ORCID Profile
0000-0001-8490-2615
Current Organisation
University of Queensland
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Publisher: The Royal Society
Date: 17-08-2016
Abstract: Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral–algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral–algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites ) interfaces with thick turf algae, macroalgae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support the importance of water-mediated transport mechanisms in coral–algal interactions. Shifts towards algal dominance, particularly dense assemblages, may lead to thicker DBLs, higher hypoxia, and higher concentrations of harmful metabolites and pathogens along coral borders, which in turn may facilitate algal overgrowth of live corals. These effects may be mediated by flow speed and orientation.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-02-2021
Abstract: Coral reef predators are overwhelmingly sustained by offshore pelagic plankton sources rather than by reef-based sources.
Publisher: Wiley
Date: 25-07-2019
Publisher: Wiley
Date: 20-03-2019
DOI: 10.1111/JFB.13939
Abstract: The grazing behaviour of two Caribbean parrotfish, a fished species, the stoplight parrotfish Sparisoma viride and a non-fished species, the striped parrotfish Scarus iseri, were studied in the presence (fished site) and absence (marine reserve) of chronic spearfishing activity. Diurnal feeding periodicity did not differ between the sites in either species: roving in iduals had significantly higher bite rates in the afternoon, while territorial in iduals foraged consistently throughout the day. Mean bite rate varied between sites in both species. Abundance, biomass and bite rates of S. viride were all significantly higher within the reserve, except for roving S. viride which had a higher mean bite rate in the afternoon outside the reserve compared with within it, attributable to maximisation of feeding in the afternoon when fishing risk was lower. Scarus iseri mean abundance and bite rate were greater outside the reserve, potentially because reduction in large territorial herbivores allowed S. iseri to feed more rapidly. By reducing the grazing potential of the remaining S. viride in iduals the effect of fishing is greater than would be predicted from biomass changes alone. Less grazing by S. viride would not be compensated for by the increase in grazing by S. iseri because the latter feeds on different algae. Spearfishing of key parrotfish species reduces grazing potential directly by extraction and indirectly by changing behaviour.
Publisher: Wiley
Date: 09-2022
DOI: 10.1002/ECE3.9221
Abstract: Fish have one of the highest occurrences of in idual specialization in trophic strategies among Eukaryotes. Yet, few studies characterize this variation during trophic niche analysis, limiting our understanding of aquatic food web dynamics. Stable isotope analysis (SIA) with advanced Bayesian statistics is one way to incorporate this in idual trophic variation when quantifying niche size. However, studies using SIA to investigate trophodynamics have mostly focused on species‐ or guild‐level (i.e., assumed similar trophic strategy) analyses in settings where source isotopes are well‐resolved. These parameters are uncommon in an ecological context. Here, we use Stable Isotope Bayesian Ellipses in R (SIBER) to investigate cross‐guild trophodynamics of 11 reef fish species within an oceanic atoll. We compared two‐ ( δ 15 N and δ 13 C) versus three‐dimensional ( δ 15 N, δ 13 C, and δ 34 S) reconstructions of isotopic niche space for interpreting guild‐, species‐, and in idual‐level trophic strategies. Reef fish isotope compositions varied significantly among, but also within, guilds. In iduals of the same species did not cluster together based on their isotope values, suggesting within‐species specializations. Furthermore, while two‐dimensional isotopic niches helped differentiate reef fish resource use, niche overlap among species was exceptionally high. The addition of δ 34 S and the generation of three‐dimensional isotopic niches were needed to further characterize their isotopic niches and better evaluate potential trophic strategies. These data suggest that δ 34 S may reveal fluctuations in resource availability, which are not detectable using only δ 15 N and δ 13 C. We recommend that researchers include δ 34 S in future aquatic food web studies.
Publisher: Wiley
Date: 04-11-2019
DOI: 10.1002/ECE3.5779
Publisher: Springer Science and Business Media LLC
Date: 09-01-2020
DOI: 10.1007/S00227-019-3634-X
Abstract: Predators on coral reefs play an important ecological role structuring reef fish communities and are important fishery targets. It is thought that reef predator assemblages increase in density and ersity from inner lagoonal to outer edge reefs. Oceanic atolls may differ though, as nutrients are available throughout. Reef predator populations are declining, but there is little known about how their distributions may vary across oceanic atolls. Using a combination of underwater visual census and baited remote underwater video, this study aimed to compare reef predator populations between inner and outer reefs of North Malé Atoll (Mal es) and determine which reef metrics may drive any differences in assemblage structure. We found that predator assemblages were significantly different between inner and outer atoll. Body sizes of several predator families were consistently larger in the outer atoll, however, abundance, biomass and species richness were similar between outer edge reefs and inner lagoonal reefs suggesting atoll lagoons may be undervalued habitats. Depth and complexity were consistently important predictors of the predator assemblage. Inner atoll lagoonal habitat is equally as important for reef predator assemblages as outer reef slopes, although the dominant species differ. This study provides important information on reef predator populations in the Mal es, where detailed assessments of the reef predator assemblage are lacking but the reef fishery is thriving and annual catch will continue to increase.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Christina Skinner.