Lecture 9 – INTERTIDAL ZONATION BIOLOGICAL FACTORS

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Lecture 9 INTERTIDAL ZONATION BIOLOGICAL FACTORS. BIOLOGICAL FACTORS. grazing. competition. larval settlement. survival. reproductive mode. predation. 1. Grazing. -growth of Laminaria - zone ends abruptly. Why?. 1. Grazing. Experiment done in New South Wales, Australia. - PowerPoint PPT Presentation

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  • Lecture 9 INTERTIDAL ZONATIONBIOLOGICAL FACTORS

  • reproductive modecompetitionlarval settlementpredationsurvivalgrazingBIOLOGICAL FACTORS

  • 1. Grazing-growth of Laminaria- zone ends abruptlyWhy?

  • 1. GrazingExperiment done in New South Wales, Australia

  • Underwood (1980 Oecologia 46:201)Used exclusion cages1- Open2 - Fence3 - Roof4 - CageGrazers excludedGrazers excludedGrazers inGrazers inNormalShadeShadeNormal

  • 1- Open2 - Fence3 - Roof4 - CageGrazers excludedGrazers excludedGrazers inGrazers inNormalShadeShadeNormalNo growth or recruitmentRecruitment but poor growthNo growth or recruitmentRecruitment and growth to nearly adult sizeTherefore - upper limit dictated by exposure + grazers

  • 2. PredationPisaster ochraceous on Mytilus californianusR. Paine

  • 2. PredationPisaster ochraceous on Mytilus californianus

  • 2. PredationPisaster ochraceous on Mytilus californianusTime (Years)0246810Height above chart datum1.51.00.5Pisaster removal beginsPisaster removal ends

  • 3. CompetitionChthalamusSemibalanus

  • 3. CompetitionMillport, Isle of Cumbrae

  • 3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zone

  • 3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zoneRemove Semibalanus

  • 3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zoneRemove Chthalamus

  • 3. CompetitionLifted SmotheredCrushed??100500Source of Mortality

  • 3. CompetitionMHWSMTLMHWNMLWNMLWSLarval settlementEffects of physical factorsCompetitionChthamamusSemibalanus

  • Distribution of Semibalanus and ChthalamusWethey 1983. Biol.Bull. 165:330Semibalanus Chthalamus

  • Wethey 1983. Biol.Bull. 165:330Nahant, Mass.No ChthalamusGuilford & Horse Island, Conn.Semibalanus & Chthalamus coexistDistribution of Semibalanus and Chthalamus

  • Percent cover by each species100

    50100

    50100

    50Tidal HeightMHWNMLWNVertical-NorthVertical-West10 Slope-SouthChthalamusSemibalanusWethey 1983. Biol.Bull. 165:330Distribution of Semibalanus and Chthalamus

  • 100

    50100

    50ChthalamusSemibalanusDripDryPercent cover by each speciesTidal HeightMHWNMLWNWethey 1983. Biol.Bull. 165:330Distribution of Semibalanus and Chthalamus

  • Wethey 1983. Biol.Bull. 165:330Percent cover by each speciesTidal HeightMHWNMLWNChthalamusSemibalanusIncreasing sun exposureDistribution of Semibalanus and Chthalamus

  • Wethey 1983. Biol.Bull. 165:330Tidal HeightMHWNMLWNVertical-NorthVertical-West10 Slope-SouthChthalamusSemibalanusSettlement density ( no./cm21.0

    0.52.0

    1.01.0

    0.5Distribution of Semibalanus and Chthalamus

  • 4. Larval SettlementGeneralized life cycle for marine invertebratesDispersing larva (planktonic)settlejuvenileadultegg

  • 4. Larval SettlementLarval settlementFinal distribution patternhappens because of 1. Indiscriminate settlementand high mortality2. Discriminate settlementand low mortality

  • 4. Larval SettlementFlustrellidra lives on AscophyllumDistribution of BryozoansHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103

  • 4. Larval SettlementHurlbut 91 - Distribution of BryozoansAlcyonidiumChondrusFucusRockGeukensiaHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103

  • 4. Larval SettlementHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103

  • 4. Larval SettlementHurlbut 91 - Distribution of BryozoansFlustrellidraAscophyllumHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103

  • 4. Larval SettlementResultsFlustrellidra larvae selectively settle on Ascophyllum greater survivorship on AscophyllumAlcyonidiumlarvae show preferential settlement on Fucus and Chondrus most adult colonies occur on rockHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103

  • SummaryObserved distribution andabundancetemperaturedesiccationicewave exposure reproductive modecompetitionlarval settlementpredationsurvivalgrazing

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