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ContextAgroecology combines agronomic and ecological concepts. It relies on the enhancement of biodiversity and related ecosystem services to support agricultural production. It is dependent on biological interactions for the design and management of agricultural systems in agricultural landscapes.ObjectivesWe review the role of landscape ecology to understand and promote biodiversity, pest regulation and crop pollination for the designing of “agroecology landscapes”. We illustrate the use of landscape ecological methods for supporting agroforestry systems as an example of agroecological development, and we propose pathways to implement agroecology at landscape scale.MethodsThe state of the art of how landscape ecology contributes to agroecology development is summarized based on a literature review.ResultsAgroecology requires thinking beyond the field scale to consider the positioning, quality and connectivity of fields and semi-natural habitats at larger spatial scales. The spatial and temporal organisation of semi-natural elements and the crop mosaic interact. Understanding this interaction is the pre-requisite for promoting patterns and mechanisms that foster biodiversity and ecosystem service provision. Promoting agroecological practices beyond individual farm borders can be rooted in a bottom-up approach from agroecological lighthouse farms to farm networks to amplify agroecology adoption at the landscape scale.ConclusionsAchieving agricultural landscapes composed of fields and farms following agroecological management requires understanding of biodiversity patterns, biological interactions and mechanisms that determine and boost ecosystem functioning to improve services at landscape scale, involving farmers in a bottom-up and context-specific approach.

Predictive theory on how plant diversity promotes herbivore suppression through movement patterns, host associations, and predation promises a potential alternative to pesticide-intensive monoculture crop production. We used meta-analysis on 552 experiments in 45 articles published over the last 10 years to test if plant diversification schemes reduce herbivores and/or increase the natural enemies of herbivores as predicted by associational resistance hypotheses, the enemies hypothesis, and attraction and repellency model applications in agriculture. We found extensive support for these models with intercropping schemes, inclusion of flowering plants, and use of plants that repel herbivores or attract them away from the crop. Overall, herbivore suppression, enemy enhancement, and crop damage suppression effects were significantly stronger on diversified crops than on crops with none or fewer associated plant species. However, a relatively small, but significantly negative, mean effect size for crop yield indicated that pest-suppressive diversification schemes interfered with production, in part because of reducing densities of the main crop by replacing it with intercrops or non-crop plants. This first use of meta-analysis to evaluate the effects of diversification schemes, a potentially more powerful tool than tallies of significant positive and negative outcomes (vote-counting), revealed stronger overall effects on all parameters measured compared to previous reviews. Our analysis of the same articles used in a recent review facilitates comparisons of vote-counting and meta-analysis, and shows that pronounced results of the meta-analysis are not well explained by a reduction in articles that met its stricter criteria. Rather, compared to outcome counts, effect sizes were rarely neutral (equal to zero), and a mean effect size value for mixed outcomes could be calculated. Problematic statistical properties of vote-counting were avoided with meta-analysis, thus providing a more precise test of the hypotheses. The unambiguous and encouraging results from this meta-analysis of previous research should motivate ecologists to conduct more mechanistic experiments to improve the odds of designing effective crop diversification schemes for improved pest regulation and enhanced crop yield.

Agricultural landscapes provide the essential ecosystem service of food to growing human populations; at the same time, agricultural expansion to increase crop production results in forest fragmentation, degrading many other forest‐dependent ecosystem services. However, surprisingly little is known about the role that forest fragments play in the provision of ecosystem services and how fragmentation affects landscape multifunctionality at scales relevant to land management decisions. We measured the provision of six ecosystem services (crop production, pest regulation, decomposition, carbon storage, soil fertility and water quality regulation) in soya bean fields at different distances from adjacent forest fragments that differed in isolation and size across an agricultural landscape in Quebec, Canada. We observed significant effects of distance‐from‐forest, fragment isolation and fragment size on crop production, insect pest regulation, and decomposition. Distance‐from‐forest and fragment isolation had unique influences on service provision for each of the ecosystem services we measured. For example, pest regulation was maximized adjacent to forest fragments, while crop production was maximized at intermediate distances‐from‐forest. As a consequence, landscape multifunctionality depended on landscape heterogeneity: the range of field and forest fragment types present. We also observed strong negative and positive relationships between ecosystem services that were more prevalent at greater distances‐from‐forest. Synthesis and applications. Our study is one of the first to empirically measure and model the effects of forest fragments on the simultaneous provision of multiple ecosystem services in an agro‐ecosystem at the landscape and field scales relevant to landowners and managers. Our results demonstrate that forest fragments, irrespective of their size, can affect the provision of multiple ecosystem services in surrounding fields, but that this effect is mediated by fragment isolation across the landscape. Our results also suggest that managing habitat fragmentation and landscape structure will improve our ability to optimize ecosystem service provision and create multifunctional agricultural landscapes.

