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• The proportion of maize in the landscape overrides management effects on maize stemborer. • At field level, stemborer infestation was positively associated with plant density. • At high infestation levels, infestation was positively associated with planting date. • At high infestation levels, infestation was negatively associated with the botanic diversity of hedges. • Maize grain yield was weakly negatively associated with stemborer infestation level. Lepidopteran stemborers are a serious pest of maize in Africa. While farmers have adopted cultural control practices at the field scale, it is not clear how these practices affect stemborer infestation levels and how their efficacy is influenced by landscape context. The aim of this 3-year study was to assess the effect of field and landscape factors on maize stemborer infestation levels and maize productivity. Maize infestation levels, yield and biomass production were assessed in 33 farmer fields managed according to local practices. When considering field level factors only, plant density was positively related to stemborer infestation level. During high infestation events, length of tunnelling was positively associated with planting date and negatively with the botanical diversity of hedges. However, the proportion of maize crop in the surrounding landscape was strongly and positively associated with length of tunnelling at 100, 500, 1000 and 1500 m radius, and overrode field level management factors when considered together. Maize grain yield was positively associated with plant density and soil phosphorus content, and not negatively associated with the length of tunnelling. Our findings highlight the need to consider a landscape approach for stemborer pest management, but also indicate that maize is tolerant to low and medium infestation levels of stemborers. [ABSTRACT FROM AUTHOR]

Pollination by insects is key for the productivity of many fruit and non-graminous seed crops, but little is known about the response of pollinators to landscapes dominated by small-holder agriculture. Here we assess the relationships between landscape context, pollinator communities (density and diversity) and pollination of oilseed rape in 18 landscapes with proportions of small-holder farming ranging from 10% to 70% in southern China. To quantify the contribution of pollinators to oilseed rape yield, we manipulated pollinator access in a focal oilseed rape field in each landscape using open and closed cages. The pollinator communities in the focal fields were sampled using pan traps. The abundance of wild pollinators increased significantly with the proportion of cultivated land, but the diversity of the wild pollinator communities declined. The responses of pollinator abundance and diversity to cultivated land were best explained at scales of around 1000 m. The abundance of the unmanaged honey bee Apis cerana was positively associated with the proportion of cultivated land, whereas the abundance of the managed A. mellifera was not. A pollination services index (PSI) was calculated by comparing the reproductive investment in seeds between plants with or without pollinator access. PSI was positively correlated with wild pollinator abundance, but not with the abundance of honeybee species. PSI was also not significantly correlated with the area proportion of cultivated land. Our results indicate that crop dominated landscapes with numerous small fields supported an abundant, but relatively species poor bee community that delivered pollination services to oilseed rape. Conservation of (semi-)natural habitats, however, is important for maintaining the diversity of wild pollinators. [ABSTRACT FROM AUTHOR]

Abstract: The potential impact of nectar availability for biological pest control is of increasing relevance due to the disappearance of non-crop plants in intensified agricultural landscapes. However, little is known about how floral resources and their spatial distribution in and around crop fields influence cereal aphid parasitoid (Hymenoptera, Aphidiidae) survival and population dynamics. Cereal aphid parasitoids may be less dependent on flowers as they can use honeydew from their aphid hosts as an alternative food resource. However, honeydew appears to be less suitable as a food source for parasitoids when compared to nectar. Here the effects of flower distribution (nectar), aphid abundance (honeydew quantity) and honeydew quality on parasitoid life history parameters were explored using a spatially explicit, individual-based simulation model. In addition, effects of the availability of floral resources in field margins on parasitism levels in winter wheat were investigated in a field study. In the simulation study three flower distributions were compared: (i) flowers restricted to the field margin (most common in agricultural landscapes) or (ii) flowers in strips within the crop, and (iii) random flower distribution in the field. Simulations suggest that nectar feeding increases parasitoid longevity and parasitism at low aphid densities, but only in fields with randomly distributed flowers. In contrast, the spatial distribution of flowers did not affect the parasitoid longevity and parasitism rate at high aphid densities, where parasitoid feeding was restricted to the abundant honeydew resources. In simulations, parasitoid survival and the number of aphids parasitized were also affected by the nutritional quality of the honeydew, with low quality honeydew having a less positive effect on parasitoid longevity and parasitism rate. The field study did not indicate evidence of a significant relationship between flower cover in field margins and parasitism rates in wheat near the margins. This finding is compatible with results from simulations and suggests that honeydew feeding is more prevalent in cereal aphid parasitoids than nectar feeding. In conclusion, nectar may be an important factor for the potential biocontrol success of cereal aphid parasitoids, but most likely only at low aphid densities and especially when flowers are broadly distributed in the field. [Copyright &y& Elsevier]

