Agroecological approaches harnessing in-field biodiversity have been highlighted as a sustainable way to reduce yield gaps, but long-term assessments of their ability to buffer production from weather extremes and increasing interannual and intraseasonal climate variability are scarce. Here, we analyze a 12-year dataset from 642 control vs. push-pull maize field pairs in western Kenya, where long-term climate trends include increasing temperatures and intensifying drought and rainfall. In push-pull, maize is intercropped with a fodder legume that improves soil fertility, suppresses weeds, and deters pests, and is bordered with fodder grasses attracting and suppressing the pests. We assess interactions between push-pull and climate effects on yields, stemborer pest damage and densities of parasitic weeds during the long and short rainy seasons, and how these drive push-pull effects on yield. Push-pull maize yields were always higher than control yields, but varying climate conditions affected the two field types differently. During the long rainy seasons, differences between push-pull and control yields were higher in years with high temperatures. Yield benefits of push-pull were also higher in years when dry spells were longer early in the long rainy season. During the short rainy seasons, push-pull increased yields, particularly when accumulated seasonal rainfall was optimal, while still doubling yield under very low or very high precipitation. Interactions between push-pull and climate variables were partly mediated by pests and weeds. Our results show that smallholder maize production using push-pull not only increases yields but also buffers adverse effects of weather extremes that are already becoming more frequent and intense.

In the tropics, agroforestry has the potential to support flower visitor interactions, yet how the structure of flower-visitor networks and functioning differ between agroforestry and conventional systems across the wet and dry seasons has rarely been studied. In addition, landscape-level woody cover can affect network interactions through shifts in plant and flower-visitor communities. To investigate these dynamics, we assessed insect visitation to flowering plants on 16 paired agroforestry and conventional farms across a gradient of woody cover on the lower slopes of Mt. Kilimanjaro in Tanzania, in both long wet and long dry seasons. We tested if the number of interactions, richness and species assemblages of flowering plants and flower visitors, as well as network connectance, nestedness, and specialisation differed between farming system, season, and along landscape woody cover gradient. Across seasons, agroforestry had more interactions and flowering plant and flower visitor richness, but lower network connectance. Number of interactions and flowering plant richness was higher in the wet than in the dry seasons. The effect of farming system on flower visitor richness and nestedness depended on season, with visitor richness being highest, and nestedness at its lowest, in agroforests in the wet season. At the same time, increasing woody cover in the landscape affected plant and flower visitor species assemblages, but did not alter network characteristics. Our results highlight that agroforestry can sustain ecological interactions even during resource-scarce dry seasons in simplified landscapes, with local management outweighing landscape woody cover. Therefore, farmers could prioritise diverse agroforestry plantings at farm-level.

Flower plantings in agricultural landscapes can contribute to sustainable crop production by enhancing pollination and biological control services. However, selecting plant species that promote multiple ecosystem services is challenging, since plants that favor pollinators may not equally foster natural enemies, and potential trade-offs, such as inadvertently promoting crop pests, must be considered. This complexity increases when accounting for belowground effects. We evaluated 27 candidate plant species for their ability to host functionally important above- and belowground organisms—pollinators, natural enemies, herbivores, and decomposers—and assessed how plant characteristics such as floral area, timing of peak bloom, life cycle, and plant cover affect these organism groups. We found that certain plant species have the potential to support several groups of beneficial organisms, suggesting they can enhance multiple ecosystem services. Annual plants had higher abundances of both above- and belowground beneficial organisms compared to perennials. Greater plant cover was positively associated with hoverfly abundance. Several functionally important organism groups were positively correlated across plant species, but these positive correlations were not explained by shared responses to plant characteristics. Our findings underscore the significance of plant species identity and characteristics in designing flower plantings for enhancing biodiversity and ecosystem services and highlight the importance of including belowground organisms like nematodes in future studies. Our results for specific plant species and plant characteristics can be used to design flower mixtures supporting several ecosystem service providers while considering potential trade-offs, thereby increasing the efficiency of flower plantings.