Disentangling the effects of plant diversity on the control of herbivores is important for understanding agricultural sustainability. Recent studies have investigated the relationships between plant diversity and arthropod communities at the landscape scale, but few have done so at the local scale. We conducted a meta‐analysis of 32 papers containing 175 independent measures of the relationship between plant diversity and arthropod communities. We found that generalist predators had a strong positive response to plant diversity, that is, their abundance increased as plant diversity increased. Herbivores, in contrast, had an overall weak and negative response to plant diversity. However, specialist and generalist herbivores differed in their response to plant diversity, that is, the response was negative for specialists and not significant for generalists. While the effects of scale remain unclear, the response to plant diversity tended to increase for specialist herbivores, but decrease for generalist herbivores as the scale increased. There was no clear effect of scale on the response of generalist predators to plant diversity. Our results suggest that the response of herbivores to plant diversity at the local scale is a balance between habitat and trophic effects that vary according to arthropod specialization and habitat type. Synthesis and applications. Positive effects of plant diversity on generalist predators confirm that, at the local scale, plant diversification of agroecosystems is a credible and promising option for increasing pest regulation. Results from our meta‐analysis suggest that natural control in plant‐diversified systems is more likely to occur for specialist than for generalist herbivores. In terms of pest management, our results indicate that small‐scale plant diversification (via the planting of cover crops or intercrops and reduced weed management) is likely to increase the control of specialist herbivores by generalist predators. We conducted a meta‐analysis of 32 papers containing 175 independent measures of the relationship between plant diversity and arthropod communities. We found that generalist predators and herbivores had a strong positive and a weak negative response to plant diversity, respectively. The response was negative for specialists and not significant for generalists. Our results suggest that the response of herbivores to plant diversity at the local scale is a balance between habitat and trophic effects that vary according to arthropod specialization and habitat type.

Carabid beetles are abundant in temperate agroecosystems and can play a pivotal role as biocontrol agents. While there is good knowledge regarding their effects on invertebrate pests in some systems, comparably little is known on the rate of seed feeding under field conditions. Molecular approaches are ideally suited for investigating carabid feeding interactions; to date, however, they have only been applied to animal prey. We sampled adult carabid beetles in organic cereal fields in three regions along a Central European transect. Regurgitates from populations of the three most common species, Poecilus cupreus, Pseudoophonus rufipes and Pterostichus melanarius , were screened for plant DNA, cereal aphids, collembolans and earthworms. The frequency of carabid individuals positive for plant DNA was high (> 70%) and independent of carabid species, sex, region and the time point of sampling. Detections for non-pest and pest prey were comparably lower, with 21.6% for collembolans, 18.1% for earthworms and 4.2% for aphids, respectively. Despite the prolonged detection period of plant DNA in carabid guts, as compared to animal prey, these first results suggest that weed seeds form an important part of the adult carabid diet. It would also lend support to the hypothesis that seed-feeding carabids are biocontrol agents of weeds, with effects of regulation on the weed seedbank that depend on behavioural and contextual factors including carabid species preferences for weed seed species, their life stage and tillage practices.

In ecosystems that have been disturbed by agricultural management, ecosystem services such as adequate pest control are also disturbed. Exploiting interactions between beneficial insects and plants can contribute to improving ecosystem service delivery and biological control. One of the effective methods of naturally increasing the biodiversity of beneficial insects on crop plantations is the use of plant strips. The aim of our work was to demonstrate the role of flower strips in the sustainable management of vineyards. In particular, the relationship between the composition and flowering time of plants in flower strips and beneficial insects such as predators, parasitoids, and wild pollinators from Central Europe and the Western USA was shown. Most plants used for flower strips belong to the Asteraceae family. The most attractive to beneficial insects were Eriogonum niveum, Ericameria nauseosa, and Purshia tridentata in the USA, while in the vineyard in Poland they were garden plant species but also native species, especially Erigeron annuus, Taraxacum ssp., and Polygonum persicaria. The planned replacement of flowering times of plant species was observed from March to October, which ensured continuity in the availability of food for beneficial insects. Appropriately selected plants can attract selected species of predators and parasitoids, which can regulate the number of a specific pest species. Diversifying agricultural ecosystems is a promising pest control strategy that reduces pesticide use and thus supports sustainable agriculture.

This study investigates the spatial behaviour and social dynamics of immature carrion crows ( Corvus corone ) caught in Paris, with the objective of discussing the efficiency of current culling strategies used to mitigate crop damage. Using GPS tracking data from 80 first-year crows of four different cohorts, we characterized seasonal variations in movement, roosting behaviour, and fission-fusion spatial dynamics. Results show that young crows remain closely associated with their natal sites until March of the year following hatching, after which they disperse to urban, peri-urban and rural areas, particularly in April and May, with peak daily movement distances averaging 2.7 km. This period coincides with the sowing of sensitive crops such as maize and sunflower, during which culling campaigns are often conducted. Furthermore, we document fission-fusion dynamics, with fluid group associations centred around predictable anthropogenic food sources and communal roosts, certainly facilitating repeated interactions and social learning. These findings suggest that current culling practices, largely targeting transient juveniles, are unlikely to achieve long-term reductions in population size or crop damage. Instead, the study highlights the importance of addressing particularly anthropogenic food availability as a potentially more effective and ethical strategy for managing urban, peri-urban and even rural crow populations.