Abstract: Flowering plants have been shown to differ with regard to their attractiveness to parasitoids and nectar accessibility. These floral traits are likely to affect the foraging performance of parasitoids in agricultural landscapes. Using a spatially explicit simulation model we explore how the attractiveness and nectar availability of flowering field margins affects their impact on parasitoids and ultimately on pest populations in crops. The model simulates the movement, nectar feeding and parasitism of parasitoids in an agroecosystem composed of a crop and adjacent flower margin. The perception of olfactory cues emitted by flowers and host-infested plants drives the movement of the parasitoid. Its preference for floral nectar or hosts is described as a function of its internal energy status. Model validation reveals that simulations and measurements of the spatial distribution and energy status of parasitoids are generally in good agreement. Model simulations suggest that aggregation of parasitoids at flower strips are caused by a prolonged longevity of parasitoids feeding on floral nectar as well as by attraction of parasitoids from the surrounding area. We found no indication for depletion of parasitoids in the field interior as a result of migration towards flower strips. Simulations further suggest that the attractiveness of flowers is an important characteristic that should be taken into account for the selection of flowering plants. This study implies that tailoring nectar supply to the requirements of parasitoids holds potential to increase their effectiveness as biological control agents. [Copyright &y& Elsevier]

The availability of alternative prey is considered to be an important factor for the conservation of predators in agro-ecosystems. However, only a limited number of studies have investigated the effect of prey availability in non-crop habitats on predator impact. We studied the potential of the generalist predator Coccinella septempunctata to control pest aphids in wheat fields in landscapes with varying levels of prey in non-crop habitats using a spatially explicit simulation model. Simulations indicate that C. septempunctata reproduction and the associated control of pest aphids is affected by both the availability of non-pest aphids in non-crop habitats and the infestation date of pest aphids in wheat fields. When the infestation of wheat by pest aphids takes place early in the season, prey availability of pest aphids alone is sufficient to allow C. septempunctata to attain its maximal reproduction. However, when the infestation by pest aphids is somewhat delayed, C. septempunctata becomes increasingly dependent on aphids in non-crop habitats. Scarcity of prey may prevent C. septempunctata from reproducing or initiate long distance migration. Therefore, prey availability in non-crop habitats may play a significant part in the conservation of ladybeetles and the related biological control in agro-ecosystems. [Copyright &y& Elsevier]

Scenario studies were carried out with a process-based model for control of wild-type and genetically modified baculoviruses in populations of Spodoptera exigua in glasshouse chrysanthemum (BACSIM). These scenario studies were used to evaluate the effectiveness of different spraying regimes, concentrations, UV-protection agents, and mean time to kill insect. In simulations on concentration and timing of S. exigua multicapsid nucleopolyhedrovirus (SeMNPV), good control efficacy was obtained with SeMNPV concentrations of 1×107 polyhedra/m2 or higher. An early timing of virus applications, soon after egg deposition, is essential for effective control, especially at high temperatures, when the developmental rate of larvae is high and the window of opportunity for virus control is short. UV-protection agents contribute only marginally to effective biological control in the glasshouse because the decay rates of SeMNPV and Autographa californica multicapsid nucleopolyhedrovirus already ensure a period of exposure to active virus that is long enough for caterpillars to acquire a lethal concentration under practical conditions. The effect of genetic improvement towards shortening the survival time of infected larvae depends on the ability to time virus applications accurately and the mean time to kill the unmodified virus. Recombinant viruses with a lower mean time to kill are more effective than wild-type viruses when applied against second, third, and fourth instars because in these stages S. exigua infests a considerable number of plants and the rate of foliage consumption increases rapidly. When applied against first instars that infest only a small number of plants and have low consumption rates, recombinants will only be slightly more effective than wild-type viruses. In the case of an unmodified virus that already has a relatively high mean time to kill, a further reduction in the time to kill will not result in improved control. Thus, accurate monitoring followed by virus application is indispensable for adequate control and may even alleviate the need for fast killing viruses. [Copyright &y& Elsevier]

