Xueying (Shirley) Han, R Schmitt, S Holbrook, A Brooks, T Adam University of California, Santa Barbara 7 August 2013 ESA

Disturbances  Ocean acidification  Disease outbreaks  Large storms  Global warming Herbivores  Herbivorous fishes and sea urchins  Controls macroalgae  Crucial to coral reef systems

Acanthaster planci: Crown-of-thorns starfish (COTS) outbreak February 2010 Cyclone Oli

 Decrease in fore reef coral cover from ~40% to ~3%  Decline in corallivores and coral dwellers  Increase in herbivores Adam et al. (in prep)

Habitats (3): fringing, backreef, and fore reef Sites (6): LTER1-6 Total: 18 sites Annual fish surveys: Browsers Detritivores Excavators Farmers Grazer/detritivores Scrapers

Browser—consumes standing macroalgae (e.g. Naso lituratus)

Browser—consumes standing macroalgae (e.g. Naso lituratus) Detritivore—consumes detritus (e.g. Ctenochaetus striatus)

Browser—consumes standing macroalgae (e.g. Naso lituratus) Detritivore—consumes detritus (e.g. Ctenochaetus striatus) Excavator—consumes epilithic algal turf and removes large amounts of the calcium carbonate substrata (e.g. Chlorurus sordidus)

Farmer—site-attached, territorial species that maintain algal farms (e.g. Stegastes nigricans)

Farmer—site-attached, territorial species that maintain algal farms (e.g. Stegastes nigricans) Grazer/detritivore—feeds on epilithic algal turf without scraping/excavating the substratum (e.g. Acanthurus nigrofuscus)

Farmer—site-attached, territorial species that maintain algal farms (e.g. Stegastes nigricans) Grazer/detritivore—feeds on epilithic algal turf without scraping/excavating the substratum (e.g. Acanthurus nigrofuscus) Scraper—consume epilithic algal turf and small portions of the reef substratum (e.g. Scarus psittacus)

1.How did functional groups respond on an island- wide scale? 2.Are there differences in the functional community assemblage among the three habitats? 1.Did these habitats respond similarly to the disturbance? 3.Are responses related to the initial biomass of a species?

Functional groups responded differently in both direction and magnitude.

Functional group response is not related to pre-disturbance biomass.

1.Habitats have different functional assemblages. 2.Despite difference, the response among habitats was the same—increased scrapers.

Response is not related to a species’ pre-disturbance biomass. Browser Detritivore Excavator Farmer Grazer/detritivore Scraper

1.How did functional groups respond on an island-wide scale? Herbivore functional groups responded differently Direction and magnitude of response was not related to the pre-disturbance biomass of a functional group

1.How did functional groups respond on an island-wide scale? Herbivore functional groups responded differently Direction and magnitude of response was not related to the pre-disturbance biomass of a functional group 2.Are there differences in the functional community assemblage among the three habitats? 1.Did these habitats respond similarly to the disturbance? Characteristically different functional assemblages among habitats All habitats moved towards a community with increased scrapers

1.How did functional groups respond on an island-wide scale? Herbivore functional groups responded differently Direction and magnitude of response was not related to the pre-disturbance biomass of a functional group 2.Are there differences in the functional community assemblage among the three habitats? 1.Did these habitats respond similarly to the disturbance? Characteristically different functional assemblages among habitats All habitats moved towards a community with increased scrapers 3.Are responses related to the initial biomass of a species? Differences in post-disturbance response are not related to the initial biomass of a species

Thank you!

 Background/introduction  Recent dynamics in Moorea, French Polynesia  Study site  Herbivore functional groups  Research questions  How did functional groups respond on an island-wide scale?  Are there differences in the functional community assemblage among the three habitats?  Did these habitats respond similarly to the disturbance?  Are responses related to the initial biomass of a species?