The re-establishment of seagrass meadows following dieback events depends on the availability of viable propagules, particularly vegetative fragments that facilitate recovery beyond the local meadow through long-distance dispersal. The dispersal of vegetative fragments by ocean currents, waves and wind can be predicted by biophysical models. Among the model parameters, the duration of fragment buoyancy is an important determinant of dispersal but remains poorly quantified for tropical seagrass species. Yet, few empirical studies have assessed fragment dispersal traits and only for a small number of seagrass taxa. This limitation is particularly pronounced in tropical ecosystems, including the Great Barrier Reef (GBR), Australia, where tropical species exhibit diverse life histories and form extensive mixed-species meadows. This study aims to improve the accuracy of biophysical dispersal models for tropical seagrass by generating robust, species-specific data. We quantified the buoyancy duration of fragments from three species-Halophila ovalis, Halodule uninervis, and Zostera muelleri-over 48 days, and assessed whether initial morphological traits influenced buoyancy, finding species type was the primary determinant rather than fragment size. We then incorporated these empirical estimates into a biophysical model to evaluate their effects on dispersal. Our results highlight major differences between species. Z. muelleri floated the longest (24.7 ± 3.0 days); H. uninervis sank the fastest; and H. ovalis was intermediate, generating broken fragments available for further dispersal. Integrating these experimental derived buoyancy values into a biophysical model reduced the mean predicted dispersal distances by 44% on average compared to previous models. These findings highlight interspecific dispersal behaviours and provide useable empirical data to refine future modelling studies. Such improvements are essential for predicting seagrass recovery, guiding restoration site selection, and informing management strategies that maintain connectivity and ecosystem resilience.

Coastal marine species and ecosystems face increasing pressure from anthropogenic threats. Green turtles (Chelonia mydas), listed as Vulnerable in Australia, are ecologically important and culturally significant for Indigenous Traditional Owners. This study co-developed a spatial risk assessment with eight Indigenous ranger groups to assess threats to green turtles in waters of Australia’s Northern Territory. Six anthropogenic hazards (comprising 11 threats) were mapped and combined with turtle occupancy, derived from the satellite tracks of 45 green turtles, to quantify threat exposure. Expert knowledge from Indigenous rangers on the impact and occurrence of 24 threats was combined to assess turtle vulnerability, generating a spatially explicit map of relative risk. Darwin Harbour had the highest concentration of overlapping threats, including artificial light, recreational vessels, oil infrastructure and shipping. Turtle vulnerability varied by region, reflecting local knowledge. Nest predation (West Arnhem, Tiwi Islands), sea-level rise, traditional hunting and industrial pollution had the highest threat scores. Foraging turtles were concentrated in eight areas, and Channel Island (Darwin Harbour) posed the highest relative risk for foraging turtles. Migration routes near Darwin Harbour and Bynoe Harbour were risk hotspots. Mixed-effects analyses showed that perceived vulnerability was structured primarily by threat type, with ranger experience contributing to variation in threat perceptions, highlighting the importance of retaining experienced Indigenous rangers for effective place-based conservation. Integrating Indigenous knowledge with spatial data, the study identifies high-risk areas for a culturally and ecologically important species and supports targeted management and sustained investment in Indigenous ranger programs amid increasing climate and industrial pressures.

