Peer-reviewed publications

Reliable and comparable estimates of biodiversity are the foundation for understanding ecological systems and informing policy and decision-making, especially in an era of massive anthropogenic impacts on biodiversity. Environmental DNA (eDNA) metabarcoding is at the forefront of technological advances in biodiversity monitoring, and the last few years have seen major progress and solutions to technical challenges from the laboratory to bioinformatics. Water eDNA has been shown to allow the fast and efficient recovery of biodiversity signals, but the rapid pace of technological development has meant that some important principles regarding sampling design, which are well established in traditional biodiversity inventories, have been neglected. Using a spatially explicit river flow model, we illustrate how sampling must be adjusted to the size of the watercourse to increase the quality of the biodiversity signal recovered. We additionally investigate the effect of sampling parameters (volume, number of sites, sequencing depth) on detection probability in an empirical data set. Based on traditional sampling principles, we propose that aquatic eDNA sampling replication and volume must be scaled to match the organisms' and ecosystems' properties to provide reliable biodiversity estimates. We present a generalizable conceptual equation describing sampling features as a function of the size of the ecosystem monitored, the abundance of target organisms, and the properties of the sequencing procedure. The aim of this formalization is to enhance the standardization of critical steps in the design of biodiversity inventory studies using eDNA. More robust sampling standards will generate more comparable biodiversity data from eDNA, which is necessary for the method's long-term plausibility and comparability.

Marine spatial planning (MSP) is an approach to ocean management with an increasingly global reach. However, existing evaluation strategies have yet to ascertain the extent to which MSP achieves social, ecological, and economic goals to benefit coastal environments and human communities. Here, we experiment with a theory-based approach as a means of overcoming long-standing obstacles to MSP evaluation. We developed and applied an eight-step evaluation protocol to five diverse cases of MSP, focusing on the evaluative feasibility of the protocol as we moved from identifying objectives to assessing the sustainability of outcomes. We found evidence that theory-based evaluation (operationalized via theories of change) can bridge quantitative outcome and qualitative process evaluations, two essential approaches that on their own produce incomplete pictures of MSP. Our work suggests that a theory-based approach can enhance opportunities to incorporate diverse knowledge sources and data types into outcome evaluations and thus better capture complex social, political, and historical dimensions that are difficult to quantify but critical to MSP success. We also uncovered likely challenges to implementing theory-based evaluation for MSP, including the apparent data- and time-intensive nature of the approach. We found that applying theory-based evaluation is difficult for plans lacking well-defined goals, objectives, and intended outcomes and that increased documentation of planning motivations and the planning process are needed to rigorously evaluate MSP. Ultimately, we join others in the marine conservation and management fields who are optimistic about theory-based evaluation. Our evaluation protocol provides a first step towards a practical guide to accelerate the use of this assessment approach.

Well-resourced marine protected areas (MPA) are better managed, leading to improved ecological outcomes. Tourism is often cited as an important source of financial support for MPA management, yet it is unclear whether funding from visitor entry fees improves the effectiveness of the world's MPAs. Here we ask whether fees to enter MPAs associate with enhanced fish biomass, a key ecological goal of many MPAs, and whether relations exist among entry fees and management effectiveness. In an analysis of 86 MPAs, we found entry fees were associated with greater fish biomass when compared to parks without entry fees, but only for parks with lower scores for management effectiveness. A global assessment of management survey responses from 214 MPAs suggested the hypothesis that MPA entry fees benefit budget security and staff capacity to carry out critical management activities. Together, the results suggest a mechanism whereby entry fees support greater capacity to educate parks users on rules and enforce those rules. Future work should look at the details of MPA budgets to unravel the relationship between funding, management activities and ecological outcomes. Dependency on tourism also comes with the important implication that declines in tourism caused by socio-economic shocks and geopolitical events may have affected the financial security and therefore possibly the ecological effectiveness of MPAs.

Climate change is one of the most pressing issues of our time, and the evidence base on observed impacts to date, and projected impacts, is growing. The impacts to island ecosystems and low-lying nations is particularly severe, including sea level rise, heavy precipitation events, and ocean warming, resulting in destruction of property, declining fish yields, and coral bleaching, among many other impacts. Decision support tools and other climate services are increasingly being used, but many gaps remain, and financing and implementation fall far short of what is needed. This chapter explores initiatives implemented by World Wildlife Fund to better understand how climate change is impacting people and wildlife, and how the research informs on-the-ground interventions which help people and wildlife adapt to a changing climate.

Forest regeneration can be a low-cost solution to mitigate climate change, and mapping its extent can support global goals such as the Bonn Challenge, which set a goal to put 350 million hectares of degraded forests and landscapes into restoration by 2030. Our study combined multiple remote sensing datasets and expert surveys, identifying 55.7+/- 6.2 million hectares of likely regenerated forests between 2000 and 2015 across areas that were not forested before 2000 and have remained forested from 2015 to 2018. The identified forest regeneration could potentially represent 22-25 billion young trees and a total biomass of about 3.2 billion tonnes. For every country, forest regeneration took place in sites with less opportunity cost for agriculture. However, in more developed regions, forest regeneration took place in sites with higher suitability for cultivation. Expert feedback associated agricultural land use transitions and the establishment of protected areas, coupled with effective management and local support, as the key factors leading to successful forest regeneration. The results, publicly available, can facilitate discussions and help identify strategic locations to foster forest regeneration to achieve the global goals of mitigating climate change and restoring biodiversity.

