Survive in new habitat
Reproduce in new habitat
Naturalize (establish permanent population)
Become a problem (immigrant vs invasive spp)
lag phase when not know if spp will become invasive
Some conditions can promote invasiveness
Vacant “niches”: ecosystems with few species
Escape from predators and competators
Disturbance of ecosystem
Consequences of invasion: Great Lakes case study
Ricciardi et al 2001
Great Lakes Introductions increase over time
Routes of introduction
Canals (sea lamprey) alewife
Ballast water importation zebra mussels spiny water flea goby ruffe
Aquaculture and aquarium trade and intentional release carp
The Sea Lamprey(Petromyzon marinus)
Primative (jawless) fish
Native to Atlantic Ocean
Adults predatory on large fish
Probably entered Great Lakes via the Hudson River and its artificial extension, the Erie Canal (opened to Lake Ontario in 1819)
Hudson
Erie Canal
Thereafter invasion quickened; found in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946.
Gained access to Lake Erie through Welland Canal around Niagara Falls (completed 1829), but not noted in Lake Erie until 1921
http://www.glfc.org/slft.htm
Lampreys devastated lake trout populations in Great Lakes
Removal of top predator allowed smaller fish such as alewife (also introduced through canals) to boom
Lamprey control (pesticide applied to juvenile form in streams)- continues today
Coho & Chinook salmon easier to grow in hatcheries than lake trout. These exotic species were heavily stocked
Euryhaline species Traveled through canals (maybe native to Ontario)
Alewife
Population expanded when lake trout died
Efficient zooplankton eater, changed zooplankton and contribute to decline of native fish (e.g. bloater)
Lake Trout
AlewifeBloater
Whitefish
Large zooplankton Small zooplankton
Sea LampreyPacific Salmon
Phytoplankton
Ballast-mediated species Introduction
uptake
transport
discharge
Water is used for ballast, but sediments accumulate too
Can contain resting stages or live animals
Dreissenid Mussels
Ponto-Caspian origin Ballast transport First found in Lake St. Clair
Adults attach to substrate Planktonic larvae High population density High filtration rate
History
Biology
http://www.earthwave.org/zmussel.htm
Zebra mussel covering hard substrate and spreading over soft sediment in Oneida Lake, NY
Total coverage of sediments in St Lawrence Seaway
Covering hard objects
2
3
4
5
1975 1980 1985 1990 1995 2000
Sec
chi
dep
th (
m)
zebra mussels
Increase in water clarity in Oneida Lake, NY
Bay of Quinte; S. Millard, DFO
Onieda Lake; CBFS
Lake Erken; P. Eklov, Uppsala U.
Naroch Lakes chain; L. Brulakova & A. Karatayev, Austin St. U.
Western Lake Erie; S. Ludsin
0
1
2
3
4
5
6
7
Naroch Oneida Erie Erken Quinte N Quinte B Myastro Batorino
Lake
Mea
n a
nn
ual
Sec
chi
dep
th (
m)
0
10
20
30
40
50
60
70
80
90
Mea
n p
re-z
ebra
mu
ssel
TP
(u
g/L
)
pre zebra musselpost zebra musselpre zebra mussel
Some species extremely long lived, > 100 yearsDo not mature for relatively long time ~> 10 years
Dreissena and Unionid Clams
Zebra mussels encrust unionid shells. Interference competition
Populations already hurt by water quality problems and dams
Native clams usually disappear w/ in 5 yr of zebra mussel introduction
http://www.miseagrant.org/ans/zoo.html
Bythotrephes
A native of Great Britain and northern Europe
Discovered in Lake Huron in 1984
Spread to all the Great Lakes and some inland lakes.
Native Daphnia spp.
http://ebiomedia.com/gall/classics/Daphnia/feature_main.html
short vs. long spine
big vs. small body
Feeds on smaller zooplankton in the Great Lakes
May be reducing food for native plankton and fish species
http://www.miseagrant.org/ans/zoo.html
http://ebiomedia.com/gall/classics/Daphnia/feature_main.html
Which would fish rather eat??
Round Goby
Eat zebra mussels
May compete with native darters or sculpins
May consume eggs of natives (lake trout)
http://www.miseagrant.org/ans/fish.html
http://www.miseagrant.org/ans/fish.html
Eurasian RuffeEuropean perch family
discovered in Duluth harbor in 1985.
Have spread around Lakes Superior and have established a population in Thunder Bay near Alpena, Michigan.
In some areas, explosive population growth and displace native species such as y.p. and emerald shiners
Sharp spines make them difficult for larger fish to eat
Aquaculture Releases
Carp European settlersfor food and fishingwell established population
Asian CarpSouthern fish farms
Knocking on the door: Asian carp
several species, accidentally released from aquaculture facility.
~ 40 mi from Lake Michigan.
Electrical barrier in place in Chicago.
http://www.glfc.org/fishmgmt/carp.asp
Economics of electrical barrier
Construction cost?
Maintenance cost?
Will it work?
MN proposing bubble and sound curtain
57% effective
Lake Trout
AlewifeBloater
Whitefish
Large zooplankton Small zooplankton
Sea LampreyPacific Salmon
Phytoplankton
Zebra mussels
goby
Asian carp
Spiny flea
Benthic algae
Invasional Meltdown
Theory that suggests that current invasions may facilitate future invasions
Exotics don’t necessarily compete with one another, may make it easier for others to get in.
Compare to “biotic resistance” or “empty niche” theories described in reading
Prevention and Control
Prevent entry:
International trade treatiesInternational and interstate commerce
Examples: Garden plants, pets, aquarium fish, agricultural species
Shipping industry regulations
Examples: all GL species
Very difficult to predict which species will become invasive
How to decide which species cannot be imported
Eradication
Possible if detected early
Biology of species important, ex. it has slow dispersal or depends on few other spp. for survival
Long-term effort: funding for eradication program is not cut
Public support
Maintenance Control
Keep population at low level to avoid ecological damage
Some successful examples
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