Transcript Invasive Species - Environmental studies

Invasive Species
September 5th, 2007
Announcements:
 Check out Case Studies posted on website (if you forgot
which group you are in, scroll through to find your name,
or ask me)
Come prepared for class discussion tomorrow
 Background Field Trip Questions:
now posted
 Field Trip Waiver Forms: I need you to sign them
 Field final: will be passed out tomorrow
Summary of Monday:
• How do communities change?
• Succession
• Primary vs. Secondary
• Who wins at the beginning? Who winds at the end?
• Facilitation: biotic/abiotic interactions
• Early colonizers vs. Pine vs. Oak
• Grasses on sand dunes, eelgrass
• Acceleration
• Climax communities?
• Plant vs.Animal Succession?
• Intermediate Disturbance Hypothesis
• Role of fire in Chaparral Biome
Why study invasive species?
• Invasive species are the second greatest threat
to conservation of biodiversity
• economic consequences (good and bad)
• human health consequences
Invasive Species Glossary
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native: an organism that is living in its home environment
Endemic: organism that is only found in/confined to a particular location
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exotic
non-native
foreign/alien
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naturalized: a non-native that has become a part of its new
environment
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invasive: a non-native that has spread to become a dominant member
of its new environment
originally from a different location
weed: an invasive species of plant that causes
environmental or economic problems
- Noxious weed: legally designated as a pest
How do non-native
species arrive?
• Accidentally
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seeds
parasites
unintended cargo
Data source: Eurostat. Source of figure: CNT, 2004
• Deliberately
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food
timber
pets
biocontrol
Data source: US Department of Transportation, 2004
Who are these invaders?
• Plants
• Animals
• Microorganisms
What made the green
crab successful?
What makes an invader successful?
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r-strategists
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grow quickly
produce many offspring
short generation time
good dispersion
• generalists: highly adaptable to new conditions
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broad geographic range in native environment
broad diet
It has not coevolved with members of its new environment
What makes a community vulnerable to
invasion?
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human disturbance
early succession
climate similar to native habitat
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absence of predators or pathogens
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•wrong ones for the invader
•no predators or pathogens at all - islands
What do invasive plants do?
Change ecosystem structure
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fire suppression/enhancement
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grassland  shrubland
And vice-versa
Change nutrient cycling
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Spartina alterniflora
Change physical structur of landscape
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European beachgrass
use up limiting resources, such as water, light
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riparian zone  desert
woodland  kudzu-dominated land
Grassland to shrubland
Changes fire regime!
Shrubland to Grassland
Changes fire regime!
Woodland to Kudzuland
Can you guess its strategy?
Riparian zone to desert
Local Invaders: Castor Bean, Fennel
Pampasgrass, Iceplant…
What do invasive
animals do?
Change foodweb structure
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Hyperpredation
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drive out native competitors
and prey
A case study: zebra mussels
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native to Russian lakes
introduced to North America in 1985 from bilge of
a ship
after <1 year, can produce 1,000,000 eggs
large colonies clog pipes
very efficient filterers
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clear water
eliminate native species
Zebra mussel range map
Microorganisms: virus, fungi, bacteria
Invasive Plant and Animal Mutualism
+
Can an invasive be unwanted at
times, and desirable other times?
Management Options
 Do nothing
 Understand life strategy
Vulnerabilities, limiting factor
 Predict where it will invade, rate of spread,
during what time periods….
Remote sensing
Mathematical models!
 ERADICATE!
Eradication
 Physical control
 Chemical control
 Thermal control
 Biological control
Predator
Virus
Grazing
www.dailynexus.com
Coalition Drops Black Rat Poison
on Anacapa Island
- Staff Writer
Thursday, December 6, 2001
by Rebecca Turek
Biological control: lessons from
the Outback
 Cane toads
 Rabbits
1950’s: myxoma virus
1990’s: Calcivirus
 Success stories:
Schisto.
How can we avoid invasive species
and preserve biodiversity?
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“Co-habitable” land use
Land uses consistent with biota
– Give up the green lawn!
– Organic/crop rotation based agriculture (but what is the cost?)
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Habitat enhancement
Variation of landscape
Restore disturbance regimes
Re-introduction
 Laws and Regulations
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Pop Quiz!
Which plant/animal would you say is the
MOST invasive???
Questions to Ponder:
 How long do you have to inhabit an area to be a
native?
 What point in time should we restore to?
 Is fighting invasives a losing battle? What are
the costs of doing nothing?
Where is biodiversity loss most
prominent?
Conservation International: Biodiversity Hotspots
CI quantified by number of endemic plant species and threat
Assessing Biodiversity
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Indicator species: Species that are present only under
strict environmental conditions
Can be used to detect healthy/unhealthy ecosystems
Example: steelhead, certain diatoms
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Species diversity/richness: number of species in sample
-diversity: number of species within a single habitat type
-diversity: difference in species composition between habitats
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Species evenness: equality of relative abundance
Unevenness might indicate unhealthy ecosystem
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Biodiversity Index
Community
I
II
III
Robin
0.2
0.3
0.25
Relative Abundance
Mallard
Crow
Cardinal
0.2
0.2
0.2
0.07
0.1
0.5
0.25
0.25
0.25
Geese
0.2
0.03
Shannon-Wiener Biodiversity Index
Community
Robin
0.2
0.3
0.25
I
II
III
Relative Abundance
Mallard
Crow
Cardinal
0.2
0.2
0.2
0.07
0.1
0.5
0.25
0.25
0.25
H index
Geese
0.2
0.03
1.61
1.23
1.39
s
H   pi loge pi
i 1
Where:
H = the Shannon-Wiener biodiversity index
pi = proportion of each species in the sample (relative abundance)
loge = the natural log of pi
s = the number of species in the community (species richness)
H(Community II) = -(.3*ln(.3)+.07*ln(.07)+.1*ln(.1)+.5*ln(.5)+.03*ln(.03))
How to Protect Biodiversity?
 Protect Species
Endangered Species Act
Classic Fisheries Managment
 Protect Habitat
Reserves
Conservation Easements
Marine Reserves
Species Protection
 Minimum Viable Population (MVP)
 Inbreeding, genetic drift
 Genetic bottleneck
 Minimum Viable Area—habitat protection
Most genetic
diversity is
retained
Genetic
bottleneck
-Population loses much of
its genetic diversity from a
population decline
Which Species to Protect?
 Umbrella species
 Flagship species
 Keystone species
Habitat Protection: Reserves
 One large or many small?
 Shape?
 Connectivity?
SLOSS Debate: Single Large vs. Several Small
Species-area curve
Management implications:
•Small reserves:
area =
species
•As area increases, diminishing returns
To consider:
Genetic exchange
Extinction events
Edge effects
Future Pressures
Cost/Flexibility
Reserves…. Size matters!
Shape Matters too! Cores and Buffers:
Connectivity: Nodes and Corridors
Is connectivity important in MPA’s?
Habitat Conservation
Management Tools
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Conceptual diagrams
Collaboration (with stakeholders, community)
Mathematical/computer models
GIS (Geographic Information Systems)
Remote sensing
Environmental Impact Reports
The new trend……
Ecosystem Based Management (EBM)
"EBM looks at all the links among living and nonliving resources, rather than considering single issues
in isolation . . . Instead of developing a management plan for one issue . . ., EBM focuses on the
multiple activities occurring within specific areas that are defined by ecosystem, rather than political,
boundaries." US Ocean Commission Report, 2004
http://ebm.nceas.ucsb.edu/faq/definition/