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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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Cumulative replacement of excised tissue (PVR) by sponges.A. Cumulative mean percent of tissue excised that was replaced at each 3 month period, in terms of volume, by all sponges surviving for 15 months: Aplysina cauliformis (N = 29), Aplysina sp. (N = 34), Niphates erecta (N = 39). Standard error bars are shown. Aplysina cauliformis and Aplysina sp. replaced tissue significantly (P<0.05) more rapidly than N. erecta (determined by pairwise comparison of means with Bonferroni correction) (See Table S4).
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pone-0064945-g007: Cumulative replacement of excised tissue (PVR) by sponges.A. Cumulative mean percent of tissue excised that was replaced at each 3 month period, in terms of volume, by all sponges surviving for 15 months: Aplysina cauliformis (N = 29), Aplysina sp. (N = 34), Niphates erecta (N = 39). Standard error bars are shown. Aplysina cauliformis and Aplysina sp. replaced tissue significantly (P<0.05) more rapidly than N. erecta (determined by pairwise comparison of means with Bonferroni correction) (See Table S4).

Mentions: Each species replaced tissue severed from branch tips, though the congeners A. cauliformis and Aplysina sp. were most adept. Twelve months after excision, A. cauliformis and Aplysina sp. had, on average, replaced the entire volume of tissue excised (Figure 7). Fifteen months post excision, N. erecta individuals had, on average, managed to replace only 71%, and lagged well behind A. cauliformis and Aplysina sp. (Figure 7). Percent volume replaced (PVR) over the fifteen month period differed significantly among species (LME, F 2, 158 = 6.85, P = 0.001), with the congeners A. cauliformis and Aplysina sp. replacing tissue significantly (P<0.05) more rapidly over time than N. erecta (Table S4). The interaction between species and log transformed initial volume as well as the fixed effect of log transformed initial volume failed to survive the model selection process.


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

Biggs BC - PLoS ONE (2013)

Cumulative replacement of excised tissue (PVR) by sponges.A. Cumulative mean percent of tissue excised that was replaced at each 3 month period, in terms of volume, by all sponges surviving for 15 months: Aplysina cauliformis (N = 29), Aplysina sp. (N = 34), Niphates erecta (N = 39). Standard error bars are shown. Aplysina cauliformis and Aplysina sp. replaced tissue significantly (P<0.05) more rapidly than N. erecta (determined by pairwise comparison of means with Bonferroni correction) (See Table S4).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0064945-g007: Cumulative replacement of excised tissue (PVR) by sponges.A. Cumulative mean percent of tissue excised that was replaced at each 3 month period, in terms of volume, by all sponges surviving for 15 months: Aplysina cauliformis (N = 29), Aplysina sp. (N = 34), Niphates erecta (N = 39). Standard error bars are shown. Aplysina cauliformis and Aplysina sp. replaced tissue significantly (P<0.05) more rapidly than N. erecta (determined by pairwise comparison of means with Bonferroni correction) (See Table S4).
Mentions: Each species replaced tissue severed from branch tips, though the congeners A. cauliformis and Aplysina sp. were most adept. Twelve months after excision, A. cauliformis and Aplysina sp. had, on average, replaced the entire volume of tissue excised (Figure 7). Fifteen months post excision, N. erecta individuals had, on average, managed to replace only 71%, and lagged well behind A. cauliformis and Aplysina sp. (Figure 7). Percent volume replaced (PVR) over the fifteen month period differed significantly among species (LME, F 2, 158 = 6.85, P = 0.001), with the congeners A. cauliformis and Aplysina sp. replacing tissue significantly (P<0.05) more rapidly over time than N. erecta (Table S4). The interaction between species and log transformed initial volume as well as the fixed effect of log transformed initial volume failed to survive the model selection process.

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