Current and future coral reef resilience will depend heavily on larval connectivity between reef systems, enabling populations to recover from repeated disturbance. However, climate warming is rapidly reducing larval dispersal, threatening reef recovery potential following mass bleaching. Using a stochastic biophysical Lagrangian particle-tracking model, this study examined large-scale dispersal of coral larvae across the southern Pacific Ocean, focusing on reefs classified using an eco-evolutionary framework ('resistance, recovery, avoidance'). Dispersal was simulated across 850 reefs in the southwestern Pacific (2011-2024) for two coral species representing branching or massive corals under three warming scenarios (+1 degrees C, +2.5 degrees C, +4 degrees C), and analysed for source-sink dynamics. We identified key stepping-stone reefs in the Coral Sea and show that resilient, heat-tolerant reefs have limited source-sink connectivity within this larger region. Lord Howe Island (LHI) may represent a potential refugium in a future of significant larval dispersal limitation under projected climate warming. However, its limited connectivity constrains its natural contribution to regional larval supply, making it simultaneously a conservation priority and a candidate for managed intervention. Synthesis and applications. Our results demonstrate the importance of integrating connectivity into conservation planning by highlighting that the current marine protected area networks across the southwestern Pacific should be managed as an interconnected network rather than as isolated reserves. Additionally, a prioritisation of the enhanced protection of Coral Sea reefs and LHI is warranted given their importance as stepping-stone reefs bridging distant reef systems or isolated dispersal, respectively. Finally, the intentional movement of larvae from resilient, heat-tolerant reefs to other locations could be investigated given their lower relative outward connectivity, with the aim to boost heat tolerance in surrounding reefs. Taken together, these results show that a potential expansion of transboundary management frameworks will be critical to maintain important larval corridors between the southern Great Barrier Reef, New Caledonia and LHI to sustain regional metapopulation resilience under the pressure of a warming world.Read the free Plain Language Summary for this article on the journal's .

Intraspecific trait variation (ITV) enhances the precision of applying functional trait approaches in plant ecology. Despite its benefits, ITV is rarely considered in functional trait-based seagrass research. The goal of our research is to measure ITV in the tropical seagrass species Halodule uninervis and assess the environmental factors associated with its variation. We measured eight traits of H. uninervis collected along the Queensland coast. Statistical analyses were conducted to identify the range of ITV, determine the relationship between environmental factors and trait variation, and estimate the potential effect of ITV on ecosystem services supported by these meadows. H. uninervis exhibits a distinct dimorphic pattern of ITV, particularly evident in leaf width and rhizome diameter, with air exposure and mean sediment grain size associated with variation in these traits. These findings highlight the importance of accounting for ITV in seagrass field surveys and suggest that variation within species may influence their ecological responses and functional roles in meadows.

Abstract Underwater photogrammetry is routinely used to monitor large areas of complex and heterogeneous ecosystems, such as coral reefs. However, deriving data on benthic components (i.e. sand, rubble, coral and algae) from photogrammetry products has remained challenging due to the highly time‐consuming process of manual data extraction. We developed a machine learning approach to quantify benthic community composition in coral reefs from orthomosaics, which requires no manual delineation of benthic components for training or implementation. The current study presents RapidBenthos, an automated workflow that segments and classifies large‐area images. Our pipeline (1) uses a pre‐trained segmentation model, eliminating the need for manually generated fine‐scale segmented training data, and (2) classifies the resulting segments from multiple views using the underlying survey images, allowing for classification to fine taxonomic levels. Within a test photomosaic built from a coral reef area of 40 m−2, the model automatically detected 43 different benthic classes. Validation resulted in an overall classification accuracy of 0.96 and a segmentation accuracy of 0.87, when compared to a manually digitised replica. The RapidBenthos workflow was 195 times faster than manual segmentation and classification. Additional validation of 524 Acropora coral colonies from 11 additional test plots resulted in a segmentation accuracy of 0.92 and classification accuracy of 0.88 to the coarser ‘Acropora’ group. RapidBenthos has the capability to extract an unprecedented level of data from photomosaics of coral reefs or other complex environments, allowing to sustainably scale photogrammetric monitoring technique both in replicate and survey extent, which consequently can lead to new research questions and more informed ecosystem management.

