Habitat characterization,anthropogenic impacts and conservation of rhodolith beds off southeastern Malta

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Coral reef organisms as bioregion indicators off Halmahera,Moluccas, Indonesia

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Essential fish habitats and hotspots of nekto‐benthic diversity and density in the western Mediterranean

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Combining geomorphologic,biological and accessibility values for marine natural heritage evaluation and conservation

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Utilizing benthic habitat maps to inform biodiversity monitoring in marine protected areas

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Integrating fine‐scale seafloor mapping and spatial pattern metrics into marine conservation prioritization

1. Marine protected area (MPA) planning often relies on scientific principles that help ensure that an area selected for conservation will effectively protect biodiversity. Capturing ecological processes in MPA network planning has received increased attention in recent years. High‐resolution seafloor maps, which show patterns in seafloor bio‐physical characteristics, can support our understanding of ecological processes.
2. In part, owing to a global lack of high‐resolution seafloor maps, studies that aim to integrate seascape spatial pattern and conservation prioritization often focus on shallow biogenic habitats with less attention paid to deeper benthic seascapes (benthoscapes) mapped using acoustic techniques. Acoustic seafloor mapping strategies yield the spatial information required to extend conservation prioritization research into these environments, making incorporating seafloor ecological processes into conservation prioritization increasingly achievable.
3. Here, a new method is proposed and tested that combines benthoscape mapping, landscape ecology metrics and a conservation decision support tool to prioritize areas with structural and potential connectivity value in MPA placement. Using a case study in eastern Canada, benthoscape composition and configuration were quantified using spatial pattern metrics and integrated into Marxan.
4. Results illustrate how large patches of seafloor habitat in close proximity to neighbouring patches can be preferentially selected when benthoscape configuration is considered. The flexibility of the method for including relevant spatial pattern metrics or species‐specific movement data is discussed to illustrate how benthic habitat maps can improve existing conservation planning methods and complement existing and future work to support marine biodiversity conservation.

     

Coralligenous assemblages along their geographical distribution: Testing of concepts and implications for management

• 1. The coralligenous habitat was studied at the large Mediterranean scale, by applying a standardized, non‐destructive photo‐sampling protocol, developed in the framework of the CIGESMED project.
• 2. The results provided evidence to support the following statements: (a) the assemblage pattern is not homogeneously distributed across the four Mediterranean ecoregions studied (biotic gradients hypothesis); and (b) the assemblage pattern does not change significantly when the information is aggregated to higher taxonomic levels (taxonomic sufficiency hypothesis).
• 3. Surrogate taxonomic categories higher than species, such as genus and family, can be used to reveal the multivariate pattern of the coralligenous assemblages.
• 4. Although preliminary at the pan‐Mediterranean scale, these outcomes set the scene for future comparisons as more data sets become available but also for comparisons between taxonomic and functional patterns.

     

Conservation of Mediterranean habitats and biodiversity countdowns: what information do we really need?

• 1. The relentless increase in both human activities and exploitation of marine resources is a threat to marine habitats and species.
• 2. For marine systems, several protection initiatives have been outlined over the past decade to significantly reduce the current rate of biodiversity loss at global, regional, and national levels, and to establish representative networks of marine protected areas with the aim of protecting 10–30% of marine habitats.
• 3. Reliable estimates of the total area occupied by each habitat are crucial to set adequate protection initiatives. Habitat mapping requires a sound habitat classification. Many classification schemes have been developed in different areas of the world, sometimes based on questionable criteria.
• 4. A critical analysis of the most recent marine habitat classification list produced for the Mediterranean Sea from the Regional Activity Centre for Specially Protected Areas (RAC/SPA) showed that (i) 39% of habitats and associated species considered in the list are scarcely covered by scientific knowledge from Web‐based resources; (ii) 62% of the species/genera included in the list are primary producers; (iii) quantitative information about the geographical distribution of selected habitats and associated species is scant; and (iv) when available, information is largely unbalanced and biased towards the shallow western Mediterranean Sea.
• 5. Improved inventories of marine habitats are needed to support accurate and consistent mapping activities. The combination of large‐scale mapping and sound habitat classifications will allow better estimates of biodiversity distribution, to reverse regional/global habitat loss rates through the achievement of conservation targets and deadlines that, for the moment, are systematically not met. Copyright © 2011 John Wiley & Sons, Ltd.

