An informed thought experiment exploring the potential for a paradigm shift in aquatic food production

The Neolithic Revolution began c. 10000 years ago and is characterised by the ultimate, near complete transition from hunting and gathering to agricultural food production on land. The Neolithic Revolution is thought to have been catalysed by a combination of local population pressure, cultural diffusion, property rights and climate change. We undertake a thought experiment that examines trends in these key hypothesised catalysts and patters of today to explore whether society could be on a path towards another paradigm shift in food production: away from hunting of wild fish towards a transition to mostly fish farming. We find similar environmental and cultural pressures have driven the rapid rise of aquaculture, during a period that has now been coined the Blue Revolution, providing impetus for such a transition in coming decades to centuries. We also highlight the interacting and often mutually reinforcing impacts of 1)technological and scientific advancement, 2)environmental awareness and collective action and 3)globalisation and trade influencing the trajectory and momentum of the Blue Revolution. We present two qualitative narratives that broadly fall within two future trajectories: 1)a ubiquitous aquaculture transition and 20commercial aquaculture and fisheries coexistence. This scenarios approach aims to encourage logical, forward thinking, and innovative solutions to complex systems dynamics. Scenario-based thought experiments are useful to explore large scale questions, increase the accessibility to a wider readership and ideally catalyse discussion around proactive governance mechanisms. We argue the future is not fixed and society now has greater foresight and capacity to choose the workable balance between fisheries sand aquaculture that supports economic, environmental, cultural and social objectives through combined planning, policies and management

Equitable representation of ecoregions is slowly improving despite strategic planning shortfalls

Representing all ecosystem types in protected areas (PAs) is central to international conservation agreements (i.e., Aichi Target 11) and ensuring the persistence of biodiversity. In response to these agreements, we have seen rapid growth of PA networks, but we do not know how this affects ecosystem representation. We explored this question by investigating drivers and trends of representation during periods of rapid land acquisition using the protection equality metric. We found that 90.9% of the studied countries have improved protection equality through time. Periods of rapid area expansion resulted in greater increases in protection equality, particularly through multiple, smaller PAs as opposed to fewer, larger PAs. However, observed increases may not be due to strategic planning, as protection equality from random PA allocation was statistically similar to observed values within six country-level simulations. Future international agreements should hold countries accountable to meeting multiple objectives and prioritize conservation outcomes over individual targets

To Achieve Big Wins for Terrestrial Conservation, Prioritize Protection of Ecoregions Closest to Meeting Targets

Most of the terrestrial world is experiencing high rates of land conversion despite growth of the global protected area (PA) network. There is a need to assess whether the current global protection targets are achievable across all major ecosystem types and to identify those that need urgent protection. Using recent rates of habitat conversion and protection and the latest terrestrial ecoregion map, we show that if the same approach to PA establishment that has been undertaken over the past three decades continues, 558 of 748 ecoregions (ca. 75%) will not meet an aspirational 30% area protection target by 2030. A simple yet strategic acquisition plan that considers realistic futures around habitat loss and PA expansion could more than double the number of ecoregions adequately protected by 2030 given current funding constraints. These results highlight the importance of including explicit ecoregional representation targets within any new post-2020 global PA target

Integrating Life Cycle and Impact Assessments to Map Food's Cumulative Environmental Footprint

Producing food exerts pressures on the environment. Understanding the location and magnitude of food production is key to reducing the impacts of these pressures on nature and people. In this Perspective, Kuempel et al. outline an approach for integrating life cycle assessment and cumulative impact mapping data and methodologies to map the cumulative environmental pressure of food systems. The approach enables quantification of current and potential future environmental pressures, which are needed to reduce the net impact of feeding humanity. © 2020 The AuthorsFeeding a growing, increasingly affluent population while limiting environmental pressures of food production is a central challenge for society. Understanding the location and magnitude of food production is key to addressing this challenge because pressures vary substantially across food production types. Applying data and models from life cycle assessment with the methodologies for mapping cumulative environmental impacts of human activities (hereafter cumulative impact mapping) provides a powerful approach to spatially map the cumulative environmental pressure of food production in a way that is consistent and comprehensive across food types. However, these methodologies have yet to be combined. By synthesizing life cycle assessment and cumulative impact mapping methodologies, we provide guidance for comprehensively and cumulatively mapping the environmental pressures (e.g., greenhouse gas emissions, spatial occupancy, and freshwater use) associated with food production systems. This spatial approach enables quantification of current and potential future environmental pressures, which is needed for decision makers to create more sustainable food policies and practices. © 2020 The Author

Methods for calculating Protection Equality for conservation planning

Protected Areas (PAs) are a central part of biodiversity conservation strategies around the world. Today, PAs cover c15% of the Earth’s land mass and c3% of the global oceans. These numbers are expected to grow rapidly to meet the Convention on Biological Diversity’s Aichi Biodiversity target 11, which aims to see 17% and 10% of terrestrial and marine biomes protected, respectively, by 2020. This target also requires countries to ensure that PAs protect an “ecologically representative” sample of their biodiversity. At present, there is no clear definition of what desirable ecological representation looks like, or guidelines of how to standardize its assessment as the PA estate grows. We propose a systematic approach to measure ecological representation in PA networks using the Protection Equality (PE) metric, which measures how equally ecological features, such as habitats, within a country’s borders are protected. Extending research in Barr et al. (2011), we present an R package and two Protection Equality (PE) measures; proportional to area PE, and fixed area PE, which measure the representativeness of a country’s PA network. We illustrate the PE metrics with two case studies: coral reef protection across countries and ecoregions in the Coral Triangle, and representation of ecoregions of six of the largest countries in the world. Our results provide repeatable transparency to the issue of representation in PA networks and provide a starting point for further discussion, evaluation and testing of representation metrics. They also highlight clear shortcomings in current PA networks, particularly where they are biased towards certain assemblage types or habitats. Our proposed metrics should be used to report on measuring progress towards the representation component of Aichi Target 11. The PE metrics can be used to measure the representation of any kind of ecological feature including: species, ecoregions, processes or habitats