The resilience of seagrass meadows strongly depends on the dispersal of their propagules, which fosters recovery and replenishment after disturbances. However, predicting dispersal patterns across dynamic coastal environments and large spatial and temporal scales remains challenging due to the lack of empirical observations. Biophysical models, integrating oceanic and atmospheric drivers with species-specific traits such as buoyancy and lifespan, are commonly used to simulate propagule transport. Yet, few studies account for the interspecific and interannual variability inherent in tropical seagrass ecosystems. Here we present a high-resolution seagrass biophysical dispersal model applied to 11 tropical seagrass species across the entire Great Barrier Reef World Heritage Area (GBRWHA), Australia, and run this model over a 6-year period (2011-2016). We use this model to assess how the interspecific variability in the buoyancy and windage of seagrass propagules affect their dispersal patterns and how these patterns further vary both seasonally and interannually. Our results reveal that species-specific factors such as their windage and buoyancy, as well as the season and region in which they disperse had the largest influence on dispersal distance. H. spinulosa and S. isoetifolium showed the greatest dispersal in the Whitsunday region, while the wet season promoted higher local retention due to lower wind speeds. From a management perspective, this highlights the need to account for species-specific information when devising seagrass management strategies. The outcomes of this research reveal the inherent complexities of predicting multi-species dispersal over large spatial and temporal scales, with broader implications for predicting dispersal in complex coastal ecosystems.

Context Green turtles (Chelonia mydas) are listed as vulnerable in Australia and are culturally significant to Indigenous Traditional Owners. However, their foraging habitats remain poorly understood, particularly in northern Australia. Aims To map green turtle foraging habitats in the Northern Territory, through collaboration with Traditional Owners and ranger groups to support Sea Country management. Methods Visual classifications of towed video transect data were used in a Support Vector Machine Learning Model to predict habitat across 379 km2 of remotely sensed satellite imagery, encompassing two green turtle foraging grounds within jointly managed parks, namely, Trepang Bay (Garig Gunak Barlu Marine Park) and Field Island (Kakadu National Park). Key results Foraging turtle habitat; algae and seagrass made up 30% of the Trepang Bay and 18.05% of the Field Island foraging areas. The classification accuracy of the model showed a high level of agreement at both sites (0.63 and 0.75 respectively). Conclusion These habitats provide good foraging grounds for green turtles and support different age classes for various behaviours, including resting and predator avoidance. Implications The simple and repeatable field methods used in this study allow for ongoing monitoring by ranger groups. The findings will support conservation planning and management in the Northern Territory.

Aim: Dispersal and connectivity play important roles in shaping the population structure of giant kelp, Macrocystis pyrifera, across the western coast of South America. Its high potential dispersal capacity suggests the existence of metapopulations, where discrete habitat patches or groups of patches form subpopulations that interact at some level. However, the dispersal patterns of giant kelp in this region have not been quantified. This study assesses the dispersal and settlement of Macrocystis pyrifera in the southeast Pacific, specifically focusing on the impact of environmental variables and ocean currents within the Humboldt Current System. Location: Southeast Pacific (coast of Chile and Peru). Time Period: 1997-2008. Major Taxa Studied: Macrocystis pyrifera (giant kelp). Methods: Using a combination of hydrodynamic and individual-based models, we analysed kelp fragment movements over 12 years, with a particular emphasis on the effects of the El Nino-Southern Oscillation (ENSO) and seasonal changes. Results: Our results highlight a key settlement area in the southern Chilean region. We found that shorter travel distances of kelp fragments increased the likelihood of reaching a suitable habitat, underscoring the importance of local environmental conditions. We delineated intricate northward dispersal paths for kelp fragments, which appear to be governed by the interplay of wind and ocean current dynamics. Seasonal variations, notably in autumn and winter, favour the likelihood of reaching a settlement area due to favourable winds. Furthermore, ENSO events appear to influence dispersal distances, with fragments travelling the longest distances during El Ni & ntilde;o phases. Main Conclusion: These findings are essential for informing kelp conservation strategies in the context of climate change, emphasizing the necessity of considering local and seasonal environmental factors alongside ENSO impacts.

