Rocky subtidal habitats

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Rocky subtidal habitats

• A sticky business

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Review Potential regulatory patterns in benthic
ecosystems

• Mosaic patterns
• Physical processes
• Sediment structure
• Turbulence
• Biological processes
• Bioturbation
• Larval settling
• Competition
• Predation

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Rocky outcrops differ from sediments

• Allows firm attachment of organisms
• Much less burrowing into substrate
• Turbulence affects attached organisms, less
  influence on the substrate
• Feeding from surfaces and water column
• Fewer places to hide
• Surfaces often are 100 occupied
• High local diversity

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Major components of vertical wallsfleshy
algaecoralline algaecolonial animals ascidians
gorgonianscrustaceansspongespolychaete
wormscnidarians
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Horizontal surfacescoralline red algaemussel
bedsurchins
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Encrusting algae, foliose algae, urchins
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Galapagos green sea urchins, pencil urchin
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Shoals of fish feed and use cover
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Diagrammatic View of Rocky Outcrops
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Major processes affecting diversity

• Predation
• e.g., exclosure experiments on urchins
• Competition
• access to currents for feeding (overtopping)
• Spreading and interference
• Larval settling dynamics (priority)
• Disturbance dynamics
• random events create openings
• colonization probability varies with time

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Alternate stable states for ecosystems
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Kelp attached, but photosynthetic
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Additional vertical complexity
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Rocky surfaces with little open space
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High diversity of attached organisms
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Anemone
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Otter A keystone species
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Subtidal Zonation
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Kelp microhabitats
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