Kelp Forest Zonation Canopy Understory Inshore Kelp Canopy (Z1) Algal Turf Offshore (Z3)

Phyllospadix Egregia Macrocystis Nereocystis Laminaria

A. Canopy Assemblages (isopods, tubeworms, hydrozoans and bryozoans) B. Planktonic Assemblages (jellyfish, fish larvae, diatoms, and crustaceans). C. Holdfast Assemblages (sea urchins, crustaceans, brittle stars, and sea anemones) D. Horizontal Substrate Assemblages (urchins, sea stars, algae, tunicates, and bottom fish). E. Vertical Wall Assemblages (coralline algae, anemones, cup corals, sponges, and bryozoans)

Canopy Plankton Holdfast Community

Vertical Wall Horizontal Surface

Ecological Relationships in Kelp Forests Orca Sea Otter Urchins

Ecological Relationships in Kelp Forests - Aleutian Archipelago Adak Island

Ecological Relationships in Kelp Forests - Aleutian Archipelago Otter # 1972 1997

Ecological Relationships in Kelp Forests - Aleutian Archipelago Otter # Urchin Biomass 1972 1997

Ecological Relationships in Kelp Forests - Aleutian Archipelago Otter # Urchin Biomass Grazing Intensity 1972 1997

Ecological Relationships in Kelp Forests - Aleutian Archipelago Otter # Urchin Biomass Grazing Intensity Kelp Density 1972 1997

Kelp settlement and mature Mortality of Kelp - Effect of El Niño event Recovery of community (Ebeling et al., 1985) Original situation - Macrocystis canopy, understory kelp (Pterygophora) - urchins S. purpuratus & S. franciscanus feed in crevices on drift kelp Destroyed kelp (Macrocystis) canopy but left understory kelp Storm 1 Reduction in drift kelp used by urchins Urchins forage in open on understory kelp Kelp settlement and mature forest (1 year) Urchins destroy remaining kelp Storm 2 Kills urchins and left bare rock

Mortality of Kelp - Effect of El Niño event Other El Niño Effects -rip up holdfasts  no vegetative growth -high water temperature  retards growth -reduction in nitrogen  retards growth

General Model for Maintenance of Barrens and Kelp areas Low drift abundance High grazing activity Low grazing activity High drift abundance Low algal recruitment High algal recruitment Low standing stock of attached algae High standing stock of attached algae Severe storms Low nutrient Warm temperatures Benign storms High nutrient Low temperatures STABLE STATES

General Model for Maintenance of Barrens and Kelp areas Barren Ground Kelp Forest - created by urchin grazing -abundant drift kelp -little drift kelp - urchins remain in crevices - urchins actively forage Recruitment of kelp Effect of urchins due to a change in behaviour not numbers Harold & Reed, 1985

General Model for Maintenance of Barrens and Kelp areas Effect of urchins due to a change in behaviour not numbers Harold & Reed, 1985

General Model for Maintenance of Barrens and Kelp areas Harold & Reed, 1985

Small herbivorous fish & invertebrates Kelp Forest Food Web (with otters) Sharks Larger fish & octopus Sea otter Larger crabs Sea stars Abalone Smaller predatory Fish and invertebrates Sea urchins Drift algae & dead animals Small herbivorous fish & invertebrates Sessile invertebrates Planktonic invertebrates Kelp and other algae Planktonic algae

Small herbivorous fish & invertebrates Kelp Forest Food Web (without otters) Sharks Larger fish & octopus Sea otter Larger crabs Sea stars Abalone Smaller predatory Fish and invertebrates Sea urchins Drift algae & dead animals Small herbivorous fish & invertebrates Sessile invertebrates Planktonic invertebrates Kelp and other algae Planktonic algae

Kelp Forest Productivity 50 40 30 20 10 3.0 2.5 2.0 1.5 1.0 0.5 Producer Biomass Kg/m2 Annual Net Production Kg/m2/yr Litter Mass Kg/m2/yr Tropical Rain Forest Tropical Seasonal Forest Evergreen Forest Deciduous Forest Boreal Forest Kelp Forest

Kelp Forest Productivity SUSPENSION FEEDERS Mussel Soft coral Barnacle Sea Anemone Rock Jingle Mysid DETRITIVORES Amphipod Crab PREDATORS Rock greenling Sea star Cormorant 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Percent of Kelp Derived Carbon

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