Pollinating insects rely on floral resources for survival and reproduction. Early flowering plants offer food resources for pollinating insects when floral resources are scarce, but they may also distract pollinating insects from pollination-dependent crops. Here we assessed how the abundance of bees and the pollination success of Korla fragrant pear (Pyrus sinkiangensis) is influenced by early flowering apricot trees within pear orchards or in the landscape at large, and how this influence is moderated by apricot flowering. The abundance of bees was measured using colored pan traps and pollination success was assessed by recording the initial fruit set and seed set. The density of apricot trees and land use types in radii of 0.5, 1.0, 1.5, and 2.0 km around focal pear orchards were assessed by landscape survey. The abundance of wild bees and honeybees was significantly higher in pear orchards with interspersed apricot trees than in mono-pear orchards. Pear trees next to an apricot tree row (5 m) had significantly higher wild bee abundance than pear trees at further distances (15 m, 30 m, 50 m, and 100 m). However, the positive effect of apricot trees on bee abundance in pear trees was only observed during apricot blooming, and the presence of apricot trees within or adjacent to pear orchards did not influence pear pollination success. The density of apricot trees in the surrounding landscape of pear orchards did not influence bee abundance and initial fruit set in pear orchards but it decreased seed set. Overall, our findings indicate that apricot trees in pear orchards can enhance bee abundance, but this effect only occurs at a relatively small spatial scale and during a short time span, and does not result in marked differences in pollination success. This indicates that flowering resources need to be close to or within the focal crop to have a positive effect on pollinating insect abundance. • Scattered apricot trees in pear orchards increased abundance of wild bees in pear orchards. • Apricot tree rows increased the abundance of wild bees on the adjacent pear trees, but not on pear trees further away. • The positive effect of apricot trees on bee abundance was only observed during apricot blooming. • Increased bee abundance did not lead to increased fruit set in pear. • Apricot tree density at the landscape scale did not influence bee abundance in pear orchards. [ABSTRACT FROM AUTHOR]

While large-scale agriculture is an important driver of biodiversity loss, diversified agricultural cropping systems may have potential to support farmland biodiversity. Strip cropping is a form of crop diversification in which crop strips are alternated in the same field and thereby increasing in-field crop heterogeneity and edge-density while using existing farm machinery. Although strip cropping may provide more diversity in habitat, food, and shelter at small spatial scales, it is still unknown how arthropod communities respond to a variety of strip widths of intensively managed vegetable crops, and whether strip cropping can provide nearby refuge sites for arthropods during and after harvest. We studied responses of the ground-dwelling arthropod community to strip widths of 6, 12, 24 and 48 m, both pre- and post-harvest. The study was conducted in cauliflower strips in a large-scale, commercial organic strip cropping field in 2018 and 2019. The cauliflower strips were bordered by annual flower strips on one side and by grass-clover (year 1) or potato (year 2) on the other side. Increasing strip width was associated with lower spider activity density and lower richness of the ground-dwelling arthropod community, and higher rove beetle activity density. Ground beetles showed variable responses to strip width depending on genus and year. Ground beetles of the genus Harpalus showed negative responses to increasing strip width in both years and genera Bembidion and Pterostichus showed positive responses to increasing strip width in 2019. Crop harvest had a negative influence on ground-dwelling arthropod activity density and community richness, and this effect was more pronounced in narrow strips than in wider strips. Our results indicate that strip cropping cauliflower can support ground-dwelling arthropod community richness and activity density of certain species groups in large-scale agricultural fields, but does not enhance short-term post-harvest recolonization. • Arthropod activity density was assessed in 6, 12, 24, 48 m wide cauliflower strips. • Spider activity density was enhanced by narrower cauliflower strip widths. • Rove beetle activity density was enhanced by wider cauliflower strip widths. • Crop harvest reduced activity density and richness of most ground beetle genera. [ABSTRACT FROM AUTHOR]

