intertidal zonation biological factors. 1. grazing -growth of laminaria - zone ends abruptly why?

Download INTERTIDAL ZONATION BIOLOGICAL FACTORS. 1. Grazing -growth of Laminaria - zone ends abruptly Why?

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  • Slide 1
  • INTERTIDAL ZONATION BIOLOGICAL FACTORS
  • Slide 2
  • 1. Grazing -growth of Laminaria - zone ends abruptly Why?
  • Slide 3
  • 1. Grazing Experiment done in New South Wales, Australia
  • Slide 4
  • Underwood (1980 Oecologia 46:201) Used exclusion cages 1- Open2 - Fence3 - Roof4 - Cage Grazers excluded Grazers in Normal Shade Normal
  • Slide 5
  • 1- Open2 - Fence3 - Roof4 - Cage Grazers excluded Grazers in Normal Shade Normal No growth or recruitment Recruitment but poor growth No growth or recruitment Recruitment and growth to nearly adult size Therefore - upper limit dictated by grazers
  • Slide 6
  • 2. Predation Pisaster ochraceous on Mytilus californianus
  • Slide 7
  • 2. Predation Pisaster ochraceous on Mytilus californianus
  • Slide 8
  • 2. Predation Pisaster ochraceous on Mytilus californianus Time (Years) 0246810 Height above chart datum 1.5 1.0 0.5 Pisaster removal beginsPisaster removal ends
  • Slide 9
  • 3. Competition ChthalamusSemibalanus
  • Slide 10
  • 3. Competition EHWS MTL ELWS Chthalamus zone Semibalanus zone
  • Slide 11
  • 3. Competition EHWS MTL ELWS Chthalamus zone Semibalanus zone Remove Semibalanus
  • Slide 12
  • 3. Competition EHWS MTL ELWS Chthalamus zone Semibalanus zone Remove Chthalamus
  • Slide 13
  • 3. Competition Lifted SmotheredCrushed?? 100 50 0 Source of Mortality
  • Slide 14
  • 3. Competition MHWS MTL MHWN MLWN MLWS Larval settlementEffects of physical factorsCompetition Chthamamus Semibalanus
  • Slide 15
  • 4. Larval Settlement Generalized life cycle for marine invertebrates Dispersing larva (planktonic) settle juvenile adult egg
  • Slide 16
  • 4. Larval Settlement Larval settlementFinal distribution pattern
  • Slide 17
  • 4. Larval Settlement Larval settlementFinal distribution pattern happens because of 1. Indiscriminate settlement and high mortality
  • Slide 18
  • 4. Larval Settlement Larval settlementFinal distribution pattern happens because of 1. Indiscriminate settlement and high mortality 2. Discriminate settlement and low mortality
  • Slide 19
  • 4. Larval Settlement Flustrellidra lives on Ascophyllum Hurlbut 91 - Distribution of Bryozoans
  • Slide 20
  • 4. Larval Settlement Hurlbut 91 - Distribution of Bryozoans Alcyonidium Chondrus Fucus Rock Geukensia
  • Slide 21
  • 4. Larval Settlement Hurlbut 91 - Distribution of Bryozoans Flustrellidra Ascophyllum
  • Slide 22
  • 4. Larval Settlement
  • Slide 23
  • Results Flustrellidra - larvae selectively settle on Ascophyllum - greater survivorship on Ascophyllum Alcyonidium -larvae show preferential settlement on Fucus and Chondrus - most adult colonies occur on rock
  • Slide 24
  • Summary Observed distribution and abundance temperature desiccationice wave exposure reproductive mode competition larval settlement predationsurvival grazing
  • Slide 25
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  • Slide 30

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