     

Improving benthic biodiversity assessments in turbid aquatic environments

1. Biodiversity in turbid aquatic environments is commonly assessed using extractive sampling methods that damage the seabed. Underwater cameras equipped with clear liquid optical chambers (CLOCs) for the assessment of seabed habitats and species are a non-extractive alternative and have been applied in turbid environments globally. A CLOC is a body of clear liquid positioned in front of a camera to reduce the scattering of light that would otherwise occur when passing through the turbid water it displaces. Here, we test and quantify the effectiveness of a CLOC for marine benthic biodiversity assessments over gradients of increasing turbidity.
2. The addition of a CLOC to a conventional benthic camera system significantly enhanced the quality of information gathered. Images acquired using the CLOC system consistently recorded statistically higher values of image quality (49% increase, based on the clarity of the image), seabed visible within the drop-down frame (34% increase), and European Nature Information System habitat level identification (49% increase). Furthermore, it was found that the ‘annotation success’ of taxa (classification of a specimen to family level or higher) was found to increase between individual experts in the presence of a CLOC. A reduced sampling effort was also identified when using a CLOC. Taxonomic richness increased by 27% when comparing the same number of image stills collected with and without the CLOC.
3. By reducing the limitations of underwater visibility previously attributed to underwater cameras, this concept extends the potential for use of non-destructive survey techniques and allows for future users to collect robust information of an area, making better informed management decisions.

     

Benthic habitat modelling and mapping as a conservation tool for marine protected areas: A seamount in the western Mediterranean

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Sediment organic carbon integrates changing environmental conditions to predict benthic assemblages in shallow Arctic seas

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Effectiveness of acoustic cameras as tools for assessing biogenic structures formed by Sabellaria in highly turbid environments

1. Accurately mapping the extent and status of biogenic reefs formed by polychaete worms of the genus Sabellaria is of conservation importance given their protected status across Europe.
2. Traditionally, side‐scan sonar (SSS) combined with ground‐truthing in the form of seabed photography and videography has been widely accepted as the most suitable approach for mapping these reefs in the subtidal zone. In highly turbid environments visibility at the seabed can be near zero, however, rendering optical‐based ground‐truthing redundant. Consequently, the true distribution and status of Sabellaria reefs in some shallow subtidal areas around the UK remains unclear despite their designation as Annex‐I features of several Special Areas of Conservation (SACs) under the Habitats Directive.
3. Acoustic camera imagery (ACI) collected using acoustic cameras in two deployment configurations matched well with the backscatter signatures of seabed features in corresponding SSS data. The ACI was of suitable resolution for visualizing Sabellaria colony structures, allowing for their Annex‐I ‘reef’ defining attributes (extent, patchiness, and elevation) to be assessed. Colony formation ‘type’ was also distinguishable in the ACI, although confidence in differentiating between low‐lying Sabellaria formations and surrounding substrates was low, particularly when using a pole‐mounted configuration.
4. This study provides a proof of concept for using acoustic cameras as tools for ground‐truthing SSS interpretation and assessing the status of Sabellaria bioconstructions in low‐visibility environments. Further development of this approach and incorporating it into statutory monitoring programmes could improve the management of the reef habitats in subtidal areas of the Severn Estuary and other highly turbid environments.

     

Evaluating the distribution of priority benthic habitats through a remotely operated vehicle to support conservation measures off Linosa Island (Sicily Channel,Mediterranean Sea)

1. Explorations of the Mediterranean deep sea using remotely operated vehicles have shown that the sea bed hosts rich habitats, supporting high biodiversity. However, there have been only a few studies dealing with the southern part of the basin, leading to limited protection and conservation efforts in this area.
2. This study aimed to explore the sea bed off Linosa Island (Sicily Channel, southern Mediterranean Sea), which is considered a ‘sentinel area’ for alien species and global environmental changes owing to its geographic position, thus deserving special attention.
3. Remotely operated vehicle surveys, carried out in 2016 and 2017, were analysed to provide the first ecological characterization of benthic assemblages at depths −19 – −384 m around Linosa Island.
4. Communities were dominated by three priority habitats, amounting to 39% of the almost 5 km of the sea floor that was surveyed. These are represented in the euphotic zone by Posidonia oceanica meadows and, at greater depth, by newly discovered dense coral forests and extended rhodolith/maërl beds. Sixteen habitat-forming species included in the Red List of the International Union for Conservation of Nature (e.g. gorgonians Eunicella cavolini and Paramuricea clavata, and black corals Antipathella subpinnata and Leiopathes glaberrima) were recorded, as well as individuals of Sargassum sp. at −100 m depth.
5. The volcanic island of Linosa represents a small, naturally preserved area, with very limited human pressure, hosting rich marine benthic biodiversity. Given the high species and habitat richness, we recommend its inclusion in the Special Protected Areas of Mediterranean Importance project (United Nations Environment Programme) and suggest a redefinition of the existing marine protected area extension.