ABSTRACT Push‐pull technology is increasingly promoted in sub‐Saharan Africa, particularly for pest management and enhancing crop productivity. However, its influence on soil properties remains understudied, despite its potential implications for soil health and sustainable soil fertility management. This study examines soil properties in push‐pull and conventional non‐push‐pull cropping systems. Soil samples were collected from push‐pull and conventional plots in Ethiopia, Kenya, Rwanda, and Uganda. We examined the associations between soil physicochemical properties and cropping systems, along with key components of push‐pull, namely Desmodium coverage and plot age, and manure and mineral fertiliser application. Overall, there were a few differences in soil properties between push‐pull and conventional cultivation. In Kenya and Uganda, where Desmodium cover varied considerably, higher cover was positively associated with soil organic matter, cation‐exchange capacity, and multiple nutrients. In Rwanda, Desmodium cover was positively associated only with phosphorus. Plot age in Kenya was negatively associated with pH and potassium, suggesting acidification from N2 fixation and potassium mining in the system. In Kenya, manure application was negatively associated with soil pH, CEC and several nutrients, while in Uganda, it was positively associated with calcium, sodium and zinc. In Ethiopia, manure application was positively associated with potassium and zinc, but only when testing the push‐pull systems separately. Mineral fertiliser use was negatively associated with potassium and pH in Kenya, the only country with considerable use of mineral fertilisers. The data highlight a need for adaptive soil and crop management, including affordable non‐acidifying N fertilisers and liming products for long‐term sustainability of the push‐pull system. The complexity in farmer adoption and practices, and the underlying soil and climate conditions, limit our ability to disentangle the contribution of system components to the effects of the push‐pull system. Nevertheless, our findings highlight the complex and context‐dependent associations of push‐pull cropping and soil properties, underscoring the need for site‐specific management to sustain soil health and crop productivity across sub‐Saharan Africa.

Agroecological approaches harnessing in-field biodiversity have been highlighted as a sustainable way to reduce yield gaps, but long-term assessments of their ability to buffer production from weather extremes and increasing interannual and intraseasonal climate variability are scarce. Here, we analyse a 12-year dataset from 647 control vs. push-pull maize field pairs in western Kenya, where long-term climate trends include increasing temperatures and intensifying drought and rainfall. In push-pull, maize is intercropped with a fodder legume that improves soil fertility, suppresses weeds, and deters pests, and is bordered with fodder grasses attracting and suppressing the pests. We assess interactions between push-pull and climate effects on yields, stemborer pest damage and densities of parasitic weeds during the long and short rains, and how these drive push-pull effects on yield. Push-pull yields were always higher than control yields, but varying climate conditions affected the two field types differently. During the long rains, differences between push-pull and control yields were higher in years with temperature extremes. Yield benefits of push-pull were also higher in years when dry spells were longer early in the long-rain season. During the short rains, push-pull increased yields, particularly when accumulated seasonal rainfall was optimal, while still doubling yield in seasons with very low or very high precipitation. Interactions between push-pull and climate variables were partly mediated by pests and weeds. Our results show that smallholder maize production using push-pull not only increases yields but also buffers adverse effects of weather extremes that are already becoming more frequent and intense.

Flower strips are an agri-environmental measure to contribute to sustainable crop production by enhancing pollinators and natural enemies of pests. However, most strips are designed to target a single ecosystem service, often overlooking simultaneous effects on multiple functional groups of arthropods. In Sweden, large-scale adoption of flower strips to promote pollinators through the 'Sweden Blossom' initiative represents an opportunity to deliver benefits beyond single goals, and to support multiple ecosystem services. We assessed how an annual flower strip mixture influences the pollinators targeted as well as the abundance of natural enemies and herbivores, their spillover 10 m into neighbouring crops and pest control. Pollinators were recorded via visual observations in the strips. Leaf-dwelling arthropods were recorded with yellow sticky traps, and ground-dwelling predators with pitfall traps in both the strips and adjacent spring barley fields. Natural enemies and herbivores in the crop were also assessed through tiller counts, while aphid predation rates were estimated using sentinel prey cards for leaf- and ground-dwelling predators. The flower strips strongly increased pollinator abundances as intended but also increased the abundance of certain natural enemy and herbivore taxa, some of which also dispersed into neighbouring crops. However, arthropods present on crop tillers or pest control rates by leaf-dwelling predators were not affected. Aphid predation by ground-dwelling predators tended to increase in crop areas near the flower strips. These findings have implications for designing agri-environmental measures, stressing the importance of context-specific factors to maximise ecosystem service delivery and minimise potential unintended consequences.

