Natural Resources Institute

Some of the most important impacts of global climate change will be felt among the populations, predominantly in developing countries, referred to as "subsistence" or "smallholder" farmers. Their vulnerability to climate change comes both from being predominantly located in the tropics, and from various socioeconomic, demographic, and policy trends limiting their capacity to adapt to change. However, these impacts will be difficult to model or predict because of (i) the lack of standardised definitions of these sorts of farming system, and therefore of standard data above the national level, (ii) intrinsic characteristics of these systems, particularly their complexity, their location-specificity, and their integration of agricultural and nonagricultural livelihood strategies, and (iii) their vulnerability to a range of climate-related and other stressors. Some recent work relevant to these farming systems is reviewed, a conceptual framework for understanding the diverse forms of impacts in an integrated manner is proposed, and future research needs are identified.

Abstract Root-associated microbes play a key role in plant performance and productivity, making them important players in agroecosystems. So far, very few studies have assessed the impact of different farming systems on the root microbiota and it is still unclear whether agricultural intensification influences the structure and complexity of microbial communities. We investigated the impact of conventional, no-till, and organic farming on wheat root fungal communities using PacBio SMRT sequencing on samples collected from 60 farmlands in Switzerland. Organic farming harbored a much more complex fungal network with significantly higher connectivity than conventional and no-till farming systems. The abundance of keystone taxa was the highest under organic farming where agricultural intensification was the lowest. We also found a strong negative association (R2 = 0.366; P < 0.0001) between agricultural intensification and root fungal network connectivity. The occurrence of keystone taxa was best explained by soil phosphorus levels, bulk density, pH, and mycorrhizal colonization. The majority of keystone taxa are known to form arbuscular mycorrhizal associations with plants and belong to the orders Glomerales, Paraglomerales, and Diversisporales. Supporting this, the abundance of mycorrhizal fungi in roots and soils was also significantly higher under organic farming. To our knowledge, this is the first study to report mycorrhizal keystone taxa for agroecosystems, and we demonstrate that agricultural intensification reduces network complexity and the abundance of keystone taxa in the root microbiome.

SUMMARY This review compares and contrasts postharvest food losses (PHLs) and waste in developed countries (especially the USA and the UK) with those in less developed countries (LDCs), especially the case of cereals in sub-Saharan Africa. Reducing food losses offers an important way of increasing food availability without requiring additional production resources, and in LDCs it can contribute to rural development and poverty reduction by improving agribusiness livelihoods. The critical factors governing PHLs and food waste are mostly after the farm gate in developed countries but before the farm gate in LDCs. In the foreseeable future (e.g. up to 2030), the main drivers for reducing PHLs differ: in the developed world, they include consumer education campaigns, carefully targeted taxation and private and public sector partnerships sharing the responsibility for loss reduction. The LDCs’ drivers include more widespread education of farmers in the causes of PHLs; better infrastructure to connect smallholders to markets; more effective value chains that provide sufficient financial incentives at the producer level; opportunities to adopt collective marketing and better technologies supported by access to microcredit; and the public and private sectors sharing the investment costs and risks in market-orientated interventions.

Coccidiosis is recognized as the major parasitic disease of poultry and is caused by the apicomplexan protozoan Eimeria. Coccidiosis seriously impairs the growth and feed utilization of infected animals resulting in loss of productivity. Conventional disease control strategies rely heavily on chemoprophylaxis and, to a certain extent, live vaccines. Combined, these factors inflict tremendous economic losses to the world poultry industry in excess of USD 3 billion annually. Increasing regulations and bans on the use of anticoccidial drugs coupled with the associated costs in developing new drugs and live vaccines increases the need for the development of novel approaches and alternative control strategies for coccidiosis. This paper aims to review the current progress in understanding the host immune response to Eimeria and discuss current and potential strategies being developed for coccidiosis control in poultry.

Abstract The increasing demand for food and other basic resources from a growing population has resulted in the intensification of agricultural and industrial activities. The wastes generated from agriculture are a burgeoning problem, as their disposal, utilisation and management practices are not efficient or universally applied. Particularly in developing countries, most biomass residues are left in the field to decompose or are burned in the open, resulting in significant environmental impacts. Similarly, with rapid global urbanisation and the rising demand for construction products, alternative sustainable energy sources and raw material supplies are required. Biomass wastes are an under-utilised source of material (for both energy and material generation), and to date, there has been little activity focussing on a ‘low-carbon’ route for their valorisation. Thus, the present paper attempts to address this by reviewing the global availability of biomass wastes and their potential for use as a feedstock for the manufacture of high-volume construction materials. Although targeted at practitioners in the field of sustainable biomass waste management, this work may also be of interest to those active in the field of carbon emission reductions. We summarise the potential of mitigating CO 2 in a mineralisation step involving biomass residues, and the implications for CO 2 capture and utilisation (CCU) to produce construction products from both solid and gaseous wastes. This work contributes to the development of sustainable value-added lower embodied carbon products from solid waste. The approach will offer reduced carbon emissions and lower pressure on natural resources (virgin stone, soil etc.).

