IV. Contribution of larval behavior to vertical zonation patterns A) Processes affecting zonation  4 possibilities 1) Larvae may be stratified in water column (behavior or hydrodynamic effects) and land at different tidal heights Adult pattern (zonation): a a a A a A a A a a A a a a A a A a b B B b b b B B b B B b b b b b b b b

IV. Contribution of larval behavior to vertical zonation patterns A) Processes affecting zonation  4 possibilities 2) Larvae may  (1) be mixed in water column, (2) exhibit settlement behavior (3) settle within appropriate zone Adult pattern (zonation): a a a A a b b A a a A b A a a a A A a b b a b B B b a b B B b a B B b b b b b a

IV. Contribution of larval behavior to vertical zonation patterns A) Processes affecting zonation  4 possibilities 3) larvae may (1) be mixed in water column, (2) show no settlement behavior (3) settle randomly and (4) die back to appropriate zonation (post-settlement processes!) Adult pattern (zonation): a a a A b b b A a a A b A a a b A A b b a b B B b a a B B b a B a b B b b a

IV. Contribution of larval behavior to vertical zonation patterns A) Processes affecting zonation  4 possibilities 4) Individuals may move after settlement Adult pattern (zonation): a a a A b b b A a a A b A a a b A A b b a b B B b a a B B b a B a b B b b a

IV. Contribution of larval behavior to vertical zonation patterns B) Stratification of larvae in water column Grosberg 1982, senior thesis! seminal paper never repeated to my knowledge a) System: Santa Cruz harbor, 2 species of barnacle on pier pilings i) Balanus glandula – upper intertidal barnacle ii) Balanus crenatus –lower intertidal barnacle Tide height (m) -1.2 1.8 Adult Density (#/100 cm2) B. glandula B. crenatus 100 b) Pattern:

B) Stratification of larvae in water column c) Question: What causes vertical zonation? d) Hypotheses: i) HA1: early post-settlement mortality limits species distribution (sensu Connell) ii) HA2: stratification of larvae limits distribution  via behavior Tidal height e) Test: 2.1 i) HA1 early post-settlement mortality 10 x 10 cm plates Sampled weekly during a period of high settlement - allows detection of 1–7 day old individuals -1.2

B) Stratification of larvae in water column Question: What causes vertical zonation? f) Results: Settlement pattern… 1.8 Adult pattern… B. glandula Adult Density (#/100 cm2) -1.2 1.8 B. glandula B. crenatus 100 Tidal height -1.2 800 Settler density (#/100cm2) 1.8 B. crenatus -1.2 1000 Settler density (#/100cm2)

B) Stratification of larvae in water column Question: What causes vertical zonation? g) Conclusions: 1) settlement was same distribution as adults 2) not post-settlement processes causing adult distribution

B) Stratification of larvae in water column Question: What causes vertical zonation? ii) HA2: stratification of larvae limits distribution  via behavior d) Test — clever i) sampled on 3 days: new, full, half moon — plankton pulls ii) sampled hourly for 24 hour periods on each day iii) sampled from a floating dock at 4 depths: surface, 0.5 m, 1.5 m, and 3 m sampling range: -4 m to 1.8 m Time of day Tidal range sampled -4.0 1.8 surface 3m 3m depth

e) Results — differ between species: ii) HA2: stratification of larvae limits distribution  via behavior e) Results — differ between species: 1) 94% of glandula larvae taken in surface waters (irrespective of tidal sequence) 2) 98% of crenatus larvae were collected < 0 m mllw, (meaning their distribution in water column changed as a function of tide B. glandula B. crenatus Larval abundance -4.0 1.8 -4.0 1.8 1.8 surface Tidal range sampled B. glandula B. crenatus -4.0 Time of day

Larval Distribution in water column corresponds to settler and adult distribution on pilings Settlers Adults Larvae 1.8 1.8 surface B. glandula Tidal range sampled Tidal height B. crenatus -4.0 -4.0 Time of day

ii) HA2: stratification of larvae limits distribution  via behavior f) Conclusions- 1) Distribution of adults determined by position of larvae in water column 2) Larval distribution set by two different behaviors: a) B. glandula stays in surface water, which over tidal sequences travels from about -1.2 to 1.8 m (abundances correspond to time at tidal height) b) B. crenatus stays below a particular tidal level  orients to bottom?

