Peer-reviewed publications

Hydropower continues to expand globally as the power sector transitions away from carbon-intensive fossil fuels. New dam sites vary widely in the magnitude of their adverse effects on natural ecosystems and human livelihoods. Here, we discuss how strategic planning of hydropower expansion can assist decision makers in comparing the benefits of building dams against their socioenvironmental impacts. Advances in data availability and computational analysis now enable accounting for an increasing array of social and environmental metrics at ever-larger spatial scales. In turn, expanding the spatial scale of planning yields more options in the quest to improve both economic and socioenvironmental outcomes. There remains a pressing need to incorporate climate change into hydropower planning. Ultimately, these innovations in evaluating prospective dam sites should be integrated into strategic planning of the entire energy system to ensure that social and environmental disruption of river systems is minimized.

The Hudson Bay Lowlands (HBL) is a vast contiguous peatland extending over >370,000 km2 in Canada's boreal-subarctic, and is the traditional land of the Omushkego Cree. It is currently undergoing climatic warming alongside other anthropogenic stressors, and contains a large below-ground carbon pool. Understanding how climate variability and multiple stressors impact peat accumulation in this region is critical to discerning how northern peatlands will respond to future climate and land-use changes. Pollen- and macrofossil-based paleoecological reconstructions, and analyses of aluminum (Al) and titanium (Ti) fluxes in a Holocene-aged peat core (VM375) taken from a bog in the Attawapiskat watershed were conducted to link ecosystem changes with hydroclimate and long-term carbon storage. Peat initiation is dated to 5780 cal yr B.P., coincident with land emergence driven by glacial isostatic adjustment. From 4500 to 4200 cal yr B.P., apparent rate of carbon accumulation increased, and was linked to more rapid rates of peat accretion and increases in minerotrophic indicators in the pollen record. This increase in peat accretion and shift in vegetation composition co-occur with higher rates of mineral influx as shown by Ti and Al concentrations, which may have supplied nutrients. A fen to bog transition takes place ~3300 cal yr B.P., with increases in Sphagnum spores and macrofossils, and a decline in the apparent rate of carbon accumulation relative to the earlier half of the record, where paleoecological proxies indicate treed wetland and fen stages. Since peat inception, the total carbon stock of the 260-cm peat column is 110 kg C m−2. This multi-proxy record shows an association between changing peat types and variability in apparent rates of carbon accumulation, and supports the hypothesis that mineral nutrients either supplied by surface hydrology or by eolian deposition played a role in Holocene peat carbon accumulation in eastern North American boreal peatlands.

Rivers act as the arteries of the planet, flowing and pulsing across landscapes as they carry vital resources to sustain the health of the Earth. The vast global network of rivers and streams conveys sediments and nutrients to fertile valleys and river deltas, provides habitat corridors and transportation routes, and delivers life-sustaining freshwater to aquatic ecosystems and human populations alike. As surface runoff forms in headwater catchments, drains them as small mountain streams and ultimately accumulates into mighty lowland rivers that discharge into the world’s oceans, waterways both influence and are influenced by the landscapes and ecosystems which they traverse. Understanding and managing surface water resources therefore requires fundamental hydrographic data and associated tools that support mapping and analysis of natural river and catchment characteristics, such as climate, landscape, and soil conditions, as well as anthropogenic influences including water abstractions, pollution, and river fragmentation.

There is an urgent need to halt and reverse loss of mangroves and seagrass to protect and increase the ecosystem services they provide to coastal communities, such as enhancing coastal resilience and contributing to climate stability.1,2Ambitious targets for their recovery can inspire public and private investment in conservation,3 but the expected outcomes of different protection and restoration strategies are unclear. We estimated potential recovery of mangroves and seagrass through gains in ecosystem extent to the year 2070 under a range of protection and restoration strategies implemented until the year 2050. Under a protection-only scenario, the current trajectories of net mangrove loss slowed, and a minor net gain in global seagrass extent (∼1%) was estimated. Protection alone is therefore unlikely to drive sufficient recovery. However, if action is taken to both protect and restore, net gains of up to 5% and 35% of mangroves and seagrasses, respectively, could be achieved by 2050. Further, protection and restoration can be complementary, as protection prevents losses that would otherwise occur post-2050, highlighting the importance of implementing protection measures. Our findings provide the scientific evidence required for setting strategic and ambitious targets to inspire significant global investment and effort in mangrove and seagrass conservation.

