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On the 100-year anniversary of the Australian Coral Reef Society (ACRS), previously known as the Great Barrier Reef Committee (GBRC), we provide an overview of ACRS activities throughout its history, with a detailed account of key milestones in the last 40 years. We outline how the ACRS as promoted the protection and conservation of reefs, through expert advice, reviews, and submissions to enquiries. Examples are provided under the following themes: ACRS consultancy on zoning the Great Barrier Reef (GBR) Marine Park, marine protected area design, water quality on the GBR, port expansions along the Queensland coastline and environmental reform for the offshore oil and gas industry. We illustrate how scientists over recent decades have worked to better understand and encourage policy responses to the impacts of climate change on Australia's coral reefs. For a hundred years, the GBRC-ACRS has provided an avenue for Australian coral reef scientists, managers and conservationists to influence reef governance through policy. While these unique avenues for delivering timely and targeted expertise have helped to reduce proximate threats to reefs at local scales, their outcome in relation to climate change, arguably the largest threat to Australia's coral reefs, remains to be seen. We review ACRS activities under the following themes: consulting on the Capricorn Bunker Group to zone the Great Barrier Reef Marine Park, marine protected area design, water quality on the GBR, Queensland port expansions, environmental reform for the offshore oil and gas industry and the impacts of climate change on Australian reefs. We outline how the ACRS has promoted the exchange of scientific information to protect and conserve Australian reefs for a 100 years. [ABSTRACT FROM AUTHOR]

Sand aprons are distinctive landforms that offer important insights into sedimentary dynamics for reef platform development. Here we link temporal and spatial scales of 21 sand aprons in the southern Great Barrier Reef to understand their Holocene formation and evolution in response to relative sea-level changes, the depth of the Pleistocene base, and contemporary morphodynamics. Our results show that lagoon infilling is a function of reef size and is a self-limiting process controlled by hydrodynamics and relative sea-level changes. Lagoon infilling does not depend on the type of reef or degree of exposure to waves, but it could reflect past wave climates. Our carbonate productivity estimates based on lagoon infilling are remarkably similar to those inferred from habitat classification. Finally, we hypothesize that current carbonate productivity has slowed because of the effects of climate change. [ABSTRACT FROM AUTHOR]

Previous studies of dispersion of intertidal seagrass-associated macrobenthos in subtropical Moreton Bay, Queensland, showed that patchiness characterised its assemblage abundance with scale-invariant magnitude across areas ranging from >8000 to 0.1 m2. Those studies were here continued across the smaller scales (down to 0.014 m2) arguably more relevant to the dominant 2–10 mm long animals, using 16 replicate blocks of 5x5 contiguous 0.0024 m2 cores nested within the previously studied site. At microscales ≥0.09 m2, the earlier congruence of conclusions derived from patchiness indices and spatial autocorrelation broke down. At >0.014 m2, adjacent points (cores) no longer together formed larger spatial units of related abundance (i.e. showed no autocorrelation), but point abundances were still highly disparate (as reflected in patchiness indices). Congruent indications of patchiness only manifested at 0.014 m2 spatial scales. Assemblage dispersion pattern was partly consequent on one microgastropod (Pseudoliotia) occurring superabundantly in scattered 0.0024 m2 hotspots. [Display omitted] • Earlier studies at 8000 → 0.1 m2 scales were continued down to 0.014 and 0.0024 m2 • At >0.014 m2, spatial-autocorrelation and dispersion-index results contradictory. • Dispersion was not spatially-autocorrelated but point abundances were very disparate. • Hotspots manifested only at ≤0.014 m2 and were randomly dispersed. • Level of assemblage patchiness effectively constant across 8000 → 0.014 m2 [ABSTRACT FROM AUTHOR]

How we understand the contemporary socio-environmental challenges associated with climate change is shaped by our research disciplines. This paper explores how interdisciplinary collaboration can form new understandings of, and communication about, environmental change. On Australia's Great Barrier Reef, mass coral bleaching prompts researchers to consider how our work can contribute to environmental stewardship that more effectively addresses the causes and consequences of climate change. Here, we report on one element of an ongoing collaboration involving researchers working in the fields of coastal geomorphology, human geography and art. In the spirit of geohumanities as an interdisciplinary approach to understanding places, we explore the work of narrative as a device for engaging with and communicating about the environmental challenge of coral reef degradation. Through independent and plaited narratives based on field research on the Great Barrier Reef, we undertake a deconstructive practice of "uncommoning" to consider what interdisciplinary collaboration enables, and how it opens up possibilities for engaging with, and communicating about, environmental crises. Sharing a curiosity about the island environment, each participant uses metaphors to evoke landscape features; however, they each work through different imaginative and emotional connections to place, by: reducing observations to measurements, evoking emotional responses, and provoking thinking about the multifarious, often global, processes contributing to the state of the environment. [ABSTRACT FROM AUTHOR]

