Coral responses to macroalgal reduction and fisheries closure on Caribbean patch reefs

McClanahan, Tim R.; Huntington, Brittany; Cokos, B.

doi:10.3354/meps09285

Cited by 16 publications

(6 citation statements)

References 59 publications

(68 reference statements)

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“…The recovery of herbivores in fisheries closures may have lasting effects on coral reef functioning by influencing algal succession (Hoey & Bellwood 2011, McClanahan et al 2011b. Our data show that largebodied parrotfishes are vital in preventing dominance by un palatable macroalgae where fishing is prohibited.…”

Section: Discussionmentioning

confidence: 85%

Differential impacts of coral reef herbivores on algal succession in Kenya

Humphries¹,

McClanahan²,

McQuaid³

2014

Mar. Ecol. Prog. Ser.

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In shallow-water systems, fisheries management influences herbivory, which mediates ecosystem processes by regulating algal biomass, primary production, and competition between benthic organisms, such as algae and corals. Sea urchins and herbivorous fishes (scrapers, grazers, browsers) are the dominant herbivores in Kenya's fringing coral reef and their grazing influences coral−macroalgal dynamics and dominance. Using experimental substrata and grazer exclusions, we tested the hypothesis that herbivores differentially affect algal composition and succession using 3 levels of fisheries management: fished reefs, community-managed closures (<10 yr old, < 0.5 km 2 ), and government-managed closures (20 to 40 yr old, 5 to 10 km 2 ). In fished reefs and government closures, herbivores facilitated maintenance of early successional algal species, such as turfs, associated with sea urchins in the former and scraping fishes in the latter. Crustose coralline algae were only abundant in government closures, and video recordings showed that fish grazing was greatest at these sites, most notably for parrotfishes (scrapers). A combination of sea urchins and small grazing and detritivorous fishes was present in community closures, which allowed macroalgae to quickly develop from turf into early then late successional stages. These reefs may represent an intermediate or transitional system of herbivore dominance characterized by macroalgae. Consequently, reefs in heavily fished seascapes initially protected from fishing may require additional management efforts to facilitate the recovery of larger-bodied scraping fishes, including bans on capturing parrotfishes and restricting gear (e.g. spearguns) that target these species.

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Section: Discussionmentioning

confidence: 85%

Differential impacts of coral reef herbivores on algal succession in Kenya

Humphries¹,

McClanahan²,

McQuaid³

2014

Mar. Ecol. Prog. Ser.

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“…Increased herbivory can rapidly reduce macroalgae cover (Hughes et al ., ; Stockwell et al ., ) and, in turn, increase hard‐coral cover and drive changes in benthic communities (e.g. Australia: Hughes et al ., ; Mumby and Harborne, ; Panama and Fiji: Rasher and Hay, ; Caribbean: Olds et al ., ) (but see Stockwell et al ., ; McClanahan et al ., ; and Rasher et al ., ). Protection is expected to be particularly beneficial on reefs where both mechanisms occur.…”

Section: Introductionmentioning

confidence: 94%

How much sampling does it take to detect trends in coral‐reef habitat using photoquadrat surveys?

Molloy

Evanson

Nellas³

et al. 2013

Aquatic Conservation

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1. Coral-reef managers must detect and reverse collapses in habitat and evaluate the success of such interventions. Since these responsibilities must be met with limited time and resources, methods used should balance statistical power with practical and logistical constraints.2. Photoquadrat analysis is a commonly used method to survey coral habitats. This method, which involves photographing substratum along transects and digitally analysing habitat at points on the 'photoquadrats', affords efficiency in the field but is costly and requires extensive desk-based analysis. It remains unclear what is the optimal combination of sampling units (points, photoquadrats and transects) needed to detect important trends in coral habitat.3. Here, a dataset on Philippine coral-reef habitats, collected using intensive photoquadrat surveys, was used to explore the reliability of using different numbers of points per photoquadrat, photoquadrats per transect and transects per site to detect spatial differences in habitat.4. Results of leave-some-out analyses were compared with analysis of the complete dataset. Using fewer points per photoquadrat and fewer photoquadrats per transect caused little decline in ability to detect key trends, and lessened desk-based time; reducing the number of photoquadrats also lessened field time. Using fewer transects reduced time requirements but at the expense of statistical reliability. 5. Prospective power analyses revealed that common rates of coral recovery could not be detected using even the most intensive photoquadrat protocols. This result implies that coral recoveries within protected areas might go undetected using standard surveying techniques. 6. Using fixed rather than randomly placed photoquadrats, or more sensitive indicators of habitat recovery than coral cover (e.g. coral surface area) may improve power to detect coral recoveries. Finally, protocols that minimize desk time rarely also minimize field time and vice versa, which highlights the need to prioritize different logistical constraints when designing methods.

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“…Finally, scrapping turf and fleshy macroalgae for 10–12 days from the edge of M. annularis tissue restored hyperoxia [17]. Nonetheless, two studies [28], [29] reported that some coral species did not display positive responses (in terms of coverage, growth, fecundity and mortality) to the removal of algae.…”

Section: Discussionmentioning

confidence: 97%

Biological Responses of the Coral Montastraea annularis to the Removal of Filamentous Turf Algae

et al. 2013

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Coral reef degradation increases coral interactions with filamentous turf algae (FTA) and macroalgae, which may result in chronic stress for the corals. We evaluated the effects of short (2.5 month) and long (10 month) periods of FTA removal on tissue thickness (TT), zooxanthellae density (ZD), mitotic index (MI), and concentration of chlorophyll a (Chl a) in Montastraea annularis at the beginning and end of gametogenesis. Ramets (individual lobes within a colony) consistently surrounded by FTA and ramets surrounded by crustose coralline algae (CCA) were used as controls. FTA removal reduced coral stress, indicated by increased TT and ZD and lower MI. The measured effects were similar in magnitude for the short and long periods of algal removal. Ramets were more stressed at the end of gametogenesis compared with the beginning, with lower ZD and Chl a cm−2, and higher MI. However, it was not possible to distinguish the stress caused by the presence of FTA from that caused by seasonal changes in seawater temperature. Ramets surrounded by CCA showed less stress in comparison with ramets surrounded by FTA: with higher TT, Chl a cm−2 and ZD, and lower MI values. Coral responses indicated that ramets with FTA suffered the most deleterious effects and contrasted with those measured in ramets surrounded by CCA. According to published studies and our observations, there could be at least six mechanisms associated to FTA in the stress caused to M. annularis by FTA. Owing to the high cover of FTA (in contrast to macroalgae and CCA) in the Caribbean, the chronic stress, the overgrowth and mortality that this functional algal group can cause on M. annularis species complex, a further decline of this important reef-building coral in the Caribbean is expected.

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Coral responses to macroalgal reduction and fisheries closure on Caribbean patch reefs

Cited by 16 publications

References 59 publications

Differential impacts of coral reef herbivores on algal succession in Kenya

Differential impacts of coral reef herbivores on algal succession in Kenya

How much sampling does it take to detect trends in coral‐reef habitat using photoquadrat surveys?

Biological Responses of the Coral Montastraea annularis to the Removal of Filamentous Turf Algae

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