The Sindhudurg coast in Maharashtra, India, supports diverse fisheries and is a vital habitat for the Indian Ocean humpback dolphin Sousa plumbea , a species found nearshore along the west coast of India. Here, dolphins cause economic losses to fishermen by competing for catch and damaging fishing gear. Dolphins are also affected by entanglement in or ingestion of parts of fishing nets. There is a need for a systematic assessment of the distribution of risks to dolphins and the specific fisheries most impacted by interactions with dolphins. To bridge this information gap, we (1) analysed the behaviour and locations of dolphin groups in the absence and presence of fishing vessels (2012-2015) and (2) mapped the spatial overlap of dolphins and fishing vessels (2014-2015) to determine high-risk areas for dolphins. We observed 175 dolphin groups, of which 75 groups (43%) engaged in foraging behaviours. Dolphins occurred in approximately 50% (164 km 2 ) of the total survey area, and fishing vessels were observed in 100% of the total survey area (333 km 2 ). The proportion of dolphin groups engaged in foraging behaviours was significantly higher when fishing vessels were present compared to when absent. Gillnet (55%) and trawl (32%) accounted for the majority of observed fishing vessels when dolphins were present. Gillnet vessels had a 95% spatial overlap with dolphin habitat, and trawl and purse-seine vessels each had 86%. We identified 8 high-risk areas that were within ~500 m of the coastline, coinciding with high-density dolphin habitat near estuaries. These results have the potential to inform marine mammal conservation and fishery management in Sindhudurg.

Context Seagrasses form an important habitat that provides diverse ecosystem services essential for both the environment and people. In tropical Queensland, Australia, these meadows hold significant economic and cultural value, serving as nurseries for marine species and sustaining dugongs and green turtles. The biomass and size of tropical seagrass meadows in Queensland varies considerably and are influenced by various factors, both biotic and abiotic.Aims Functional trait-based approaches can improve the estimation of seagrass-meadow resilience and services provision by describing the relationship between environment and individual performance. To support these approaches, we provide a seagrass functional-trait database focusing on resilience and function provision for tropical Queensland.Methods We employed a combination of literature reviews, database searches, botanical information, and structured expert elicitation to target 17 functional traits across 13 seagrass species in tropical Queensland.Key results We developed a traits database to inform functional trait-based approaches to assessing seagrass-meadow resilience and dynamics. The outputs included trait information for approximately 78% of the targeted traits (of 221 unique trait-seagrass combinations).Conclusions With current information on functional traits, we can improve the estimation of resilience and ecosystem services for tropical Queensland seagrass species. We have also highlighted trait data gaps and areas for further research.Implications We have provided examples of applying this database within the tropical Queensland context, with the potential to facilitate regional comparative studies. Our database complements existing plant-trait databases and serves as a valuable resource for future trait-based seagrass research in tropical Queensland.

The rate of exchange, or connectivity, among populations affects population and metapopulation dynamics and genetics, responses to species invasions and disease transmission, species expansion, and population growth (Cowen and Sponaugle 2009). In the case of marine aquatic plants such as seagrasses, dispersal of propagules (seeds, fruit, or viable plant fragments) is critical to the distribution, structure, and resilience of populations (Kendrick et al. 2012). The convective forces of ocean waves and currents are efficient vectors for dispersal of seagrass and facilitate the replenishment and recovery of populations after disturbance at multiple spatial and temporal scales (McMahon et al. 2014; Grech et al. 2016; Kendrick et al. 2017). Connectivity underpins the persistence of seagrass populations, so knowledge on mechanisms and pathways for seagrass dispersal are integral to the design of management and conservation actions.

