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Sustainably feeding the next generation is often described as one of the most pressing "grand challenges" facing the 21st century. Generally, scholars propose addressing this problem by increasing agricultural production, investing in technology to boost yields, changing diets, or reducing food waste. In this paper, we explore whether global food production is nutritionally balanced by comparing the diet that nutritionists recommend versus global agricultural production statistics. Results show that the global agricultural system currently overproduces grains, fats, and sugars while production of fruits and vegetables and protein is not sufficient to meet the nutritional needs of the current population. Correcting this imbalance could reduce the amount of arable land used by agriculture by 51 million ha globally but would increase total land used for agriculture by 407 million ha and increase greenhouse gas emissions. For a growing population, our calculations suggest that the only way to eat a nutritionally balanced diet, save land and reduce greenhouse gas emissions is to consume and produce more fruits and vegetables as well as transition to diets higher in plant-based protein. Such a move will help protect habitats and help meet the Sustainable Development Goals., Competing Interests: The authors have declared that no competing interests exist.

Given the pressures on land to produce ever more food, doing it 'sustainably' is growing in importance. However, 'sustainable agriculture' is complex to define, not least because agriculture impacts in many different ways and it is not clear how different aspects of sustainability may be in synergy or trade off against each other. We conducted a meta-analysis to assess the relationships between multiple measures of sustainability using novel analytical methods, based around defining the efficiency frontier in the relationship between variables, as well as using correlation analysis. We define 20 grouped variables of agriculture's impact (e.g. on soil, greenhouse gas, water, biodiversity) and find evidence of both strong positive and negative correlations between them. Analysis based on the efficiency frontier suggests that trade-offs can be 'softened' by exploiting the natural between-study variation that arises from a combination of farming best practice and context. Nonetheless, the literature provides strong evidence of the relationship between yields and the negative externalities created by farming across a range of measures., (© 2016 Cambridge Philosophical Society.)

Land management intrinsically influences the distribution of animals and can consequently alter the potential for density-dependent processes to act within populations. For declining species, high densities of breeding territories are typically considered to represent productive populations. However, as density-dependent effects of food limitation or predator pressure may occur (especially when species are dependent upon separate nesting and foraging habitats), high territory density may limit per-capita productivity. Here, we use a declining but widespread European farmland bird, the yellowhammer Emberiza citrinella L., as a model system to test whether higher territory densities result in lower fledging success, parental provisioning rates or nestling growth rates compared to lower densities. Organic landscapes held higher territory densities, but nests on organic farms fledged fewer nestlings, translating to a 5 times higher rate of population shrinkage on organic farms compared to conventional. In addition, when parental provisioning behaviour was not restricted by predation risk (i.e., at times of low corvid activity), nestling provisioning rates were higher at lower territory densities, resulting in a much greater increase in nestling mass in low density areas, suggesting that food limitation occurred at high densities. These findings in turn suggest an ecological trap, whereby preferred nesting habitat does not provide sufficient food for rearing nestlings at high population density, creating a population sink. Habitat management for farmland birds should focus not simply on creating a high nesting density, but also on ensuring heterogeneous habitats to provide food resources in close proximity to nesting birds, even if this occurs through potentially restricting overall nest density but increasing population-level breeding success.

There is increasing recognition that ecosystems and their services need to be managed in the face of environmental change. However, there is little consensus as to the optimum scale for management. This is particularly acute in the agricultural environment given the level of public investment in agri-environment schemes (AES). Using a novel multiscale hierarchical sampling design, we assess the effect of land use at multiple spatial scales (from location-within-field to regions) on farmland biodiversity. We show that on-farm biodiversity components depend on farming practices (organic vs. conventional) at farm and landscape scales, but this strongly interacts with fine- and coarse-scale variables. Different taxa respond to agricultural practice at different spatial scales and often at multiple spatial scales. Hence, AES need to target multiple spatial scales to maximize effectiveness. Novel policy levers may be needed to encourage multiple land managers within a landscape to adopt schemes that create landscape-level benefits.