The effectiveness of commitments to zero-deforestation remains debated. An overlooked aspect is the mixture of private and public policies. We study its potential with the concept of hybrid governance applied to two case studies: mandatory FSC certification for forest concessionaires in Gabon and the National Strategy against Imported Deforestation in France. We find that hybrid governance provides flexibility to adapt to shifting sustainability concerns and can enable public and private features to mutually compensate for their respective weaknesses. Hybrid governance experiments may only be transitory to give way to stronger public policies as illustrated by Gabon. The France case shows that the integration of voluntary private standards in public policies remains sensitive. Overall, we show that hybrid governance should not resort to a mere accumulation of private and public components; a real dialogue between both spheres is required. Such a dialogue can take place before or after hybrid governance materialises as illustrated by the two case studies, which suggests that it should not be taken for granted but can be a positive outcome of the process. The ways through which economic and business aspects, as well as political ones, shape hybrid governance appear to be diverse and not straightforward.

The past few years have been an important time for food systems. Numerous studies (1, 2) have pointed to the sweeping benefits of a global food system transformation, the first ever United Nations Food Systems Summit brought together a broad group to stakeholders to accelerate action on food systems, and global scientific bodies, such as the Intergovernmental Panel on Climate Change (3) and Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (4), have highlighted the central importance of food systems in achieving global goals. Despite these positive trends at the global level, national-level action on food system transformation has lagged, and the world is off course to meet many global nutrition targets (5), which in turn will also have disastrous consequences for the environment.

Wildlife conservation in the Anthropocene requires bold conservation solutions including restoration of ecosystems and species. The recovery of large carnivore populations is a conservation goal which can generate significant benefits in terms of ecosystem services, ecological functionality, and human well-being. Tigers Panthera tigris, Asia’s most iconic species, are currently restricted to less than 10% of their historic range with recent national extinctions from a number of countries in mainland Southeast Asia. Tiger recovery through range expansion requires suitable habitat, a robust prey base, and high levels of institutional support for conservation. We explored government support for conservation to produce a ranking of the political opportunities for tiger restoration across current and former tiger range countries. We used this analysis, in combination with globally remotely sensed data-sets on human impact, to show that there is potential for significant tiger range expansion. We identified large expanses of currently unoccupied, but potentially suitable, habitat in at least 14 countries including all extant tiger range countries and four countries with extirpated tiger populations – Cambodia, Lao PDR, Viet Nam, and Kazakhstan. Thirty-two percent of expansion areas were within 50-km, and 50% within 100-km, of current tiger populations highlighting that in many landscapes range expansion could be driven by the natural dispersal of tigers provided connectivity is maintained or enhanced. The proportion of potential range within existing protected areas varied between <5% in India, Indonesia, and China, to >60% in Thailand and Cambodia. As such socially appropriate conservation approaches, in collaboration with local communities, will be necessary to support tiger recovery in many areas. We recommend that some of the areas which we have identified should be highlighted as significant for future tiger conservation by tiger range country governments. Whilst the landscapes and sites which we identify will require detailed ground-truthing, and all tiger reintroductions need extensive planning and feasibility assessments, safeguarding these areas for human-carnivore coexistence could provide significant planetary benefits and support both tiger recovery and Global Sustainable Development Goals.

Sustaining ecosystem services (ES) critical to human well-being is hindered by many practitioners lacking access to ES models (“the capacity gap”) or knowledge of the accuracy of available models (“the certainty gap”), especially in the world’s poorer regions. We developed ensembles of multiple models at an unprecedented global scale for five ES of high policy relevance. Ensembles were 2 to 14% more accurate than individual models. Ensemble accuracy was not correlated with proxies for research capacity, indicating that accuracy is distributed equitably across the globe and that countries less able to research ES suffer no accuracy penalty. By making these ES ensembles and associated accuracy estimates freely available, we provide globally consistent ES information that can support policy and decision-making in regions with low data availability or low capacity for implementing complex ES models. Thus, we hope to reduce the capacity and certainty gaps impeding local- to global-scale movement toward ES sustainability.

Harmful fisheries subsidies contribute to overfishing leading to environmental and societal impacts. If only fisheries and ecosystems within the subsidising nations’ jurisdiction were affected, then unilateral actions might be sufficient to help safeguard our ocean and the people reliant upon it. However, just as fish move between jurisdictions, so too do the subsidised fishing fleets that target them. As such, the impacts and solutions to subsidies-induced overfishing are often matters of international concern. Mapping the distribution and flows of harmful subsidies is therefore key to understanding these concerns, informing multilateral reform, and empowering impacted nations to strengthen the terms of access to their waters and resources. Here we quantify the amount of harmful fisheries subsidies that supports fishing in the high seas, domestic and foreign waters. We estimate that between 20% and 37% of all harmful fisheries subsidies support fishing in foreign waters or the high seas, that is outside the jurisdictions of the subsidising nations. We show that harmful subsidies primarily originate from nations with high-Human Development Index (HDI), strong fisheries management capacity and relatively sustainable fish stocks, yet disproportionately impact nations with low or very low-HDI, lower management capacity and more vulnerable fish stocks—40% of the harmful subsidies that support fishing in very low-HDI nations waters originate from high-HDI and very-high HDI nations. We show that Asia, Europe, and North America, are net subsidy sources; they provide more harmful subsidies to their fishing fleets than their respective ecosystems are impacted by; while Africa, South, Central America and Caribbean, and Oceania are net subsidy-sinks. This discrepancy between the source of harmful subsidies and the nations that are ultimately impacted is unsustainable and unjust. Prohibiting all harmful subsidies to distant-water fishing and fishing in the high seas—with narrow exceptions for Small Island Developing States—should be prioritised to support the advancement of sustainable and equitable fisheries worldwide.