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This study provides an integrated perspective to ecosystem based management (EBM) by considering a diverse array of societal goals, i.e. sustainable food supply, clean energy and a healthy marine ecosystem, and a selection of management measures to achieve them. The primary aim of this exercise is to provide guidance for (more) integrated EBM in the North Sea based on an evaluation of the effectiveness of those management measures in contributing to the conservation of marine biodiversity. A secondary aim is to identify the requirements of the knowledge base to guide such future EBM initiatives. Starting from the societal goals we performed a scoping exercise to identify a “focal social-ecological system” which is a subset of the full social-ecological system but considered adequate to guide EBM towards the achievement of those societal goals. A semi-quantitative risk assessment including all the relevant human activities, their pressures and the impacted ecosystem components was then applied to identify the main threats to the North Sea biodiversity and evaluate the effectiveness of the management measures to mitigate those threats. This exercise revealed the need for such risk-based approaches in providing a more integrated perspective but also the trade-off between being comprehensive but qualitative versus quantitative but limited in terms of the “focal” part of the SES that can be covered. The findings in this paper provide direction to the (further) development of EBM and its knowledge base that should ultimately allow an integrated perspective while maintaining its capacity to deliver the accuracy and detail needed for decision-making.

Study concepts, oversight, and funding for the RODEO Program were provided by the US Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC, under HDR’s IDIQ Contract No. M15PC00002. The Block Island Wind Farm (BIWF), situated offshore of Block Island, Rhode Island, is the first commercial offshore wind farm (OWF) in the United States. We briefly review pre-siting studies, which provide contextual information about the benthic habitats and fish in the Block Island Sound area before the BIWF jacket foundations were installed in 2015. We focus on benthic monitoring that took place within the BIWF. This monitoring allowed for assessments of spatiotemporal changes in sediment grain size, organic enrichment, and macrofauna, as well as the colonization of the jacket structures, up to four years post-installation. The greatest benthic modifications occurred within the footprint of the foundation structures through the development of mussel aggregations. Within four years, changes in benthic habitats (defined as biotopes) were observed within the 90 m range of the study, clearly linked to the mussel-dominated colonization of the structures, which also hosted numerous indigenous fish species. We discuss the evident structural and functional effects and their ecological importance at the BIWF and for future US OWFs, drawing on similarities with European studies. While reviewing lessons learned from the BIWF, we highlight the need to implement coordinated monitoring for future developments and recommend a strategy to better understand environmental implications. Publisher PDF

10 pages, 6 figures, 1 table, supplementary data https://doi.org/10.1016/j.scitotenv.2020.138118, Ecosystem-based management requires an assessment of the cumulative effects of human pressures and environmental change. The operationalization and integration of cumulative effects assessments (CEA) into decision-making processes often lacks a comprehensive and transparent framework. A risk-based CEA framework that divides a CEA in risk identification, risk analysis and risk evaluation, could structure such complex analyses and facilitate the establishment of direct science-policy links. Here, we examine carefully the operationalization of such a risk-based CEA framework with the help of eleven contrasting case studies located in Europe, French Polynesia, and Canada. We show that the CEA framework used at local, sub-regional, and regional scales allowed for a consistent, coherent, and transparent comparison of complex assessments. From our analysis, we pinpoint four emerging issues that, if accurately addressed, can improve the take up of CEA outcomes by management: 1) framing of the CEA context and defining risk criteria; 2) describing the roles of scientists and decision-makers; 3) reducing and structuring complexity; and 4) communicating uncertainty. Moreover, with a set of customized tools we describe and analyze for each case study the nature and location of uncertainty as well as trade-offs regarding available knowledge and data used for the CEA. Ultimately, these tools aid decision-makers to recognize potential caveats and repercussions of management decisions. One key recommendation is to differentiate CEA processes and their context in relation to governance advice, marine spatial planning or regulatory advice. We conclude that future research needs to evaluate how effective management measures are in reducing the risk of cumulative effects. Changing governance structures takes time and is often difficult, but we postulate that well-framed and structured CEA can function as a strategic tool to integrate ecosystem considerations across multiple sectorial policies., This article is a product of the working group on cumulative effects assessment under the framework of COST Action 15121 “Advancing marine conservation in the European and contiguous seas” (MarCons; http://www.marcons-cost.eu; (Katsanevakis et al., 2017)—supported by COST (European Cooperation in Science and Technology, CA15121), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

