1. Larval production 4. Post-settlement

Transcription

1 V. Fctors ffecting recruitment 2. Lrvl dispersl 3. Settlement 1. Lrvl production 4. Post-settlement

2 V. Fctors ffecting recruitment B) Lrvl delivery Wht influences the fte of propgule production? 1) Survivl - they cn t get there if they don t survive! 2) Dispersl (dvection) smll nd lrge-scle processes tht effect trnsport 3) Depletion (y settlement) - fewer ville s they settle elsewhere

3 Processes ffecting lrvl delivery to hitt 1. Vrile production i) species trits ii) environmentl vrition (in productivity) 2. Physicl ocenogrphic processes i) iogeogrphic scle (mjor currents) ii) intermedite scle processes ) Locl currents (leewrd vs. windwrd side of islnds) 3. Episodic events - storms

4 V. Fctors ffecting recruitment B. Lrvl delivery iv. Lrvl depletion - ecologicl filters Gines nd Roughgrden 1987 Science Pttern: from yer-to-yer, recruitment of B. glndul ws negtively correlted with kelp undnce offshore rncle recruitment (no. / cm 2 / wk) kelp cnopy re (m 2 ) ð kelp or something ssocited with it my ffect settlement supply? A1) Hypothesis: if delivery is eing limited y kelp, lrvl undnce should e lower on inside edge of kelp ed thn outside it No. Current competent lrve per hr S h o r e X inshore K e l p X offshore inshore offshore

5 iv) Lrvl depletion - ecologicl filters Test A : smple lrvl concentrtions with plnkton pump inshore nd offshore of kelp ed Results A : i) Cyprid lrve - the settlement stge for rncles - re 70 times greter concentrtion offshore thn inshore! No. competent lrve per hr ii) Nuplius lrve - pre-settlement stge - relesed y dults = opposite pttern! S h o r e nuplii K e l p cyprids No. competent lrve per hr inshore inshore offshore offshore

6 iv) Lrvl depletion - ecologicl filters New Pttern! New Hypotheses B : 1) simple hydrodynmic effects of kelp i) wter slows down prticles sink ii) get entrined in (or settle on) kelp 2) predtion y kelp-ssocited plnktivores No. competent lrve per hr inshore offshore Test B : looked t distriution of prticles tht were sme size nd shpe s rncle lrve ut tht were not living or edile = molts of lrvl rncles! Results B : No difference! Suggests predtion is responsile ecuse only edile things were ffected. No. cyprid molts Per volume inshore offshore

7 iv) Lrvl depletion - ecologicl filters (predtion) Gines nd Roughgrden 1987 Science New hypothesis C : Predtion y juvenile rockfish filters cyprids Test C : Looked t the reltionship etween undnce of juvenile rockfish (Sestes) nd Blnus glndul recruitment over three yer period. Yer rockfish density # oserved / min Blnus recruitment #/cm 2 kelp ed re (m 2 ) , , ,500 Results C : Rockfish hypothesis not rejected ut chnge in kelp ed size complictes the interprettion it

8 iv) Lrvl depletion ecologicl filters recruitment shdow Gines et l Oecologi ) Hypothesis: s th of lrve pss over site, settlement cuses there to e decrese in the # of lrve ville to settlement down current: propgules I II III ) Predictions: 1) cyprid concentrtion should decrese with distnce 2) settlement should decrese c) Tests: 1) counted cyprid concentrtion (supply) in wter column 2) followed settlement t Hopkins Mrine Sttion t three sites long unidirectionl current

9 iv) Lrvl depletion ecologicl filters d) Results: recruitment shdow Gines et l Oecologi cyprid concentrtion settlement rtes #/cm 2 /dy I II III site I II III site Results were consistent with lrvl depletion hypothesis, ut other hypotheses not rejected (ssumption tht chnge in cyprid # = depletion) Prticulrly likely lterntive: hydrodynmic -- difference in cyprid # cused y hydrodynmic resons (e.g., greter wter movement/exchnge t site 1 more wter more cyprids more settlement)

