Trade-offs in the externalities of pig production are not inevitable.

Farming externalities are believed to co-vary negatively, yet trade-offs have rarely been quantified systematically. Here we present data from UK and Brazilian pig production systems representative of most commercial systems across the world ranging from 'intensive' indoor systems through to extensive free range, Organic and woodland systems to explore co-variation among four major externality costs. We found that no specific farming type was consistently associated with good performance across all domains. Generally, systems with low land use have low greenhouse gas emissions but high antimicrobial use and poor animal welfare, and vice versa. Some individual systems performed well in all domains but were not exclusive to any particular type of farming system. Our findings suggest that trade-offs may be avoidable if mitigation focuses on lowering impacts within system types rather than simply changing types of farming.

Conflicts and opportunities for commercial tree plantation expansion and biodiversity restoration across Brazil.

Substantial global restoration commitments are occurring alongside a rapid expansion in land-hungry tropical commodities, including to supply increasing demand for wood products. Future commercial tree plantations may deliver high timber yields, shrinking the footprint of production forestry, but there is an as-yet unquantified risk that plantations may expand into priority restoration areas, with marked environmental costs. Focusing on Brazil-a country of exceptional restoration importance and one of the largest tropical timber producers-we use random forest models and information on the economic, social, and spatial drivers of historic commercial tree plantation expansion to estimate and map the probability of future monoculture tree plantation expansion between 2020 and 2030. We then evaluate potential plantation-restoration conflicts and opportunities at national and biome-scales and under different future production and restoration pathways. Our simulations show that of 2.8 Mha of future plantation expansion (equivalent to plantation expansion 2010-2020), ~78,000 ha (3%) is forecast to occur in the top 1% of restoration priority areas for terrestrial vertebrates, with ~547,500 ha (20%) and ~1,300,000 ha (46%) in the top 10% and 30% of priority areas, respectively. Just ~459,000 ha (16%) of expansion is forecast within low-restoration areas (bottom 30% restoration priorities), and the first 1 Mha of plantation expansion is likely to have disproportionate impacts, with potential restoration-plantation overlap starkest in the Atlantic Forest but prominent in the Pampas and Cerrado as well. Our findings suggest that robust, coherent land-use policies must be deployed to ensure that significant trade-offs between restoration and production objectives are navigated, and that commodity expansion does not undermine the most tractable conservation gains under emerging global restoration agendas. They also highlight the potentially significant role an engaged forestry sector could play in improving biodiversity outcomes in restoration projects in Brazil, and presumably elsewhere.

Global priority areas for ecosystem restoration.

Extensive ecosystem restoration is increasingly seen as being central to conserving biodiversity1 and stabilizing the climate of the Earth2. Although ambitious national and global targets have been set, global priority areas that account for spatial variation in benefits and costs have yet to be identified. Here we develop and apply a multicriteria optimization approach that identifies priority areas for restoration across all terrestrial biomes, and estimates their benefits and costs. We find that restoring 15% of converted lands in priority areas could avoid 60% of expected extinctions while sequestering 299 gigatonnes of CO2-30% of the total CO2 increase in the atmosphere since the Industrial Revolution. The inclusion of several biomes is key to achieving multiple benefits. Cost effectiveness can increase up to 13-fold when spatial allocation is optimized using our multicriteria approach, which highlights the importance of spatial planning. Our results confirm the vast potential contributions of restoration to addressing global challenges, while underscoring the necessity of pursuing these goals synergistically.

Author Correction: Strategic approaches to restoring ecosystems can triple conservation gains and halve costs.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Characterising the spatial distribution of opportunities and constraints for land sparing in Brazil.

Brazil is a megadiversity country with more tropical forest than any other, and is a leading agricultural producer. The technical potential to reconcile these roles by concentrating agriculture on existing farmland and sparing land for nature is well-established, but the spatial overlap of this potential with conservation priorities and institutional constraints remains poorly understood. We mapped conservation priorities, food production potential and socio-economic variables likely to influence the success of land sparing. Pasture occupies 70% of agricultural land but contributes ≤11% of the domestic food supply. Increasing yields on pasture would add little to Brazil's food supply but - if combined with concerted conservation and restoration policies - provides the greatest opportunities for reducing land demand. Our study illustrates a method for identifying municipalities where land-sparing policies are most likely to succeed, and those where further effort is needed to overcome constraints such as land tenure insecurity, lack of access to technical advice, labour constraints, and non-compliance with environmental law.