Rights and representation support justice across aquatic food systems

Injustices are prevalent in food systems, where the accumulation of vast wealth is possible for a few, yet one in ten people remain hungry. Here, for 194 countries we combine aquatic food production, distribution and consumption data with corresponding national policy documents and, drawing on theories of social justice, explore whether barriers to participation explain unequal distributions of benefits. Using Bayesian models, we find economic and political barriers are associated with lower wealth-based benefits; countries produce and consume less when wealth, formal education and voice and accountability are lacking. In contrast, social barriers are associated with lower welfare-based benefits; aquatic foods are less affordable where gender inequality is greater. Our analyses of policy documents reveal a frequent failure to address political and gender-based barriers. However, policies linked to more just food system outcomes centre principles of human rights, specify inclusive decision-making processes and identify and challenge drivers of injustice

The emergent role of small-bodied herbivores in pre-empting phase shifts on degraded coral reefs

Natural and anthropogenic stressors can cause phase shifts from coral-dominated to algal-dominated states. In the Caribbean, over-fishing of large herbivorous fish and disease among the long-spined urchin, Diadema, have facilitated algal growth on degraded reefs. We found that diminutive species of urchin and parrotfish, which escaped die-offs and fishing pressure, can achieve abundances comparable to total herbivore biomass on healthier, protected reefs, and exert sufficient grazing function to pre-empt macroalgal dominance following mass coral mortality. Grazing was highest on the most degraded reefs, and was driven by small herbivores that made up >93% of the average herbivore biomass (per m). We suggest that previously marginal species can achieve a degree of functional redundancy, and that their compensatory herbivory may play an important role in ecosystem resilience. Management strategies should consider the potential role of these additional herbivore functional groups in safeguarding natural controls of algal growth in times of increased uncertainty for the world's reefs

Assessing the status of existing and tentative marine World Heritage areas reveals opportunities to better achieve World Heritage Convention goals

The 1972 World Heritage Convention (WHC) and 1994 Global Strategy aim to preserve the outstanding universal value of internationally important cultural and natural sites within a “representative, balanced and credible” network of highly-protected areas. Increasing human pressures and shortfalls in representation have been documented across the World Heritage network, particularly in terrestrial and cultural sites, threatening the integrity and primary goals of the WHC. However, the conservation status of current and tentative (i.e., proposed) marine natural World Heritage areas (mnWHA) remains relatively unknown. We assessed the extent of recent (2013) and historical (2008–2013) cumulative human impacts and several metrics of representation (country, continent, ecoregion, wilderness, and ‘at-risk’ species) within existing and tentative mnWHAs. We found moderate yet increasing cumulative human impacts across most existing sites, and high or very high impacts across the majority of tentative sites. Climate change impacts comprised nearly 75% of impact scores, on average, and differences between land- and marine-based impacts across sites could help prioritise management decisions. Over 75% of marine ecoregions and 80% of ‘at-risk’ species considered in this study have no representation within the existing sites. We outline how prioritizing representation across tentative sites for future World Heritage listing could greatly increase these metrics. We urge the WHC to adopt quantitative, systematic and transparent evaluations of how current and tentative sites contribute to the overarching goals of maintaining a representative World Heritage network and preserving outstanding universal value for future generations.</p

The resilience of reef invertebrate biodiversity to coral mortality

Foundation species provide many important ecosystem functions including the provision of habitat for diverse communities, but their degradation and mortality has the potential to compromise these roles. Corals are widely recognized foundation species that create reef habitats that are hotspots for biodiversity. However, the impact of global reef degradation on overall patterns of biodiversity remains difficult to predict because of our limited knowledge of mechanistic relationships between reef structure and community composition. We examined the resilience of invertebrate abundance and biodiversity on reefs following a recent coral mass mortality event on the Caribbean coast of Panama. First, we surveyed mobile invertebrate communities at both healthy and degraded reef sites and found that dead coral habitats support invertebrate assemblages that can be more diverse and abundant than live coral habitats and that coral habitat (whether live or dead) in turn supports higher diversity and abundance than structurally simple sand areas without coral. Second, we experimentally tested mechanisms of reef habitat suitability for invertebrate colonization by manipulating coral mortality and structural complexity. We found that the abundance and species richness of mobile invertebrates were significantly affected by substrate complexity rather than whether coral was live or dead. However, we detected shifts in species identity between live and dead coral. Moreover, the sensitivity of the community to reef structural complexity indicates that the ability of degraded coral reefs to sustain invertebrate assemblages is unlikely to persist if declines in reef complexity outpace recovery of living corals to the reef. Our findings suggest that the biodiversity-sustaining function of reefs has the potential to persist following coral disturbance at the scale of entire reefs and that some metrics of community structure are therefore resilient to events of foundation species mortality