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Aim To investigate some of the environmental variables underpinning the past and present distribution of an ecosystem engineer near its poleward range edge. Location >500 locations spanning >7,400 km around Ireland. Methods We collated past and present distribution records on a known climate change indicator, the reef‐forming worm Sabellaria alveolata (Linnaeus, 1767) in a biogeographic boundary region over 182 years (1836–2018). This included repeat sampling of 60 locations in the cooler 1950s and again in the warmer 2000s and 2010s. Using species distribution modelling, we identified some of the environmental drivers that likely underpin S. alveolata distribution towards the leading edge of its biogeographical range in Ireland. Results Through plotting 981 records of presence and absence, we revealed a discontinuous distribution with discretely bounded sub‐populations, and edges that coincide with the locations of tidal fronts. Repeat surveys of 60 locations across three time periods showed evidence of population increases, declines, local extirpation and recolonization events within the range, but no evidence of extensions beyond the previously identified distribution limits, despite decades of warming. At a regional scale, populations were relatively stable through time, but local populations in the cold Irish Sea appear highly dynamic and vulnerable to local extirpation risk. Contemporary distribution data (2013–2018) computed with modelled environmental data identified specific niche requirements which can explain the many distribution gaps, namely wave height, tidal amplitude, stratification index, then substrate type. Main conclusions In the face of climate warming, such specific niche requirements can create environmental barriers that may prevent species from extending beyond their leading edges. These boundaries may limit a species’ capacity to redistribute in response to global environmental change.

The goal of this paper is to propose a screening method for assessing the environmental risk to aquatic systems in harbours worldwide. A semi-quantitative method is based on environmental pressures, environmental conditions and societal response. The method is flexible enough to be applied to 15 harbours globally distributed through a multinational test using standardised and homogenised open data that can be obtained for any port worldwide. The method emerges as a useful approach towards the foundation of a global environmental risk atlas of harbours that should guide the harbour sector to develop a more globally informed strategy of sustainable development.

Climate change and coastal urbanization are driving the replacement of natural habitats with artificial structures and reclaimed land globally. These novel habitats are often poor surrogates for natural habitats. The application of integrated greening of grey infrastructure (IGGI) to artificial shorelines demonstrates how multifunctional structures can provide biodiversity benefits whilst simultaneously serving their primary engineering function. IGGI is being embraced globally, despite many knowledge gaps and limitations. It is a management tool to compensate anthropogenic impacts as part of the Mitigation Hierarchy. There is considerable scope for misuse and ‘greenwashing’ however, by making new developments appear more acceptable, thus facilitating the regulatory process. We encourage researchers to exercise caution when reporting on small-scale experimental trials. We advocate that greater attention is paid to when experiments ‘fail’ or yield unintended outcomes. We advise revisiting, repeating and expanding on experiments to test responses over broader spatio-temporal scales to improve the evidence base. Synthesis and applications. Where societal and economic demand makes development inevitable, particular attention should be paid to avoiding, minimizing and rehabilitating environmental impacts. Integrated greening of grey infrastructure (IGGI) should be implemented as partial compensation for environmental damage. Mutual benefits for both humans and nature can be achieved when IGGI is implemented retrospectively in previously developed or degraded environments. We caution, however, that any promise of net biodiversity gain from new developments should be scrutinized and any local ecological benefits set in the context of the wider environmental impacts. A ‘greened’ development will always impinge on natural systems, a reality that is much less recognized in the sea than on land.

Ecological risk assessment is often applied to guide the decision-making process that underpins ecosystem-based management and prioritisation of risk factors for management. Several studies have recently used ecological risk assessment approaches to identify risk factors of greatest concern, but rarely are the underlying methodological decisions discussed in terms of the effect that those decisions have on the outcome of the assessment and ultimately, how that affects prioritisation of risk factors for management. This study therefore evaluates the effect of methodological decisions involving (1) the choice and definition of risk factors, and (2) the calculation of risk scores, providing, where possible, recommendations on what should be the most appropriate methodologies. The definition of risk factors is often determined by the policy context and could result in the comparison of one broadly defined risk meta-factor (e.g. Food Production) with corresponding specific risk factors defined more narrowly (i.e. Oil and Gas production or Offshore Wind). Depending on the method to calculate risk this may result in a systematic bias prioritising any risk meta-factor. For the calculation of individual impact chain risk scores we compared weighted scores with ordinal scores, where the former allows more flexibility to represent the qualitative categories that determine risk and provided results better supported by scientific evidence. A consideration of different risk assessment applications in EBM showed there is no one-size-fits-all solution to this as these methodological decisions need to be considered in concert and the preferred methodology may depend on the context in which the risk assessment is applied. The outcome of the risk assessment should always be accompanied by an explicit consideration of these methodological issues and description of the resulting methodological choices.