Myriad tiny insect species take to the air to engage in windborne migration, but entomology also has its 'charismatic megafauna' of butterflies, large moths, dragonflies and locusts. The spectacular migrations of large day-flying insects have long fascinated humankind, and since the advent of radar entomology much has been revealed about high-altitude night-time insect migrations. Over the last decade, there have been significant advances in insect migration research, which we review here. In particular, we highlight: (1) notable improvements in our understanding of lepidopteran navigation strategies, including the hitherto unsuspected capabilities of high-altitude migrants to select favourable winds and orientate adaptively, (2) progress in unravelling the neuronal mechanisms underlying sun compass orientation and in identifying the genetic complex underpinning key traits associated with migration behaviour and performance in the monarch butterfly, and (3) improvements in our knowledge of the multifaceted interactions between disease agents and insect migrants, in terms of direct effects on migration success and pathogen spread, and indirect effects on the evolution of migratory systems. We conclude by highlighting the progress that can be made through inter-phyla comparisons, and identify future research areas that will enhance our understanding of insect migration strategies within an eco-evolutionary perspective.

The agricultural sector remains the main source of livelihoods for rural communities in Ethiopia, but faces the challenge of changing climate. This study investigated how smallholder farmers perceive climate change, what adaptation strategies they practice, and factors that influence their adaptation decisions. Both primary and secondary data were used for the study, and a multinomial logit model was employed to identify the factors that shape smallholder farmers’ adaptation strategies. The results show that 90% of farmers have already perceived climate variability, and 85% made attempts to adapt using practices like crop diversification, planting date adjustment, soil and water conservation and management, increasing the intensity of input use, integrating crop with livestock, and tree planting. The econometric model indicated that education, family size, gender, age, livestock ownership, farming experience, frequency of contact with extension agents, farm size, access to market, access to climate information and income were the key factors determining farmers’ choice of adaptation practice. In the Central Rift Valley of Ethiopia, climate change is a pressing problem, which is beyond the capacity of smallholders to respond to autonomously. Farmers’ capacity to choose effective adaptation options is influenced by household demography, as well as positively by farm size, income, access to markets, access to climate information and extension, and livestock production. This implies the need to support the indigenous adaptation strategies of the smallholder farmers with a wide range of institutional, policy, and technology support; some of it targeted on smaller, poorer or female-headed households. Moreover, creating opportunities for non-farm income sources is important as this helps farmers to engage in those activities that are less sensitive to climate change. Furthermore, providing climate change information, extension services, and creating access to markets are crucial.

The sweetpotato whitefly Bemisia tabaci is a highly destructive agricultural and ornamental crop pest. It damages host plants through both phloem feeding and vectoring plant pathogens. Introductions of B. tabaci are difficult to quarantine and eradicate because of its high reproductive rates, broad host plant range, and insecticide resistance. A total of 791 Gb of raw DNA sequence from whole genome shotgun sequencing, and 13 BAC pooling libraries were generated by Illumina sequencing using different combinations of mate-pair and pair-end libraries. Assembly gave a final genome with a scaffold N50 of 437 kb, and a total length of 658 Mb. Annotation of repetitive elements and coding regions resulted in 265.0 Mb TEs (40.3%) and 20 786 protein-coding genes with putative gene family expansions, respectively. Phylogenetic analysis based on orthologs across 14 arthropod taxa suggested that MED/Q is clustered into a hemipteran clade containing A. pisum and is a sister lineage to a clade containing both R. prolixus and N. lugens. Genome completeness, as estimated using the CEGMA and Benchmarking Universal Single-Copy Orthologs pipelines, reached 96% and 79%. These MED/Q genomic resources lay a foundation for future 'pan-genomic' comparisons of invasive vs. noninvasive, invasive vs. invasive, and native vs. exotic Bemisia, which, in return, will open up new avenues of investigation into whitefly biology, evolution, and management.