• Plant diversity plays a key role for the sustainability of agroecological systems. • Soil fertility and crop yields are similar in agroecological and conventional systems. • Agroecological management promotes soil biological quality in coffee systems. • Increased plant diversity in pastures needs to be combined with other management practices than currently adopted. The development of agroecosystems that can provide multiple ecosystem services with a reduced need of external inputs, requires management practices that foster ecological processes to enhance soil quality and crop productivity. We assessed the direct and indirect impacts of farmers' management practices on plant diversity, soil quality and crop productivity in coffee and pasture fields belonging to different types of farms: agroecological, conventional, and large-scale. The study was carried out in twelve farms in the Zona da Mata, Brazil. For each of the total of 24 fields (twelve pastures and twelve coffee) we recorded 41 variables associated with management practices, indicators of plant diversity (taxonomical, structural and functional diversity) and soil quality (biological, chemical and physical properties). The direct and indirect effects of management on plant diversity, soil quality and in the case of coffee, crop productivity, were assessed using structural equation models. In the case of pastures, we found that increased plant diversity due to agroecological management resulted in higher soil quality, probably due to higher soil litter cover and plant structural heterogeneity. Yet, practices presented in the agroecological farms also had a direct negative effect on soil quality, which indicates that increased plant diversity in pastures needs to be combined with other agroecological management practices than currently adopted. In the case of coffee, we show that despite the higher weeding intensity and higher use of external inputs in large-scale and conventional coffee farming systems, these practices did not result in increased soil quality or coffee productivity as compared to agroecological systems. In contrast, agroecological coffee management was associated with increased plant diversity, which, in turn, was positively associated with soil microbial biomass carbon. Our results highlight a causal pathway of agroecological management leading to increased plant diversity and, in turn, maintenance or increase in soil quality. While no causal link between agroecological coffee management and coffee productivity could be demonstrated, the biodiversity-mediated pathway resulted in similar coffee productivity in agroecological farms as compared to conventionally managed farms, which relied on pesticides and higher inputs of chemical fertilizers. We conclude that agroecological practices can be efficient to maintain satisfactory crop yields and soil fertility without the need of intensive use of external inputs and weeding. [ABSTRACT FROM AUTHOR]

• Weather conditions influenced parasitoid foraging behavior in the field. • Humidity, wind speed, temperature and barometric pressure affected foraging success. • Odor-guided upwind flight was only observed at wind speeds below 3 m/s. • Responsiveness of parasitoids to HIPVs tended to be reduced at low humidity. • High wind speed and low humidity constrain pest control potential of parasitoids. Biological pest control depends on the ability of natural enemies to find herbivore-infested plants, which is often guided by herbivore-induced plant volatiles (HIPVs). While foraging behavior of natural enemies has been extensively studied under controlled conditions, little is known on how odor-guided foraging behavior is influenced by fluctuating weather conditions in the field. Here we investigated how HIPV-guided foraging of Cotesia glomerata parasitoids is influenced by prevailing weather conditions in the field. C. glomerata females were released in 5 m radius circles of cabbage plants infested with Pieris brassicae caterpillars, and host finding success and direction of foraging activity was assessed by recapturing parasitoids on the host-infested plants. Wind speed and direction, humidity, barometric pressure and temperature was recorded and related to parasitoid foraging activity. Parasitoid foraging behavior was studied in more detail by observing individually released parasitoids in 0.5 m circles with host-infested cabbages. Recapture rates and movement direction of parasitoids was influenced by an interaction between humidity, wind speed, temperature and change in barometric pressure. High humidity and low wind speed was generally positively associated with host finding success. Direct observations of parasitoid flight behavior confirmed the influence of humidity and wind speed. Successful host finding in upwind direction was only observed at wind speeds below 3 m/s. Our study highlights the complex ways in which weather variables moderate parasitoid foraging behavior under field conditions. Since unfavorable weather conditions result in a strong reduction in parasitoid foraging efficiency, weather conditions are an important factor in the effectiveness of parasitoids as biocontrol agents. [ABSTRACT FROM AUTHOR]