Natural enemies, including arthropod predators and parasitoids, provide essential pest control services in agricultural systems by reducing pest populations. However, studies examining how natural enemies respond to environmental gradients, such as elevation and grass cover, are limited in sub-Saharan Africa. This study investigates the effect of elevation (1150–1970 m above sea level) and grassland cover in the surrounding landscape (2–30%) on natural enemy communities in maize fields in western Kenya over two consecutive sampling seasons. We selected maize fields along gradients of elevation and percentage of grassland and conducted field surveys using pitfall traps to assess the diversity and composition of natural enemies. Natural enemy diversity, richness, evenness, abundance and community composition were compared across gradients using Generalised Linear Mixed Models and Non-Metric Multidimensional Scaling. Across gradients, ants were the most abundant predator group. Lower elevations supported natural enemy communities with higher evenness, while higher elevations were dominated by Myrmicaria ants. Grassland cover had limited overall effects, with a non-significant but positive association with species richness. Notably, community composition shifted along the elevational gradient, with Myrmicaria ants being less dominant < 1600 masl. Their dominance at high elevations, where grass cover is lower, may reduce overall pest control resilience, as low evenness and reliance on a single genus diminish functional redundancy. This underscores the need for integrated pest management strategies that consider multiple environmental variables. Overall, our findings highlight the importance of environmental gradients in shaping natural enemy biodiversity in agricultural fields with implications for pest control in western Kenya.

Flower strips are a valuable agri-environmental measure to foster ecological intensification by providing floral and nesting resources to beneficial organisms. Nevertheless, few flower strip studies integrate assessments of multiple ecosystem services and their providers (simultaneous promotion of pollinators and natural enemies) or consider trade-offs (unintended promotion of pests in adjacent crops). This gap is further exacerbated if below-ground functions are considered. We sampled pollinators, natural enemies, and herbivores using visual observations, yellow sticky traps, pitfall traps, and tiller counts in ten pairs of perennial flower strips and control field margins, and their adjacent cereal fields in Scania, Sweden, in 2021. In addition, we estimated predation and below-ground decomposition rates with sentinel prey cards and bait lamina strips. Flower strips increased floral availability, pollinator, natural enemy and herbivore abundances, relative to control field margins. Natural enemy and herbivore responses to the implemented strips were taxon-specific. The positive effects of flower strips extended beyond the strips themselves, as spillover effects were evident for several natural enemy groups, with increased abundances in adjacent crop fields. A trade-off was also observed: pest thrips were more abundant in crop tillers near flower strips than near controls. No effect of flower strips on aphid predation rates was observed. Decomposition rates were as high in flower strips as in controls, despite flower strips only being established for two years. These findings emphasize flower strips’ potential to support multiple ecosystem service providers, while underscoring the importance of context-specific design and management to maximize benefits and avoid unintended trade-offs.

Insect-mediated pollination is a crucial ecosystem service that supports crop yields and wild plant populations, contributing to global food security and ecosystem stability. However, the alarming decline in insect pollinators, largely driven by agricultural practices, has raised global concern. As the human population grows, the pressure on crop production intensifies, necessitating sustainable farming practices. Agroforestry, an agricultural system that integrates woody plants with crops, has the potential to enhance crop production while providing a favorable environment for insect pollinators. However, empirical studies on the impact of agroforestry on insect pollinators in tropical Africa are scarce. This study addresses that gap by examining whether tropical agroforestry increases insect pollinator abundance and species richness compared to non-agroforestry systems and how that is affected by season and elevation. We studied sixteen pairs of agroforestry and non-agroforestry farms located along elevation gradients in northern Tanzania over wet and dry seasons. Results showed that agroforestry plots had nearly twice the insect pollinator abundance and higher species richness than non-agroforestry plots. Additionally, the wet season recorded greater pollinator abundance and species richness, with agroforestry consistently outperforming non-agroforestry farms. Although elevation had no significant effect on pollinator abundance or species richness, floral resources proved critical: flower richness, overall plant richness, and overall plant abundance drove pollinator species richness, while pollinator abundance was determined solely by flower richness.

Boreal forest landscapes are rapidly transformed through expanding clearcutting forestry, leading to a decline in forests with long tree continuity and an increase in even‐aged production stands. The role of remnant forests in supporting biodiversity within production forest landscapes remains poorly understood. Northern Europe provides an ideal setting for studying mosaics of clearcut and remnant continuity forests, given its long history of clearcutting and the prevalence of even‐aged forest stands. New remote‐sensing techniques have enabled the identification of forests in boreal Sweden that have maintained permanent tree cover at least since the 1950s (‘continuity forest’), meaning that they have likely never been clearcut, with removal of all trees. Using these data (including production forest as well as protected forest), we randomly selected 16 areas, each 225 km 2 in size, with the proportion of continuity forest ranging from 2% to 25%. In each study area, we selected four even‐aged production forest stands aged 0–80 years and one selectively harvested (never‐clearcut) production stand aged 81–120 years. As model organisms for assessing biodiversity, we used epiphytic lichens on randomly selected Norway spruce Picea abies trees. We recorded 164 epiphytic lichen taxa on 926 trees. Species richness (including species of conservation concern) in the even‐aged forests <80 years old increased with the proportion continuity forest in the surrounding landscape. In contrast, there was no relationship between the richness of lichens and the proportion continuity forest for the older, selectively harvested production forests. Our results suggest that continuity forests are an important dispersal source for even‐aged production forests since almost all of the epiphytic lichen occurrences represent new colonization. Our results also show that continuity production forests >80 years old are important to epiphytic biodiversity since they host many species of conservation concern. Synthesis and applications . Our study has relevance for forestry and conservation across the boreal biome where a continued rapid expansion of clearcutting into primary forest landscapes is likely. Preserving continuity forests for the future would enrich the epiphytic biodiversity of younger, even‐aged production forests due to their function as dispersal nuclei. The remnant continuity forests are also conservation targets in their own right due to their rich lichen diversity.