The Anthropocene is characterized by rapid global change, necessitating adaptive governance. But how can such adaptive governance be operationalized? The article offers a three-point argument to approach this question. First, people and environment need to be considered together, as social (human) and ecological (biophysical) subsystems are linked by mutual feedbacks, and are interdependent and co-evolutionary. These integrated systems of humans and environment (social-ecological systems) provide an appropriate unit of analysis. Second, the resilience approach deals with change in multilevel complex systems, and has stimulated much of the adaptive governance literature by addressing uncertainty and adaptation to unforeseen future changes. Third, there is a need to foster collaborative approaches to improve social and institutional learning, as for example in adaptive management, collaborative learning networks, and knowledge co-production. Collaborative learning is perhaps where further research, experimentation, and application might make a difference for operationalizing adaptive governance, with a focus on institutions, at all levels from local to international.

This paper discusses the trade-off between accuracy, reliability and computing time in global optimization. Particular compromises provided by traditional methods (Quasi-Newton and Nelder-Mead's simplex methods) and genetic algorithms are addressed and illustrated by a particular application in the field of nonlinear system identification. Subsequently, new hybrid methods are designed, combining principles from genetic algorithms and "hill-climbing" methods in order to find a better compromise to the trade-off. Inspired by biology and especially by the manner in which living beings adapt themselves to their environment, these hybrid methods involve two interwoven levels of optimization, namely evolution (genetic algorithms) and individual learning (Quasi-Newton), which cooperate in a global process of optimization. One of these hybrid methods appears to join the group of state-of-the-art global optimization methods: it combines the reliability properties of the genetic algorithms with the accuracy of Quasi-Newton method, while requiring a computation time only slightly higher than the latter.

Begomoviruses (Family Geminiviridae, Genus Begomovirus) have become the most destructive group of plant viruses in tropical and subtropical regions of the world. The recent emergence of begomoviruses is notable, as these viruses have been co-evolving with their dicotyledonous plant hosts for millennia. Agricultural intensification has been proposed as one of the main causes, together with increases in populations of their vector Bemisia tabaci, partly due to the worldwide spread of the more fecund B-biotype. Reports of new diseases and associated epidemics are frequent. Many such reports describe the evolution of more aggressive virus variants through recombination. Little is known about the selection pressures that seem to operate and drive begomovirus evolution towards increased virulence and an extended host range. It is apparent, however, that the genomes of begomoviruses show extreme plasticity leading to an ability to evolve very rapidly in response to changing cropping systems. Genetic diversity is created not only by recombination between genomic components, but also by exchange (pseudorecombination) of their genomic components, and even by acquiring DNA sequences from viruses of other genera. Recently, associations with some satellite molecules, termed DNA-β and DNA1, have also been shown to be widespread in the Old World. Functional DNA-β molecules encode pathogenicity determinants and are often critical for disease symptom development. They appear to act by suppressing host plant defense mechanism(s), such as post-transcriptional gene silencing (PTGS), enabling a diverse range of begomoviruses to infect particular hosts. In this review, suppression of PTGS is one of the driving forces discussed as a likely and important influence on the evolution of begomoviruses. The known sources of genetic variation in begomoviruses are also considered together with the factors driving evolutionary change, the potential for limiting the extent and rate of adverse change, and therefore the potential for achieving more sustainable control of crop disease epidemics.

Plant defense compounds occur in floral nectar, but their ecological role is not well understood. We provide evidence that plant compounds pharmacologically alter pollinator behavior by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times as likely to remember a learned floral scent as were honeybees rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar did not exceed the bees' bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success.

SUMMARY How can the governance of environment and resources be devolved in a way that incorporates effective user participation and feedback learning? Approaches that use the idea of adaptive management or learning-by-doing, combined with co-management, are particularly promising. Using an interdisciplinary literature covering many types of resources, and a conceptual model with three phases (communicative action, self-organization and collective action), the paper identifies some of the major processes leading to adaptive co-management. These include deliberation, visioning, building social capital, trust and institutions, capacity-building through networks and partnerships, and action-reflection-action loops for social learning. Such adaptive co-management is not simply a theoretical possibility but something that has been documented in a number of forestry, fisheries, wildlife, protected area, and wetland cases from both developed and developing countries. However, the experience with the decentralization reforms of the 1990s is largely negative for a number of reasons. Effective devolution takes time, requiring a shift in focus from a static concept of management to a dynamic concept of governance shaped by interactions, feedback learning and adaptation over time. Sharing of governance responsibilities and an ability to learn from experience are among the emerging trends in environmental management.