Reconciling forest preservation and agricultural production is a major challenge. In Brazil, environmental laws have been introduced to reduce forest degradation associated with the expansion of agriculture. However, these laws are constraining small-scale family farmers who rely on cassava produced in shifting cultivation. Faced by scarcity of land, farmers are reducing the fallow periods on their farms. In this study, our hypothesis was that the reduction of the fallow period in shifting cultivation systems leads to a depletion of soil fertility and an increase in weed pressure. In the Brazilian Eastern Amazon region, soil fertility and weed infestation indicators were assessed in 36 cassava fields under shifting cultivation with different land-use histories. The frequency of cultivation of the fields in the past 10 years ranged from 1 to 7 and averaged 3.7 ± 2.3. The results show that the most frequently cultivated fields had lower soil fertility, indicated by lower soil organic carbon, total nitrogen and exchangeable potassium and pH. In addition, labor input for weeding and weeding frequency increased with the frequency of cultivation of the fields, indicating that weed pressure increased with intensified crop cultivation and shorter fallow periods. The findings of this study make clear that the current trend of reducing the fallow period in the Eastern Amazon is a threat to the sustainability and productivity of the local shifting cultivation systems. There is an urgent need for alternative production systems that allow for a better weed control and that contribute to restoring and maintaining soil fertility. • Shifting cultivation in Eastern Amazon is not sustainable in terms of crop productivity. • Soil fertility declines in fields with higher cultivation frequency. • Farmers spend more labor for weeding on fields with higher cultivation frequency. • Viable alternatives to slash-and-burn cultivation are required in the Amazon to combat forest degradation. [ABSTRACT FROM AUTHOR]

Loss of arthropod biodiversity can impair the provision of ecosystem services in agricultural landscapes. Crop diversification strategies offer the possibility to support arthropod communities without putting aside agricultural land as conservation areas. Within-field crop diversification measures, such as strip cropping and crop mixtures, may provide arthropods with continuity and diversity in food, shelter and habitat at fine spatial and temporal resolutions. However, it is unclear how strip cropping and plant species diversity within strips influences aerial arthropod and weed communities in commercially sized arable fields. In this 2-year study we tested the effects of crop heterogeneity on aerial arthropod and plant communities in organically managed strip fields. We tested effects of configurational crop heterogeneity by comparing sole cropping (MONO) with strip cropping (STRIP), and compositional crop heterogeneity by comparing STRIP with flower-legume-grain crop mixtures grown in strips (STRIPMIX). Aerial arthropod communities were assessed in 138 sweep net transects and plant communities in 124 vegetation plots in cabbage, wheat, sugar beet and barley. Higher configurational crop heterogeneity by strip cropping reduced herbivore abundances and increased natural enemy species richness in organic cabbage strips. Cabbage in MONO had a significantly higher herbivore abundance (+11%) and a lower natural enemy species richness (−57%) than cabbage in STRIP. Higher compositional crop heterogeneity by sowing additional plant species in strips (STRIPMIX) significantly increased plant abundance (+33%), plant species richness (+21%), total aerial arthropod abundance (+45%), and total aerial arthropod species richness (+21%) compared to STRIP. Our work shows that both configuration of crop areas (MONO vs. STRIP) and plant species diversity within strips (STRIP vs. STRIPMIX) can support arthropod biodiversity and natural pest suppression, but that arthropod responses differ between diversification strategies and crop combinations. Further optimization of design and management of within-field crop diversification strategies holds potential to attain biodiversity-based cropping systems which deliver multiple ecosystem services and have a reduced dependency on pesticides. [Display omitted] • Configurational heterogeneity by strip cropping reduced herbivore abundance in cabbage. • Strip cropping cabbage with wheat increased natural enemy species richness. • Compositional heterogeneity by crop mixtures increased arthropod abundance and species richness. • Compositional heterogeneity by crop mixtures increased natural enemy abundance. [ABSTRACT FROM AUTHOR]