C) Interactive effects of vertical distribution of larvae and biogenic structure on the spatial and temporal patterns of recruitment Example: Carr 1994 Ecology a) Question: Does kelp provide settlement habitat for reef fishes, and if so, does the temporal and spatial variability of kelp influence patterns of fish recruitment? b) System: Forests of giant kelp, Macrocystis pyrifera and the kelp bass, Paralabrax clathratus at Santa Catalina Island, CA

and test of first hypothesis: c) Hypothesis 1: If giant kelp influences recruitment, there will be a positive relationship between abundance of kelp and kelp bass recruits within reefs… d) Pattern: P < 0.0001 and test of first hypothesis: 30 20 Density of kelp bass recruits (No. per 60 m3 ) Greater density of kelp bass settlers in areas of a reef with giant kelp compared to areas without 10 Absent Present Macrocystis

d) Pattern: among reefs and years… 10 20 30 100 200 300 400 1 2 3 5 Macrocystis density (Stipes per 30 m2) kelp bass recruit density (Number per 60 m ) Density of kelp bass settlers increases with increasing density of giant kelp… but it is not linear!

c) Hypothesis 2: Local kelp bass recruitment should respond to manipulated density of giant kelp kelp bass recruit density: (Number / 10 m ) 2 40 80 120 160 1 3 4 5 A B kelp bass recruit density: blade biomass (gm per 5 m3 ) 500 1,000 1,500 2 4 6 (Number per 10 m2) blade biomass per reef area: Macrocystis density (stipes / 30 m2 ) A B 400 800 1,200 (grams / 10 m ) 2 40 80 120

e) Conclusions: i) Local and “regional” patterns of kelp bass recruitment are influenced by dynamics of giant kelp abundance ii) The relationship is not based strictly on plant density, but on biomass (shelter!). Because kelp biomass changes with plant density, recruitment relationship is asymptotic. iii) Giant kelp facilitates recruitment of kelp bass by providing habitat that they encounter as they pass over reefs

Settlement (post-settlement): habitat structure (1) Macrocystis (kelp bass in southern California) e.g., Carr 1994, Ecology - manipulated kelp density and monitored recruitment - greater kelp bass recruitment with increase in kelp (2) Macrocystis (kelp surfperch in so. California) e.g., Anderson 1994, MEPS manipulated presence of giant kelp canopy and monitored recruitment greater kelp perch recruitment in presence of canopy (3) Sea urchins (blue-banded goby in southern California) e.g., Hartney and Grorud 2002, Oecologia - manipulated presence of urchins and monitored recruitment e.g., Rogers-Bennet and Pearse 2001, Conserv. Biology - compared abalone recruitment in and out of MPAs with and without urchins

Coastally trapped waves Small-scale fronts, plumes, runoff Larval settlement 100 yrs PDO 1 decade Seagrass beds Kelp forests ENSO 1 year Seasonal upwelling Mesoscale eddies 1 month Temporal scale Coastally trapped waves 1 week Small-scale fronts, plumes, runoff 1 day Plankton migration Surface tides 1 hour Langmuir cells Internal waves Turbulent eddies 1 min Surface waves 1 cm 1 dm 1 m 10 m 100 m 1 km 10 km 100 km 1000 km 10000 km Linear spatial scales

V. (Early) post-settlement processes as sources of variation in recruitment a) Recall that “recruitment” estimates occur at some point subsequent to settlement b) Do post-settlement processes alter patterns of settlement and recruitment? c) Can post-settlement processes cause density-dependent mortality that would (de-couple) patterns of settlement and recruitment? d) How important are competition and predation as sources of variation in recruitment AND density-dependent mortality?

Sources of spatial and temporal variation in recruitment Post-settlement: - survival - growth - movement competition predation

Early post-settlement: competition Conspecific and interspecific resident effects e.g., Steele 1997a, Ecology - black-eyed and blue-banded gobies in So. CA - manipulated presence of adults of both - settlement of black-eyed (-) “influenced” in presence of adult conspecifics - settlement of black-eyed not influenced by presence of adult blue-banned - settlement of blue-banded (+) influenced in presence of adult conspecifics - settlement of blue-banded not influenced in presence of adult black-eyed

Sources of spatial and temporal variation in recruitment Post-settlement: - survival - growth - movement predation competition

V. (Early) post-settlement processes as sources of variation in recruitment General approach: i) To test for predator effects, manipulate presence and absence of predators ii) To test for density-dependence, manipulate density of settlers iii) To test for density dependence caused by predation, manipulate BOTH orthogonally

Early post-settlement mortality: predation black eyed goby 1.0 0.8 per-capita mortality Steele 1997 Oecologia 0.6 0.4 0.2 Note! Predators present! 0.0 kelp perch 5 10 15 Initial density kelp rockfish 1.0 Anderson 2002 Ecology 1.0 Johnson 2006 Ecology predators present predators absent 20 40 60 20 40 60 80 100

Conclusions (1) Post-settlement mortality is a source of variation in recruitment (2) Predation is an important source of post-settlement mortality (3) Predation is also a source of density-dependent mortality, which can decouple estimates of settlement and recruitment (think about this with respect to testing for recruitment limitation)

VI) Settlement, density dependence and recruitment How would this occur? if post-settlement processes act in a (complete) density-dependent manner Density-independent Density-dependent survivorship: 50% 2 10 survivorship: # adults: recruits! # adults: recruits! 50 30% 2% 100% 100 2 10 5 2 1 100 2 10 100 2 10 100 #settlers #settlers #settlers #settlers density independence: same probability of surviving regardless of density  direct relationship between settler # and recruit # density dependence: no relationship between settler # and recruit #