Abstract Following earlier studies across 2115 → 33 m2 scales (Barnes and Laurie, 2018), patchiness of macrobenthic abundance in intertidal Queensland seagrass was assessed by dispersion indices, spatial autocorrelation and hotspot analysis across a hierarchically-nested series of smaller scales (5.75 → 0.09 m2). Overall patterns of distribution and abundance over larger extents and with greater lag were mirrored across these smaller ones. Assemblage abundance per station varied by a factor of >10, but all three approaches showed effective constancy of total assemblage patchiness across all sub-2115 m2 scales (across-scales-mean Lloyd's I P of 1.06 and global Moran's I of 0.13). Equivalent constancy was also shown by most numerically-dominant species (scaling exponent β = 0.93–1.15). Decreasing patchiness of some species with decreasing scale, however, resulted in two no longer being patchily dispersed across small scales. Significant hotspots of abundance occurred at a constant proportion of stations across scales, against a background of randomly scattered peak-abundance points. Graphical abstract Image 1 Highlights • Patchiness of macrobenthic abundance investigated across small nested scales. • Assessment by dispersion indices, spatial autocorrelation and hotspot analysis. • Patchiness of assemblage abundance constant across all 0.09–2115 m2 scales. • Most numerically-dominant component species also isometrically patchy. • Significant hotspots of abundance a constant 5% of stations across all scales. [ABSTRACT FROM AUTHOR]

Coastlines are dynamic environments, with their Eco-geomorphology controlled by a complex range of natural and anthropic processes. Estuarine environments and associated wetland ecosystems are a critical shoreline types with regards to biodiversity, and are particularly susceptible to the influence of sea-level rise. This project applied future sea-level rise of Intergovernmental Panel on Climate Change (IPCC) hydro-scenarios to assess its impact on the eco-geomorphic aspects of coastal ecosystems in terms of risk assessment and sustainability. Comerong Island is used as a case study and is compared with other surrounding ocean-influenced and lagoonal deltas to assess the regional effects of sea-level rise. Applying the IPCC scenarios to the chosen geomorphic coastal data-sets resulted in a hydro-geomorphic model that shows the study site was already under pressure in 2015, with significant land area projected to be lost by 2050 and 2100. These findings are also expected to occur across the remaining estuaries in southeastern Australia. Applying this broad-scale, multi-strand application of geoinformatics simulation (GIS & RS), together with the various IPCC sea-level rise scenarios, will be necessary to assess future ecosystem sustainability management plans for coastal zones worldwide. [ABSTRACT FROM AUTHOR]

Coral reef environments support high levels of marine biodiversity, they are important sites for coastal habitation and they provide a range of goods and ecosystemservices such as nearshore fisheries, economic revenue from tourism and breeding sites for seabirds and turtles. Mapping is a fundamental activity that underpins our understanding of coral reef environments and helps to shape policies in resourcemanagement and conservation. This is particularly the case for quantifying the area of landcover types associated with reef environments, including coral patches, seagrasses and mangroves, but also for monitoring how these change over time and modelling how spatial patterns apparent on reefs are related to environmental drivers. Field techniques and aerial photography have historically played a crucial role in mapping coral reef environments, which has recently seen a transition toward the processing of satellite remote sensing images. This paper examines a series of maps produced of Low Isles, the most mapped island on the Great Barrier Reef, to review historical methods for mapping coral reefs because of the critical importance of understanding how past maps were made, which determines appropriate uses to which they can be put. Recent advances and future opportunities for the application ofmapping technologies to coral reefs are also evaluated, including the use of unmanned aerial vehicle (UAV) platforms for airborne surveys, delivery of information through web-based platforms and improvements in the quality of information formaking and presentingmaps. Maps have transformed thewaywehave responded to both historic and contemporary coral reef problems. This timely reviewcommunicates howmaps, and the fast growing technologies that are employed to produce them, are central to our understanding of coral reef environments. Recent advances that may drive exciting new environmental management tools are identified. [ABSTRACT FROM AUTHOR]