Linking global drivers of agricultural trade to on-the-ground impacts on biodiversity.

Consumption of globally traded agricultural commodities like soy and palm oil is one of the primary causes of deforestation and biodiversity loss in some of the world's most species-rich ecosystems. However, the complexity of global supply chains has confounded efforts to reduce impacts. Companies and governments with sustainability commitments struggle to understand their own sourcing patterns, while the activities of more unscrupulous actors are conveniently masked by the opacity of global trade. We combine state-of-the-art material flow, economic trade, and biodiversity impact models to produce an innovative approach for understanding the impacts of trade on biodiversity loss and the roles of remote markets and actors. We do this for the production of soy in the Brazilian Cerrado, home to more than 5% of the world´s species. Distinct sourcing patterns of consumer countries and trading companies result in substantially different impacts on endemic species. Connections between individual buyers and specific hot spots explain the disproportionate impacts of some actors on endemic species and individual threatened species, such as the particular impact of European Union consumers on the recent habitat losses for the iconic giant anteater (Myrmecophaga tridactyla). In making these linkages explicit, our approach enables commodity buyers and investors to target their efforts much more closely to improve the sustainability of their supply chains in their sourcing regions while also transforming our ability to monitor the impact of such commitments over time.

Strategic approaches to restoring ecosystems can triple conservation gains and halve costs.

International commitments for ecosystem restoration add up to one-quarter of the world's arable land. Fulfilling them would ease global challenges such as climate change and biodiversity decline but could displace food production and impose financial costs on farmers. Here, we present a restoration prioritization approach capable of revealing these synergies and trade-offs, incorporating ecological and economic efficiencies of scale and modelling specific policy options. Using an actual large-scale restoration target of the Atlantic Forest hotspot, we show that our approach can deliver an eightfold increase in cost-effectiveness for biodiversity conservation compared with a baseline of non-systematic restoration. A compromise solution avoids 26% of the biome's current extinction debt of 2,864 plant and animal species (an increase of 257% compared with the baseline). Moreover, this solution sequesters 1 billion tonnes of CO2-equivalent (a 105% increase) while reducing costs by US$28 billion (a 57% decrease). Seizing similar opportunities elsewhere would offer substantial contributions to some of the greatest challenges for humankind.

Carbon Storage and Land-Use Strategies in Agricultural Landscapes across Three Continents.

The loss of carbon stocks through agricultural land-use change is a key driver of greenhouse gas emissions [1-4], and the methods used to manage agricultural land will have major impacts on the global climate in the 21st century [4-9]. It remains unresolved whether carbon losses would be minimized by increasing farm yields and limiting the conversion of natural habitats ("land sparing"), or maximizing on-farm carbon stocks, even at the cost of reduced yields and therefore greater habitat clearance ("land sharing"). In this paper, we use field surveys of over 11,000 trees, in-depth interviews with farmers, and existing agricultural data, to evaluate the potential impacts of these contrasting approaches, and plausible intermediate strategies, on above-ground carbon stocks across a diverse range of agricultural and natural systems. Our analyses include agroforestry and oil palm plantations in the humid tropics of Ghana; cattle ranching in dry tropical forest in Mexico; and arable cropping in temperate wetlands and forests in Poland. Strikingly, despite the range of systems investigated, land sparing consistently had a higher potential to sustain regional above-ground carbon stocks than any other strategy. This was the case in all three regions and at all plausible levels of food production, including falls in demand. However, if agricultural production increases to meet likely future demand levels, we project large decreases in above-ground carbon stocks, regardless of land-use strategy. Our results strongly suggest that maintaining above-ground carbon stocks will depend on both limiting future food demand and minimizing agricultural expansion through linking high-yield farming with conserving or restoring natural habitats.

New law puts Bolivian biodiversity hotspot on road to deforestation.

In August 2017, the Bolivian government passed a contentious law downgrading the legal protection of the Isiboro-Sécure National Park and Indigenous Territory (TIPNIS, for its Spanish acronym), the ancestral homeland of four lowland indigenous groups and one of Bolivia's most iconic protected areas. Due to its strategic position straddling the Andes and Amazonia, TIPNIS represents not only a key biodiversity hotspot in Bolivia, but one of the most biodiverse regions on Earth, harboring exceptional levels of endemism and globally important populations of megafauna, as well as protecting substantial topographic complexity likely to support both wildlife migration and species range shifts in response to climate change [1]. The new law, set to authorize the construction of a deeply-contested road through the core of the park, has reopened one of the highest profile socio-environmental conflicts in Latin America. Roads in tropical forests often lead to habitat conversion, and indeed within TIPNIS more than 58% of deforestation is concentrated 5 km or less away from existing roads. It, therefore, seems very likely that the planned road will magnify the current scale and pace of deforestation in TIPNIS, underscoring the urgent need for revisiting the road plans.

