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Invasive species II: management

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?

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Invasive species II: management

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  1. Invasive species II:management Bio 415/615

  2. 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?

  3. What harm do invaders cause?

  4. Melaleucain S Florida • Transpiration higher • Lower water table • Hotter fire • Deeper burn in organic matter, more severe effects

  5. Invasive Plant Effects in Natural Areas Plant to Plant: Direct Effects Competition for resources, space Growth, repro. Hybridization 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

  6. Economic & other impacts to human well-being • 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?

  7. The Homogeocene • Globally, species diversity is going down. Locally, species diversity is going up. What does this mean for communities?

  8. Rahel 2000Science 288:854-856 % Introduced

  9. Rahel 2000Science 288:854-856 All Extirpations Introductions

  10. Non-indigenous birds in HawaiiLockwood 2006. Biol. Invasions 8:449-457.

  11. Invasion hypotheses:What to do? Innate biology: Weediness, competitiveness, tolerance, preadaptation: Enemy release/Biotic resistance: Community invasibility: diversity, productivity, disturbance: Availability: Rapid evolution:

  12. 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

  13. Detection Containment Eradication Prevention Exclusion Preclearance Control Other Countries USA Traditional Strategies for Invasive Species

  14. Management costs accumulate: • Prevention • Early detection, narrow window near entry point for eradication • Controlling in selected locations • Bearing the cost of change

  15. 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

  16. 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)

  17. Islands and eradication of exoticsKrajick 2005. Science 310:1410-1413.

  18. Eradication over large areas

  19. Classical Biocontrol: Cactoblastis on Opuntia Female Cactoblastis ovipositingon Opuntia, linear egg mass attached to a cactus spine Damage to Opuntia by Cactoblastis larvae,pad destroyed, plant open to infection

  20. Following this stunning success, C. cactorum has been widely used to control Opuntia spp. around the world. Before CactoblastisAfter Cactoblastis This lodged the idea of biological control of weeds in the minds of scientists and launched succeeding programs.

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