10 V. Processes ffecting lrvl supply to hitt 1. Vrile production i) species trits ii) environmentl vrition (in productivity) 2. Physicl ocenogrphic processes i) iogeogrphic scle (mjor currents) ii) intermedite scle processes ) Locl currents (leewrd vs. windwrd side of islnds) 3. Episodic events - storms 4. Mortlity nd Depletion i) rockfish predtion ii) or hydrodynmic influence of kelp iii) lrvl depletion

11 V. Fctors ffecting recruitment 2. Lrvl dispersl 3. Settlement 1. Lrvl production 4. Post-settlement

12 V) Fctors ffecting recruitment C) Processes ffecting settlement 1) Physicl processes (e.g., turulence, current speed) 2) Lrvl ehvior I) types II) history of lrvl ehvior studies - rncles III) conditions for evolution of ehviorl cues (settlement) IV) contriution to verticl zontion

13 C) Processes ffecting settlement 1) Physicl processes (e.g., turulence, current speed) Increses in velocity or turulence cn either enhnce or decrese settlement, depending on the species or experiment Flumes, field experiments, models used to test effects of flow Turulence cn increse resuspension or fcilitte ttchment

14 C) Processes ffecting settlement 1) Physicl processes (e.g., turulence, current speed) Pttern: Turulence increses in pproprite hitt for lrvl settlement Hypothesis: Turulence is used s cue for settlement Turulence Brin Gylord et l. PNAS 2013;110:

15 C) Processes ffecting settlement System: Purple se urchin Key stges in the life cycle of the purple se urchin s individuls trnsit etween open ocen nd shoreline hitts. Pluteus Lrve Brin Gylord et l. PNAS 2013;110:

16 C) Processes ffecting settlement System: Purple se urchin Echinoderm metmorphosis

17 Test: Exposed pluteus lrve to turulence levels comprle to field (recreted in the l) nd then try to settle Brin Gylord et l. PNAS 2013;110:

18 Results: Settlement higher in lrve exposed to turulence Turulent flows in the shllow surf zone cn ct s cue to induce metmorphosis nd settlement Brin Gylord et l. PNAS 2013;110:

19 V) Fctors ffecting recruitment C) Processes ffecting settlement 1) Physicl processes (e.g., turulence, current speed) 2) Lrvl ehvior I) types II) history of lrvl ehvior studies - rncles III) conditions for evolution of ehviorl cues (settlement) IV) contriution to verticl zontion

20 Lrvl Behvior à Pre-settlement à Settlement I. Some types of lrvl ehvior ) Phototxis response to light (e.g., ryozons, corls, fish) ) Geotxis swim up or swim down (mny inverts nd fish) c) Rheotxis currents (mny inverts nd fish) d) Rugotxis surfce texture (inverts, not fish) e) Chemotxis wter or surfce chemistry (inverts nd fish)

21 II. Erly work on lrvl ehvior (mostly rncles) Reserch on ehvior hd golden ge ( ) when it received lot of ttention nd gret dvnces (e.g., Crisp, Knight Jones, Rylnd (ryozons), Brnes) Most of the work ws motivted y field oservtions ut generlly done in l with field collected or cultured lrve Exmple 1: Gregrious settlement Knight Jones 1953 ) Pttern: Brncle ggregtions on shoreline seemed to e species-specific (like settled next to like)

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23 Exmple 1: Gregrious settlement Knight Jones 1953 ) Pttern: Limited mixing mong 3 species of rncles ) Hypothesis: Gregrious settlement response is species specific (i.e., conspecific fcilittion ) c) Test: In lortory quri, presented cyprids (rncle lrve) with choice of settling on surfces with either: 1) dults of own species, or 2) nother species, or 3) no rncles

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25 d) Results. 2 generl results! Settlement of: (1) B. lnoides (2) B. crentus (3) E. modestus % settlement Surfce with dults of: I 2 0 I 2 0 I 3 0 1) Strong conspecific ttrction 2) No settlement in sence of rncles e) Conclusions: 18 i.e. no settlement without some sort of cue (inducer)! 1) Settlement much greter in presence of inducer 2) Inducer is species-specific ( gregrious) 15