Abstract: A comprehensive model was developed to simulate virus epizootics in a stage structured insect population and analyse scenarios for the biological control of cotton bollworm (CBW), Helicoverpa armigera, in cotton, using wild-type or genetically modified baculoviruses. In simulations on dosage and timing of a wild-type strain and a genetic recombinant of H. armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV), the economic injury level was not exceeded against a prevailing population of 12larvaem−2 when virus was applied 10 times during the season. An early start of virus applications in each of three successive CBW generations, with sprays starting soon after egg deposition, and a short, 3-day spray interval were necessary for effective control. A recombinant virus with a lower mean time to kill provided better short-term protection than the wild-type virus. However, the number of pupae entering diapause at the end of the growing season was higher due to reduced horizontal transmission. These pupae are founders of H. armigera populations in the next season indicating that the use of fast acting genetically modified viruses in one year may enhance CBW populations in the following year. Hence, simulations indicate that there is a trade-off between short-term and long-term objectives in the biocontrol with insect viruses: fast acting recombinant viruses provide better control in the short-term at the expense of potentially inferior population suppression in the long-term. The model may be used as a decision tool for evaluating virus application strategies in interaction with virus genotype and climatic conditions that affect the phenology and population dynamics of CBW. [Copyright &y& Elsevier]

Tropical soils are prone to rapid degradation if not managed well, and agroforestry systems have the potential to restore degraded soils and support agricultural production together with other ecosystem services. In Brazil, an increasing number of pioneering farmers are establishing agroforestry systems on previously cleared farmland. However, while there are a wide range of agroforestry systems, this diversity has hardly been quantified, and it is not clear how these systems differ in their capacity for nutrient cycling to reverse soil degradation. The objectives of the study were to assess innovative agroforestry systems in terms of taxonomic and functional diversity, spatial structure and management, and to assess how these systems differ in terms of structural complexity and their potential for nutrient cycling. We assessed a LiDAR-derived stand structural complexity index (SSCI), interrow spacing, stem density, tree species richness and diversity, community weighted means (CWM) of foliar nitrogen and wood density, livestock density, pruning and mowing regimes in 30 agroforestry systems in the state of São Paulo, Brazil. We used N, P, K, Ca and Mg stocks in litter as a proxy for nutrient cycling. The agroforestry systems could be broadly categorized into silvopastures, multistrata and successional agroforestry systems. These types spanned a gradient of structural complexity, and this complexity was positively associated with tree species richness and planting density. Litter nutrient stocks were positively associated with pruning and mulching, and negatively associated with CWM of wood density, indicating the importance of pioneer trees. Overall, our results suggest that densely planted, pruned agroforestry systems that contain high species richness, including pioneer trees, contain relatively high amounts of N, P, K, Ca and Mg in their litter. These findings provide insight in the key characteristics of agroforestry systems to support nutrient cycling, and can inform the design of agroforestry systems for the regeneration of degraded agricultural land. • There is a wide diversity of agroforestry systems established in Brazil. • Terrestrial LiDAR-derived index showed a structural complexity gradient among agroforests. • Structural complexity is associated with tree species richness and planting density. • Pruning & mulching of pioneer tree species can enhance nutrient cycling of N, P, K, Ca and Mg. [ABSTRACT FROM AUTHOR]

