The Effect of the Invasive Species Caulerpa taxifolia among Native Species

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The Effect of the Invasive Species Caulerpa
taxifolia among Native Species

• Lena Collins
• IROP 2007
• Wollongong, Australia

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Sydney Opera House
me
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Wollongong, Australia
http//www.tourismwollongong.com/regions/wollongon
g_map.asp
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Study Site St. Georges Basin
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Species of Interest
Anadara trapezia
Caulerpa taxifolia
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Invasive Species

• One the of largest environmental crises that we
  face today
• Exotic species are considered the second greatest
  threat to imperiled species in the United States

http//images.wri.org/photo_invasivespecies_print.
jpg
http//www.samab.org/Focus/Invasive/1PhotoGallery/
photos.html
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Before
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After
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C.tax in St. Georges Basin
http//www.fisheries.nsw.gov.au/threatened_species
/general/species/caulerpa_st_georges_basin_aug_5
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Research Objectives

• 1. Clam Recovery Experiment
• - C.taxifolia effect on predation
• - C.taxifolia effect on clam metrics
• 2. Parasite Study
• - Habitat effect on parasite damage
• - Habitat effect on clam metrics

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Part I Clam RecoveryExperiment
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Predators
Octopus
Blue Swimming Crab
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Experimental Design
Habitat Caulerpa taxifolia
Habitat bare sediment
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Results

• 22/240 clams missing
• 14 of 22 in closed cages
• Significant effect of vegetation (p0.0071)
• Artifact of collection
• Not the right season for predation study

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Results Continued

• Examine treatment effects on growth
• No significant changes in length or mass
  detected
• Bare and open treatment trended toward better
  growth
• Evidence that cages may act like C.taxifolia but
  the effect is not additive

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Australia ahhh
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Part II Parasite Study
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Dipolydora spp.1
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Network
Spot
Borehole
Blister
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Habitat Clam Metrics

• Habitat significantly affected all clam metrics
• Overall best growth occurs in unvegetated habitat

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Habitat Parasites

• Controlled for clam metrics in this analysis
• For most part, habitat did not affect variables
• Interaction did play a role in
• Network Damage
• Borehole Damage

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Conclusions

• No mortality data significant, summer study may
  result in more insightful findings
• Trend that cages are acting like C.taxifolia
• Habitat significantly affects clam metrics
• Habitat has minimal impact on parasites
• Some evidence that network parasite is more
  prevalent in C.taxifolia

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Finally

• C. taxifolia is still at large more questions
  unfold
• Hard it is to unravel the mysterious of nature
• Importance of wonder in our world

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CHEERS!

• Dr. James E. Byers!!
• Dr. Jeffery Wright
• Anna, Darcy, and Finn
• Collins family
• Mark, my lifeline