26 Why settle gregriously? Benefits: 1) Indictes good hitt 2) Benefit in numers (e.g., swmp predtors) 3) Higher likelihood of finding mtes fertiliztion, reproductive success But, wht is the reltionship etween gregrious settlement nd post-settlement growth nd mortlity? (wht does gregrious ehvior do minimize distnce to nerest neighor) post-settlement growth, survivorship Distnce etween neighors Distnce etween neighors

27 Exmple 2: Territorility t settlement - Crisp 1960 ) Species: Blnus lnoides ) Pttern: 1) just showed tht B. lnoides settle gregriously 2) however, t smller sptil scle, individuls seem to e spced out more thn expected y purely gregrious settlement. c) Hypothesis: pttern of settlement t smller sptil scle different from gregrious

28 3 types of distriutions re possile generted y 3 ehviorl mechnisms: Dispersion: clumped rndom uniform Mechnism: gregriousness no ehvior territorility

29 d) Test: smpled settlement distriution of B. lnoides to test for these predicted frequency distriutions of distnce % frequency of occurrence clumped rndom uniform short distnce to nerest neighor (mm) fr

30 d) Test: smpled settlement distriution of B. lnoides to test for these predicted frequency distriutions of distnce % frequency of occurrence clumped rndom uniform short distnce to nerest neighor (mm) fr e) Results: normlly distriuted frequency distriution uniform f) Conclusions: Territoril ehvior t settlement - cked up w/oservtions of lrve settling in the l.

31 Exmple 3) Fcilittive settlement in corl reef fishes Anderson et l MEPS ) System: lue dmselfish, Chromis cyne on corl reefs ) Pttern: highly ggregted distriution, especilly recently settled juveniles c) Hypothesis: ggregtions creted y fcilittive settlement: ehviorl preference to settle with resident conspecifics d) Test: estlish different densities of resident individuls nd determine if settlement rte increses with resident density level

32 e) Results: 1) No settlement in sence of resident dults or recruits 2) Strong positive reltionship etween settlement rte nd numer of residents Men no. settlers / Men corl no. settlers hed / hed Present Asent Residents Present Residents Asent f) Conclusion: Conspecific residents fcilitte settlement Cumultive no. settlers / hed Cumultive no. settlers / corl hed Men no. residents / hed Men # residents / corl hed

33 C) Processes ffecting settlement 2) Lrvl ehvior III. The evolution of ehviorl cues (for settlement) ) Utility of ehviorl cues lrvl period criticl reloction fter settlement is difficult or impossile life-long fitness consequences consequence of settlement i) indictes good hitt / conditions for the species ii) fcilittes reproduction (prticulrly) for individuls tht re sessile iii) sfety in numers (e.g., swmping predtors) ) Why not lwys hve cues? costs

34 ) Why not lwys hve cues? two kinds of costs (mistkes) 1) cue is in inpproprite leds to settlement in inpproprite conditions 2) plces without cue re in fct pproprite think out corl heds without lue chromis = deth cost of mistke (not using cue) high high Proility of evolving response to cue low low low reliility of cue high

35 Given i) the costs of dpting to inpproprite cues, ii) how mny species exhiit this ehvior to so mny different kinds of cues iii) the implied strength of selection for these ehviorl responses iv) the importnce of settlement s life-long consequence for fitness (especilly for sessile species) then settlement must e n extremely importnt stge in the life cycle of mrine orgnism. Cn ll this ehvior t settlement contriute to those ptterns tht drove ecologists to study intertidl ecology (i.e. ptterns of zontion)?

