Report cards that are designed to monitor environmental trends have the potential to provide a powerful communication tool because they are easy to understand and accessible to the general public, scientists, managers and policy makers. Given this functionality, they are increasingly popular in marine ecosystem reporting. We describe a report card method for seagrass that incorporates spatial and temporal variability in three metrics—meadow area, species and biomass—developed using long-term (greater than 10 years) monitoring data. This framework summarises large amounts of spatially and temporally complex data to give a numeric score that provides reliable comparisons of seagrass condition in both persistent and naturally variable meadows. We provide an example of how this is applied to seagrass meadows in an industrial port in the Great Barrier Reef World Heritage Area of north-eastern Australia.

Seagrass habitats provide critical ecosystem services, yet there is ongoing concern over mounting pressures and continuing degradation. Defining a desired state for these habitats is a key step in implementing appropriate management but is often difficult given the challenges of available data and an evaluation of where to set benchmarks. We use more than 20 years of historical seagrass biomass data (1995-2018) for the diverse seagrass communities of Australia's Great Barrier Reef World Heritage Area (GBRWHA) to develop desired state benchmarks. Desired state for seagrass biomass was estimated for 25 of 36 previously defined seagrass communities with the remainder having insufficient data. Desired state varied by more than one order of magnitude between community types and was influenced by the mix of species in the communities and the range of environmental conditions. We identify a historical, decadal-scale cycle of decline with recovery to desired state in coastal intertidal communities. In contrast a number of the estuary and coastal subtidal communities have not recovered to desired state biomass. Understanding a historical context is critically important for setting benchmarks and making informed management decisions on the present state of seagrass in the GBRWHA. The approach we have developed is scalable for monitoring, management and assessment of pressures for other management areas and for other jurisdictions. Our results guide conservation planning through prioritization of the at-risk seagrass communities that are continuing to fall below their desired state.

The Great Barrier Reef World Heritage Area (GBRWHA) in north eastern Australia spans 2500 km of coastline and covers an area of ~ 350,000 km2. It includes one of the world's largest seagrass resources. To provide a foundation to monitor, establish trends and manage the protection of seagrass meadows in the GBRWHA we quantified potential seagrass community extent using six random forest models that include environmental data and seagrass sampling history. We identified 88,331 km2 of potential seagrass habitat in intertidal and subtidal areas: 1111 km2 in estuaries, 16,276 km2 in coastal areas, and 70,934 km2 in reef areas. Thirty-six seagrass community types were defined by species assemblages within these habitat types using multivariate regression tree models. We show that the structure, location and distribution of the seagrass communities is the result of complex environmental interactions. These environmental conditions include depth, tidal exposure, latitude, current speed, benthic light, proportion of mud in the sediment, water type, water temperature, salinity, and wind speed. Our analysis will underpin spatial planning, can be used in the design of monitoring programs to represent the diversity of seagrass communities and will facilitate our understanding of environmental risk to these habitats.

Abstract The Great Barrier Reef World Heritage Area in Queensland, Australia contains globally significant seagrasses supporting key ecosystem services, including habitat and food for threatened populations of dugong and turtle. We compiled 35 years of data in a spatial database, including 81,387 data points with georeferenced seagrass and species presence/absence, depth, dominant sediment type, and collection date. We include data collected under commercial contract that have not been publicly available. Twelve seagrass species were recorded. The deepest seagrass was found at 76 m. Seagrass meadows are at risk from anthropogenic, climate and weather processes. Our database is a valuable resource that provides coastal managers and the global marine community with a long‐term spatial resource describing seagrass populations from the mid‐1980s against which to benchmark change. We address the data issues involved in hindcasting over 30 years to ensure confidence in the accuracy and reliability of data included.

