Assessment of habitat representation across a network of marine protected areas with implications for the spatial design of monitoring

Deep-sea coral habitats off the north atlantic Morocco: Distribution and associated communities

The recent decline in the health status of deep-sea habitats around the world has pushed the need to document and map their distribution to preserve them in their marine ecosystems. This work describes deep-water coral habitats (133-729 m) and their associated communities, based on nine ROV video transects. These transects cover a 171 km sub-seafloor profile within a predefined 5560 km2 area along the North Atlantic coast of Morocco, surveyed in 2020 as part of a coral habitat mapping study under the FAO-NANSEN programme. The nine sites were initially explored using multibeam echosounder, to generate a detailed bathymetry map allowing for the positioning of video transects. Megafauna and sediment composition was recorded along transects, and in total 1854 individuals were annotated, and 59 taxa were identified. To identify coral communities and related species assemblages, we used a cluster analysis for classification and the ordination analysis Detrended Correspondence Analysis (DCA) to identify the environmental drivers behind the community patterns. Eight environmental variables were compared with the DCA ordination results, and the important variables were bedrock, mud and depth. The results revealed six megabenthic communities. Three groups were associated with soft sediments, mainly mud. Group I, at depths of 605-726 m, was characterized by Ceriantharia and Synaphobranchus kaupii. Group V, at 133 m depth, was dominated by Ceriantharia. Group VI, consisting of Centrostephanus sp. and a fish community (Scorpaenidae, Capros aper, and Macroramphosus sp.), was found at 201 m depth. In mixed bottoms, where mud is the dominant substrate, Group II was characterized by Crinoidea and sea pens (Funiculina quadrangularis and Virgularia mirabilis) at a depth range of 207-369 m, while Group III, found at depths of 465-602 m, was characterized by sea pens (Pennatula phosphorea and Funiculina quadrangularis), Crinoidea, and the key species Isidella elongata. Group IV, at 207 m depth, was represented by Sertularella sp. and Ellisella paraplexauroides as the dominant species. This first study about mapping deep sea coral habitats in the North Atlantic coast of Morocco reveals the identification of different habitats and new species. It contributes to Strengthen Science for Conservation and Sustainable Management of Deep-Water Corals in Morocco.

A spatial analysis of seagrass habitat and community diversity in the Great Barrier Reef World Heritage Area

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.

China's little-known efforts to protect its marine ecosystems safeguard some habitats but omit others

China’s stature as the world’s major producer and consumer of seafood is legendary, but its long-standing tradition of protecting marine life domestically is virtually unknown. We present the most comprehensive database on area-based marine conservation in China including 326 sites that conserve 12.98% of China’s seas and address 142 conservation objectives. Twenty-two percent of shallow habitats (<10 meters) were fully or highly protected and 20% of waters 10 to 50 meters deep were conserved to some degree. Ecosystems in deeper waters (>50 meters) are critical to protect, yet <5% of these waters in China were conserved, primarily in areas with the highest chlorophyll-α concentrations. Habitats such as underwater canyons and seamounts beyond the continental shelf had no area-based protection. While China has made progress in marine protection within its boundaries, there is more work to be done to ensure that the full suite of marine life is safeguarded.

Benthic diversity patterns and predictors: A study case with inferences for conservation

Understanding which drivers cause diversity patterns is a key issue in conservation. Here we applied a spatially explicit model to predict marine benthic diversity patterns according to environmental factors in the NW Mediterranean Sea. While most conservation-oriented diversity studies consider species richness only and neglect equitability, we measured separately species richness, equitability, and 'overall' diversity (i.e., the Shannon-Wiener H' function) on a dataset of 890 benthic species × 209 samples. Diversity values were predicted by means of Random Forest regression, on the basis of 10 factors: depth, distance from the coast, distance from the shelf break, latitude, sea-floor slope, sediment grain size, sediment sorting, distance from harbours and marinas, distance from rivers, and sampling gear. Predictions by Random Forests were accurate, the main predictors being latitude, sediment grain size, depth and distance from the coast. Based on predicted values, diversity hotspots were identified as those localities where indices were in the 15% top segment of ranked values. Only a minority of the diversity hotspots was included within the boundaries of the protection institutes established in the region. Marine protected areas are often created in sites harbouring important coastal habitats, which risks neglecting the diversity hidden in the sedimentary seafloor. We suggest that marine protected areas should accommodate portions of sedimentary habitat within their boundaries to improve diversity conservation.

An ecological framework for informing permitting decisions on scientific activities in protected areas

There are numerous reasons to conduct scientific research within protected areas, but research activities may also negatively impact organisms and habitats, and thus conflict with a protected area’s conservation goals. We developed a quantitative ecological decision-support framework that estimates these potential impacts so managers can weigh costs and benefits of proposed research projects and make informed permitting decisions. The framework generates quantitative estimates of the ecological impacts of the project and the cumulative impacts of the proposed project and all other projects in the protected area, and then compares the estimated cumulative impacts of all projects with policy-based acceptable impact thresholds. We use a series of simplified equations (models) to assess the impacts of proposed research to: a) the population of any targeted species, b) the major ecological assemblages that make up the community, and c) the physical habitat that supports protected area biota. These models consider both targeted and incidental impacts to the ecosystem and include consideration of the vulnerability of targeted species, assemblages, and habitats, based on their recovery time and ecological role. We parameterized the models for a wide variety of potential research activities that regularly occur in the study area using a combination of literature review and expert judgment with a precautionary approach to uncertainty. We also conducted sensitivity analyses to examine the relationships between model input parameters and estimated impacts to understand the dominant drivers of the ecological impact estimates. Although the decision-support framework was designed for and adopted by the California Department of Fish and Wildlife for permitting scientific studies in the state-wide network of marine protected areas (MPAs), the framework can readily be adapted for terrestrial and freshwater protected areas.

A predictive approach to benthic marine habitat mapping: Efficacy and management implications

The availability of marine habitats maps remains limited due to difficulty and cost of working at sea. Reduced light penetration in the water hampers the use of optical imagery, and acoustic methods require extensive sea-truth activities. Predictive spatial modelling may offer an alternative to produce benthic habitat maps based on complete acoustic coverage of the seafloor together with a comparatively low number of sea truths. This approach was applied to the coralligenous reefs of the Marine Protected Area of Tavolara - Punta Coda Cavallo (NE Sardinia, Italy). Fuzzy clustering, applied to a set of observations made by scuba diving and used as sea truth, allowed recognising five coralligenous habitats, all but one existing within EUNIS (European Nature Information System) types. Variable importance plots showed that the distribution of habitats was driven by distance from coast, depth, and lithotype, and allowed mapping their distribution over the MPA. Congruence between observed and predicted distributions and accuracy of the classification was high. Results allowed calculating the occurrence of the distinct coralligenous habitats in zones with different protection level. The five habitats are unequally protected since the protection regime was established when detailed marine habitat maps were not available. A SWOT (Strengths-Weaknesses-Opportunities-Threats) analysis was performed to identify critical points and potentialities of the method. The method developed proved to be reliable and the results obtained will be useful when modulating on-going and future management actions in the studied area and in other Mediterranean MPAs to develop conservation efforts at basin scale.