36 V) Fctors ffecting recruitment C) Processes ffecting settlement 1) Physicl processes (e.g., turulence, current speed) 2) Lrvl ehvior I) types II) history of lrvl ehvior studies - rncles III) conditions for evolution of ehviorl cues (settlement) IV) contriution to verticl zontion

37 IV. Contriution of lrvl ehvior to verticl zontion ptterns A) Processes ffecting zontion 4 possiilities 1) lrve my (1) e mixed in wter column, (2) show no settlement ehvior (3) settle rndomly nd (4) die ck to pproprite zontion (post-settlement processes!) Adult pttern (zontion): A A A A A A B B B B B B

38 IV. Contriution of lrvl ehvior to verticl zontion ptterns A) Processes ffecting zontion 4 possiilities 2) Individuls my move fter settlement Adult pttern (zontion): A A A A A A B B B B B B

39 IV. Contriution of lrvl ehvior to verticl zontion ptterns A) Processes ffecting zontion 4 possiilities 3) Lrve my (1) e mixed in wter column, (2) exhiit settlement ehvior (3) settle within pproprite zone Adult pttern (zontion): A A A A A A B B B B B B

40 IV. Contriution of lrvl ehvior to verticl zontion ptterns A) Processes ffecting zontion 4 possiilities 4) Lrve my e strtified in wter column (ehvior or hydrodynmic effects) nd lnd t different tidl heights Adult pttern (zontion): A A A A A A B B B B B B

41 IV. Contriution of lrvl ehvior to verticl zontion ptterns B) Strtifiction of lrve in wter column Groserg 1982, senior thesis! ) System: Snt Cruz hror, 2 species of rncle on pier pilings i) Blnus glndul upper intertidl rncle ii) Blnus crentus lower intertidl rncle ) Pttern: Tide height (m) B. glndul Adult Density (#/100 cm 2 ) B. crentus

42 B) Strtifiction of lrve in wter column c) Question: Wht cuses verticl zontion? d) Hypotheses: i) H A1 : erly post-settlement mortlity limits species distriution (sensu Connell) ii) H A2 : strtifiction of lrve limits distriution vi ehvior e) Test: i) H A1 erly post-settlement mortlity Tidl height x 10 cm pltes Smpled weekly during period of high settlement - llows detection of 1 7 dy old individuls -1.2

43 Tidl height B) Strtifiction of lrve in wter column Question: Wht cuses verticl zontion? f) Results: Adult pttern B. glndul B. crentus Adult Density (#/100 cm 2 ) Settlement pttern B. glndul 800 Settler density (#/100cm 2 ) B. crentus Settler density (#/100cm 2 )

44 B) Strtifiction of lrve in wter column Question: Wht cuses verticl zontion? g) Conclusions: 1) settlement ws sme distriution s dults 2) not post-settlement processes cusing dult distriution

45 B) Strtifiction of lrve in wter column Question: Wht cuses verticl zontion? ii) H A2 : strtifiction of lrve limits distriution vi ehvior d) Test clever i) smpled on 3 dys: new, full, hlf moon plnkton pulls ii) smpled hourly for 24 hour periods on ech dy iii) smpled from floting dock t 4 depths: surfce, 0.5 m, 1.5 m, nd 3 m 1.8 Tidl rnge smpled smpling rnge: -4 m to 1.8 m surfce 3m 3m depth -4.0 Time of dy

46 ii) H A2 : strtifiction of lrve limits distriution vi ehvior e) Results differ etween species: 1) 94% of glndul lrve tken in surfce wters (irrespective of tidl sequence) 2) 98% of crentus lrve were collected < 0 m mllw, (mening their distriution in wter column chnged s function of tide) Lrvl undnce B. glndul B. crentus Tidl rnge smpled -4.0 Time of dy surfce B. glndul B. crentus

47 ii) H A2 : strtifiction of lrve limits distriution vi ehvior f) Conclusions- 1) Distriution of dults determined y position of lrve in wter column 2) Lrvl distriution set y two different ehviors: ) B. glndul stys in surfce wter, which over tidl sequences trvels from out -1.2 to 1.8 m (undnces correspond to time t tidl height) ) B. crentus stys elow prticulr tidl level orients to ottom?