Limits...
Impact of herbivore identity on algal succession and coral growth on a Caribbean reef.

Burkepile DE, Hay ME - PLoS ONE (2010)

Bottom Line: On new substrates, rapid grazing by ocean surgeonfish and princess parrotfish kept communities in an early successional stage dominated by short, filamentous algae and crustose coralline algae that did not suppress coral growth.These patterns contrast with patterns from established communities not undergoing primary succession; on established substrates redband parrotfish significantly reduced upright macroalgal cover while ocean surgeonfish and princess parrotfish allowed significant increases in late successional macroalgae.The species-specific effects of herbivorous fishes suggest that a species-rich herbivore fauna can be critical in providing the resilience that reefs need for recovery from common disturbances such as coral bleaching and storm damage.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America. deron.burkepile@fiu.edu

ABSTRACT

Background: Herbivory is an important top-down force on coral reefs that regulates macroalgal abundance, mediates competitive interactions between macroalgae and corals, and provides resilience following disturbances such as hurricanes and coral bleaching. However, reductions in herbivore diversity and abundance via disease or over-fishing may harm corals directly and may indirectly increase coral susceptibility to other disturbances.

Methodology and principal findings: In two experiments over two years, we enclosed equivalent densities and masses of either single-species or mixed-species of herbivorous fishes in replicate, 4 m(2) cages at a depth of 17 m on a reef in the Florida Keys, USA to evaluate the effects of herbivore identity and species richness on colonization and development of macroalgal communities and the cascading effects of algae on coral growth. In Year 1, we used the redband parrotfish (Sparisoma aurofrenatum) and the ocean surgeonfish (Acanthurus bahianus); in Year 2, we used the redband parrotfish and the princess parrotfish (Scarus taeniopterus). On new substrates, rapid grazing by ocean surgeonfish and princess parrotfish kept communities in an early successional stage dominated by short, filamentous algae and crustose coralline algae that did not suppress coral growth. In contrast, feeding by redband parrotfish allowed an accumulation of tall filaments and later successional macroalgae that suppressed coral growth. These patterns contrast with patterns from established communities not undergoing primary succession; on established substrates redband parrotfish significantly reduced upright macroalgal cover while ocean surgeonfish and princess parrotfish allowed significant increases in late successional macroalgae.

Significance: This study further highlights the importance of biodiversity in affecting ecosystem function in that different species of herbivorous fishes had very different impacts on reef communities depending on the developmental stage of the community. The species-specific effects of herbivorous fishes suggest that a species-rich herbivore fauna can be critical in providing the resilience that reefs need for recovery from common disturbances such as coral bleaching and storm damage.

Show MeSH

Related in: MedlinePlus

Skeletal growth (mean ± SE) of corals at the end of Year 1.Data are for (A) Porites astreoides and (B) Porites porites. R  =  redband parrotfish and S  =  ocean surgeonfish. Statistics are from two-factor ANOVA. * indicates a single-herbivore treatment that differs from the mixed-herbivore treatment as determined via resampling statistics. Sample size is in parenthesis next to each treatment.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2813280&req=5

pone-0008963-g005: Skeletal growth (mean ± SE) of corals at the end of Year 1.Data are for (A) Porites astreoides and (B) Porites porites. R  =  redband parrotfish and S  =  ocean surgeonfish. Statistics are from two-factor ANOVA. * indicates a single-herbivore treatment that differs from the mixed-herbivore treatment as determined via resampling statistics. Sample size is in parenthesis next to each treatment.

Mentions: Ocean surgeonfish enhanced the growth of Porites astreoides and Porites porites by 2-3X, while redband parrotfish had no effects on either coral (Fig. 5). There was no effect of herbivore richness for the growth of either coral species. Although some Sparisoma spp. feed directly on corals [35], [36], we detected no grazing scars on either coral species while sectioning them to measure growth, suggesting negligible influence of predation on net growth in the enclosures housing redband parrotfish. Across treatments, linear regression showed significant negative correlations between total algal cover and growth of P. astreoides (slope = −0.017, r2 = 0.216, P = 0.007) and P. porites (slope = −0.14, r2 = 0.332, P = 0.001). These results are consistent with direct competition with algae leading to decreased coral growth rates in those treatments where algae became abundant.


