Spatial and temporal variability of green turtle and dugong herbivory in seagrass meadows of the southern Great Barrier Reef

2021 ◽  
Author(s):  
AL Scott ◽  
PH York ◽  
PI Macreadie ◽  
MA Rasheed
Keyword(s):  
Great Barrier Reef ◽  
Temporal Variability ◽  
Green Turtle ◽  
Spatial And Temporal Variability ◽  
Barrier Reef ◽  
Seagrass Meadows

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

Green turtle somatic growth dynamics in a spatially disjunct Great Barrier Reef metapopulation

Coral Reefs ◽  
2004 ◽  
Vol 23 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Milani Chaloupka ◽  
Colin Limpus ◽  
Jeffrey Miller
Keyword(s):  
Great Barrier Reef ◽  
Green Turtle ◽  
Somatic Growth ◽  
Growth Dynamics ◽  
Barrier Reef

The green turtle, Chelonia mydas, in Queensland: breeding males in the southern Great Barrier Reef

1993 ◽  
Vol 20 (4) ◽  
pp. 513 ◽  
Author(s):  
CJ Limpus
Keyword(s):  
Great Barrier Reef ◽  
Green Turtle ◽  
Carapace Length ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Adult Males ◽  
Green Turtles ◽  
Adult Females ◽  
Breeding Seasons ◽  
Slow Growing

Breeding male green turtles, Chelonia mydas, at any one courtship area in the southern Great Barrier Reef mate with females that will nest on rookeries spread throughout the region. In comparison with the breeding females from the same breeding unit, the males are smaller in curved carapace length, and a higher proportion of males remigrate for additional breeding seasons at 1-2-year intervals. Like the adult females, adult males are slow-growing, averaging 0.046 cm year-1. Each male appears to display a fidelity to a particular courtship area, to which it returns in successive breeding migrations. At the conclusion of the courtship period, the males disperse to widely scattered feeding areas.

scholarly journals A Bayesian approach to understanding the key factors influencing temporal variability in stream water quality: a case study in the Great Barrier Reef catchments

2021 ◽  
Author(s):  
Shuci Liu ◽  
Dongryeol Ryu ◽  
J. Anugs Webb ◽  
Anna Lintern ◽  
Danlu Guo ◽  
...  
Keyword(s):  
Water Quality ◽  
Great Barrier Reef ◽  
Temporal Variation ◽  
Temporal Variability ◽  
Stream Water ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Barrier Reef ◽  
Key Factors ◽  
Stream Water Quality

Abstract. Stream water quality is highly variable both across space and time. Water quality monitoring programs have collected a large amount of data that provide a good basis to investigate the key drivers of spatial and temporal variability. Event-based water quality monitoring data in the Great Barrier Reef catchments in northern Australia provides an opportunity to further our understanding of water quality dynamics in sub-tropical and tropical regions. This study investigated nine water quality constituents, including sediments, nutrients and salinity, with the aim of: 1) identifying the influential environmental drivers of temporal variation in flow event concentrations; and 2) developing a modelling framework to predict the temporal variation in water quality at multiple sites simultaneously. This study used a hierarchical Bayesian model averaging framework to explore the relationship between event concentration and catchment-scale environmental variables (e.g., runoff, rainfall and groundcover conditions). Key factors affecting the temporal changes in water quality varied among constituent concentrations, as well as between catchments. Catchment rainfall and runoff affected in-stream particulate constituents, while catchment wetness and vegetation cover had more impact on dissolved nutrient concentration and salinity. In addition, in large dry catchments, antecedent catchment soil moisture and vegetation had a large influence on dissolved nutrients, which highlights the important effect of catchment hydrological connectivity on pollutant mobilisation and delivery.

Spatio-temporal variability in surface Chlorophyll distribution in the Central Great Barrier Reef as derived from CZCS imagery

1990 ◽  
Vol 41 (3) ◽  
pp. 313 ◽  
Author(s):  
AJ Gabric ◽  
P Hoffenberg ◽  
W Boughton
Keyword(s):  
Great Barrier Reef ◽  
Temporal Variability ◽  
Large Scale ◽  
Nutrient Loads ◽  
Barrier Reef ◽  
Phytoplankton Abundance ◽  
Wet Season ◽  
Chlorophyll Distribution ◽  
Consistent Feature ◽  
Spatio Temporal

A series of Coastal Zone Colour Scanner (CZCS) images has been used to compare the surface phytoplankton variation in the central Great Barrier Reef waters over the period 1979-81. Near- concurrent field data have been obtained for all the scenes so that approximate chlorophyll concentrations have been applied in the image classification. A consistent feature in the dry-season chlorophyll distribution is a cross shelf gradient with high chlorophyll levels inshore and lower levels in the mid-lagoonal waters increasing to higher concentrations in the reef matrix. The effects of higher nutrient loads in the wet season are also evident, although correlation between riverine discharge and phytoplankton abundance in the lagoon is problematic. In fact, a large scale 'bloom' event occurs before the start of the 1980-81 wet season and may be related to wind resuspension of sedimentary nutrients.

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.

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