Pollination services by insects contribute strongly to food security and ecosystem stability. However, especially in Africa, little is known about farmer's knowledge and awareness of pollination services. Here, we first surveyed home garden farmers about their knowledge on pollination services, and their ability to recognize insect pollinators. Then we evaluated their home gardens for the availability of pollinator forage resources. We found that a majority of the farmers (89.1%) were not aware of pollination services and that awareness was higher for males and those with higher education levels. All farmers were able to recognize at least one insect species (especially, Apis mellifera) but most farmers did not know them as pollinators. We also found that 293 woody plant species from 62 families in Chagga home gardens (CHGs), provided insect pollinator forage. There was higher alpha diversity for exotic forage plants but higher gamma diversity for natives. The increase in diversity of pollinator forage plants reduced the temporal variability of flower richness. Our findings suggest that farmers should be made more aware of pollination services as well as insect pollinators specifically regarding their benefits to increase willingness to conserve them. Awareness programs should be accessible to women and those with little formal education as they exhibit the least knowledge. Also, various media tools should be used for effective dissemination to the different target audiences. Our findings also provide evidence that if managed properly some traditional agricultural land use systems can enhance pollination services by providing diverse forage resources for insect pollinators.

Boreal forests undergo rapid transformation from more or less intact states to even-aged production stands, due to the expanding clearcutting practice. Deepened knowledge on how species diversity and composition vary with local resource availability, such as dead wood, as well with remaining never clearcut forest (having long continuity = ‘continuity forest’) in the surrounding landscape, is essential for the formulation of conservation strategies. In each of six 15 × 15 km study areas in mid-boreal Sweden (12 000 km2) we sampled saproxylic beetles through sieving of bark from Picea abies logs in early stages of decay with bark still attached, within 5 production forests and 5 woodland key habitats (biodiversity hotspots, used as reference; ‘WKH’). A total number of 5147 individuals and 78 taxa were found. Beetle diversity related positively to the local factor of sieved bark area, while the share of continuity forest in the surroundings (5 km buffer; varying 5 − 29

The niche variation hypothesis states that the population niche width expands with increasing interindividual differences in prey utilization (i.e., individual dietary specialization). The main ecological drivers forming this relationship include a) ecological opportunity, b) food limitation and exploitative competition, and c) intraguild interference. Only a limited number of empirical studies have tested the impact of these drivers on the niche variation-width relationship and focused only on vertebrates. Using molecular gut content analysis, we investigated how prey diversity (proxy for ecological opportunity), prey abundance (proxy for exploitative competition / food-limitation), and activity density of guild members (proxy for intraguild interference) affect the short-term individual dietary specialization and consequently the population niche width in local communities of 13 species of predatory beetles and spiders. The study took place in 10 spring barley fields in Sweden in 2011. We found that the niche variation and consequently the average population niche width of the species in the predator community decreased with prey abundance but increased with activity density of guild members. The results indicate that intraguild interference and exploitative competition / food limitation increased dietary variation. The increased diet variation led to the observed population diet expansion. Our results support the niche variation hypothesis and, in contrast to the traditional view, show that negative intraguild interactions may act as a diversifying force.