Background and aim Billfish are epipelagic marine predators facing increasing pressures such as overfishing and rising global temperatures. Overfishing is a major concern, as they are caught by industrial longline fishers targeting tuna. Billfish are targeted by multiple fishing sectors, which provides food, socio-economic and cultural benefits. To support effective billfish management and conservation, it is essential to understand their spatial distribution and the environmental factors that may influence it. Location The focus of this study is the Indian Ocean (IO), where there are gaps in understanding the interactions between fisheries and billfish distribution. Three of six billfish species are at risk from overfishing. Therefore, determining their distribution is crucial to their management and conservation. Methods Using Ocean Biogeographic Information System (OBIS) occurrence data, Indian Ocean Tuna Commission (IOTC) catch data, and environmental covariates, we applied species distribution models to investigate the spatial extent of the realized niches of six billfish species in the IO. We also determined the role and relative importance of environmental drivers. Moreover, we evaluated the association between species’ spatial distribution and the fishing effort distribution. Results We found niche partitioning and overlap among the six species identified spatial distribution, with higher species richness in the northern region of the IO and off the East coast of Africa. Temperature, mixed layer depth and salinity were identified as the most important predictors of species distribution, with moderately warm and stable environments preferred by most billfish species. Areas with high species richness and high fishing effort overlap were primarily found in the Areas Beyond National Jurisdiction (ABNJ). In contrast, areas with high species diversity richness and low fishing effort were found mainly in the Exclusive Economic Zone (EEZ). Main conclusion Spatial overlap between fishing effort and billfish projected distribution suggests inadvertent fishing pressure on billfish populations as they are caught together with targeted tuna. Spatial distribution transcends maritime zones, reinforcing a need to formulate effective management policies for marine areas beyond national jurisdictions.

Conventional flood control has emphasized structural measures such as levees, reservoirs, and engineered channels—measures that typically simplify river channels and cut them off from their floodplain, both with adverse environmental consequences. Structural measures tend to be rigid and not easily adapted to increased flooding regimes resulting from environmental change. Such actions also limit the natural hydrologic benefits of floodplains such as storing floodwaters, improving water quality, providing habitat for invertebrates and fish during periods of inundation, and supporting a multitude of cultural services. As these benefits are more widely recognized, policies are being adopted to encourage projects that reduce flood risks and restore floodplain ecosystems, while acknowledging the social-ecological context. The number of such projects, however, remains small. We assessed four multi-benefit floodplain projects (two in California, United States, and two in Germany) and characterized their drivers, history, and measures implemented. In both United States cases, the dominant driver behind the project was flood risk reduction, and ecosystem restoration followed, in one case inadvertently, in the other as a requirement to receive a subsidy for a flood risk reduction project. One German case was motivated by ecosystem restoration, but it was more widely accepted because it also offered flood management benefits. The fourth case was conceived in terms of balanced goals of flood risk reduction, ecosystem restoration, and recreation. We conclude that projects that both reduce flood risk and restore ecosystems are clearly possible and often cost-effective, and that they could be more widely implemented. The principal barriers are often institutional and regulatory, rather than technical.

Marine Protected Areas (MPAs) often have dual goals of protecting biodiversity and increasing sustainability of fisheries. To understand how MPAs are performing at these goals, evaluation of fish biomass outcomes against management targets is needed. However, the evaluation of performance should consider multiple biophysical and social drivers that vary over the seascape to inform spatially explicit targets for fish biomass. Including spatial variation when evaluating MPA performance is particularly important for MPA networks because it enables managers to set more realistic expectations for MPA outcomes and adapt management across individual areas. Here we develop a modelling approach to predict how fishing pressure and biophysical conditions affect expected recovery of fish biomass. We apply the approach to model herbivore and predator biomass at 57 sites for two MPAs in Raja Ampat, Indonesia. We then use this model to predict biomass recovery towards reference sites indicative of low-fishing pressure. We found that historical fishing pressure, wave exposure and proximity to coastal habitats were all important determinants of pre-MPA fish biomass. Our predictions therefore, indicated the implemented MPA no-take zones should have some of the highest reef fish biomass based on both their location within the MPA, and the removal of fishing pressure. We also identify sites that may be underperforming and warrant further management, for instance, further investigation of poaching as a cause of poor recovery trends. We suggest that evaluation of MPA performance needs to consider the link to historical fishing pressure and biophysical conditions with biodiversity outcomes.