Carbonate production on coral reefs is responsible for the provision of beach sands, for the maintenance of seawater chemical balances and for the growth of reef structure and associated habitat complexity. Key carbonate producers including hard coral, crustose coralline algae, foraminiferal sand and Halimeda were mapped from satellite imagery (spatial resolution 2.5 m, mean overall accuracy = 81%) and an upscaling model was applied to estimate carbonate production. A sensitivity analysis was conducted to evaluate the influence of employing different calcification rates for live coral on the upscaling model. Contemporary coral reef carbonate production for the 21 reef platforms of the Capricorn-Bunker Group (southern Great Barrier Reef) is estimated to be between 489,000 and 659,000 t per year based on seawater chemistry, community composition, calcification rates and reef structural complexity (rugosity). The upscaling model was relatively insensitive to different parameterisations of live coral calcification employed, probably due to live coral being a relatively minor contributor by area (approximately 18% of total reef area throughout the study region). This suggests regional scale seafloor characteristics, such as percentage of area dominated by substrates prone to dissolution (e.g. coral rubble), have a strong bearing on calcium carbonate production and need to be given greater consideration The upscaling framework presented provides a new method for quantifying regional carbonate production that could be applied globally, and provides a valuable baseline against which future changes to carbonate production in this region can be assessed. [ABSTRACT FROM AUTHOR]

Linking surficial sediment patterns in reef environments to the processes that underlie their depositional dynamics enables predictions to be made of how environmental changes will influence reef-associated sedimentary landforms, such as islands and beaches. Geomorphic linkages between sediment deposition patterns and the biophysical processes that drive them are often poorly resolved, particularly at broad landscape scales where tangible statements can be made about structural changes to landforms. The present study applies geospatial techniques to link patterns in reef sediment dynamics at Lady Musgrave Island to the underlying processes driving them. In situ calcification is characterized by developing a high resolution map of the surficial calcium carbonate producing communities inhabiting the reef platform, and associated sediments across the reef flat are analysed for grain size, kurtosis, sorting and threshold bed shear stress to explore transport pathways across the reef flat and lagoon. Wave energy is modelled across the entire reef platform as a potential driver of sediment dynamics, and morphometric linkages are empirically defined between wave energy and grain size. Findings indicate that carbonate sediments are primarily sourced from calcifying communities colonizing the outer periphery of the reef platform and that sediment grain size can be reliably linked to wave energy by virtue of a linear model. [ABSTRACT FROM AUTHOR]

Adnan, F.A.F.; Hamylton, S.M., and Woodroffe, C.D., 2016. A Comparison of Shoreline Changes Estimated Using the Base of Beach and Edge of Vegetation Line at North Keeling Island. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 967 - 971. Coconut Creek (Florida), ISSN 0749-0208. The vulnerability of reef islands is often assessed by measuring changes in shoreline positions over time. Historical aerial photographs provide valuable information of past shoreline dynamics and are commonly incorporated in shoreline change assessment. Edge of vegetation line is the most common shoreline proxy adopted for assessments of reef island change because it is a visually distinguishable feature in aerial photographs, when compared to other coastal features such as high water line and base of beach. This study assesses shoreline changes of North Keeling Island from aerial photographs taken in 1987 and 2011 to evaluate the implications of adopting edge of vegetation line (EVL) and base of beach (BB) as shoreline proxies. The Digital Shoreline Analysis System (DSAS) (ArcGIS 10.2) method was applied to calculate shoreline changes using both proxies. Results indicate that EVL and BB generated different rates of change and variations of shoreline behaviour were observed at different locations around the island. The EVL indicated that the surface area of the island reduced in size over the 24 years, while in contrast, BB indicated that the island had accreted. Findings of this study imply that reef island shorelines are dynamic features which vary spatially and an improved understanding of the processes that underlie shoreline behaviour requires a geographical spread of sites for shoreline proxies when assessing shoreline change. [ABSTRACT FROM AUTHOR]