Abstract Background Conventional agriculture is increasingly based on highly specialized, highly productive farms. It has been suggested that 1) this specialization leads to farms that lack resilience to changing market and environmental conditions; and 2) that by decreasing agricultural diversity, the resilience of the farming system also decreases. Methods We used agricultural gross margin (GM) forecasts from 1966 to 2010 and remote sensing data from agricultural landscapes in the lowland UK, in conjunction with modern portfolio theory, to test the hypothesis that decreasing land-use diversity results in landscapes that provide higher, but more volatile, economic returns. We considered the role of spatial scale on the expected levels of volatility and resilience of agricultural returns. Results We found that: 1) there was a strong linear trade-off between expected GMs and the expected volatility of those GMs in real lowland agricultural landscapes in the UK; 2) land-use diversification was negatively correlated with expected GMs from agriculture, and positively correlated with decreasing expected volatility in GMs; 3) the resilience of agricultural returns was positively correlated with the diversity of agricultural land use, and the resilience of agricultural returns rose quickly with increased land-holding size at small spatial extents, but this effect diminished after landholdings reached 12,000 hectares. Conclusions Land-use diversity may have an important role in ensuring resilient agricultural returns in the face of uncertain market and environmental conditions, and land-holding size plays a pivotal role in determining the relationships between resilience and returns at a landscape scale. Creating finer-grained land-use patterns based on pre-existing local land uses may increase the resilience of individual farms, while maintaining aggregate yield across landscapes.

Increasing concerns about global environmental change and food security have focused attention on the need for environmentally sustainable agriculture. This is agriculture that makes efficient use of natural resources and does not degrade the environmental systems that underpin it, or deplete natural capital stocks. We convened a group of 29 'practitioners' and 17 environmental scientists with direct involvement or expertise in the environmental sustainability of agriculture. The practitioners included representatives from UK industry, non-government organizations and government agencies. We collaboratively developed a long list of 264 knowledge needs to help enhance the environmental sustainability of agriculture within the UK or for the UK market. We refined and selected the most important knowledge needs through a three-stage process of voting, discussion and scoring. Scientists and practitioners identified similar priorities. We present the 26 highest priority knowledge needs. Many of them demand integration of knowledge from different disciplines to inform policy and practice. The top five are about sustainability of livestock feed, trade-offs between ecosystem services at farm or landscape scale, phosphorus recycling and metrics to measure sustainability. The outcomes will be used to guide ongoing knowledge exchange work, future science policy and funding. [ABSTRACT FROM AUTHOR]

Agricultural change is often cited as a causal factor in the decline of the UK's farmland birds because bird declines have mirrored changes in agricultural practices. Although much is known about the mechanisms driving population declines on arable systems, mechanisms in grassland systems are relatively poorly studied, despite receiving a similar degree of intensification. Agricultural intensification may affect bird declines by reducing food abundance or accessibility, forager mobility or predation risk. Here we examine experimentally the effects of sward height on the foraging behaviour of adult Common StarlingsSturnus vulgaris, and the effects of sward height and drainage on the behaviour of Northern LapwingVanellus vanelluschicks. Both species are declining across the UK and both forage in farmed grassland habitats, but they differ in their foraging methods because Starlings probe for soil invertebrates whereas Lapwing chicks glean prey from surfaces. Overall, after controlling for prey abundance, short swards were found to be more productive for both species. Prey capture rate within foraging bouts did not differ with sward height for Starlings, but Starlings spent more time foraging on short swards and captured 33.2% more prey. Starlings walked more steps on short swards. Lapwing chick foraging rates declined as sward height increased. Soil moisture was not found to be a predictor of Lapwing chick foraging rates within the observed range. Our results suggest that short swards are a more profitable foraging habitat for soil and surface invertebrate feeders. Short swards may facilitate surface prey detection, improve forager mobility and increase foraging time by altering vigilance patterns. Provision of short swards in areas where these are lacking could be simple method of improving foraging habitats for grassland birds. [ABSTRACT FROM AUTHOR]

Agricultural intensification has led to a widespread decline in farmland biodiversity measured across many different taxa. The changes in agricultural practices affect many different aspects of the farmland habitat, but agricultural industry, policy and much previous research has tended to be concerned with specific sectors or practices (e.g. pesticide use or cereal husbandry). Here, we review the empirical literature to synthesize the research effort that has been directed to investigate specific practices or goals to make general statements regarding the causes and consequences of farmland biodiversity decline. We argue that the loss of ecological heterogeneity at multiple spatial and temporal scales is a universal consequence of multivariate agricultural intensification and, therefore, that future research should develop cross-cutting policy frameworks and management solutions that recreate that heterogeneity as the key to restoring and sustaining biodiversity in temperate agricultural systems. [Copyright &y& Elsevier]

