Download Invasive Species Management

Outline
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Quiz
Assignment: Peer review due after Spring Break
Lecture: Invasive species and communities
Break
Second half of WI Fishes (ID’s)
Invasive species
and communities
A prelim exam question…
“Are invasive species more likely to have large impacts on
native communities via predation or via competition?”
First, communities…
5 Basic types of species interactions
1XXXXXXXXXX
?
2
Competition is important...just not as
important as predation
What is competition?
Competition ...common use of a limited resource
What can be limiting....?
food
space or habitat
Between and within species
Intraspecific competition
Interspecific competition
•Behavior – feeding rate
•Physiology – growth rate
•Morphological – body size
Population responses
•Abundance
•Distribution
Population
Abundance
How do we see it or measure
it?
Individual Responses
Time
3 types of competition
Interference competition
Exploitation competition
Apparent competition
Interference competition - occurs directly between individuals
via aggression etc. when the individuals interfere with foraging,
survival, reproduction of others, or by directly preventing their
physical establishment in a portion of the habitat.
A
(-)
(-)
B
Exploitation competition - occurs indirectly through a
common, limiting resource, which acts as an intermediate. Ex.
depletes the amount of food or fill up all the available space.
(-)
A
(-)
-
+ +
R
B
-
Apparent competition - occurs indirectly between two species
which are both preyed upon by the same predator.
B
-
P
+
A
+
-
B
- -
+
P
Competition's role in ecology
and evolution
Resource partitioning
Population
Abundance
Population
Abundance
"species packing"
Resource
Gradient
Resource
Gradient
Evolution to minimize competition
Difficult (or impossible) to prove
Species evolve within communities to
utilize resources along a gradient
Food particle size
 Temperature
 Habitat
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100
90
80
Fish Abundance
70
60
Sculpin
50
Dace
40
30
20
10
0
1
2
3
Warmer Temps
4
5
6
7
8
9
Station (1=downstream)
10
11
12
Cooler Temps
Lake Tanganyika
Lake Malawi
Community Assembly and
Invasive Species
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Sequence of invasions is important
As species #’s increase, so does partitioning of
resources
Eventually, resources cannot be partitioned any
further, and species will be excluded
Logical extension: Species-rich environments will
be resistant to invasions
This has not held true due to disturbance, importance of
abiotic factors, extirpations, unsaturated communities
 However, diverse communities may be less impacted
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M.J. Vander Zanden. 2005. The Success of
Animal Invaders, PNAS 102: 7055-7056
Invasive Species
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Why should we care?
-Leading cause of global biodiversity loss
-Particularly severe in freshwater ecosystems
- Contributing factor in 68% of fish extinctions
in US and Mexico
- Cost $137 billion/year in US alone
- Numbers are increasing
BUT…most do not establish or have negative
effects…
Why are species introduced?
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Food
Familiar or “superior” species
Enhancement (or creation) of fisheries
Manipulation of systems (biological control)
Accidental
Accidental Introductions
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Canal building
Ballast water
Bait bucket introductions
Hitchhiking on boats
Angler introduction
Aquarium escape
Aquaculture escape
Invasive species that affect the ecology of
native Wisconsin Fishes
Pelagic planktivores - Alewife, Rainbow smelt, white perch, bythotrephes
Benthic omnivores - round goby, rusty crayfish, common carp
Pelagic piscivores – Pacific salmon, brown trout, rainbow trout
Pelagic/benthic parasite – Sea lamprey
Stream insectivores – brown trout, rainbow trout
Pelagic filter-feeders – silver carp, bighead carp
Benthic filter-feeders – zebra mussel, quagga mussel
Steps to Invasiveness
Colonization
Establishment and Integration
Adapted From Vander
Zanden et al. 2004
Impact
Impacts
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Niche: the ecological role of a species in relation
to other species and the non-biological
environment
The niche represents the range of conditions
within which a species can survive and reproduce
The niche of a species in the absence of
competition is called the fundamental niche.
The niche of a species in equilibrium with competitors
is called the realized niche
Fundamental vs. Realized Niche
Prey Consumed
Realized niche
Fundamental
Realized
Prey Size
Fundamental niche
Impacts: Misunderstanding of Niche
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Niche changes throughout life history
Forage fish can compete with/prey upon
juvenile game fish (Example: smelt, alewives)
Introductions to fill “vacant” niches
Assumption: An organism will occupy the same
habitats and roles in a new system as it does in
native range
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Not always true – organism may be bound
geographically or ecologically in native range
Impacts
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Classic example of changes in realized niche:
Opossum shrimp (Mysis relicta)
Introduced to enhance fish populations
Detritus/phytoplankton feeder in native
ecosystem (realized niche)
Niche expansion upon introduction lead to
zooplankton depletion – eliminated food
resources for populations it was supposed to
enhance
Impacts: Mechanisms
Species level
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Competition (interference: brown/brook trout exploitation:
alewives/ coregonids)
Predator-Prey (Nile perch/ cichlids)
Parsite-Host (Crayfish)
Community level
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Trophic Cascade
Ecosystem Engineer (alters abiotic factors)
Hybidization
Management of Invasive Species
Eradication
 Chemical control
 Biological control
 Mechanical control
Management of Invasive Species
Prevention
 Risk analysis approaches that incorporate
ecological, economic, and social welfare show
that prevention is cost-effective
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Predictions of invaders with the biggest impact,
or predictions of which ecosystems are most
vulnerable to a specific invader, are emerging as
standard methods for directing management.
Predictions of Invasive Species
Mercado-Silva, N., J.D. Olden, J.T. Maxted, T.R. Hrabik, M.J. Vander Zanden. 2006. Forecasting the spread of invasive rainbow
smelt in the Laurentian Great Lakes region of North America. Conservation Biology 20: 1740-1749.
More predictions…
42% (1,369 km)
identified as suitable
(7% of state)
44% (8,878 km)
identified as suitable
Kornis, M.S., and Vander Zanden, M.J. 2010. Forecasting the distribution of the invasive round goby (Neogobisu melanostomus) in
Wisconsin tributaries to Lake Michigan. Can. J. Fish. Aquat. Sci. 67: 553-562.
Conclusions
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Invasive species are an increasingly important
threat to native species and biodiversity
Invasive species affect native ecosystems through
numerous pathways that are not mutually exclusive
Invasive species management is sometimes possible
once the invader has established
Prevention of invasions is key for future
management
Break