scholarly journals Habitat complexity influences the structure of food webs in Great Barrier Reef seagrass meadows

Ecosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
Author(s):  
Kristin I. Jinks ◽  
Christopher J. Brown ◽  
Michael A. Rasheed ◽  
Abigail L. Scott ◽  
Marcus Sheaves ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Food Webs ◽  
Habitat Complexity ◽  
Barrier Reef ◽  
Seagrass Meadows

scholarly journals Spatial and Temporal Patterns in Macroherbivore Grazing in a Multi-Species Tropical Seagrass Meadow of the Great Barrier Reef

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 12
Author(s):  
Abigail L. Scott ◽  
Paul H. York ◽  
Michael A. Rasheed
Keyword(s):  
Great Barrier Reef ◽  
Large Scale ◽  
Barrier Reef ◽  
Important Process ◽  
Spatial And Temporal Patterns ◽  
Video Cameras ◽  
Seagrass Meadows ◽  
One Year ◽  
The Impact ◽  
Green Island

Macroherbivory is an important process in seagrass meadows worldwide; however, the impact of macroherbivores on seagrasses in the Great Barrier Reef (GBR) has received little attention. We used exclusion cages and seagrass tethering assays to understand how the intensity of macroherbivory varies over space and time in the seagrass meadows around Green Island (Queensland), and what impact this has on overall meadow structure. Rates of macroherbivory were comparatively low, between 0.25–44% of daily seagrass productivity; however, rates were highly variable over a one-year period, and among sites. Loss of seagrass material to macroherbivory was predominantly due to fish; however, urchin herbivory was also taking place. Macroherbivory rates were of insufficient intensity to impact overall meadow structure. No macroherbivory events were identified on video cameras that filmed in the day, indicating that feeding may be occurring infrequently in large shoals, or at night. While relatively low compared to some meadows, seagrass macroherbivory was still an important process at this site. We suggest that in this highly protected area of the GBR, where the ecosystem and food webs remain largely intact, macroherbivory was maintained at a low level and was unlikely to cause the large-scale meadow structuring influence that can be seen in more modified seagrass systems.

The effects of marine reserve protection on the trophic relationships of reef fishes on the Great Barrier Reef

2003 ◽  
Vol 30 (2) ◽  
pp. 200-208 ◽  
Author(s):  
N.A.J. Graham ◽  
R.D. Evans ◽  
G.R. Russ
Keyword(s):  
Coral Reef ◽  
Great Barrier Reef ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Habitat Complexity ◽  
Prey Species ◽  
Marine Reserve ◽  
Trophic Relationships ◽  
Barrier Reef ◽  
Prey Fish

What are the effects of no-take marine reserves on trophic relationships of coral reef fish? Previous studies often have lacked detailed dietary information on major predators, and have often been confounded by differences in habitat complexity between reserve and fished sites. This study investigates the effects of marine reserve protection on predator-prey interactions of coral reef fish on the inshore islands of the Great Barrier Reef (GBR). The abundance of species of prey fish of Plectropomus leopardus (Serranidae), a piscivore and the major target of the hook and line fisheries on the GBR, were estimated in protected and fished zones. These prey species were identified from previous detailed studies of the diet of P. leopardus. Fish populations and habitat characteristics were surveyed by underwater visual census. Previous studies had determined that the biomass of P. leopardus was 3–4 times higher in protected than fished zones in the Whitsunday and Palm Islands, central GBR, after 14 years of protection. Eight of the nine prey species had a higher density within fished zones than protected zones, six significantly so. The density of all prey fish was twice that in the fished than the protected zone (p < 0.001). There were no significant differences in availability of different sized refuge holes, structural complexity or live coral cover between zones. Thus, important attributes of habitat complexity did not confound the comparisons between reserve and fished zones. Finally, a significant negative correlation (r = 0.46) between coral trout biomass and summed prey fish biomass suggested that predation may be an important structuring process in this system. The results have implications for the conservation of fishery targets and their prey. The study highlights the potential ecosystem implications of the use of no-take marine reserves as conservation and fisheries management tools.

scholarly journals Quantifying the environmental impact of a major coal mine project on the adjacent Great Barrier Reef ecosystems

2021 ◽  
Author(s):  
Antoine Saint-Amand ◽  
Alana Grech ◽  
Severine Choukroun ◽  
Emmanuel Hanert
Keyword(s):  
Great Barrier Reef ◽  
Coal Mine ◽  
Marine Species ◽  
Ocean Model ◽  
Barrier Reef ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Sediment Dispersal ◽  
Seagrass Meadows ◽  
Sediment Types

A major coal mine project in Queensland, Australia, is currently under review. It is planned to be located about 10 km away from the Great Barrier Reef World Heritage Area (GBRWHA). Sediment dispersal patterns and their impact on marine ecosystems have not been properly assessed yet. Here, we simulate the dispersal of different sediment types with a high-resolution ocean model, and derive their environmental footprint. We show that sediments finer than 32 µm could reach dense seagrass meadows and a dugong sanctuary within a few weeks. The intense tidal circulation leads to non-isotropic and long-distance sediment dispersal patterns along the coast. Our results suggest that the sediments released by this project will not be quickly mixed but rather be concentrated where the most valuable ecosystems are located. If accepted, this coal mine could therefore have a far-reaching impact on the GBRWHA and its iconic marine species.