The high importance of bathymetric character for many processes on reefs means that high-resolution bathymetric models are commonly needed by marine scientists and coastal managers. Empirical and optimisation methods provide two approaches for deriving bathymetry from multispectral satellite imagery, which have been refined and widely applied to coral reefs over the last decade. This paper compares these two approaches by means of a geographical error analysis for two sites on the Great Barrier Reef: Lizard Island (a continental island fringing reef) and Sykes Reef (a planar platform reef). The geographical distributions of model residuals (i.e., the difference between modelled and measured water depths) are mapped, and their spatial autocorrelation is calculated as a basis for comparing the performance of the bathymetric models. Comparisons reveal consistent geographical properties of errors arising from both models, including the tendency for positive residuals (i.e., an under-prediction of depth) in shallower areas and negative residuals in deeper areas (i.e., an over-prediction of depth) and the presence of spatial autocorrelation in model errors. A spatial error model is used to generate more reliable estimates of bathymetry by quantifying the spatial structure (autocorrelation) of model error and incorporating this into an improved regression model. Spatial error models improve bathymetric estimates derived from both methods. [ABSTRACT FROM AUTHOR]

Coastal Swamp Oak Forest (CSOF), a supratidal wetland community dominated by Casuarina glauca , is a widely distributed coastal ecosystem along Australia's east coast. These wetland communities are highly valuable for providing ecosystem services, including carbon sequestration. Positioned within the supratidal zone of estuaries – and often abutting upper intertidal saltmarsh and/or mangrove – CSOF may be vulnerable to salinity intrusion and increased tidal inundation due to sea-level rise. To understand spatial patterns of vegetation composition and structure in CSOF, field-based (in-situ) and remote-sensing approaches were employed on the Minnamurra floodplain, New South Wales, Australia. In-situ vegetation surveys within 23 field plots located along seaward to landward transects revealed large variations in mean tree height (2.5–13.1 m) and tree densities (100–8700 trees/ha). Unmanned Aerial Vehicles with Structure from Motion (UAV-SfM), and airborne Light Detection and Ranging (LiDAR) approaches returned mean plot canopy height estimates ranging between 0.1 and 12.8 m. Comparison of vegetation metrics between remote sensors (UAV-SfM and LiDAR) demonstrated similar capacities (R2 values > 0.85) to capture CSOF vegetation height. Comparison of field and spatial metrics elucidated a moderate correlation between the datasets for maximum canopy height (R2 > 0.6) which can be partially explained by the different spatial scales of measurement among these approaches. Canopy height, Normalised Difference Vegetation Index (NDVI), and point density (i.e., vegetation density) estimates were each positively correlated with elevation above mean sea-level. This coincides with indications of plant stress and/or mortality at the seaward edge of CSOF, and in topographic depressions. These findings suggest physico-chemical gradients exert a strong control on CSOF vegetation structure and health, with implications for the current acceleration of sea-level rise. When combined, remote sensing and field-based datasets are useful to characterise and quantify CSOF structure and distribution and can therefore be employed in future assessments of this understudied ecosystem. [Display omitted] • Surface elevation exerts a strong control on vegetation structure and health. • Different remote sensors demonstrate similar capacities to capture vegetation height. • Structural vegetation metrics were positively correlated with elevation above mean sea-level. • Combining remote sensing and field-based datasets is useful for assessing the key structural features of coastal forests. [ABSTRACT FROM AUTHOR]

Abstract: Spatial data infrastructures play a key role in coastal management decision making in the Seychelles. This paper describes four components of a web-based spatial data infrastructure that were developed to facilitate coastal management of the Amirante Islands in the Seychelles. The four components include: (i) the institutional arrangement for using spatial data effectively to address local management challenges, (ii) the production of island habitat maps from remotely sensed data, (iii) the tasks undertaken for promoting access to and use of this spatial data, and (iv) an example of how this data is used for a specific coastal management application in the Seychelles. By outlining these four components, the value of this spatial data infrastructure framework for tropical coastal management in the Seychelles is demonstrated. [Copyright &y& Elsevier]