The projected increase of the world's population and the sustainability challenges the agricultural sector is facing, call for the enhancement of multi-functionality in agriculture in order to simultaneously provide food while meeting environmental targets. Here, we use the Functional Land Management (FLM) framework to assess the supply of and the demand for soil functions to inform agri-environmental policy for Udalo, a mountainous site in the Philippines. As many emerging communities in developing nations, Udalo is on the cusp of rapid development due to the construction of a major road increasing its accessibility and attractiveness for land investment. We assessed the supply of four soil functions in relation to six land-use types and four slope categories. The function "productivity" was assessed by interviews with 128 farmers, "habitat for biodiversity" by a vegetation survey, and "soil conservation" and "water conservation" via a literature review. The demand for functions was first assessed from the "top-down" policy perspective via interviews and reviews of policy targets, then complemented by integrating the local "bottom-up" demands for functions. These were assessed by applying a Q methodology, providing insights in the prioritisation of functions from the perspective of 22 local actors. Maps of supply and demands were generated for each function: supply maps by overlaying land use and slope category, top-down demand maps from administrative zoning/land-use plans, and bottom-up demand maps from local actors designation of geomorphological areas. Our results revealed contrasting demands for functions, as well as a heterogeneous spatial distribution of supply and demands. Discrepancies emerged (i) between supply and demand, (ii) between bottom-up (local) demands and the top-down (policy driven) demand, and (iii) among local actors perspectives. Our study indicates that discrepancies are not necessarily conflicting, but can uncover pathways for defining compromises, representing attainable policy entry points. Not one single development model can meet the needs of every stakeholder; however, a combination of land uses and management strategies can meet divergent interests and allow for optimisation of functions. This integrative approach of FLM provides a socially embedded biophysical analysis and is a valuable tool for the design of customized land-use and agri-environmental policies. • We refine the Functional Land Management framework to an integrative approach to assess soil functions and foodscapes. • Soil function demands differ between policy-driven (top-down) demand and local (bottom-up) demands, and among local actors. • Diverging demands and perceptions occur but also consensus and synergies constituting attainable entry points for policy intervention. • Discrepancies in demands can uncover pathways towards compromises. • A combination of land uses and management strategies is needed to meet divergent interests. [ABSTRACT FROM AUTHOR]

Biodiversity-ecosystem functioning (BEF) research grew rapidly following concerns that biodiversity loss would negatively affect ecosystem functions and the ecosystem services they underpin. However, despite evidence that biodiversity strongly affects ecosystem functioning, the influence of BEF research upon policy and the management of 'real-world' ecosystems, i.e., semi-natural habitats and agroecosystems, has been limited. Here, we address this issue by classifying BEF research into three clusters based on the degree of human control over species composition and the spatial scale, in terms of grain, of the study, and discussing how the research of each cluster is best suited to inform particular fields of ecosystem management. Research in the first cluster, small-grain highly controlled studies, is best able to provide general insights into mechanisms and to inform the management of species-poor and highly managed systems such as croplands, plantations, and the restoration of heavily degraded ecosystems. Research from the second cluster, small-grain observational studies, and species removal and addition studies, may allow for direct predictions of the impacts of species loss in specific semi-natural ecosystems. Research in the third cluster, large-grain uncontrolled studies, may best inform landscape-scale management and national-scale policy. We discuss barriers to transfer within each cluster and suggest how new research and knowledge exchange mechanisms may overcome these challenges. To meet the potential for BEF research to address global challenges, we recommend transdisciplinary research that goes beyond these current clusters and considers the social-ecological context of the ecosystems in which BEF knowledge is generated. This requires recognizing the social and economic value of biodiversity for ecosystem services at scales, and in units, that matter to land managers and policy makers. [ABSTRACT FROM AUTHOR]