Land-use strategies to balance livestock production, biodiversity conservation and carbon storage in Yucatán, Mexico.

Balancing the production of food, particularly meat, with preserving biodiversity and maintaining ecosystem services is a major societal challenge. Research into the contrasting strategies of land sparing and land sharing has suggested that land sparing-combining high-yield agriculture with the protection or restoration of natural habitats on nonfarmed land-will have lower environmental impacts than other strategies. Ecosystems with long histories of habitat disturbance, however, could be resilient to low-yield agriculture and thus fare better under land sharing. Using a wider suite of species (birds, dung beetles and trees) and a wider range of livestock-production systems than previous studies, we investigated the probable impacts of different land-use strategies on biodiversity and aboveground carbon stocks in the Yucatán Peninsula, Mexico-a region with a long history of habitat disturbance. By modelling the production of multiple products from interdependent land uses, we found that land sparing would allow larger estimated populations of most species and larger carbon stocks to persist than would land sharing or any intermediate strategy. This result held across all agricultural production targets despite the history of disturbance and despite species richness in low- and medium-yielding agriculture being not much lower than that in natural habitats. This highlights the importance, in evaluating the biodiversity impacts of land use, of measuring population densities of individual species, rather than simple species richness. The benefits of land sparing for both biodiversity and carbon storage suggest that safeguarding natural habitats for biodiversity protection and carbon storage alongside promoting areas of high-yield cattle production would be desirable. However, delivering such landscapes will probably require the explicit linkage of livestock yield increases with habitat protection or restoration, as well as a deeper understanding of the long-term sustainability of yields, and research into how other societal outcomes vary across land-use strategies.

Crop expansion and conservation priorities in tropical countries.

Expansion of cropland in tropical countries is one of the principal causes of biodiversity loss, and threatens to undermine progress towards meeting the Aichi Biodiversity Targets. To understand this threat better, we analysed data on crop distribution and expansion in 128 tropical countries, assessed changes in area of the main crops and mapped overlaps between conservation priorities and cultivation potential. Rice was the single crop grown over the largest area, especially in tropical forest biomes. Cropland in tropical countries expanded by c. 48,000 km(2) per year from 1999-2008. The countries which added the greatest area of new cropland were Nigeria, Indonesia, Ethiopia, Sudan and Brazil. Soybeans and maize are the crops which expanded most in absolute area. Other crops with large increases included rice, sorghum, oil palm, beans, sugar cane, cow peas, wheat and cassava. Areas of high cultivation potential-while bearing in mind that political and socio-economic conditions can be as influential as biophysical ones-may be vulnerable to conversion in the future. These include some priority areas for biodiversity conservation in tropical countries (e.g., Frontier Forests and High Biodiversity Wilderness Areas), which have previously been identified as having 'low vulnerability', in particular in central Africa and northern Australia. There are also many other smaller areas which are important for biodiversity and which have high cultivation potential (e.g., in the fringes of the Amazon basin, in the Paraguayan Chaco, and in the savanna woodlands of the Sahel and East Africa). We highlight the urgent need for more effective sustainability standards and policies addressing both production and consumption of tropical commodities, including robust land-use planning in agricultural frontiers, establishment of new protected areas or REDD+ projects in places agriculture has not yet reached, and reduction or elimination of incentives for land-demanding bioenergy feedstocks.

Boom-and-bust development patterns across the Amazon deforestation frontier.

The Brazilian Amazon is globally important for biodiversity, climate, and geochemical cycles, but is also among the least developed regions in Brazil. Economic development is often pursued through forest conversion for cattle ranching and agriculture, mediated by logging. However, on the basis of an assessment of 286 municipalities in different stages of deforestation, we found a boom-and-bust pattern in levels of human development across the deforestation frontier. Relative standards of living, literacy, and life expectancy increase as deforestation begins but then decline as the frontier evolves, so that pre- and postfrontier levels of human development are similarly low. New financial incentives and policies are creating opportunities for a more sustained development trajectory that is not based on the depletion of nature and ecosystem services.