Balls Pyramid is a volcanic monolith rising 552 m from the Tasman Sea, 24 km southeast of the Pacific Ocean's southernmost modern coral reef at Lord Howe Island. High resolution seabed mapping of the shelf surrounding Balls Pyramid has revealed an extensive submerged reef structure in 30–50 m water depth, covering an area of 87 km 2 . Benthic community composition analysis of high-resolution still images revealed abundant scleractinian corals on the submerged reef, extending to a maximum depth of 94 m. Scleractinian coral occurred predominantly in 30–40 m depth where it comprised 13.3% of benthic cover within this depth range. Average scleractinian coral cover for all transects was 6.7±12.2%, with the highest average transect cover of 19.4±14.3% and up to 84% cover recorded for an individual still image. The remaining substrate comprised mixed benthos with veneers of carbonate sand. Benthic data were shown to significantly relate to the underlying geomorphology. BVSTEP analyses identified depth and backscatter as the strongest correlating explanatory variables driving benthic community structure. The prevalence of scleractinian corals on the submerged reef features at Balls Pyramid, and the mesophotic depths to which these corals extend, demonstrates the important role of this subtropical island shelf as habitat for modern coral communities in the southwest Pacific Ocean. As Balls Pyramid is located beyond the known latitudinal limit of coral reef formation, these findings have important implications for potential coral reef range expansion and deep reef refugia under a changing climate. [ABSTRACT FROM AUTHOR]

Al-Nasrawi, A.K.M.; Jones, B.G., and Hamylton, S. M., 2016. GIS-based modelling of vulnerability of coastal wetland ecosystems to environmental changes: Comerong Island, southeastern Australia. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 33-37. Coconut Creek (Florida), ISSN 0749-0208. Sustainable management of coastal zones has become a complicated issue. The majority of the human population lives along the coast, where their activities, together with a range of environmental changes, have altered the natural ecosystem processes and caused changes in coastal wetlands. To ensure sustainable use of coastal resources, a comprehensive set of modelling tools can help managers to make decisions. This study uses Comerong Island (southeastern NSW, Australia) as a case study to demonstrate the importance of modelling modifications to environmental change. Several data-based modelling approaches are employed to explore how human activities have altered this estuarine island setting over the last sixty years (1949 - 2014). Multi-temporal changes in land cover, shorelines and sediment delivery are estimated from remote sensing data, GIS analysis, and laboratory tests on water and sediment samples (grain size, X-ray diffraction and loss on ignition and water analysis). Results show there are significant changes to the areal extents and elevation of mangroves, saltmarshes and shorelines in the wetlands on Comerong Island over the time period of analysis, including northern accretion (0.4 km2), eastern, middle and southern erosion (0.7 km2) of the island. The implementation of modelling using GIS tools, water and sediment samples to monitor ecosystem processes, such as sediment transport and erosion/deposition, will allow resource managers to make more informed decisions by evaluating the potential consequences of the existing situation. [ABSTRACT FROM AUTHOR]

Despite being one of the most important and well-studied coral reefs in the world, the full extent of coral habitat of the Great Barrier Reef (GBR) is not well mapped and there is no current and comprehensive map of the GBR's geomorphic zonation or benthic composition. This paper demonstrates an approach that integrates ecological coral habitat mapping with empirical modelling to map the geomorphic zonation and benthic composition of the “shallow offshore reefs” of the GBR, using the Capricorn Bunker Group (CBG) as a case study. The approach combined environmental data sets and geo-ecological rule sets to identify geomorphic zones. The benthic composition of individual geomorphic zones was mapped for: shallow reef flat zones, using object-based image analysis with context driven rules based on coral reef ecology; and reef slope zones, using levels of wave exposure to predict the distribution of coral types. The environmental data sets used were field-based benthic composition data, Landsat 8 OLI satellite image-derived bottom reflectance, water depth and slope (15 m × 15 m pixel size) data, reef impact data, and modelled wave exposure. The study showed that the combination of geomorphic-ecological rules and models with remote sensing imagery provided robust mapping results over a large (~2500 km 2 ) reef system, of which 245 km 2 was mapped as shallow coral reefs and 88 km 2 of that was mapped as areas containing coral. Most importantly, the method produced defined the geomorphic zones and benthic composition of a study area that is significantly larger than the majority of coral reef remote sensing mapping projects previously published. With some modifications, the methods presented have the potential to be applied to the full extent of the shallow offshore reefs of the GBR, or any large reef globally. Monitoring and management of coral reefs for conservation and other purposes, at regional to global scales will benefit from the ability to produce and use this type of essential information on a regular basis. [ABSTRACT FROM AUTHOR]