It is possible to frame sustainability as occurring when the global or local system is within a set of limits and boundaries, such as the concept of safe operating spaces within planetary boundaries. However, such framings, whilst highly useful conceptually, have been difficult to translate into operation, especially in the development of policies. Here we show how it is possible to define a safe operating space, bounded by sets of constraints. These constraints can be of a variety of forms (e.g., income, or biodiversity), and, importantly, they need not all be converted to a single common metric such as money. The challenge is to identify a set of policy options that define the "safe policy space" which maintains the system within the safe operating space defined by boundaries. A formal methodology, Co-Viability Analysis (CVA), can be used to do this. This provides a coherent framework to operationalize sustainability and has a number of extra advantages. First, defining a safe policy space allows for a political choice of which policies and so is not prescriptive—such as would be the case if a single policy option were defined. Secondly, by allowing each boundary to be defined with its own scale of measurement, it avoids the necessity of having to value natural capital or ecosystem services in financial terms. This framework, therefore, has the potential to allow decision-makers to genuinely meet the needs of their people, now and in the future. [ABSTRACT FROM AUTHOR]

Natural and semi-natural habitats in agricultural landscapes are likely to come under increasing pressure with the global population set to exceed 9 billion by 2050. These non-cropped habitats are primarily made up of trees, hedgerows and grassy margins and their amount, quality and spatial configuration can have strong implications for the delivery and sustainability of various ecosystem services. In this study high spatial resolution (0.5 m) colour infrared aerial photography (CIR) was used in object based image analysis for the classification of non-cropped habitat in a 10,029 ha area of southeast England. Three classification scenarios were devised using 4 and 9 class scenarios. The machine learning algorithm Random Forest (RF) was used to reduce the number of variables used for each classification scenario by 25.5 % ± 2.7%. Proportion of votes from the 4 class hierarchy was made available to the 9 class scenarios and where the highest ranked variables in all cases. This approach allowed for misclassified parent objects to be correctly classified at a lower level. A single object hierarchy with 4 class proportion of votes produced the best result (kappa 0.909). Validation of the optimum training sample size in RF showed no significant difference between mean internal out-of-bag error and external validation. As an example of the utility of this data, we assessed habitat suitability for a declining farmland bird, the yellowhammer ( Emberiza citronella ), which requires hedgerows associated with grassy margins. We found that ∼22% of hedgerows were within 200 m of margins with an area >183.31 m 2 . The results from this analysis can form a key information source at the environmental and policy level in landscape optimisation for food production and ecosystem service sustainability. [ABSTRACT FROM AUTHOR]

Deforestation and degradation are threatening forests and woodlands globally. The deciduous miombo woodlands of sub-Saharan Africa are no exception, yet little is known about the flora and fauna they contain and the implications of their loss. Butterflies are recognised as indicators of environmental change; however the responses of butterflies in miombo woodlands have received little attention. This paper describes butterfly assemblages and their response to woodland utilisation in an understudied area of miombo woodland in south-west Tanzania. This is an area representative of miombo woodlands throughout sub-Saharan Africa, where woodland is utilised by local communities for a range of products, and is being rapidly converted to agriculture. Baited canopy traps and sweep nets were used to sample frugivorous and nectarivorous butterfly communities at different vertical stratifications in nine different study sites. 104 species were recorded, of which 16 are miombo specialists that have been recorded in Tanzania to the west of the country only. Indicator species were identified for three different levels of utilisation, with species from the sub-family Satyrinae indicating moderate utilisation. Generalised linear mixed effects models showed that butterfly species richness, diversity and abundance all decreased in response to increasing agriculture and anthropogenic utilisation. The loss of miombo woodlands is likely to result in declines in butterfly diversity. However, there was evidence of an intermediate disturbance effect for butterfly species richness, diversity and abundance with one utilisation variable, suggesting that a miombo woodland management plan that allows moderate sustainable utilisation in a heterogeneous landscape of mature miombo woodland and agriculture will simultaneously maintain butterfly communities and enable agricultural production. [ABSTRACT FROM AUTHOR]

Highlights: [•] A singular focus on increasing yield exacerbates biodiversity decline. [•] There are options that increase yield while protecting biodiversity. [•] Practices to improve production and biodiversity outcomes must reflect the heterogeneity of types production landscapes. [Copyright &y& Elsevier]