Transcript Ecosystem Effects - Plant Ecology at Syracuse

Invasive species II:
management
Bio 415/615
Questions
1. What is the ‘homogeocene’?
2. When is the best time to ‘stop’ an invader, in
terms of management cost and success?
3. Why do Barney & DiTomaso (2008
Bioscience) suggest domestication of plants
for biofuels creates a greater invasion risk
than food crop domestication?
4. What did the Cactoblastis moth do to prickly
pear cacti in Australia?
What harm do invaders cause?
Melaleuca
in S Florida
• Transpiration
higher
• Lower water table
• Hotter fire
• Deeper burn in
organic matter,
more severe
effects
Invasive Plant Effects
in Natural Areas
Plant to Plant: Direct
Competition for resources, space
Hybridization
Effects
Growth, repro.
Reproduction
Plant to Plant: Indirect
Competition for pollinators, dispersers Reproduction
Introduction of disease to native spp Survival
Ecosystem Effects
Change in Processes
Growth, repro.
Disturbance, hydrology, food webs, nutrient cycling
Economic & other impacts
to human well-being
•
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•
•
•
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Forestry, agriculture
Boating, fishing, swimming, water supply
Allergies, toxins
Fire: human life and property
Cost of control
Environmental cost of toxic chemical use
• Nature Conservancy suggests annual costs of invaders
are about 5% of world economy; in US $120billion/yr
• Land ‘infested’ with invaders take up space of CA?
The Homogeocene
• Globally, species diversity is going down.
Locally, species diversity is going up.
What does this mean for communities?
Rahel 2000
Science 288:854-856
% Introduced
Rahel 2000
Science 288:854-856
All
Extirpations
Introductions
Non-indigenous birds in Hawaii
Lockwood 2006. Biol. Invasions 8:449-457.
Invasion hypotheses:
What to do?
Innate biology: Weediness, competitiveness, tolerance, preadaptation:
Enemy release/Biotic resistance:
Community invasibility: diversity, productivity, disturbance:
Availability:
Rapid evolution:
Invasion hypotheses:
What to do?
Innate biology: Weediness, competitiveness, tolerance, preadaptation:
SOME SPP ARE INVASIVE, PROHIBIT THROUGH RISK
ASSESSMENT, DEVELOP STERILE CULTIVARS—YES
Enemy release/Biotic resistance: MANY SPP ARE INVASIVE,
ESPECIALLY THOSE WITH HIGH GROWTH RATES AND HIGH
RESOURCE DEMANDS, ASSESS ROLE OF ENEMIES—YES, but
research is demanding
Community invasibility: diversity, productivity, disturbance: SOME
COMMUNITIES ARE INVASIBLE, MANAGE AGAINST INVASION,
MANAGE AGAINST DISTURBANCE AND HIGH RESOURCE
LEVELS, MANAGE FOR HIGH NATIVE RICHNESS—SOMETIMES,
but not always feasible (disturbance, low richness, high resources are
natural, too)
Availability: MOST SPP ARE INVASIVE, REDUCE AVAILABILITY—YES
Rapid evolution: RESTRICT GENETIC DIVERSITY—YES, but seems
unlikely given horticultural interest in selection
Detection
Containment
Eradication
Prevention
Exclusion
Preclearance
Control
Other
Countries
USA
Traditional Strategies
for Invasive Species
Management costs accumulate:
• Prevention
• Early detection, narrow window near
entry point for eradication
• Controlling in selected locations
• Bearing the cost of change
Prevention: Australian Weed Risk
Assessment
Pheloung et al. (1999)
tested the WRA against
370 plants present in
Australia; rate of
rejection of invaders was
100% and rate of false
positives was low (7%)
http://www.daff.gov.au/ba/reviews/weeds/system/weed_risk_assessment
INVASIVES ARE A SMALL % OF EXOTICS
INVASIVES ARE A SMALL % OF SALES
--Florida data from Lippincott & Hall 1996
Taxa
%
Exotics in cultivation
25,000
--
Naturalized
1,000
4
Weedy
750
3
Possible natural area impacts 125
0.5
Sold in the trade today
40
0.16
Economically important
13
0.05 (33%/40)
Islands and eradication of exotics
Krajick 2005. Science 310:1410-1413.
Eradication over large areas
Classical Biocontrol: Cactoblastis on Opuntia
Female Cactoblastis ovipositing
on Opuntia, linear egg mass
attached to a cactus spine
Damage to Opuntia by Cactoblastis larvae,
pad destroyed, plant open to infection
Following this stunning success, C. cactorum has been widely
used to control Opuntia spp. around the world.
Before Cactoblastis
After Cactoblastis
This lodged the idea of biological control of weeds in the minds
of scientists and launched succeeding programs.