Background and aims: Long distance dispersal (LDD) contributes to the replenishment and recovery of tropical seagrass habitats exposed to disturbance, such as cyclones and infrastructure development. However, our current knowledge regarding the physical attributes of seagrass fragments that influence LDD predominantly stems from temperate species and regions. The goal of this paper is to measure seagrass fragment density and viability in two tropical species, assessing various factors influencing their distribution. Methods: We measured the density and viability of floating seagrass fragments for two tropical seagrass species (Zostera muelleri and Halodule uninervis) in two coastal seagrass meadows in the central Great Barrier Reef World Heritage Area, Australia. We assessed the effect of wind speed, wind direction, seagrass growing/senescent season, seagrass meadow density, meadow location and dugong foraging intensity on fragment density. We also measured seagrass fragment structure and fragment viability; i.e., potential to establish into a new plant. Key results: We found that seagrass meadow density, season, wind direction and wind speed influenced total fragment density, while season and wind speed influenced the density of viable fragments. Dugong foraging intensity did not influence fragment density. Our results indicate that wave action from winds combined with high seagrass meadow density increases seagrass fragment creation, and that more fragments are produced during the growing than the senescent season. Seagrass fragments classified as viable for Z. muelleri and H. uninervis had significantly more shoots and leaves than non-viable fragments. We collected 0.63 (+/- 0.08 SE) floating viable fragments 100 m 2 in the growing season, and 0.13 (+/- 0.03 SE) viable fragments 100 m 2 in the senescent season. Over a third (38%) of all fragments collected were viable. Conclusion: There is likely to be a large number of viable seagrass fragments available for long distance dispersal. This study's outputs can inform dispersal and connectivity models that are used to direct seagrass ecosystem management and conservation strategies.

Nearly a billion people depend on tropical seascapes. The need to ensure sustainable use of these vital areas is recognised, as one of 17 policy commitments made by world leaders, in Sustainable Development Goal (SDG) 14 (‘Life below Water’) of the United Nations. SDG 14 seeks to secure marine sustainability by 2030. In a time of increasing social-ecological unpredictability and risk, scientists and policymakers working towards SDG 14 in the Asia–Pacific region need to know: (1) How are seascapes changing? (2) What can global society do about these changes? and (3) How can science and society together achieve sustainable seascape futures? Through a horizon scan, we identified nine emerging research priorities that clarify potential research contributions to marine sustainability in locations with high coral reef abundance. They include research on seascape geological and biological evolution and adaptation; elucidating drivers and mechanisms of change; understanding how seascape functions and services are produced, and how people depend on them; costs, benefits, and trade-offs to people in changing seascapes; improving seascape technologies and practices; learning to govern and manage seascapes for all; sustainable use, justice, and human well-being; bridging communities and epistemologies for innovative, equitable, and scale-crossing solutions; and informing resilient seascape futures through modelling and synthesis. Researchers can contribute to the sustainability of tropical seascapes by co-developing transdisciplinary understandings of people and ecosystems, emphasising the importance of equity and justice, and improving knowledge of key cross-scale and cross-level processes, feedbacks, and thresholds.

Close-range underwater photogrammetry, hereafter referred to as photogrammetry, is rapidly emerging as a new standard in measuring and monitoring coral reefs due to its potential to record colony- and habitat-scale metrics in two and three dimensions at sub-centimetre scales. Despite the recent popularisation of photogrammetry, a comprehensive assessment of its applications to coral reefs seascape ecology has not yet been conducted. We systematically reviewed 125 publications on coral reef photogrammetry to assess: 1) its global trends and use; 2) how benthic community data is extracted from imagery; 3) the range of metrics derived and their ecological applications; and 4) key limitations of the approach. Results indicate that development and application of photogrammetry to coral reef ecology has accelerated rapidly in the last 15 years. In total, 55 metrics derived from photogrammetry, grouped in 10 categories, have been used to inform ecological studies on benthic assemblage, habitat structural complexity, and ecosystem condition and trajectory. The high level of effort required to quantify benthic assemblages was identified as a primary workflow bottleneck. We highlight the versatility of photogrammetry to study and monitor coral reef ecosystems and its capacity to quantify benthic community dynamics, habitat, and trajectories, which are vital to inform coral reef conservation and restoration.