Queensland’s coasts have significant and diverse tropical seagrass habitats that we have mapped and researched. This includes the Great Barrier Reef World Heritage Area (GBR) with ~35 000 km2 and Torres Strait with ~15 000 km2 of seagrass ecosystem. Programs have documented these seagrasses since the 1980s and early 2000s respectively including: (1) GBR-wide coastal seagrass mapping (1980s-1990s); (2) seabed biodiversity mapping (2004-2005); (3) mapping marine environments in Queensland’s shipping lanes and ports (2002-2014); (4) long-term (>15 years) mapping at Cairns, Thursday Island, Townsville, Abbot Point and Gladstone ports. Until recently managers could not access the full suite of seagrass spatial data in a format that included a range of spatial scales, site and meadow information; nor could they interrogate the reliability and age of the data available. We evaluated and incorporated over 300 seagrass spatial data sets (seagrass presence/absence, species present, dominant species, meadow area and survey date) and more than 60,000 data points spanning the 30 years into a publicly available set of GIS layers. This tool allows coastal managers and scientists to reliability interrogate seagrass data in these areas for management decision making. This data also provides a valuable benchmark; providing a long-term snapshot of seagrass meadow status and a base for modelling meadow response to spatial/temporal impacts. We look at a recent climate related ecological event in northern Australia and make a case for using our spatial approach and to advocate for improving both the reliability and availability of seagrass data.

The rate of exchange, or connectivity, among populations effects their ability to recover after disturbance events. However, there is limited information on the extent to which populations are connected or how multiple disturbances affect connectivity, especially in coastal and marine ecosystems. We used network analysis and the outputs of a biophysical model to measure potential functional connectivity and predict the impact of multiple disturbances on seagrasses in the central Great Barrier Reef World Heritage Area (GBRWHA), Australia. The seagrass networks were densely connected, indicating that seagrasses are resilient to the random loss of meadows. Our analysis identified discrete meadows that are important sources of seagrass propagules and that serve as stepping stones connecting various different parts of the network. Several of these meadows were close to urban areas or ports and likely to be at risk from coastal development. Deep water meadows were highly connected to coastal meadows and may function as a refuge, but only for non‐foundation species. We evaluated changes to the structure and functioning of the seagrass networks when one or more discrete meadows were removed due to multiple disturbance events. The scale of disturbance required to disconnect the seagrass networks into two or more components was on average >245 km, about half the length of the metapopulation. The densely connected seagrass meadows of the central GBRWHA are not limited by the supply of propagules; therefore, management should focus on improving environmental conditions that support natural seagrass recruitment and recovery processes. Our study provides a new framework for assessing the impact of global change on the connectivity and persistence of coastal and marine ecosystems. Without this knowledge, management actions, including coastal restoration, may prove unnecessary and be unsuccessful.

Seagrass species form important marine and estuarine habitats providing valuable ecosystem services and functions. Coastal zones that are increasingly impacted by anthropogenic development have experienced substantial declines in seagrass abundance around the world. Australia, which has some of the world's largest seagrass meadows and is home to over half of the known species, is not immune to these losses. In 1999 a review of seagrass ecosystems knowledge was conducted in Australia and strategic research priorities were developed to provide research direction for future studies and management. Subsequent rapid evolution of seagrass research and scientific methods has led to more than 70% of peer reviewed seagrass literature being produced since that time. A workshop was held as part of the Australian Marine Sciences Association conference in July 2015 in Geelong, Victoria, to update and redefine strategic priorities in seagrass research. Participants identified 40 research questions from 10 research fields (taxonomy and systematics, physiology, population biology, sediment biogeochemistry and microbiology, ecosystem function, faunal habitats, threats, rehabilitation and restoration, mapping and monitoring, management tools) as priorities for future research on Australian seagrasses. Progress in research will rely on advances in areas such as remote sensing, genomic tools, microsensors, computer modeling, and statistical analyses. A more interdisciplinary approach will be needed to facilitate greater understanding of the complex interactions among seagrasses and their environment.

