Alien Species by chenmeixiu

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									Invasive Species & the Hudson




                   Photo by Kara Goodwin
           Activity


Which of these photos shows an
invasive species?

How do you know?
                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 (doesn’t 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”.
Why worry about invasive species?
1) Can change habitats or alter
   ecosystem function and ecosystem
   services
2) Can crowd out or replace native
   species
3) Can damage human activities
   (agriculture, forestry, fisheries)
   – $137 billion/ year in damages and pest
     control costs (Pimentel, 2000)
              Disease
                  Examples:

                  -wooly hemlock
                  adelgid
                  -beech bark disease
                  -Asian chestnut
                  blight



www.dnr.gov
                           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
               Predators
Example: Nile Perch

-introduced as food
to Lake Victoria
-eliminated over
100 species of native
Cichlid fish
                        Source: russelure.com/photos/
Predators: Goats
Competition & Habitat Alteration
              Example from the Hudson River




 Zebra mussel (invasive)         Pearly mussel (native)
           Competition: Mile a Minute




www.plants.usda.gov
                          www.rutgers.edu
Competition:    • Grows up to 6 inches per
Mile a Minute     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
              Pop Quiz
How many alien species are in the Hudson
 River?
 a. 0≤5
 b. 5 ≤ 25
 c. 25 ≤ 100
 d. 100 ≤ 150
 e. More than 150
More than 100
species,
including many of
our most familiar
plants and
animals
               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
               Pop Quiz
What invasive species arrived in the Hudson
 River watershed in 2008?

a.Asian clam
b.Northern snakehead
c.Chinese mitten crab
d.All of the above
  Chinese mitten
       crab




Mound of crabs
trying to get over a
dam in Germany
Northern
snakehead




            Asian clam
            (Corbicula)
           Pop Quiz

Are more alien plants or animals
currently arriving in the Hudson
River estuary?

a.Plants
b.Animals
c.Don’t know
Aliens began to arrive a long time ago and are still coming…


                                 25
                                                                     total
                                                                     plants
       Number of alien species



                                 20                                  animals


                                 15


                                 10


                                  5


                                  0
                                      1810-39 1840-69 1870-99 1900-29 1930-59 1960-92

                                                                               Mills, et al 1996
The aliens came from all over the
             world


                 1 plant
 Interior                    48 plants
Basin (40)                                Europe
               39 animals
                                           (60)
                             12 animals

  Pacific Coast (1)

             Asia (6)


                               •Canals
                               •Shipping
                               •Agriculture
                Southern       •Stocking
               and eastern
                 United
                States (8)
                               Mills, et al 1996
Major Hudson River Invaders




           Water Chestnut

           Common Reed

           Zebra Mussels
 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
 Water Chestnut, Trapa natans
• Floating leaves, air
  bladders
• Found on surface
• Blocks lights
• Spiny nuts
                               Inbocht Bay, south of
                               Catskill on the Hudson
                               River




Photos courtesy of H. Malcom
       Inbocht Bay
1995       1997      2002
Native submerged plant in the
Hudson
Water celery: Vallisneria
americana
Why does the dissolved oxygen
     change so much?




                      Caraco et.al., 2006
Common reed
            Percentage of the most common 11 marsh dependant bird species
                             surveyed at each marsh in 2005



                  Red Winged Blackbird



                                            Marsh Wren


                                                           Swamp Sparrow




                                                                                                Virginia Rail




                                                                                                                                                           Least Bittern
                                                                                                                  Common Yellowthroat




                                                                                                                                                                             American Goldfinch
                                                                             Yellow Warbler




                                                                                                                                          Canada Goose




                                                                                                                                                                                                                     Song Sparrow
                                                                                                                                                                                                       Wood Duck
Iona           77.12                     0.98            0.33              2.94               0.65              4.58                    5.23             0.33              1.63                   0.33             1.31


Constitution   46.88                     20.13           5.19              3.12               8.57              4.29                    0.91             2.73              1.17                   1.82             1.43

Tivoli         23.4                      42.4            12.6              3.7                3.8               4.2                     0.64             3.8               1.28                   0.32             0.16


Stockport      33.6                      27.1            11.2              8.9                6.8               3.7                     0.93             1.87              2.34                    -               2.57
What are these critters good at?
              Zebra Mussel Life Cycle
                                                           Up to 700,000
                                                           mussels per
                                                           m2


               Growth

                                        Filter
                                        Feeding: 1 liter
                                        of water per day
                    40,000- 1,000,000
                    eggs per year




                                                                           Settling:
                                                                           10,000 per m3 /day




                                                    Veliger
                                                                                       95% die
200,000,000 sperm
                                                    Larvae
                                                    500,000 per m3
http://www.dgif.state.va.us/zebramussels/




                                            www.zeestop.com
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/).
Native Mussels & Clams Have
          Declined
Phytoplankton have declined
                                          Change associated with
                                          zebra mussel invasion




                                                -100
                                                 -50
                                                   0
                                                  50
                                                 100
                                                 150
                                                 200
                                                 250



                             phytoplankton

                          microzooplankton

                             native bivalves

                          macrozooplankton

                      deepwater benthos

      American shad (YOY)




Institute of Ecosystem
Changing Hudson Project
                          dissolved oxygen

                             littoral benthos
                                                                      Ecological Effects




                              transparency
                                                           INCREASE




                                                DECREASE




                                  soluble P

  redbreast sunfish YOY
      Fish that live in the open water and whose young feed on zooplankton for a long time
      will become less abundant, grow slower, and/or shift downriver.




•   “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
   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

								
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