This paper contributes to the FaCE-It and PERSUADE projects financed by the Belgian Science Policy Office, and the Belgian WinMon.BE offshore wind farm environmental monitoring program. Joop Coolen was funded by NWO Domain Applied and Engineering Sciences under grant 14494. Offshore wind farms (OWFs) are proliferating globally. The submerged parts of their structures act as artificial reefs, providing new habitats and likely affecting fisheries resources. While acknowledging that the footprints of these structures may result in loss of habitat, usually soft sediment, we focus on how the artificial reefs established by OWFs affect ecosystem structure and functioning. Structurally, the ecological response begins with high diversity and biomass in the flora and fauna that gradually colonize the complex hard substrate habitat. The species may include nonindigenous ones that are extending their spatial distributions and/or strengthening populations, locally rare species (e.g., hard substrate-associated fish), and habitat-forming species that further increase habitat complexity. Functionally, the response begins with dominant suspension feeders that filter organic matter from the water column. Their fecal deposits alter the surrounding seafloor communities by locally increasing food availability, and higher trophic levels (fish, birds, marine mammals) also profit from locally increased food availability and/or shelter. The structural and functional effects extend in space and time, impacting species differently throughout their life cycles. Effects must be assessed at those larger spatiotemporal scales. Publisher PDF

Stelzenmüller, Vanessa ... et al.-- 9 pages, 5 figures, 2 tables, supplementary data https://doi.org/10.1016/j.scitotenv.2017.08.289, Marine ecosystems are increasingly threatened by the cumulative effects of multiple human pressures. Cumulative effect assessments (CEAs) are needed to inform environmental policy and guide ecosystem-based management. Yet, CEAs are inherently complex and seldom linked to real-world management processes. Therefore we propose entrenching CEAs in a risk management process, comprising the steps of risk identification, risk analysis and risk evaluation. We provide guidance to operationalize a risk-based approach to CEAs by describing for each step guiding principles and desired outcomes, scientific challenges and practical solutions. We reviewed the treatment of uncertainty in CEAs and the contribution of different tools and data sources to the implementation of a risk based approach to CEAs. We show that a risk-based approach to CEAs decreases complexity, allows for the transparent treatment of uncertainty and streamlines the uptake of scientific outcomes into the science-policy interface. Hence, its adoption can help bridging the gap between science and decision-making in ecosystem-based management, This article is based upon work from COST Action 15121 ‘Advancing marine conservation in the European and contiguous seas (MarCons) - supported by COST (European Cooperation in Science and Technology, CA15121)

The European flat oyster, Ostrea edulis, is an emblematic and ecologically important species that was fished to virtual extinction in Belgian and Dutch waters in the 19th century. We report on recent findings of live specimens in Belgian and Dutch waters, an indication for the presence of O. edulis in these waters. Though small, these relict populations provide possibilities for natural recovery of O. edulis reefs in Belgian and Dutch waters, provided the oyster’s habitat requirements are restored (e.g., exclusion of bottom disturbance). We suggest investigating whether a natural, yet slow, recovery using fisheries closures and gravel bed restoration is a feasible alternative to the currently envisaged human-mediated re-introduction of O. edulis in the North Sea. We identify and address the challenge of O. edulis detection and identification as an important issue blurring the true presence and distribution of oysters.

The current study presents the ostracod communities recovered from 26 shallow waterbodies in southern Kenya, combined with an ecological assessment of habitat characteristics. A total of 37 waterbodies were sampled in 2001 and 2003, ranging from small ephemeral pools to large permanent lakes along broad gradients in altitude (700–2 800 m) and salinity (37–67 200 μS cm−1). Between 0 and 12 species were recorded per site. Lack of ostracods was associated with either hypersaline waters, or the presence of fish in fresh waters. Three of the 32 recovered ostracod taxa, Physocypria sp., Sarscypridopsis cf. elizabethae and Oncocypris mulleri, combined a wide distribution with frequent local dominance. Canonical correspondence analysis on species–environment relationships indicated that littoral vegetation, altitude, surface water temperature and pH best explain the variation in ostracod communities. Presence of fish and water depth also influence species occurrence, with the larger species being more common in shallow waterbodies lacking fish. Based on Chao’s estimator of total regional species richness, this survey recovered about two-thirds (60–68%) of the regional ostracod species pool. Scanning electron micrographs (SEM) of the valve morphology of 14 ostracod taxa are provided, in order to facilitate their application in biodiversity and water-quality assessments and in palaeoenvironmental reconstruction.Keywords: aquatic ecosystem functioning, biodiversity, fish predation, littoral vegetation