Migrating animals have an impact on ecosystems directly via influxes of predators, prey, and competitors and indirectly by vectoring nutrients, energy, and pathogens. Although linkages between vertebrate movements and ecosystem processes have been established, the effects of mass insect "bioflows" have not been described. We quantified biomass flux over the southern United Kingdom for high-flying (>150 meters) insects and show that ~3.5 trillion insects (3200 tons of biomass) migrate above the region annually. These flows are not randomly directed in insects larger than 10 milligrams, which exploit seasonally beneficial tailwinds. Large seasonal differences in the southward versus northward transfer of biomass occur in some years, although flows were balanced over the 10-year period. Our long-term study reveals a major transport process with implications for ecosystem services, processes, and biogeochemistry.

Many insects undertake long-range seasonal migrations to exploit temporary breeding sites hundreds or thousands of kilometers apart, but the behavioral adaptations that facilitate these movements remain largely unknown. Using entomological radar, we showed that the ability to select seasonally favorable, high-altitude winds is widespread in large day- and night-flying migrants and that insects adopt optimal flight headings that partially correct for crosswind drift, thus maximizing distances traveled. Trajectory analyses show that these behaviors increase migration distances by 40% and decrease the degree of drift from seasonally optimal directions. These flight behaviors match the sophistication of those seen in migrant birds and help explain how high-flying insects migrate successfully between seasonal habitats.

COVID-19 is characterized by an infectious pre-symptomatic period, when newly infected individuals can unwittingly infect others. We are interested in what benefits facemasks could offer as a non-pharmaceutical intervention, especially in the settings where high-technology interventions, such as contact tracing using mobile apps or rapid case detection via molecular tests, are not sustainable. Here, we report the results of two mathematical models and show that facemask use by the public could make a major contribution to reducing the impact of the COVID-19 pandemic. Our intention is to provide a simple modelling framework to examine the dynamics of COVID-19 epidemics when facemasks are worn by the public, with or without imposed ‘lock-down’ periods. Our results are illustrated for a number of plausible values for parameter ranges describing epidemiological processes and mechanistic properties of facemasks, in the absence of current measurements for these values. We show that, when facemasks are used by the public all the time (not just from when symptoms first appear), the effective reproduction number, R e , can be decreased below 1, leading to the mitigation of epidemic spread. Under certain conditions, when lock-down periods are implemented in combination with 100% facemask use, there is vastly less disease spread, secondary and tertiary waves are flattened and the epidemic is brought under control. The effect occurs even when it is assumed that facemasks are only 50% effective at capturing exhaled virus inoculum with an equal or lower efficiency on inhalation. Facemask use by the public has been suggested to be ineffective because wearers may touch their faces more often, thus increasing the probability of contracting COVID-19. For completeness, our models show that facemask adoption provides population-level benefits, even in circumstances where wearers are placed at increased risk. At the time of writing, facemask use by the public has not been recommended in many countries, but a recommendation for wearing face-coverings has just been announced for Scotland. Even if facemask use began after the start of the first lock-down period, our results show that benefits could still accrue by reducing the risk of the occurrence of further COVID-19 waves. We examine the effects of different rates of facemask adoption without lock-down periods and show that, even at lower levels of adoption, benefits accrue to the facemask wearers. These analyses may explain why some countries, where adoption of facemask use by the public is around 100%, have experienced significantly lower rates of COVID-19 spread and associated deaths. We conclude that facemask use by the public, when used in combination with physical distancing or periods of lock-down, may provide an acceptable way of managing the COVID-19 pandemic and re-opening economic activity. These results are relevant to the developed as well as the developing world, where large numbers of people are resource poor, but fabrication of home-made, effective facemasks is possible. A key message from our analyses to aid the widespread adoption of facemasks would be: ‘my mask protects you, your mask protects me’.

