Larval dispersal simulations: correlation with the crown-of-thorns starfish outbreaks database

1992 ◽  
Vol 43 (3) ◽  
pp. 569 ◽  
Author(s):  
MK James ◽  
JP Scandol
Keyword(s):  
Great Barrier Reef ◽  
Larval Dispersal ◽  
Large Scale ◽  
Numerical Models ◽  
Temporal Distribution ◽  
Research Programme ◽  
Strong Positive Correlation ◽  
Barrier Reef ◽  
Central Hypothesis ◽  
Scale Population

The work reported in this paper is a further development of results from a research programme whose principal objective is to achieve an understanding of the large-scale population dynamics of Acanthaster planci. The research is based on the development and use of numerical models of hydrodynamics and resulting larval dispersal throughout a large portion of the Great Barrier Reef. It is chiefly concerned with the large-scale statistical patterns of larval dispersal, the central hypothesis being that passive hydrodynamic dispersal plays an important role in the recruitment process. The present aim is to examine more closely than has been done before the consistencies between the modelling results and the database of recorded observations of crown-of-thorns starfish outbreaks. Reefs in the Cairns and Central Sections of the Great Barrier Reef Marine Park that were recorded as carrying active outbreaks during the period 1979-89 were used as sources in a programme of intensive simulations of Acanthaster larval dispersal under forcing by the wind, tidal action and the East Australian Current. The resulting broad-scale patterns of larval dispersal were found to be in strong qualitative agreement with the observed spatial and temporal distribution of adult Acanthaster populations. Statistical analysis of the results revealed a strong positive correlation between potential recruitment on surveyed reefs, as estimated by the dispersal simulations, and the observed presence of outbreak populations on those reefs. The correlation was particularly strong when different cross-shelf zones were considered separately.

Hydrodynamics and larval dispersal: a population model of Acanthaster planci on the Great Barrier Reef

1992 ◽  
Vol 43 (3) ◽  
pp. 583 ◽  
Author(s):  
JP Scandol ◽  
MK James
Keyword(s):  
Great Barrier Reef ◽  
Large Scale ◽  
Larval Transport ◽  
Barrier Reef ◽  
Acanthaster Planci ◽  
Dispersal Patterns ◽  
Transport Models ◽  
Southward Shift ◽  
Scale Population ◽  
Flow Through

This paper presents results of a modelling study of the large-scale population dynamics of Acanthaster planci in the central Great Barrier Reef. Dispersal patterns generated by larval transport models are used to drive the simulation. Population flow through the reef matrix during outbreaks is simulated by using an elementary representation of the starfish life cycle. Features of the results include the following: (I) Population patterns generated by the model are consistent with observations of starfish outbreaks. (2) The overall impact of starfish populations undergoing an outbreak on the reef system decreases with a southward shift in the location of initial outbreaks. (3) Within the central Great Barrier Reef, outbreak populations of starfish generally occur more frequently on the inner- and central-matrix reefs than on the outer-matrix reefs.

scholarly journals Effects of trawling on sessile megabenthos in the Great Barrier Reef and evaluation of the efficacy of management strategies

2015 ◽  
Vol 73 (suppl_1) ◽  
pp. i115-i126 ◽  
Author(s):  
C. Roland Pitcher ◽  
Nick Ellis ◽  
William N. Venables ◽  
Ted J. Wassenberg ◽  
Charis Y. Burridge ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Environmental Sustainability ◽  
Large Scale ◽  
Regional Scale ◽  
Regional Distribution ◽  
Dynamic Modelling ◽  
Barrier Reef ◽  
Worst Case ◽  
Management Actions ◽  
Management Interventions

Abstract A series of related research studies over 15 years assessed the effects of prawn trawling on sessile megabenthos in the Great Barrier Reef, to support management for sustainable use in the World Heritage Area. These large-scale studies estimated impacts on benthos (particularly removal rates per trawl pass), monitored subsequent recovery rates, measured natural dynamics of tagged megabenthos, mapped the regional distribution of seabed habitats and benthic species, and integrated these results in a dynamic modelling framework together with spatio-temporal fishery effort data and simulated management. Typical impact rates were between 5 and 25% per trawl, recovery times ranged from several years to several decades, and most sessile megabenthos were naturally distributed in areas where little or no trawling occurred and so had low exposure to trawling. The model simulated trawl impact and recovery on the mapped species distributions, and estimated the regional scale cumulative changes due to trawling as a time series of status for megabenthos species. The regional status of these taxa at time of greatest depletion ranged from ∼77% relative to pre-trawl abundance for the worst case species, having slow recovery with moderate exposure to trawling, to ∼97% for the least affected taxon. The model also evaluated the expected outcomes for sessile megabenthos in response to major management interventions implemented between 1999 and 2006, including closures, effort reductions, and protected areas. As a result of these interventions, all taxa were predicted to recover (by 2–14% at 2025); the most affected species having relatively greater recovery. Effort reductions made the biggest positive contributions to benthos status for all taxa, with closures making smaller contributions for some taxa. The results demonstrated that management actions have arrested and reversed previous unsustainable trends for all taxa assessed, and have led to a prawn trawl fishery with improved environmental sustainability.

