Transcript No Slide Title

Introduced Species:
Impacts on Biodiversity
Threats to biodiversity
Scientists agree that the following five
factors are the major problems contributing
to the current loss of biodiversity:
 habitat destruction
 introduced species
 pollution
 overexploitation
 population growth
Terms
 Alien
 Exotic
Indigenous
 Native

 Introduced
 Invasive
 Nonnative
 Noxious
 Nuisance
Bumblebee on flower of introduced thistle
Introduced Species
 Introduced
species have been moved from their
native habitats to new habitats - usually by
humans, accidentally or intentionally.
 Some
introduced species become invasive in
their new habitats = successfully reproduce and
spread; cause economic or environmental harm
or harm to human health
Herb robert
(Geranium robertianum)
Pathways:
How are species introduced?
 Intentional
introductions for
agriculture, horticulture, research,
biological control
 Unintentional introductions through
contaminated agricultural products,
timber, etc.
 Attached to or carried in freight,
packing materials, shipping
containers, ships, boats, cars, planes
and other modes of transport
Biological attributes of
invasive species
 This
is an area of current research
 Difficult to generalize
 Usually a lag phase before a species
becomes invasive - difficult to tell
which introduced species will die out
and which will become invasive
= difficult to decide whether to make the
effort to control the species at this point or
not
 Pinpointing
these attributes would
provide a valuable tool for preventing
invasions
Theories about why some
introduced species succeed:
These theories take into account
attributes both of the species and the
communities being invaded:
escape from natural constraints
(predators, parasites, etc.)
 occupation of a niche that was
vacant
 aided by humans, usually through
disturbance of the native community
Impacts on Biodiversity
 Invasive
species can have a
multitude of impacts:





prey on or cause disease of native
species
outcompete native species for
resources or breeding sites
hybridization with native species
habitat modification (change
hydrology, encourage fire, alter
nutrient cycles)
agricultural/natural resource losses
(pests, diseases)
Impacts on Biodiversity
Herb robert
(Geranium robertianum)
Cichlid fish
English ivy (Hedera helix)
Western pond turtle
 populations
have declined, in large part
due to predation by introduced bullfrogs
Photo by Kate Slavens
Economic Impacts of
Invasive Species
 Loss



of potential economic gain:
crop production
domestic animal and fisheries industries
forest products
 Expense



of fighting invasions
preventing invasions (quarantine)
controlling populations of invasive species
eradication
What is being done?
Regulating Introductions
 In February of 1999, President Clinton
signed an executive order which
expands and coordinates federal
efforts to address the threat of
invasive introduced species and to
prevent the future introduction of
nonnative species.
 The Invasive Species Council, created
by the order, has developed a National
Management Plan for invasive species.
www.invasivespecies.gov
What is being done?
Regulating Introductions
 Invasive
species, once
established, are very difficult to
eradicate
 prevention of invasions is key
 International
treaty:
Agreement on the Application of Sanitary
and Phytosanitary Measures (SPS)
 WTO members can restrict movement of
species that may pose a threat to
human, animal or plant life
What is being done?
Regulating Introductions
 Animal
and Plant Health Inspection
Service (APHIS) of the Department of
Agriculture

attempts to prevent the introduction of
nonnative agricultural pests and diseases

focused mainly on protecting agriculture,
but also serves to prevent ecosystem
damage caused by nonnative species and
diseases
What is being done?
Eradication and Control
 Methods

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of eradication:
chemical
mechanical (including manual)
biological
 Often,
eradication efforts are too little,
too late
 If eradication fails, then maintenance
control is the goal
same methods as for eradication
The goal is to maintain or increase native
species diversity and to maintain a functional
ecosystem that leads to that level of diversity
(may have to accept invasives in the mix).

What is being done?
Eradication and Control
Efforts to eradicate foxes in Western Australia
What can you do?
In the garden - choose native plants
and pull exotic weeds
Do not release exotic pets or
dump aquariums containing
exotic pets or plants
Avoid transporting fresh fruits,
vegetables, grains or meats across state
or country lines
Volunteer to control invasive species
or plant native species in a local
natural area
Be aware of the issues and help to
educate others
Not if you can help it!
Produced by
Woodland Park Zoo
Education Department
2001
Photo credits:
All photos by K. Remine/M. White except:
Slide 11 - Western pond turtle by Kate Slavens.
Used with permission.