Steel monopiles, jackets requiring four steel pinpiles, and gravity-based foundations were applied in offshore wind farms in the Belgian part of the North Sea. This paper compares the underwater noise generated during the piling activities of steel monopiles at the Belwind wind farm (Blighbank) with that of jacket pinpiles at the C-Power project (Thorntonbank). Underwater noise was measured at various distances from the pile driving location. The underwater noise was quantified by its zero to peak sound pressure level ( ), unweighted sound exposure level (SEL), cumulative SEL, and 1/3 octave spectra. No significant differences in could be demonstrated (monopile : 179–194 dB re 1 μPa, jacket : 172–189 dB re 1 μPa). SEL showed no statistical difference between monopile and jacket and varied between 145 and 168 dB re 1 μPa 2s. Furthermore, near identical spectra were measured for both types of piling. Piling of the jacket pinpiles took, however, about 2.5 times the time of the monopile. When standardised to megawatt installed per foundation both types of piling scored near equally. As an illustration, the radius of major behavioural disturbance ( dB re 1 μPa) in the harbour porpoise Phocoena phocoena was estimated by a model at 16 km for monopiles and at 8 km for jacket.

In this study, we analyse the distribution and species richness of epibenthic and planktonic Cladocera (Crustacea: Branchiopoda) in 62 Uganda crater lakes, spread across the climatic gradient between the sub-humid shoulder and semi-arid floor of the East African Rift Valley. Together, these lakes cover large environmental gradients in salinity, trophic conditions and depth. In total, 36 species of Cladocera were encountered in the freshwater lakes ( 10,000 μS/cm). Cladoceran species richness in individual lakes was found to be determined primarily by the presence of a well-developed littoral belt of submerged and emergent aquatic macrophytes, pH and salinity. The highest species richness occurred in fresh but eutrophic shallow waters, with relatively low pH (6.5–7) and dense aquatic macrophyte growth. As identified by multivariate statistical analysis, the distribution of Cladocera species among the Uganda lakes was most strongly determined by nutrient availability (measured as total phosphorus), the presence and diversity of aquatic macrophyte habitat, pH, mean annual temperature and the fraction of the crater catchment that is currently under agriculture. Since Cladocera play an important role in aquatic food webs, and as such contribute to the ecological integrity of aquatic ecosystems, an increased understanding of the environmental controls underlying their distribution provides valuable information on aquatic ecosystem functioning needed for management and conservation. The significant turnover of cladoceran species composition along the sampled environmental gradients demonstrates their potential as biological indicators for water quality and ecosystem health in East African lakes. Our results suggest that changes in land use are the greatest threat to natural ecosystem functioning in these African lakes, and particularly so in the shallower lakes.

Background and aims - With a depth of at least 220 in, Lake Kyaninga is the deepest known maar crater lake in western Uganda. We studied its limnology and phytoplankton community to determine how the frequency and depth of water-column mixing influences nutrient cycling and seasonality in this aquatic ecosystem. Methods - Water-column temperature was measured continuously during a full annual cycle between August 2007 and August 2008. Other physical and chemical variables as well as diatom and other phytoplankton communities were investigated on three occasions, namely during the dry season in August of 2007 and 2008, and during the main wet season in April 2009. Key results and conclusions - The water column of Lake Kyaninga is permanently stratified (meromictic) below similar to 100 m depth. Above this depth, mixing frequency varies from daily (down to 8-12 m depth) over at least once per year (down to 39-47 m depth), to once in several years or decades (between 39-47 and similar to 100 m depth). Nutrient and chlorophyll concentrations as well as phytoplankton data classify the lake as low in aquatic productivity (oligotrophic). Its pelagic, open-water phytoplankton community is dominated by Cyanobacteria (blue-green algae) and Chlorophyta (green algae). Bacillariophyta (diatoms) contribute only a minor part of total phytoplankton biomass in both wet and dry seasons, and are characterized by an assemblage of small Nitzschia species. Epiphytic and epipelie diatoms are relatively few, because steep rocky crater slopes limit the littoral zone even though water-column transparency is high. The composition of recently deposited diatom assemblages preserved in offshore surface sediments gives a good, annually integrated representation of the present-day pelagic diatom community. The documented species richness of the diatom flora of Lake Kyaninga is moderate with about 150 taxa. Only similar to 17% of these are biogeographically restricted to tropical Africa; and most of these belong to the genus Nitzschia.

