Lecture 9 – INTERTIDAL ZONATION BIOLOGICAL FACTORS

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<ul><li><p>Lecture 9 INTERTIDAL ZONATIONBIOLOGICAL FACTORS</p></li><li><p>reproductive modecompetitionlarval settlementpredationsurvivalgrazingBIOLOGICAL FACTORS</p></li><li><p>1. Grazing-growth of Laminaria- zone ends abruptlyWhy?</p></li><li><p>1. GrazingExperiment done in New South Wales, Australia</p></li><li><p>Underwood (1980 Oecologia 46:201)Used exclusion cages1- Open2 - Fence3 - Roof4 - CageGrazers excludedGrazers excludedGrazers inGrazers inNormalShadeShadeNormal</p></li><li><p>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</p></li><li><p>2. PredationPisaster ochraceous on Mytilus californianusR. Paine</p></li><li><p>2. PredationPisaster ochraceous on Mytilus californianus</p></li><li><p>2. PredationPisaster ochraceous on Mytilus californianusTime (Years)0246810Height above chart datum1.51.00.5Pisaster removal beginsPisaster removal ends</p></li><li><p>3. CompetitionChthalamusSemibalanus</p></li><li><p>3. CompetitionMillport, Isle of Cumbrae</p></li><li><p>3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zone</p></li><li><p>3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zoneRemove Semibalanus</p></li><li><p>3. CompetitionEHWSMTLELWSChthalamus zoneSemibalanus zoneRemove Chthalamus</p></li><li><p>3. CompetitionLifted SmotheredCrushed??100500Source of Mortality</p></li><li><p>3. CompetitionMHWSMTLMHWNMLWNMLWSLarval settlementEffects of physical factorsCompetitionChthamamusSemibalanus</p></li><li><p>Distribution of Semibalanus and ChthalamusWethey 1983. Biol.Bull. 165:330Semibalanus Chthalamus </p></li><li><p>Wethey 1983. Biol.Bull. 165:330Nahant, Mass.No ChthalamusGuilford &amp; Horse Island, Conn.Semibalanus &amp; Chthalamus coexistDistribution of Semibalanus and Chthalamus</p></li><li><p>Percent cover by each species100</p><p>50100</p><p>50100</p><p>50Tidal HeightMHWNMLWNVertical-NorthVertical-West10 Slope-SouthChthalamusSemibalanusWethey 1983. Biol.Bull. 165:330Distribution of Semibalanus and Chthalamus</p></li><li><p>100</p><p>50100</p><p>50ChthalamusSemibalanusDripDryPercent cover by each speciesTidal HeightMHWNMLWNWethey 1983. Biol.Bull. 165:330Distribution of Semibalanus and Chthalamus</p></li><li><p>Wethey 1983. Biol.Bull. 165:330Percent cover by each speciesTidal HeightMHWNMLWNChthalamusSemibalanusIncreasing sun exposureDistribution of Semibalanus and Chthalamus</p></li><li><p>Wethey 1983. Biol.Bull. 165:330Tidal HeightMHWNMLWNVertical-NorthVertical-West10 Slope-SouthChthalamusSemibalanusSettlement density ( no./cm21.0</p><p>0.52.0</p><p>1.01.0</p><p>0.5Distribution of Semibalanus and Chthalamus</p></li><li><p>4. Larval SettlementGeneralized life cycle for marine invertebratesDispersing larva (planktonic)settlejuvenileadultegg</p></li><li><p>4. Larval SettlementLarval settlementFinal distribution patternhappens because of 1. Indiscriminate settlementand high mortality2. Discriminate settlementand low mortality</p></li><li><p>4. Larval SettlementFlustrellidra lives on AscophyllumDistribution of BryozoansHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103</p></li><li><p>4. Larval SettlementHurlbut 91 - Distribution of BryozoansAlcyonidiumChondrusFucusRockGeukensiaHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103</p></li><li><p>4. Larval SettlementHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103</p></li><li><p>4. Larval SettlementHurlbut 91 - Distribution of BryozoansFlustrellidraAscophyllumHurlbut 1991. J.Exp. Mar. Biol. Ecol. 147:103</p></li><li><p>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</p></li><li><p>SummaryObserved distribution andabundancetemperaturedesiccationicewave exposure reproductive modecompetitionlarval settlementpredationsurvivalgrazing</p></li></ul>

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