Marine harbours are the focus of a diverse range of activities and subject to multiple anthropogenically induced pressures. Support for environmental management options aimed at improving degraded harbours depends on understanding the factors which influence people's perceptions of harbour environments. We used an online survey, across 12 harbours, to assess sources of variation people's perceptions of harbour health and ecological engineering. We tested the hypotheses: 1) people living near impacted harbours would consider their environment to be more unhealthy and degraded, be more concerned about the environment and supportive of and willing to pay for ecological engineering relative to those living by less impacted harbours, and 2) people with greater connectedness to the harbour would be more concerned about and have greater perceived knowledge of the environment, and be more supportive of, knowledgeable about and willing to pay for ecological engineering, than those with less connectedness. Across twelve locations, the levels of degradation and modification by artificial structures were lower and the concern and knowledge about the environment and ecological engineering were greater in the six Australasian and American than the six European and Asian harbours surveyed. We found that people's perception of harbours as healthy or degraded, but not their concern for the environment, reflected the degree to which harbours were impacted. There was a positive relationship between the percentage of shoreline modified and the extent of support for and people's willingness to pay indirect costs for ecological engineering. At the individual level, measures of connectedness to the harbour environment were good predictors of concern for and perceived knowledge about the environment but not support for and perceived knowledge about ecological engineering. To make informed decisions, it is important that people are empowered with sufficient knowledge of the environmental issues facing their harbour and ecological engineering options.

Estimating the potential environmental risks of worldwide coastal recreational navigation on water quality is an important step towards designing a sustainable global market. This study proposes the creation of a global atlas of the environmental risk of marinas on water quality by applying the Marina Environmental Risk Assessment (MERA) procedure. Calculations integrate three main risk factors: Pressure, State and Response. Applying the MERA approach to 105 globally distributed marinas has confirmed the utility, versatility and adaptability of this procedure as a novel tool to compare the environmental risks within and among regions (i.e. for area-based management), to identify the world's best practices (i.e. to optimize existing management) and to understand and adjust global risks in future development (i.e. improved planning).

International audience; Inter-individual variation in behavioural traits has important implications for evolutionary and ecological processes. Site fidelity, where individuals consistently use the same foraging site, is common among marine predators. Sex differences in foraging are also well studied in marine vertebrates, but the extent to which consistent inter-individual differences in foraging vary between the sexes is poorly known. Here we quantify the effects of sex on individual foraging site fidelity (IFSF), both within and between years, in chick brooding Campbell albatross (Thalassarche impavida). Using bird-borne Global Positioning System loggers, we calculated route fidelity (nearest neighbour distance), repeatability of site fidelity (terminal latitude and longitude), and foraging effort (total distance travelled and trip duration) during two to ten repeat trips. Overall, Campbell albatrosses showed a high degree of site fidelity. Birds travelled to similar sites not only within the same year, but also between two consecutive years, suggesting that the within-year consistency is not simply in response to short-term patches of food. Moreover, within the same year there were differences in terms of IFSF between the sexes. Females that foraged closer to the colony in neritic and shelf waters were more likely to follow similar routes on repeated foraging trips and were more consistent in their foraging effort than males. Males that foraged further offshore in pelagic waters had more repeatable foraging longitudes than females. Our study provides further evidence of the importance of IFSF among marine vertebrates. However, it also reveals that the strength of such specialisations may vary with sex.

Ecosystem-based management (EBM) is promoted as the solution for sustainable use. An ecosystem-wide assessment methodology is therefore required. In this paper, we present an approach to assess the risk to ecosystem components from human activities common to marine and coastal ecosystems. We build on: (i) a linkage framework that describes how human activities can impact the ecosystem through pressures, and (ii) a qualitative expert judgement assessment of impact chains describing the exposure and sensitivity of ecological components to those activities. Using case study examples applied at European regional sea scale, we evaluate the risk of an adverse ecological impact from current human activities to a suite of ecological components and, once impacted, the time required for recovery to pre-impact conditions should those activities subside. Grouping impact chains by sectors, pressure type, or ecological components enabled impact risks and recovery times to be identified, supporting resource managers in their efforts to prioritize threats for management, identify most at-risk components, and generate time frames for ecosystem recovery.

An ecosystem approach forms the basis of many recent environmental policies. The underlying concept states that decision-makers must consider the environmental, social and economic costs and benefits in the course of deciding whether to implement a management action. Decision-making can be undermined by uncertainty. Here, we discuss potential sources of uncertainty and their effect on an ecosystem approach-driven environmental policy, the factors affecting the choice and potential for management actions to achieve their objectives, the challenges associated with setting realistic and achievable targets, and how we can prioritise management of detrimental activities. We also consider how human challenges such as the availability of infrastructure and political will and ways of measuring costs and benefits and Member State interactions could also undermine environmental management. Potential limitations along with areas where further effort may be required to support ecosystem-based management objectives are highlighted and the advantages of a structured step-wise interdisciplinary approach to ecosystem management is shown. (C) 2014 Elsevier Ltd. All rights reserved.