The Great Barrier Reef World Heritage Area (GBRWHA) includes one of the world's largest areas of seagrass (around 40,000 km2) including 20% of the world's species. Coastal development including expanding urban centres and ports poses a significant threat to seagrasses in the region. Mitigating anthropogenic and natural threats to seagrass requires a method to effectively quantify the resource for management and the development of management tools to protect and quantify change. The Queensland Ports Seagrass Monitoring Program conducts long-term seagrass mapping and monitoring in the majority of Queensland's commercial ports and a range of targeted research for management application. We present the major elements of the program and the latest results to demonstrate how effective research and industry partnerships can help solve the challenges facing seagrasses and other coastal habitats high from development. Monitoring focuses on seagrass habitat that is most at risk from the various threats that seagrasses face, providing port managers and regulators with key information to plan and implement port development and maintenance programs that will have minimal impact on seagrasses. The program has been successful in changing coastal development and ports and shipping industry practices, and has improved the ability of managers to protect marine habitats. In addition the industry partnership has led to major research programs including developing new molecular tools to rapidly assess the health of seagrasses; development of appropriate management triggers and thresholds for light and turbidity; investigating seagrass resilience and recovery; quantifying productivity of tropical seagrass systems; valuing the ecosystem services seagrasses provide and deciphering the role climate plays in shaping tropical seagrass change. In addition the extensive spatial network provides excellent information on the overall condition and trend of seagrasses in the GBRWHA providing great context when combined with other seagrass monitoring efforts in the region.

Seagrasses are one of the most productive marine habitats and provide a variety of ecosystem services with substantial economic value. Queensland's coasts and ports have significant and diverse seagrass habitat including one of the world's largest seagrass ecosystems ( 35 000 km2) in the Great Barrier Reef (GBR) World Heritage Area and 15 000 km2 of seagrass in Torres Strait. Key to understanding and managing this important ecosystem is reliable data on seagrass distribution, species composition, and how this changes through time. A range of mapping and monitoring programs with spatial data have documented Queensland's east coast seagrasses since the 1980s and Torres Strait seagrass since the early 2000s. These include: (1) GBR-wide coastal seagrass mapping (1980s-1990s); (2) seabed biodiversity mapping (2004-2005); (3) mapping marine environments in areas identified as high risk for Queensland's shipping lanes and ports as part of the oil spill response atlas (2002-2014); (4) long-term monitoring programs for coastal ports (ongoing). Until recently managers could not access the full suite of seagrass spatial data in a format that included a range of spatial scales, site and meadow information; nor could they interrogate the reliability and age of the dataset. To address this we found, evaluated and incorporated over 300 seagrass spatial data sets from Queensland's east coast and Torres Strait spanning 30 years (1984- 2014) into a now publicly available suite of GIS layers. We included information on seagrass presence/absence, species present, dominant species, meadow area and survey date. This tool allows coastal managers and scientists to interrogate seagrass data according to their specific needs. It can be used to inform habitat and management zoning. It will enable a better understanding of seagrass change and will identify regions of key dugong and turtle habitat, regions where seagrass information is deficient, and where seagrass exists in high-risk areas.

This project provides an up to date synthesis of the available information on seagrass in the Great Barrier Reef World Heritage Area (GBRWHA). It brings together more than 30 years of spatial information and data collection into easy to use spatial GIS layers that provide key information on species, meadow type and age and reliability of the data. The project provides: Seagrass site and meadow-specific data in Geographic Information System (GIS) layers to provide seagrass data to inform research analysis and management advice. A site layer that includes >66,000 individual survey sites with information including latitude/longitude, Natural Resource Management region, site depth, seagrass presence/absence, dominant seagrass species, presence/absence of individual species, survey date, survey method, and data custodian. A meadow layer that includes 1169 individual and/or composite seagrass meadows with information including individual meadow persistence, meadow location (intertidal/subtidal), meadow density based on mean biomass and/or mean percent cover, meadow area, dominant seagrass species, seagrass species present, range of survey dates, survey method, and data custodian. Metadata to enable interpretation of the information and to identify the original data custodians for assistance with interpretation. Outcomes: This study consolidates all available seagrass spatial data for the GBRWHA collected from 1984 to December 2014 by the TropWATER Seagrass Group and CSIRO in a GIS database. It assembles and documents the state of spatial knowledge of seagrass in the GBRWHA. The spatial data is based on methods developed by TropWATER and CSIRO for seagrass habitat surveys of subtidal meadows, and TropWATER methods for intertidal surveys. Methods include sampling by boat (free divers, underwater video camera, grabs, sled with net sampling), helicopter and walking. 447,530 hectares of seagrasses were mapped (modelled deep water seagrass areas are not included in area figures in this report) within the GBRWHA; much of which provides habitat for commercial and traditional fishery species, and an important food resource for dugong and green turtle populations. Data is included for twelve seagrass species from three families. Seagrass was present at 39% of all sites visited. The study identifies areas where much of the data available for management is more than 20 years old or where there are specific habitats unsurveyed. Large areas of central and northern Queensland require updating. Several key habitat types such as reef platform seagrass meadows are poorly represented in the data.

Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.

Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows.Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies.We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content.The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability.Nitrogen concentrations were also determined for each seagrass species present at the sites.Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor.Species composition and/or nitrogen content influenced consumption to a lesser degree.Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia

Aim The movement of propagules among plant populations affects their ability to replenish and recover after a disturbance. Quantitative data on recovery strategies, including the effectiveness of population connectivity, are often lacking at broad spatial and temporal scales. We use numerical modelling to predict seagrass propagule dispersal and settlement to provide an approach for circumstances where direct, or even indirect, measures of population dynamics are difficult to establish.Location Great Barrier Reef, Australia.Methods We used the finite-element Second-generation Louvain-la-Neuve Iceocean Model (SLIM) to resolve the hydrodynamics of the central Great Barrier Reef and to simulate the dispersal of seagrass. We predicted dispersal and settlement patterns by releasing 10.6 million passive particles representing seagrass propagules at known sites of seagrass presence. We considered two fractions when modelling seagrass dispersal: floating and suspended propagules. Both fractions were modelled using 34 simulations run for a maximum of 8 weeks during the peak seagrass reproductive period, capturing variability in winds, tides and currents.Results The 'virtual' seagrass propagules moved on average between 30 and 60 km, but distances of over 900 km also occurred. Most particle movement was to the north-west. The season (month) of release and source locations of the particles correlated with their dispersal distance, particularly for particles released offshore, with the complex coastal topography impeding movements close to the coast. The replenishment and recovery potential of the northernmost meadows was influenced by southern meadows. Protected north-facing bays were less likely to receive particles.Main conclusions Our approach advances the conservation and management of marine biodiversity by predicting a key component of ecosystem resilience at a spatial scale that informs marine planning. We show a complex interaction among time, wind, water movement and topography that can guide a management response to improving replenishment and recovery after disturbance events.

The unique values of Australia's Great Barrier Reef (GBR) are under threat from environmental change and the unforeseen, cumulative consequences of coastal development. Development decisions are underpinned by Environmental Impact Assessments (EIAs) but these are plagued by inconsistent methods and a lack of independent evaluation, leading to perceptions of inadequate scientific rigor. To be credible and effective, EIAs should be subject to independent peer review, the yardstick applied in the normal process of science. Without it, decisions based on EIA are at best contestable and potentially invalid. Peer review should be applied to the whole EIA process from project development to reporting and auditing approval requirements. It should be based on rigorous, standard protocols, and produce standardized and publicly available data. Securing the future of the GBR and other global natural assets requires refocusing EIA so it becomes a tool for strategic environmental protection rather than ad hoc permitting of development.

The Great Barrier Reef World Heritage Area includes one of the world's largest areas of seagrass (35, 000 km2) including 20% of the world's species. Mitigating natural and anthropogenic threats to this biodiverse region requires quantifying the resource for its' effective management. The Queensland Ports Seagrass Monitoring Program conducts long-term seagrass mapping and monitoring in the majority of Queensland's commercial ports. Monitoring focuses on seagrass habitat that is most at risk from the various threats that seagrasses face, providing port managers and regulators with key information to plan and implement port development and maintenance programs that will have minimal impact on seagrasses. The program has been successful in changing coastal development and ports and shipping industry practices, and has improved the ability of managers to protect marine habitats. As a by-product of the program a range of seagrass research projects have been established including developing tools to rapidly assess the health of seagrasses and to implement management triggers and thresholds; investigating seagrass resilience and recovery; quantifying productivity of tropical seagrass systems; and deciphering the role climate plays in shaping tropical seagrass communities. One of the limitations of the program is a sampling bias towards shallow coastal seagrasses within developed regions. This bias creates a problem if using monitoring data for building species and habitat maps. The data produced from the program results in a patchwork distribution of data sets that do not cover the entire ranges of seagrass habitats of the GBR and do not effectively represent relevant spatio-temporal changes making it difficult to produce broad-scale species and habitat maps to aid in management. The Queensland Ports Association is working alongside the Seagrass Ecology Group to try and fill these gaps in knowledge.