Abstract This paper presents data on the abundance, biomass and species richness of termites in the Mbalmayo Forest Reserve, southern Cameroon. Five plots of differing disturbance level (near primary forest, old secondary forest, young plantation, weeded Chromolaena fallow, and completely cleared forest) were sampled for termites in two successive years (July 1992 and July 1993, giving a total of ten sampling areas, plus one in the completely cleared plot in November 1992). A stratified sampling regime of soil pits, wood samples, mound samples and soil scrape samples was used. Estimated abundance and biomass were extremely high in the near primary and old secondary plot (maximum estimated abundance, old secondary sampling area 1, 10488 m-2, maximum biomass density, near primary sampling area 1,123.2 g m-2). In all cases termite abundance was highly clumped. Disturbance had apparently little effect on termite abundances and biomass in forested plots, but there were clear reductions in abundance and biomass in the cleared plots. In the completely cleared plot, abundance and biomass fell sharply from year 1 to year 2, presumably because colonies left after clearance had dried out and died. There were large differences in the taxonomic-, nesting- and feeding-group composition of the plots, with soil feeding termites being especially strongly affected by disturbance. The sources of error associated with this sampling programme are discussed. It is argued that the near primary forest plot may have higher microhabitat and concomitant termite assemblage heterogeneity than the more disturbed plots. In most cases over 90 % of the overall abundance in a sampling area was due to a few species; extinction, and will make areas. This may be due to the unpredictable dynamics of colony foundation and extinction, and will make estimations of the effect of termites on overall ecosystem processes (from abundance and biomass data alone) problematical. There is no evidence of immigration of savanna termites into the forest reserve, and thus cleared areas have depauperate forest assemblages. It is concluded that this is the most accurate estimation of termite assemblage parameters yet attempted.

Radar has been used to study insects in flight for over 40 years and has helped to establish the ubiquity of several migration phenomena: dawn, morning, and dusk takeoffs; approximate downwind transport; concentration at wind convergences; layers in stable nighttime atmospheres; and nocturnal common orientation. Two novel radar designs introduced in the late 1990s have significantly enhanced observing capabilities. Radar-based research now encompasses foraging as well as migration and is increasingly focused on flight behavior and the environmental cues influencing it. Migrant moths have been shown to employ sophisticated orientation and height-selection strategies that maximize displacements in seasonally appropriate directions; they appear to have an internal compass and to respond to turbulence features in the airflow. Tracks of foraging insects demonstrate compensation for wind drift and use of optimal search paths to locate resources. Further improvements to observing capabilities, and employment in operational as well as research roles, appear feasible.

The world has responded to climate change phenomenon through two broad response mechanisms (mitigation and adaptation strategies) with the aim of moderating the adverse effects of climate change and/or to exploit any arising beneficial opportunities. The paper aims to examine the trend in climate parameters, farmers’ perception of climate change, constraints faced in production and to identify the strategies (if any) that farmers have adopted to cope with the effects of changing climate. A one-way analysis of variance, percentage analysis and Garrett ranking technique were applied to a set of primary data collected from 150 randomly sampled farmers with the aid of questionnaires in three purposively selected provinces through the months of June to August 2015. The analytical results of obtained recent weather data revealed that the climate parameters have significantly changed over time and these were substantiated by farmers’ experiences. The farmers are engaging in various climate-response strategies, among which, the planting of drought-tolerant varieties is most common. Therefore, it is important to enhance farmers’ access to improved drought-tolerant seeds and efficient irrigation systems. Also observed, is that the lack of awareness of insurance products and inability to afford insurance premiums were the principal reasons majority of the farmers did not have insurance. These present a need to strengthen insurance adoption among farmers through various supporting programmes that may include premium subsidies and media outreach. The paper under one platform provides evidence of changing climate, farmers’ responses towards mitigating perceived adverse effects of the changed climate, and South Africa’s national policy on adaptation and mitigation.

Summary The ecological function of secondary metabolites in plant defence against herbivores is well established, but their role in plant–pollinator interactions is less obvious. Nectar is the major reward for pollinators, so the occurrence of defence chemicals in the nectar of many species is unexpected. However, increasing evidence supports a variety of potential benefits for both plant and pollinator from these compounds. Beneficial effects may include: (i) mediating specialization in plant–pollinator interactions, (ii) protecting nectar from robbery or larceny and (iii) microbial activity including preservation of nutrients in nectar from degradation and reduction in disease levels in pollinators. Secondary metabolites in nectar can be toxic or repellent to flower visitors, but equally they can go undetected or even make nectar more apparent or attractive. These biological effects are concentration dependent, so must be considered at a range of ecologically relevant doses. For example, caffeine occurs in nectar and improves honeybee memory for odours associated with food rewards, which enhances pollen transfer at naturally occurring concentrations but is repellent to honeybees at higher concentrations. This review synthesizes evidence from recent literature that supports selection for secondary metabolites in floral nectar as an adaptation that drives the co‐evolution between plants and their pollinators. However, their presence in nectar could still simply be a consequence of their defensive role elsewhere in the plant (pleiotropy). We highlight the need for more studies demonstrating measurable benefits to the plant, the importance of exposure levels and effects on target species beyond the current emphasis on alkaloids and bees. A Lay Summary is available for this article.