This paper documents an exercise to synthesize and assess the best available scientific knowledge on the effectiveness of different farm practices at enhancing natural pest regulation in agriculture. It demonstrates a novel combination of three approaches to evidence synthesis—systematic literature search, collated synopsis and evidence assessment using an expert panel. These approaches follow a logical sequence moving from a large volume of disparate evidence to a simple, easily understandable answer for use in policy or practice. The example of natural pest regulation in agriculture was selected as a case study within two independent science-policy interface projects, one European and one British. A third funder, a private business, supported the final stage to translate the synthesized findings into a useful, simplified output for agronomists. As a whole, the case study showcases how a network of scientific knowledge holders and knowledge users can work together to improve the use of science in policy and practice. The process identified five practices with good evidence of a benefit to natural pest regulation, with the most beneficial being ‘Combine trap and repellent crops in a push–pull system’. It highlights knowledge gaps, or potential research priorities, by showing practices considered important by stakeholders for which there is not enough evidence to make an assessment of effects on natural pest regulation, including ‘Alter the timing of pesticide application.’ Finally, the process identifies several important practices where the volume of evidence of effects on natural pest regulation was too large (>300 experimental studies) to be summarised with the resources available, and for which focused systematic reviews may be the best approach. These very well studied practices include ‘Reduce tillage’ and ‘Plant more than one crop per field’.

Non-crop vegetation around farmland can be valuable habitats for enhancing ecosystem services but little is known of the importance of field margins in supporting natural enemies of insect pests in tropical agriculture. This study was conducted in smallholder bean fields in three elevation zones to assess the importance of field margin vegetation to natural enemy populations and movement to the bean crop for biological pest control. The pests and natural enemies were assessed using different coloured water pan traps (to ensure the capture of insects with different colour preferences) and the interactions of the two arthropod groups with the margin vegetation and their movement to the bean crop were monitored using fluorescent dye. Sentinel plants were used to assess predation and parasitism levels. A total of 5003 natural enemies were captured, more in the field margin than within the bean field for low and mid elevation zones, while in the high elevation zone, they were more abundant within the bean field. Pests were more abundant in the crop than margins for all the elevation zones. The use of a dye applied to margin vegetation demonstrated that common natural enemy taxa moved to the crop during the days after dye application. The proportion of dye-marked natural enemies (showing their origin to be margin vegetation) sampled from the crop suggest high levels of spatial flux in the arthropod assemblage. Aphid mortality rates (measured by prey removal and parasitism levels on sentinel plants) did not differ between the field edges and field centre in any of the three elevation zones, suggesting that for this pest taxon, the centre of the fields still receive comparable pest control service as in the field edges. This study found that field margins around smallholder bean fields are useful habitats to large numbers of natural enemy taxa that move to adjacent crops providing biological pest control service.

Smallholder farmers represent the majority of food producers around the world, yet they are often the most at risk of suffering yield gaps and not achieving their production potential. Ecological Intensification (EI) is a knowledge intensive approach to sustainable agricultural intensification which utilizes biodiversity‐based ecosystem services to support greater yield and reduce reliance on agrochemical inputs. Despite the potential benefit of EI based practices, uptake by smallholders is not as widespread as it could be. Here we test the hypothesis that application of EI on smallholder farms in Kenya is a viable approach that could be taken in order to enhance food security. Focusing on natural pest control and crop pollination, we used farmer surveys to explore the potential for EI in central Kenya. We identified to what extent farm typology and access to knowledge determine the incentives and barriers facing smallholder producers and how this influences optimal pathways for sharing knowledge and providing extension services. We found considerable potential for EI of smallholder farms in this region; most farmers grew insect pollinated crops and some farmers already employed EI practices, while others relied heavily on chemical pesticides. Based on physical, social, and economic factors, three farm typologies emerged including “semi‐commercial,” “market orientated,” and “subsistence.” These typologies influenced the appropriate EI practices available to farmers, as well as routes through which knowledge was shared, and the extent to which extension services were utilized. We propose that to support effective uptake of EI practices, smallholder farm heterogeneity should be acknowledged and characterized in order to target the needs and capabilities of farmers and identify appropriate knowledge sharing and support pathways. The approach we take here has the potential to be employed in other regions globally. Ecological intensification has the potential to improve food security in smallholder farms in Kenya. However, smallholder farms vary considerably based on socioeconomic factors, and farm typologies influenced the appropriate EI practices available to farmers, as well as routes through which extension support can be provided. To support widespread uptake of EI practices, smallholder farm heterogeneity should be acknowledged and characterized in order to target the needs and capabilities of farmers and identify appropriate knowledge sharing and support pathways.