Impact of herbivore identity on algal succession and coral growth on a Caribbean reef.

Burkepile DE, Hay ME - PLoS ONE (2010)

Skeletal growth (mean ± SE) of corals at the end of Year 1.Data are for (A) Porites astreoides and (B) Porites porites. R  =  redband parrotfish and S  =  ocean surgeonfish. Statistics are from two-factor ANOVA. * indicates a single-herbivore treatment that differs from the mixed-herbivore treatment as determined via resampling statistics. Sample size is in parenthesis next to each treatment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2813280&req=5

pone-0008963-g005: Skeletal growth (mean ± SE) of corals at the end of Year 1.Data are for (A) Porites astreoides and (B) Porites porites. R  =  redband parrotfish and S  =  ocean surgeonfish. Statistics are from two-factor ANOVA. * indicates a single-herbivore treatment that differs from the mixed-herbivore treatment as determined via resampling statistics. Sample size is in parenthesis next to each treatment.
Mentions: Ocean surgeonfish enhanced the growth of Porites astreoides and Porites porites by 2-3X, while redband parrotfish had no effects on either coral (Fig. 5). There was no effect of herbivore richness for the growth of either coral species. Although some Sparisoma spp. feed directly on corals [35], [36], we detected no grazing scars on either coral species while sectioning them to measure growth, suggesting negligible influence of predation on net growth in the enclosures housing redband parrotfish. Across treatments, linear regression showed significant negative correlations between total algal cover and growth of P. astreoides (slope = −0.017, r2 = 0.216, P = 0.007) and P. porites (slope = −0.14, r2 = 0.332, P = 0.001). These results are consistent with direct competition with algae leading to decreased coral growth rates in those treatments where algae became abundant.

Bottom Line: On new substrates, rapid grazing by ocean surgeonfish and princess parrotfish kept communities in an early successional stage dominated by short, filamentous algae and crustose coralline algae that did not suppress coral growth.These patterns contrast with patterns from established communities not undergoing primary succession; on established substrates redband parrotfish significantly reduced upright macroalgal cover while ocean surgeonfish and princess parrotfish allowed significant increases in late successional macroalgae.The species-specific effects of herbivorous fishes suggest that a species-rich herbivore fauna can be critical in providing the resilience that reefs need for recovery from common disturbances such as coral bleaching and storm damage.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America. deron.burkepile@fiu.edu

ABSTRACT

Background: Herbivory is an important top-down force on coral reefs that regulates macroalgal abundance, mediates competitive interactions between macroalgae and corals, and provides resilience following disturbances such as hurricanes and coral bleaching. However, reductions in herbivore diversity and abundance via disease or over-fishing may harm corals directly and may indirectly increase coral susceptibility to other disturbances.

Methodology and principal findings: In two experiments over two years, we enclosed equivalent densities and masses of either single-species or mixed-species of herbivorous fishes in replicate, 4 m(2) cages at a depth of 17 m on a reef in the Florida Keys, USA to evaluate the effects of herbivore identity and species richness on colonization and development of macroalgal communities and the cascading effects of algae on coral growth. In Year 1, we used the redband parrotfish (Sparisoma aurofrenatum) and the ocean surgeonfish (Acanthurus bahianus); in Year 2, we used the redband parrotfish and the princess parrotfish (Scarus taeniopterus). On new substrates, rapid grazing by ocean surgeonfish and princess parrotfish kept communities in an early successional stage dominated by short, filamentous algae and crustose coralline algae that did not suppress coral growth. In contrast, feeding by redband parrotfish allowed an accumulation of tall filaments and later successional macroalgae that suppressed coral growth. These patterns contrast with patterns from established communities not undergoing primary succession; on established substrates redband parrotfish significantly reduced upright macroalgal cover while ocean surgeonfish and princess parrotfish allowed significant increases in late successional macroalgae.

Significance: This study further highlights the importance of biodiversity in affecting ecosystem function in that different species of herbivorous fishes had very different impacts on reef communities depending on the developmental stage of the community. The species-specific effects of herbivorous fishes suggest that a species-rich herbivore fauna can be critical in providing the resilience that reefs need for recovery from common disturbances such as coral bleaching and storm damage.

Show MeSH
Related in: MedlinePlus