Abstract: Competition between virus genotypes in insect hosts is a key element of virus fitness, affecting their long-term persistence in agro-ecosystems. Little information is available on virus competition in insect hosts or during serial passages from one cohort of hosts to the next. Here we report on the competition between two genotypes of Spodoptera exigua nucleopolyhedrovirus (SeMNPV), when serially passaged as mixtures in cohorts of 4th instar S. exigua larvae. One of the genotypes was a SeMNPV wild-type isolate, SeUS1, while the other was a SeMNPV recombinant (SeMNPV-XD1) having a greater speed of kill than SeUS1. SeXD1 lacks a suite of genes, including the ecdysteroid UDP-glucosyl transferase (egt) gene. SeXD1 expresses the green fluorescent protein (GFP) gene, enabling the identification of SeXD1 in cell culture and in insects. The relative proportion of SeUS1 and SeXD1 in successive passages of mixed infections in various ratios was determined by plaque assays of budded virus from infected larvae and by polymerase chain reactions and restriction enzyme analyses. The SeUS1 genotype outcompeted recombinant SeXD1 over successive passages. Depending on the initial virus genotype ratio, the recombinant SeXD1 was no longer detected after 6–12 passages. A mathematical model was developed to characterize the competition dynamics. Overall, the ratio SeUS1/XD1 increased by a factor 1.9 per passage. The findings suggest that under the experimental conditions recombinant SeXD1 is displaced by the wild-type strain SeUS1, but further studies are needed to ascertain that this is also the case when the same baculoviruses would be used in agro-ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: Structurally complex landscapes may enhance local species richness and interactions, which is possibly due to a higher species pool in complex landscapes. This hypothesis was tested using cereal aphid parasitoids (Hymenoptera, Aphidiidae) by comparing 12 winter wheat fields in structurally complex landscapes (>50% semi-natural habitats; n =6) and structurally simple landscapes dominated by agricultural lands (>80% arable land; n =6). Surprisingly, landscape structural complexity had no effect on aphid parasitoid species diversity. In complex landscapes 12 and in simple landscapes 11 species were found; 9 species occurred in both landscape types. Hence, arable fields in high-intensity agricultural landscapes with little non-crop area can support a similar diversity of cereal aphid parasitoids as structurally complex landscapes. This finding suggests that cereal aphid parasitoids may find necessary resources even in simple landscapes, making generalisations concerning the relationship between landscape composition and biodiversity in arable fields difficult. [Copyright &y& Elsevier]

Traditional farming landscapes in China consist of small irregular fields with an intimately interspersed semi-natural habitat network of field margins, but are increasingly converted into consolidated ones that consist of standardized fields with reduced areas of field margins and other semi-natural habitat. It is unclear how such farmland consolidation influences pollinator communities, and if there is a negative effect, whether this effect is mitigated by semi-natural habitat present in the wider landscape. We compared the diversity and abundance of wild pollinators in oilseed rape fields that were embedded in landscapes that consisted either of traditional or consolidated farmland. The landscapes spanned a range of semi-natural habitat area from 10% to 73% at a scale of one km radius in Jiangxi Province, China. Pollinators were sampled using pan traps during two years (2015 and 2019). Results showed that pollinator diversity was positively associated with the proportion of semi-natural habitat in both traditional and consolidated farming landscapes, but was higher in traditional farming landscapes. In both years, there was no difference in pollinator abundance between landscapes with traditional and consolidated fields. The results indicate that the network of field margins in traditional farmland supports a diverse pollinator community, and that land consolidation has equivalent effects on pollinator diversity as substantial decreases in semi-natural habitat in the wider landscape. The role of semi-natural habitat in supporting farmland biodiversity and its associated services needs therefore to be considered in plans for farmland consolidation. • China's traditional farmland supports pollinator diversity. • Land consolidation greatly reduces pollinator diversity. • Pollinator diversity was positively associated with the proportion of semi-natural habitat. [ABSTRACT FROM AUTHOR]