     

Predictive modelling of mesophotic habitats in the north‐western Gulf of Mexico

1. Effective management of marine resources requires an understanding of the spatial distribution of biologically important communities.
2. The north‐western Gulf of Mexico contains diverse marine ecosystems at a large range of depths and geographic settings. To better understand the distribution of these marine habitats across large geographic areas under consideration for marine sanctuary status, presence‐only predictive modelling was used.
3. Results confirmed that local geographic characteristics can accurately predict the probability of occurrence for marine habitat types, and include a novel technique for assigning a single, most likely habitat in areas where multiple habitats are predicted.
4. The highest resolution bathymetric data (10 m) available for the region was used to develop raster layers that represent characteristics that have been shown to influence species occurrence in other settings.
5. A georeferenced historical photo record collected via remotely operated vehicle was classified according to six commonly found mesophotic habitats across the 18 reefs and banks under consideration for Flower Garden Banks National Marine Sanctuary boundary expansion.
6. Using maximum entropy modelling, the influence of local geographic characteristics on the presence of these habitats was measured and a spatial probability distribution was developed for each habitat type across the study area.

     

How much sampling does it take to detect trends in coral‐reef habitat using photoquadrat surveys?

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Seabed habitat mapping in the Kent Group of islands and its role in Marine protected area planning

• 1. Mapping of seabed habitats is increasingly being used to identify the distribution and structure of marine ecosystems and as surrogate measures of biodiversity for marine protected area (MPA) planning. In this study, the distribution of seabed habitats to the 3 nmi limit around the Kent Group of islands, south‐eastern Australia were mapped using video ground‐truthed single‐beam acoustics at the mesoscale level (10 m to 1 km) as part of an MPA planning process.
• 2. Six distinct seabed habitat types (continuous reef, patchy reef, sand, hard sand, sparse sponge, and seagrass) were identified based primarily on visual differences in the first and second echo and a further four (low, medium and high profile reef, and sand hills) on variations in seabed profile identified in the echogram. Extensive acoustic and video transects allowed an estimate of the broad‐scale spatial distribution of seabed habitats defined at several hierarchical levels and provided information on the cover of the dominant benthic species or assemblages.
• 3. The island group supports a range of consolidated habitats, including rocky reefs of varying profile dominated by the macroalgae Phyllospora comosa and Ecklonia radiata in depths down to around 45 m, adjacent to deeper sponge‐dominated reefs containing encrusting, erect and branching forms. Unconsolidated habitats occurred broadly through the island group, with the offshore region dominated by hard sand (sand with scallop shells and/or shell grit) and sparse sponge‐habitats (sand interspersed with low cover of sponge‐dominated assemblages). The sheltered coves were dominated by sand and seagrass habitats consisting of beds of the seagrasses Halophila australis, Zostera tasmanica and Posidonia australis, with variations in species composition, patchiness and percentage cover evident within and between coves.
• 4. In February 2004 the Kent Group MPA was announced, covering all waters out to the 3 nmi limit containing two areas defined as a Sanctuary Zone (‘no take’) and a Habitat Protection Zone (‘restricted take’). Overall, seabed habitat mapping generated a capability to define the boundary and size of potential MPA zones within the Kent Group of islands and was an essential component of the planning process to improve the likelihood that the MPA was comprehensive, adequate and representative (CAR).
• 5. The need to define habitats at multiple scales within a hierarchical classification scheme that are meaningful in terms of biodiversity and CAR principles and identifiable using mapping techniques is discussed.

Copyright © 2004 John Wiley & Sons, Ltd.     

Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez,Chile

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Using object‐based image analysis with multi‐temporal aerial imagery and LiDAR to detect change in temperate intertidal habitats

1. Intertidal habitat maps are needed at both fine and coarse scales to monitor change and inform conservation and management, but current methods of field survey and expert interpretation of aerial imagery can be time‐consuming and subjective. Object‐based image analysis (OBIA) of remote sensing data is increasingly employed for producing habitat or land cover maps. Users create automated workflows to segment imagery, creating ecologically meaningful objects, which are then classified based on their spectral or geometric properties, relationships to other objects and contextual data.
2. This study evaluates the change‐detection capability of OBIA in the intertidal environment by developing and comparing two OBIA methods for quantifying change in extent and distribution of habitats from freely available multi‐temporal aerial imagery and LiDAR data. Despite considerable variability in the data, pre‐ and post‐classification change detection methods had sufficient accuracy (mean overall accuracy from 70.5 to 82.6%) to monitor deviation from a background level of natural environmental fluctuation.
3. This insight into spatial and temporal patterns of natural cyclical change and their detectability by OBIA could inform use of remote sensing for regular, rapid coastal assessment, providing an alert system to direct survey resources to areas of ecologically relevant change.