Corrigendum to “Controls on the spatio-temporal distribution of microbialite crusts on the Great Barrier Reef over the past 30,000 years”

2020 ◽  
Vol 430 ◽  
pp. 106369
Author(s):  
Zs. Szilagyi ◽  
Jody M. Webster ◽  
Madhavi A. Patterson ◽  
Kinga Hips ◽  
Robert Riding ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Temporal Distribution ◽  
Barrier Reef ◽  
The Past ◽  
Spatio Temporal

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.

Large-scale bleaching of corals on the Great Barrier Reef

Coral Reefs ◽  
1999 ◽  
Vol 18 (1) ◽  
pp. 55-60 ◽  
Author(s):  
R. Berkelmans ◽  
J. K. Oliver
Keyword(s):  
Great Barrier Reef ◽  
Large Scale ◽  
Barrier Reef

scholarly journals Asymmetric dispersal is a critical element of concordance between biophysical dispersal models and spatial genetic structure in Great Barrier Reef corals

2018 ◽  
Author(s):  
C Riginos ◽  
K Hock ◽  
AM Matias ◽  
PJ Mumby ◽  
MJH van Oppen ◽  
...  
Keyword(s):  
Gene Flow ◽  
Great Barrier Reef ◽  
Larval Dispersal ◽  
Coral Species ◽  
Spatial Genetic Structure ◽  
Critical Element ◽  
Barrier Reef ◽  
Long Distance ◽  
Biophysical Models ◽  
Asymmetric Dispersal

AbstractAimWidespread coral bleaching, crown-of-thorns seastar outbreaks, and tropical storms all threaten foundational coral species of the Great Barrier Reef, with impacts differing over time and space. Yet, dispersal via larval propagules could aid reef recovery by supplying new settlers and enabling the spread of adaptive variation among regions. Documenting and predicting spatial connections arising from planktonic larval dispersal in marine species, however, remains a formidable challenge.LocationThe Great Barrier Reef, AustraliaMethodsContemporary biophysical larval dispersal models were used to predict longdistance multigenerational connections for two common and foundational coral species (Acropora tenuisandAcropora millepora). Spatially extensive genetic surveys allowed us to infer signatures of asymmetric dispersal for these species and evaluate concordance against expectations from biophysical models using coalescent genetic simulations, directions of inferred gene flow, and spatial eigenvector modelling.ResultsAt long distances, biophysical models predicted a preponderance of north to south connections and genetic results matched these expectations: coalescent genetic simulations rejected an alternative scenario of historical isolation; the strongest signals of inferred gene flow were from north to south; and asymmetric eigenvectors derived from north to south connections in the biophysical models were significantly better predictors of spatial genetic patterns than eigenvectors derived from symmetric null spatial models.Main conclusionsResults are consistent with biophysical dispersal models yielding approximate summaries of past multigenerational gene flow conditioned upon directionality of connections. ForA. tenuisandA. millepora, northern and central reefs have been important sources to downstream southern reefs over the recent evolutionary past and should continue to provide southward gene flow. Endemic genetic diversity of southern reefs suggests substantial local recruitment and lack of long distance gene flow from south to north.

scholarly journals Large-scale interventions may delay decline of the Great Barrier Reef

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Scott A. Condie ◽  
Kenneth R. N. Anthony ◽  
Russ C. Babcock ◽  
Mark E. Baird ◽  
Roger Beeden ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Great Barrier Reef ◽  
Tropical Cyclones ◽  
Large Scale ◽  
Coral Cover ◽  
Solar Radiation Management ◽  
Successful Implementation ◽  
Barrier Reef ◽  
Cumulative Impacts ◽  
Coral Rubble

On the iconic Great Barrier Reef (GBR), the cumulative impacts of tropical cyclones, marine heatwaves and regular outbreaks of coral-eating crown-of-thorns starfish (CoTS) have severely depleted coral cover. Climate change will further exacerbate this situation over the coming decades unless effective interventions are implemented. Evaluating the efficacy of alternative interventions in a complex system experiencing major cumulative impacts can only be achieved through a systems modelling approach. We have evaluated combinations of interventions using a coral reef meta-community model. The model consisted of a dynamic network of 3753 reefs supporting communities of corals and CoTS connected through ocean larval dispersal, and exposed to changing regimes of tropical cyclones, flood plumes, marine heatwaves and ocean acidification. Interventions included reducing flood plume impacts, expanding control of CoTS populations, stabilizing coral rubble, managing solar radiation and introducing heat-tolerant coral strains. Without intervention, all climate scenarios resulted in precipitous declines in GBR coral cover over the next 50 years. The most effective strategies in delaying decline were combinations that protected coral from both predation (CoTS control) and thermal stress (solar radiation management) deployed at large scale. Successful implementation could expand opportunities for climate action, natural adaptation and socioeconomic adjustment by at least one to two decades.

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