Shallow Subtidal Sandy Community: Zuma Beach Jon Kastendiek, Ph'D'

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Shallow Subtidal Sandy CommunityZuma BeachJon
Kastendiek, Ph.D.
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Dendraster Community Zuma Beach
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Dendaster Suspension feeder - aboral
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Dendaster Suspension feeder - aboral
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Astropecten Predator of Renilla
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Renilla kollokeri suspension feeder
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(No Transcript)
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(No Transcript)
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Armina Predator of Renilla
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Dendraster Community Zuma Beach
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Wave Zone
Renillalt2cm
Renilla and Armina
WINTER
Dendraster
Astropecten and Renillagt4cm
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Wave Zone
SUMMER
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Wave Zone
WINTER
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Factors affecting distributions

• Physical factors
• Surge/downwelling
• Substrate type
• Depth
• Biological factors
• Predation
• Competition
• Symbioses

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Experimental Manipulations

• Physical factors

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Wave Zone
SUMMER
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Wave Zone
EXPERIMENT Transplant Dendraster
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Wave Zone
EXPERIMENT Transplant Astropecten
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Wave Zone
EXPERIMENT Remove Dendraster
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Wave Zone
EXPERIMENT Transplant Renillagt2cm
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Wave Zone
EXPERIMENT Transplant Armina
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Experimental Manipulations

• Biological factors

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Armina, Astropecten and Renilla feeding predation
synergy
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Feeding synergy between Armina and Astropecten on
Renilla (lt4cm rachis diam.)
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Wave Zone
EXPERIMENT Dendraster removal Renilla transplant
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Competition Experiments

• Controlled Field Experiments (Manipulations)

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Wave Zone
Renillalt2cm
Renilla and Armina
WINTER
Dendraster
Astropecten and Renillagt4cm
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Wave Zone
EXPERIMENT Result of Dendraster removal
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Wave Zone
EXPERIMENT Dendraster removal Renilla
transplant No further removal of
Dendraster Renilla excluded
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Wave Zone
EXPERIMENT Dendraster removal Renilla
transplant Continuous removal of
Dendraster Renilla persists
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Wave Zone
Renillalt2cm
Renilla and Armina
WINTER
Dendraster
Astropecten and Renillagt4cm
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Conclusions

• Upward distribution bound of Renilla, Astropecten
  and Dendraster dictated by physical factor of
  current/surge
• Astropecten distribution also lower due to
  competition for space with Dendraster
• Only large Renilla (gt4cm) found below Dendraster
  due to Astropecten predation
• Small Renilla (gt2cm) have refuge from predators
  in upper area due to surge

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Wave Zone
SUMMER
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Wave Zone
WINTER
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END