Invasive Species

1
Invasive Species the Hudson
Photo by Kara Goodwin
2
Activity
Which of these photos shows an invasive species?
How do you know?
3
Definitions

• An alien species is one that was moved outside of
  its native range by human activities
• Usually applied only to species established in
  the wild (doesnt include wheat or chickens)
• Also called exotic, non-native, non-indigenous,
  introduced, or invasive species
• Invasive is used to designate aggressive alien
  species
• An alien species whose introduction does or is
  likely to cause economic or environmental harm or
  harm to human health.

4
Why worry about invasive species?

• Can change habitats or alter ecosystem function
  and ecosystem services
• Can crowd out or replace native species
• Can damage human activities (agriculture,
  forestry, fisheries)
• 137 billion/ year in damages and pest control
  costs (Pimentel, 2000)

5
Disease
Examples -wooly hemlock adelgid -beech bark
disease -Asian chestnut blight
www.dnr.gov
6
Predators
Example Brown Tree Snake

• Native to South Pacific
• Stowaway in ship cargo, 1950
• Eats small vertebrates and bird eggs (10 of 11
  native forest-dwelling bird species extirpated 5
  extinct)
• 40 snakes/acre

Source www.birdlife.org
7
Predators

• Example Nile Perch
• -introduced as food
• to Lake Victoria
• -eliminated over
• 100 species of native
• Cichlid fish

Source russelure.com/photos/
8
Predators Goats
9
Competition Habitat Alteration
Example from the Hudson River
Zebra mussel (invasive) Pearly mussel
(native)
10
Competition Mile a Minute
www.plants.usda.gov
www.rutgers.edu
11
Competition 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

12
Pop Quiz

• How many alien species are in the Hudson River?
• a. 05
• b. 5 25
• c. 25 100
• d. 100 150
• e. More than 150

13
More than 100 species, including many of our most
familiar plants and animals
14
Pop Quiz

• How many alien species arrive in the Hudson River
  each decade?
• a. 1-2
• b. 3-5
• c. 6-10
• d. More than 10

15
(No Transcript)
16
Pop Quiz

• What invasive species arrived in the Hudson River
  watershed in 2008?
• Asian clam
• Northern snakehead
• Chinese mitten crab
• All of the above

17
Chinese mitten crab
Mound of crabs trying to get over a dam in Germany
18
Northern snakehead
Asian clam (Corbicula)
19
Pop Quiz

• Are more alien plants or animals currently
  arriving in the Hudson River estuary?
• Plants
• Animals
• Dont know

20
Aliens began to arrive a long time ago and are
still coming
Mills, et al 1996
21
The aliens came from all over the world

• Canals
• Shipping
• Agriculture
• Stocking

Mills, et al 1996
22
Major Hudson River Invaders
Water Chestnut Common Reed Zebra Mussels
23
Water Chestnut, Trapa natans

• Native to Eurasia
• Deliberately introduced by botanists
• Collins Lake, Schenectady 1884
• 1920s Mohawk River
• Hudson River 1930s
• Grows in quiet waters

Photo C. Harris
24
Water Chestnut, Trapa natans

• Floating leaves, air bladders
• Found on surface
• Blocks lights
• Spiny nuts

25
Inbocht Bay, south of Catskill on the Hudson River
Photos courtesy of H. Malcom
26
Inbocht Bay
1995
1997
2002
27
Native submerged plant in the Hudson Water
celery Vallisneria americana
28
Why does the dissolved oxygen change so much?
Caraco et.al., 2006
29
Common reed
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
Percentage of the most common 11 marsh dependant
bird species surveyed at each marsh in 2005
34
(No Transcript)
35
(No Transcript)
36
What are these critters good at?
37
Zebra Mussel Life Cycle
38
http//www.dgif.state.va.us/zebramussels/
www.zeestop.com
39
A map showing the distribution of zebra mussels
and quagga mussels, another invasive. (USGS,
2007. Zebra Mussel Information U.S. Distribution
Maps, http//nas.er.usgs.gov/zebra.mussel/).
40
Native Mussels Clams Have Declined
41
Phytoplankton have declined
42
Ecological Effects
INCREASE
DECREASE
43

• 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

44
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