The finely laminated sediment record of a permanent, hypersaline, desert oasis lake in the Ounianga region of northeastern Chad presents a unique opportunity to document the hydrological evolution of this groundwater-fed aquatic ecosystem during mid- and late-Holocene desiccation of the Sahara. In this study we reconstruct long-term changes in zoobenthos and zooplankton communities of Lake Yoa as their early-Holocene freshwater habitat changed into the hypersaline conditions prevailing today. Chironomid production peaked during the fresh-to-saline transition period, then stabilized at about half that of the earlier freshwater ecosystem. Quantitative salinity inferences based on fossil chironomid assemblages indicate that the fresh-to-saline transition occurred fairly abruptly between ∼4100 and 3400 cal yr BP, but that the ecosystem was buffered against shorter-term climate fluctuations due to continuous inflow of fossil groundwater. The mixture of tropical-African and southern Palaearctic chironomid faunas in the Lake Yoa fossil record required us to address several methodological issues concerning chironomid-based salinity reconstruction, and the applicability of a calibration dataset based on tropical East and West African lakes to this Sahara desert locality. The most coherent reconstruction was obtained with an inference model that applies a weighted best-modern-analogue (WMAT) transfer function to the African calibration dataset expanded with six Sahara lakes.

This paper reports new multi-proxy palaeoenvironmental data on the late Glacial-Holocene transition (c. 14.8–9.3 ka) in equatorial East Africa, in the form of microfossil assemblages (chironomids, ...

In recent years, offshore wind energy in the shelf seas of the southern North Sea is experiencing a strong growth. Foundations are introduced in mainly sandy sediments, and the resulting artificial reef effect is considered one of the main impacts on the marine environment. We investigated the macrobenthic fouling community that developed on the concrete foundations of the first wind turbines built in Belgian marine waters. We observed a clear vertical zonation, with a distinction between a Telmatogeton japonicus dominated splash zone, a high intertidal zone characterised by Semibalanus balanoides, followed by a mussel belt in the low intertidal–shallow subtidal. In the deep subtidal, the species turnover was initially very high, but the community was soon dominated by few species (Jassa herdmani, Actiniaria spp. and Tubularia spp.), and only seasonal dynamics within this species assemblage were observed after 1–1½ years. Ten non-indigenous species (NIS) were found. In the intertidal, eight out of the seventeen typical intertidal species observed were NIS, while only two out of a species pool of 80 species were NIS in the deep subtidal. NIS were found to use the foundations to expand their range and strengthen their strategic position in the area.

We analysed subfossil death assemblages of aquatic invertebrate communities in a salinity series of 35 western Uganda maar-crater lakes to evaluate their potential as biological indicators of past habitat conditions in paleo-environmental research. The study region encompasses the climatological and hydrological gradient between the dry floor and moist shoulders of the Edward-George branch of the East African Rift Valley, and includes mesotrophic to hyper-eutrophic, and shallow unstratified to deep meromictic lakes with a surface-water salinity range between 101 and 135 400 μS/cm. Focusing on non-chironomid aquatic invertebrates with good fossil preservation, we found that fossil larval remains of the Dipteran families Culicidae, Ephydridae, and Stratiomyidae are good indicators of saline environments. Our data further suggest that the abundances of Bryozoan statoblasts and Chaoboridae are indicative of, respectively, the fraction of the littoral zone covered by aquatic macrophytes and of lake trophic state, but a lake reference data set more specifically designed to cover variation in these environmental factors will be needed to determine the strength of these relationships. In these small, simple lake basins, recent death assemblages recovered from a single mid-lake surface-sediment sample provides a more complete inventory of local aquatic invertebrate communities and the distribution of species among lakes than exploratory live sampling of those taxa in a selection of littoral, benthic and pelagic habitats.

The European Union (EU) has committed to an ambitious biodiversity recovery plan in its Biodiversity Strategy for 2030 and the Green Deal. These policies aim to halt biodiversity loss and move towards sustainable development, focusing on restoring degraded habitats, extending the network of protected areas (PAs), and improving the effectiveness of management, governance, and funding. The achievement of conservation goals must be founded on understanding past successes and failures. Here, we summarise the strengths and weaknesses of past EU biodiversity conservation policies and practices and explore future opportunities and challenges. We focus on four main aspects: i) coordination among and within the EU Member States, ii) integration of biodiversity conservation into socio-economic sectors, iii) adequacy and sufficiency of funds, and iv) governance and stakeholder participation.Whilst past conservation efforts have benefitted from common rules across the EU and funding mechanisms, they have failed at operationalizing coordination within and across the Member States, integrating biodiversity conservation into other sectoral policies, adequately funding and effectively enforcing management, and facilitating stakeholder participation in decision-making. Future biodiversity conservation would benefit from an extended and better-managed network of PAs, additional novel funding opportunities, including the private sector, and enhanced co-governance. However, it will be critical to find sustainable solutions to potential conflicts between conservation goals and other socio-economic objectives and to resolve inconsistencies across sectoral policies.