The functional importance of Acropora austera as nursery areas for juvenile reef fish on South African coral reefs

Floros, Camilla; Schleyer, Michael H.

doi:10.1007/s00338-016-1499-8

Cited by 7 publications

(7 citation statements)

References 53 publications

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“…While higher-level taxonomic data is more time consuming to collect, the data can be combined into functional groups if desired. Detailed benthic documentation is important even when simplified to major lifeforms, especially when results are linked to ecosystem functioning such as the critical role of plating corals in driving rapid reef recovery in the Pacific [ 60 – 62 ] and the importance of branching Acropora as a nursery habitat for juvenile fishes [ 63 ]. The attempt to make resilience assessments logistically more feasible with lower resolution data may limit the insights that can be drawn with respect to reef functioning.…”

Section: Discussionmentioning

confidence: 99%

The influence of resilience-based management on coral reef monitoring: A systematic review

2017

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With rapid changes taking place on coral reefs, managers and scientists are faced with prioritising interventions that might avoid undesirable losses in ecosystem health. The property of resilience captures how reefs react and respond to stressors and environmental changes. Therefore, in principle, management goals are more likely to be realised if resilience theory is used to inform decision making and help set realistic expectations for reef outcomes. Indeed, a new approach to reef management has been termed ‘resilience-based management’ (RBM). Yet, resilience concepts have often been criticised for being vague, difficult to operationalise, and beset by multiple definitions. Here, we evaluate how the advent of RBM has changed one aspect of reef management: assessment and monitoring. We compare the metrics used in conventional monitoring programs with those developed through resilience assessments and find that the latter have a stronger focus on ecological processes and exposure to environmental drivers. In contrast, monitoring tends to focus on metrics of reef state and has greater taxonomic resolution, which provides comprehensive information on the nature of changes but does not predict the future responses of reefs in part because it is difficult to extrapolate statistical trends of complex ecological systems. In addition, metrics measured by resilience studies are more diverse, owing in part to the reliance of state metrics as proxies of processes given the difficulty in quantifying key ecological processes directly. We conclude by describing practical ways of improving resilience assessments, and avenues for future research.

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Section: Discussionmentioning

confidence: 99%

The influence of resilience-based management on coral reef monitoring: A systematic review

2017

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“…This would have had considerable implications in the assessment of the conservation status of the coral reef, its communities and their roles in supporting ecosystem services. For example, an increase in habitat structural complexity generated by the presence of Acropora austera (ACB) has already been identified to support the diversity and abundance of the fish assemblages on South African coral reefs [78]. If representative metrics of both dispersion and central tendency are to be estimated to characterize area-density-edge metrics (i.e., LSI, LPI) for the case study area, the recommended quadrat densities provided in Table 5 are to be applied.…”

Section: Discussionmentioning

confidence: 99%

High Resolution Orthomosaics of African Coral Reefs: A Tool for Wide-Scale Benthic Monitoring

Palma¹,

Casado

Pantaleo³

et al. 2017

Remote Sensing

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Abstract:Coral reefs play a key role in coastal protection and habitat provision. They are also well known for their recreational value. Attempts to protect these ecosystems have not successfully stopped large-scale degradation. Significant efforts have been made by government and research organizations to ensure that coral reefs are monitored systematically to gain a deeper understanding of the causes, the effects and the extent of threats affecting coral reefs. However, further research is needed to fully understand the importance that sampling design has on coral reef characterization and assessment. This study examines the effect that sampling design has on the estimation of seascape metrics when coupling semi-autonomous underwater vehicles, structure-from-motion photogrammetry techniques and high resolution (0.4 cm) underwater imagery. For this purpose, we use FRAGSTATS v4 to estimate key seascape metrics that enable quantification of the area, density, edge, shape, contagion, interspersion and diversity of sessile organisms for a range of sampling scales (0.5 m × 0.5 m, 2 m × 2 m, 5 m × 5 m, 7 m × 7 m), quadrat densities (from 1-100 quadrats) and sampling strategies (nested vs. random) within a 1655 m 2 case study area in Ponta do Ouro Partial Marine Reserve (Mozambique). Results show that the benthic community is rather disaggregated within a rocky matrix; the embedded patches frequently have a small size and a regular shape; and the population is highly represented by soft corals. The genus Acropora is the more frequent and shows bigger colonies in the group of hard corals. Each of the seascape metrics has specific requirements of the sampling scale and quadrat density for robust estimation. Overall, the majority of the metrics were accurately identified by sampling scales equal to or coarser than 5 m × 5 m and quadrat densities equal to or larger than 30. The study indicates that special attention needs to be dedicated to the design of coral reef monitoring programmes, with decisions being based on the seascape metrics and statistics being determined. The results presented here are representative of the eastern South Africa coral reefs and are expected to be transferable to coral reefs with similar characteristics. The work presented here is limited to one study site and further research is required to confirm the findings.

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“…Acropora spp. and branched-coral taxa have tree-shaped carbonate skeletons that increase the structural complexity of reefs but, as erected forms, they are also the most exposed to breaks and fragmentation [2,11,12,[55][56][57]. Among the fragile group, tabular corals and free-living fungiid colonies are the most subject to breaks, for example during severe weather conditions entire colonies might be tipped over [58].…”

Section: Study Area and Experimental Designmentioning

confidence: 99%

Quantifying Coral Reef Composition of Recreational Diving Sites: A Structure from Motion Approach at Seascape Scale

et al. 2019

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Recreational diving is known to have both direct and indirect impacts on coral habitats. Direct impacts include increasing sedimentation, breaks and diseases that lead to a decrease in the richness and abundances of hard corals. Indirect impacts include urban development, land management and sewage disposal. The ecological effects of scuba diving on the spatial composition metrics of reef benthic communities are less well studied, and they have not been investigated at seascape scale. In this study, we combine orthomosaics derived from Structure from Motion (SfM) photogrammetry and data-mining techniques to study the spatial composition of reef benthic communities of recreational diving sites at seascape scale (>25 m 2 ). The study focuses on the case study area of Ponta do Ouro Partial Marine Reserve (Mozambique). Results showed that scuba-diving resistant taxa (i.e., sponges and algae) were abundant at small (>850 m 2 ) and highly dived sites (>3000 dives yr − 1 ), characterized by low diversity and density, and big organisms with complex shapes. Fragile taxa (i.e., Acropora spp.) were abundant at low (365 dives yr − 1 ) and moderately dived sites (1000–3000 dives yr − 1 ) where the greater depth and wider coral reef surfaces attenuate the abrasive effect of waves and re-suspended sediments. Highest taxa diversity and density, and lowest abundance of resistant taxa were recorded at large (>2000 m 2 ) and rarely dived sites. This study highlights the potential applications for a photogrammetric approach to support monitoring programs at Ponta do Ouro Partial Marine Reserve (Mozambique), and provides some insight to understand the influence of scuba diving on benthic communities.

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The functional importance of Acropora austera as nursery areas for juvenile reef fish on South African coral reefs

Cited by 7 publications

References 53 publications

The influence of resilience-based management on coral reef monitoring: A systematic review

The influence of resilience-based management on coral reef monitoring: A systematic review

High Resolution Orthomosaics of African Coral Reefs: A Tool for Wide-Scale Benthic Monitoring

Quantifying Coral Reef Composition of Recreational Diving Sites: A Structure from Motion Approach at Seascape Scale

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