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Harnessing natural recovery processes to improve restoration outcomes: an experimental assessment of sponge-mediated coral reef restoration.

Biggs BC - PLoS ONE (2013)

Bottom Line: Restoration is increasingly implemented to reestablish habitat structure and function following physical anthropogenic disturbance, but scientific knowledge of effectiveness of methods lags behind demand for guidelines.Differences in overall sponge species performance suggest species selection is important to consider.Employing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes; however, best practices require techniques be tailored to each system.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, Florida, USA. Biggs@bio.fsu.edu

ABSTRACT

Background: Restoration is increasingly implemented to reestablish habitat structure and function following physical anthropogenic disturbance, but scientific knowledge of effectiveness of methods lags behind demand for guidelines. On coral reefs, recovery is largely dependent on coral reestablishment, and substratum stability is critical to the survival of coral fragments and recruits. Concrete is often used to immobilize rubble, but its ecological performance has not been rigorously evaluated, and restoration has generally fallen short of returning degraded habitat to pre-disturbance conditions. Fragments of erect branching sponges mediate reef recovery by facilitating rubble consolidation, yet such natural processes have been largely overlooked in restoring reefs.

Methods: On two reefs in Curacao, four treatments - coral rubble alone, rubble seeded with sponge fragments, rubble bound by concrete, and concrete "rubble" bound by concrete - were monitored over four years to investigate rubble consolidation with and without sponges and the ecological performance of treatments in terms of the number and diversity of coral recruits. Species specific rates of sponge fragment attachment to rubble, donor sponge growth and tissue replacement, and fragment survival inside rubble piles were also investigated to evaluate sponge species performance and determine rates for sustainably harvesting tissue. FINDINGS/SIGNIFICANCE: Rubble piles seeded with sponges retained height and shape to a significantly greater degree, lost fewer replicates to water motion, and were significantly more likely to be consolidated over time than rubble alone. Significantly more corals recruited to sponge-seeded rubble than to all other treatments. Coral diversity was also greatest for rubble with sponges and it was the only treatment to which framework building corals recruited. Differences in overall sponge species performance suggest species selection is important to consider. Employing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes; however, best practices require techniques be tailored to each system.

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Consolidation of rubble piles with and without sponges by carbonate secreting organisms.A. Sea Aquarium. B. Barracuda point. Number of unconsolidated piles is represented by light grey bars and consolidated piles by black bars. Asterisks above bars indicate significant differences (* p<0.05, ** p<0.01) in the proportion of consolidated vs. unconsolidated piles between treatments within the same site, at the same time period, by the G-test of independence. Statistical results from each comparison are provided in Table S3.
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pone-0064945-g005: Consolidation of rubble piles with and without sponges by carbonate secreting organisms.A. Sea Aquarium. B. Barracuda point. Number of unconsolidated piles is represented by light grey bars and consolidated piles by black bars. Asterisks above bars indicate significant differences (* p<0.05, ** p<0.01) in the proportion of consolidated vs. unconsolidated piles between treatments within the same site, at the same time period, by the G-test of independence. Statistical results from each comparison are provided in Table S3.

Mentions: Proportions of consolidated vs. unconsolidated rubble piles differed significantly between treatments at both sites over time (Figure 5). By month 24 at SA and 21 at BP, a greater proportion of piles of sponge seeded rubble were consolidated compared to rubble alone (G-tests, df = 1, G = 7.35, P = 0.007, and df = 1, G = 5.99, P = 0.014 for SA and BP, respectively); the same was true for each successive survey (Figure 5, Table S3). In all cases where piles of rubble alone were consolidated, each had been temporarily stabilized during the previous survey by turf algae.


Harnessing natural recovery processes to improve restoration outcomes: an experimental assessment of sponge-mediated coral reef restoration.

Biggs BC - PLoS ONE (2013)

Consolidation of rubble piles with and without sponges by carbonate secreting organisms.A. Sea Aquarium. B. Barracuda point. Number of unconsolidated piles is represented by light grey bars and consolidated piles by black bars. Asterisks above bars indicate significant differences (* p<0.05, ** p<0.01) in the proportion of consolidated vs. unconsolidated piles between treatments within the same site, at the same time period, by the G-test of independence. Statistical results from each comparison are provided in Table S3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672152&req=5

pone-0064945-g005: Consolidation of rubble piles with and without sponges by carbonate secreting organisms.A. Sea Aquarium. B. Barracuda point. Number of unconsolidated piles is represented by light grey bars and consolidated piles by black bars. Asterisks above bars indicate significant differences (* p<0.05, ** p<0.01) in the proportion of consolidated vs. unconsolidated piles between treatments within the same site, at the same time period, by the G-test of independence. Statistical results from each comparison are provided in Table S3.
Mentions: Proportions of consolidated vs. unconsolidated rubble piles differed significantly between treatments at both sites over time (Figure 5). By month 24 at SA and 21 at BP, a greater proportion of piles of sponge seeded rubble were consolidated compared to rubble alone (G-tests, df = 1, G = 7.35, P = 0.007, and df = 1, G = 5.99, P = 0.014 for SA and BP, respectively); the same was true for each successive survey (Figure 5, Table S3). In all cases where piles of rubble alone were consolidated, each had been temporarily stabilized during the previous survey by turf algae.

Bottom Line: Restoration is increasingly implemented to reestablish habitat structure and function following physical anthropogenic disturbance, but scientific knowledge of effectiveness of methods lags behind demand for guidelines.Differences in overall sponge species performance suggest species selection is important to consider.Employing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes; however, best practices require techniques be tailored to each system.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, Florida, USA. Biggs@bio.fsu.edu

ABSTRACT

Background: Restoration is increasingly implemented to reestablish habitat structure and function following physical anthropogenic disturbance, but scientific knowledge of effectiveness of methods lags behind demand for guidelines. On coral reefs, recovery is largely dependent on coral reestablishment, and substratum stability is critical to the survival of coral fragments and recruits. Concrete is often used to immobilize rubble, but its ecological performance has not been rigorously evaluated, and restoration has generally fallen short of returning degraded habitat to pre-disturbance conditions. Fragments of erect branching sponges mediate reef recovery by facilitating rubble consolidation, yet such natural processes have been largely overlooked in restoring reefs.

Methods: On two reefs in Curacao, four treatments - coral rubble alone, rubble seeded with sponge fragments, rubble bound by concrete, and concrete "rubble" bound by concrete - were monitored over four years to investigate rubble consolidation with and without sponges and the ecological performance of treatments in terms of the number and diversity of coral recruits. Species specific rates of sponge fragment attachment to rubble, donor sponge growth and tissue replacement, and fragment survival inside rubble piles were also investigated to evaluate sponge species performance and determine rates for sustainably harvesting tissue. FINDINGS/SIGNIFICANCE: Rubble piles seeded with sponges retained height and shape to a significantly greater degree, lost fewer replicates to water motion, and were significantly more likely to be consolidated over time than rubble alone. Significantly more corals recruited to sponge-seeded rubble than to all other treatments. Coral diversity was also greatest for rubble with sponges and it was the only treatment to which framework building corals recruited. Differences in overall sponge species performance suggest species selection is important to consider. Employing organisms that jump start successional pathways and facilitate recovery can significantly improve restoration outcomes; however, best practices require techniques be tailored to each system.

Show MeSH
Related in: MedlinePlus