Climate change is predicted to drive various changes in hydrology that can translate into 10 risks for river ecosystems and for those who manage rivers, such as for hydropower. Here we use 11 the WWF Water Risk Filter (WRF) and geospatial analysis to screen hydropower projects, both ex-12 isting (2,488 dams) and projected (3,700 dams), for a variety of risks at a global scale, focusing on 13 biodiversity risks, hydrological risks (water scarcity and flooding), and how those hydrological risks 14 may shift with climate change, based on three scenarios. Approximately 26% of existing hydro-15 power dams and 23% of projected dams are within river basins that currently have medium to very 16 high risk of water scarcity; 32% and 20% of the existing and projected dams, respectively, are pro-17 jected to have increased risk by 2050 due to climate change. For flood risk, 75% of existing dams and 18 83% of projected dams are within river basins with medium to very high risk, and the proportion of 19 hydropower dams in basins with the highest levels of flood risk are projected to increase by nearly 20 twenty times (e.g., from 2% to 36% of dams). In addition, a large proportion of existing (76%) and 21 projected hydropower dams (93%) are located in river basins with high or very high freshwater 22 biodiversity importance. This is a high-level screening, intended to elucidate broad patterns of risk 23 to increase awareness, highlight trends, and guide more detailed study.

Marine protected areas (MPAs) are considered the go-to tool for marine area-based conservation, having rapidly expanded in many countries, yet an understanding of progress and achievement in implementation remains vastly unexplored. Here, we assess the status and trends of coverage and protection, ecological conditions, marine resource use, human well-being, and management effectiveness of MPAs in the Sunda Banda Seascape (SBS), Indonesia, and provide the first comprehensive overview of marine conservation in the region. The SBS, located in the world's epicenter for marine biodiversity, has 85 designated MPAs (8.1 million ha) as of 2018, accounting for 35% of the national target of 23.4 million ha MPAs by 2020. Most SBS MPAs were recently initiated or established, and their management was strongly influenced by policy and governance changes at the national and provincial levels. SBS MPAs protect more than 30% of mangrove, seagrass, and coral reefhabitats in the seascape, and surveys indicate relatively healthy coral reef conditions. Fishing is one of the most common livelihoods in the MPA communities; 90% of fishers use traditional gear types for fishing and destructive fishing is identified as the greatest threat to marine resources in the MPAs. Our findings suggest that balancing the expansion of MPAs with strengthening their management effectiveness and integrating diverse social-ecological local contexts are important aspects to achieve effective, equitable marine conservation.

Progress in key social-ecological challenges of the global environmental agenda (e.g., climate change, biodiversity conservation, Sustainable Development Goals) is hampered by a lack of integration and synthesis of existing scientific evidence. Facing a fast-increasing volume of data, information remains compartmentalized to pre-defined scales and fields, rarely building its way up to collective knowledge. Today's distributed corpus of human intelligence, including the scientific publication system, cannot be exploited with the efficiency needed to meet current evidence synthesis challenges; computer-based intelligence could assist this task. Artificial Intelligence (AI)-based approaches underlain by semantics and machine reasoning offer a constructive way forward, but depend on greater understanding of these technologies by the science and policy communities and coordination of their use. By labelling web-based scientific information to become readable by both humans and computers, machines can search, organize, reuse, combine and synthesize information quickly and in novel ways. Modern open science infrastructure—i.e., public data and model repositories—is a useful starting point, but without shared semantics and common standards for machine actionable data and models, our collective ability to build, grow, and share a collective knowledge base will remain limited. The application of semantic and machine reasoning technologies by a broad community of scientists and decision makers will favour open synthesis to contribute and reuse knowledge and apply it toward decision making.