Marine mammal interactions with fisheries, such as bycatch and depredation, are a common occurrence across commercial and small-scale fisheries. We conducted a systematic review to assess the management responses to marine mammal interactions with fisheries. We analyzed literature between 1995 and 2021 to measure research trends in studies on direct and indirect interactions for: (i) high and low to middle-income countries, (ii) fishery operations (commercial and small-scale), and (iii) taxonomic groups. Management responses were categorized using the framework described previously in peer-reviewed studies. Marine mammal bycatch remains a major conservation concern, followed by marine mammal depredation of fishing gear. A high proportion of studies concentrated on commercial fisheries in high-income countries, with an increase in small-scale fisheries in low to middle-income countries between 1999 and 2020. The insufficient understanding of the social dimensions of interactions and the inevitable uncertainties concerning animal and human behaviors are major challenges to effective management. Despite the key role of human behavior and socioeconomics, we found only eight articles that incorporate human dimensions in the management context. Integrating social dimensions of marine mammal interactions with fisheries could help in setting pragmatic conservation priorities based on enhanced understanding of critical knowledge gaps. An area-specific adaptive management framework could be an effective tool in reducing the risk to marine mammals from fisheries by coupling technical solutions with socio-economic and political interventions. We conclude that despite the vast body of literature on this subject, a “silver bullet” management solution to marine mammal interactions with fisheries does not yet exist.

Biophysical models simulate dispersal and connectivity in marine environments by combining numerical models that represent water circulation with biological parameters that define the attributes of species. The effects of parameters, such as the number of particles released to simulate the trajectories of individual organisms, is potentially large but rarely tested. We present a framework to measure the optimal number of particles required to capture variability in dispersal and connectivity of the marine plants, seagrasses. We found that the number of optimal release particles per element (or grid cell) for dispersal estimates varied with seagrass habitat type, season, and physical parameters of the modelled propagules (i.e., wind drag). Connectivity metrics were comparatively much less sensitive, requiring lower particle numbers to achieve stable results. We provide guidance on important factors to consider when determining the optimal number of particles required to robustly predict dispersal and connectivity in biophysical models of marine plants.

Protected areas are the primary strategy for maintaining natural landscapes and separating biodiversity features from preventable anthropogenic threats. The Convention on Biological Diversity calls for the coverage of at least 17% of land by protected areas, and the strategic prioritization of important biodiversity areas. Using the spatially explicit reserve design software, Marxan, this study combines climate refugia modelled under future climates in the year 2070 and bioregions to identify priority sites for protected area expansion under climate change in the state of New South Wales (NSW), Australia. Priority sites for new protected areas that meet bioregion and climate refugia targets were identified in central-western, northeast and patches of southeast NSW. Seven existing parks, including Kosciuszko National Park, overlapped with regions identified repeatedly as climate refugia under 12 future climate scenarios. The recommendations from this study support policy-makers in prioritizing the protection of biodiversity under a changing and uncertain climate.

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.

Protected areas aim to conserve nature by providing safe havens for biodiversity. However, protection from habitat loss, poaching and other threats, is not guaranteed without adequate investment in their management. Here, we examine the relationship between management effectiveness using the Management Effectiveness Tracking Tool (METT) and trends of 79 populations of mammals and birds in 12 Southeast Asian protected areas from Cambodia, Indonesia, Thailand and Vietnam. Despite the negative influence of corruption on species population change, we find evidence that adequate financial and human resourcing are important determinants in achieving good biodiversity outcomes. Management resourcing, national government transparency and body size collectively explain 29% of the variation in animal population trends in our model. Our paper contributes to a growing evidence base linking management resourcing shortfalls to declining biodiversity populations in protected areas. Our key findings are relevant to international funding agencies, governments and NGOs, to aid decision making around the allocation of conservation resources in Southeast Asia.