Artificial structures can create novel habitat in the marine environment that has been associated with the spread of invasive species. They are often located in areas of high disturbance and can vary significantly in the area of free space provided for settlement of marine organisms. Whilst correlation between the amount of free space available and recruitment success has been shown in populations of several marine benthic organisms, there has been relatively little focus on invasive species, a group with the potential to reproduce in vast numbers and colonise habitats rapidly. Invasion success following different scales of disturbance was examined in the invasive acorn barnacle, Austrominius modestus , on a unique art installation located in Liverpool Bay. Population growth and recruitment success were examined by comparing recruitment rates within disturbance clearings of 4 different sizes and by contrasting population development with early recruitment rates over a 10 week period. Disturbed areas were rapidly recolonised and monocultures of A . modestus formed within 6 weeks. The size of patch created during disturbance had no effect on the rate of recruitment, while a linear relationship between recruit density and patch size was observed. Density-dependent processes mediated initial high recruitment resulting in population stability after 8-10 weeks, but densities continued to greatly exceed those reported in natural habitats. Given that artificial structures are likely to continue to proliferate in light of climate change projections, free-space is likely to become more available more frequently in the future supporting the expansion of fast-colonising species.

The Marine Strategy Framework Directive (MSFD) aims to achieve Good Environmental Status (GES) in Europe's Seas. The requirement for regional sea authorities to identify and prioritise issues for management has meant that standardized methods to assess the current level of departure from GES are needed. The methodology presented here provides a means by which existing information describing the status of ecosystem components of a regional sea can be used to determine the effort required to achieve GES. A risk assessment framework was developed to score departure from GES for 10 out of the 11 GES descriptors, based on proposed definitions of ‘good’ status, and current knowledge of environmental status in each of the four regional seas (North-East Atlantic, Mediterranean Sea, Baltic Sea and Black Sea). This provides an approach for regional evaluation of environmental issues and national prioritisation of conservation objectives. Departure from GES definitions is described as ‘high’, ‘moderate’ or ‘low’ and the implications for management options and national policy decisions are discussed. While the criteria used in this study were developed specifically for application toward MSFD objectives, with modification the approach could be applied to evaluate other high-level social, economic or environmental objectives.

BackgroundDispersal is a primary driver in shaping the future distribution of species in both terrestrial and marine systems. Physical transport by advection can regulate the distance travelled and rate of propagule supply to a habitat but post-settlement processes such as predation can decouple supply from recruitment. The effect of flow-mediated recruitment and predation on the recruitment success of an intertidal species, the eastern oyster Crassostrea virginica was evaluated in two-replicated field experiments. Two key crab species were manipulated to test predator identity effects on oyster mortality.FindingsRecruitment was ∼58% higher in high flow compared to low flow, but predation masked those differences. Predation mortality was primarily attributed to the blue crab Callinectes sapidus, whilst the mud crab Panopeus herbstii had no effect on recruit mortality. Recruit mortality from predation was high when recruit densities were high, but when recruit density was low, predation effects were not seen. Under high recruitment (supply), predation determined maximum population size and in low flow environments, recruitment success is likely determined by a combination of recruitment and resource limitation but not predation.ConclusionsFour processes are demonstrated: (1) Increases in flow rate positively affect recruitment success; (2) In high flow (recruitment) environments, resource availability is less important than predation; (3) predation is an important source of recruit mortality, but is dependent upon recruit density; and (4) recruitment and/or resource limitation is likely a major driver of population structure and functioning, modifying the interaction between predators and prey. Simultaneous testing of flow-mediated recruitment and predation was required to differentiate between the role of each process in determining population size. Our results reinforce the importance of propagule pressure, predation and post-settlement mortality as important determinants of population growth and persistence, but demonstrate that they should not be considered mutually exclusive.

Harbours are a focus of intensive and diverse activities and thus have a high potential to become centres of conflict between users. Reviewing the multiple uses associated with harbours provides important insights into maritime communities and the management of conflict. In this paper, seven international, multi-disciplinary groups provide their expert synthesis of individual harbours. After a detailed discussion experts from Sydney, Qingdao, Vigo, Auckland, Jakarta, Crete and Plymouth synthesised and shared their harbour’s characteristics, user conflicts and how such conflicts have been researched and managed. The paper addresses an omission of “conflict” in most of the research literature about harbours, and ports and scopes a research agenda that includes integration, risk appreciation and other approaches to these increasingly contentious maritime environments. This process provided an opportunity for global researchers to share the ways harbour conflicts are mitigated and the kinds of adaptations that are possible.