scholarly journals Assessment of water quality from the Normanby River catchment to coastal flood plumes on the northern Great Barrier Reef, Australia

2018 ◽  
Vol 69 (6) ◽  
pp. 859 ◽  
Author(s):  
C. Howley ◽  
M. Devlin ◽  
M. Burford
Keyword(s):  
Great Barrier Reef ◽  
Inorganic Nitrogen ◽  
Suspended Sediments ◽  
River System ◽  
Marine Ecosystems ◽  
Coastal Ecosystems ◽  
Barrier Reef ◽  
Tropical River ◽  
Seagrass Meadows ◽  
Suspended Sediment Concentrations

Understanding the flux and fate of nutrients and sediments from rivers is of global importance because of the effects of these materials on coastal ecosystems. The present study followed three flood events from upper tributaries of the Normanby River to Princess Charlotte Bay in the northern Great Barrier Reef (GBR) lagoon, Australia. During each event, nutrients and suspended sediment concentrations were measured along a freshwater to marine transect. The upper catchment provided the majority of suspended sediments and nutrients supplied to the river system, although concentrations of most materials decreased by 52–85% between the upper catchment and estuary. As an exception, ammonium concentrations doubled within the estuary, indicating that undisturbed coastal ecosystems can provide a significant source of dissolved inorganic nitrogen to tropical river flood plumes. The dissolved nutrients in floodwaters stimulated phytoplankton blooms that inundated seagrass meadows and coral reefs. Northern GBR marine ecosystems are increasingly threatened by climate change and catchment development. The results of this study show that increased anthropogenic loads of nutrients and sediments from the upper Normanby catchment have the potential to affect the condition of marine ecosystems at Princess Charlotte Bay.

scholarly journals The Differential Importance of Deep and Shallow Seagrass to Nekton Assemblages of the Great Barrier Reef

Diversity ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 292
Author(s):  
Matthew A. Hayes ◽  
Eva C. McClure ◽  
Paul H. York ◽  
Kristin I. Jinks ◽  
Michael A. Rasheed ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Barrier Reef ◽  
Catch Per Unit Effort ◽  
Size Spectra ◽  
Spectra Analysis ◽  
Important Species ◽  
Seagrass Meadows ◽  
Unit Effort ◽  
Penaeus Semisulcatus ◽  
Different Depths

Seagrass meadows are an important habitat for a variety of animals, including ecologically and socioeconomically important species. Seagrass meadows are recognised as providing species with nursery grounds, and as a migratory pathway to adjacent habitats. Despite their recognised importance, little is known about the species assemblages that occupy seagrass meadows of different depths in the coastal zone. Understanding differences in the distribution of species in seagrass at different depths, and differences in species diversity, abundance, biomass, and size spectra, is important to fully appreciate both the ecological significance and economic importance of these seagrass meadows. Here, we assess differences in the assemblage characteristics of fish, crustacea, and cephalopods (collectively, nekton) between deep (>9 m; Halophila spinulosa dominant) and shallow water (<2 m; Halodule uninervis and/or Zostera muelleri dominant) seagrass meadows of the central Great Barrier Reef coast of Queensland, Australia. Nekton assemblage structure differed between deep and shallow seagrass. Deeper meadows were typified by juvenile emperors (e.g., Lethrinus genivittatus), hairfinned leatherjacket (Paramonacanthus japonicus) and rabbitfish (e.g., Siganus fuscescens) in both biomass per unit effort (BPUE) and catch per unit effort (CPUE), whereas shallow meadows were typified by the green tiger prawn (Penaeus semisulcatus) and pugnose ponyfish (Secutor insidiator) in both BPUE and CPUE. Both meadow depths were distinct in their nekton assemblage, particularly for socioeconomically important species, with 11 species unique to both shallow and deep meadows. However, both meadow depths also included juveniles of socioeconomically important species found in adjacent habitats as adults. The total nekton CPUE was not different between deep and shallow seagrass, but the BPUE and body mass of individual animals were greater in deep than shallow seagrass. Size spectra analysis indicated that in both deep and shallow meadows, smaller animals predominated, even more so than theoretically expected for size spectra. Our findings highlight the unique attributes of both shallow and deeper water seagrass meadows, and identify the distinct and critically important role of deep seagrass meadows within the Great Barrier Reef World Heritage Area (GBRWHA) as a habitat for small and juvenile species, including those of local fisheries value.

scholarly journals Spatial and temporal variability of seagrass at Lizard Island, Great Barrier Reef

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Megan I. Saunders ◽  
Elisa Bayraktarov ◽  
Chris M. Roelfsema ◽  
Javier X. Leon ◽  
Jimena Samper-Villarreal ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Biomass Productivity ◽  
Shoot Density ◽  
Spatial And Temporal Variability ◽  
Barrier Reef ◽  
Natural Ecosystems ◽  
Area Index ◽  
Seagrass Meadows ◽  
Lizard Island ◽  
Sediment Carbon

AbstractIncreasing threats to natural ecosystems from local and global stressors are reinforcing the need for baseline data on the distribution and abundance of organisms. We quantified spatial and/or temporal patterns of seagrass distribution, shoot density, leaf area index, biomass, productivity, and sediment carbon content in shallow water (0–5 m) at Lizard Island, Great Barrier Reef, Australia, in field surveys conducted in December 2011 and October 2012. Seagrass meadows were mapped using satellite imagery and field validation. A total of 18.3 ha of seagrass, composed primarily of

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