1. Pollination services contribute to crop productivity worldwide, but insect pollinators are declining in most agricultural landscapes, mainly due to agricultural expansion and an increase in intensive agricultural practices. To reduce the negative effects of agricultural expansion and intensification, farmers can adopt ecological interventions, such as diversifying agricultural systems through agroforestry. However, there have been variable results on the effectiveness of agroforestry in enhancing pollinators and pollination services. Furthermore, most of the information has been generated in temperate regions, while the impact of agroforestry in tropical East Africa is largely unknown. 2. Using common beans (Phaseolus vulgaris L.) as the focal crop, this study tested whether a tropical agroforestry system called Chagga home gardens supports pollinator communities and improves pollination and crop yield. We examined 16 agroforestry plots paired with 16 non-agroforestry plots located along a gradient of woody (trees and shrubs) cover within a 1-km radius to document the abundance, species richness and visitation rates of pollinating insects on bean flowers and how they contributed to bean yield. 3. The beans planted in the agroforestry plots had almost twice the abundance of insect pollinators, three times the richness of the species and almost twice the visitation rates than those planted in non-agroforestry plots. We also found a significant positive effect of woody cover in the surrounding landscape on insect pollinator abundances, but not on species richness and visitation rates. Additionally, the abundance and richness of insect pollinators increased significantly with flower abundance, while the overall plant richness in a plot significantly increased insect pollinator abundance and their visitation rate. The difference in bean yield between unbagged flowers (in which insect pollinators were allowed to access bean flowers) and bagged flowers and the total yield were higher in agroforestry than in non-agroforestry plots. 4. Synthesis and applications. This study showed that, compared to monoculture, agroforestry generally promotes pollination services in a tropical context. Furthermore, we found that agroforestry is likely to be particularly helpful for pollinators when it increases flower abundance and plant richness and if it is coordinated so that woody cover also increases at the landscape scale.

1. Reliably predicting pest damage would allow farmers to reduce insecticide use without incurring economic losses and thus contribute to agricultural sustainability. However, means to predict pest severity are lacking.2. We assessed whether crop feeding injury caused by flea beetles in spring oilseed rape can be predicted from flea beetle pest densities in the previous season using 22 years of suction trap catches of flea beetles in combination with crop feeding injury data from 293 fields.3. We found a strong positive relationship between the densities of flea beetles of the genus Phyllotreta in the summer and autumn activity period of the previous year and crop feeding injury caused by flea beetles in spring oilseed rape the following year. Autumn weather or the total cover of spring oilseed rape in the study region did not improve the prediction further.4. Pest monitoring using suction traps is thus a promising tool to predict crop feeding injury and can reduce insecticide use in years with low pest pressures.

This Special Issue presents articles that combine traditional approaches, novel experimental methods, and advanced techniques, to provide a more in-depth understanding of trophic interactions in biological control. Studies mainly cover behavioural and chemical ecology, molecular ecology using PCR, qPCR and high-throughput sequencing, population genetics, automated deep learning image analysis and photo trapping. Through laboratory and field investigations, articles provide novel insights into host/prey specificity of natural enemies, their multitrophic interactions, and how they behave in space and time. Ultimately, results may be useful for the development of management strategies that aim to improve biocontrol effectiveness against native and invasive herbivorous insects.

Knowledge about cold tolerance of non-native biological control agents is critical to avoid permanently establishing them in new temperate areas outside of their native range. The cold tolerance of the predatory mites, Amblydromalus limonicus and Iphiseius degenerans, was investigated in the laboratory to assess their establishment potential in northern Europe, particularly Sweden. The lethal time of I. degenerans (the number of days until 100% mortality was reached) declined steeply from 5 degrees C to 0 degrees C and was almost zero at -5 degrees C. The lethal time of A. limonicus did not differ between 5 degrees C and 0 degrees C, but was reduced at -5 degrees C. For both species, LTime50 (the number of days until 50% of the mites died) was longer for fed than for unfed mites. The lethal temperature of A. limonicus (the temperature at which 100% mortality was reached) was -17.75 degrees C, whereas most I. degenerans died at -8.5 degrees C. LTemp50 (the temperature at which 50% of the mites died) was lower for A. limonicus (-9.8 degrees C) than for I. degenerans (-0.1 degrees C). Collectively, these findings suggest that I. degenerans is unlikely to establish in Sweden but that A. limonicus is more cold tolerant. This highlights the risk associated with releasing A. limonicus in Sweden due to concerns about potential establishment.

Intensified agriculture, a driver of biodiversity loss, can diminish ecosystem functions and their stability. Biodiversity can increase functional redundancy and is expected to stabilize ecosystem functions. Few studies, however, have explored how agricultural intensity affects functional redundancy and its link with ecosystem function stability. Here, within a continental-wide study, we assess how functional redundancy of seed predation is affected by agricultural intensity and landscape simplification. By combining carabid abundances with molecular gut content data, functional redundancy of seed predation was quantified for 65 weed genera across 60 fields in four European countries. Across weed genera, functional redundancy was reduced with high field management intensity and simplified crop rotations. Moreover, functional redundancy increased the spatial stability of weed seed predation at the field scale. We found that ecosystem functions are vulnerable to disturbances in intensively managed agroecosystems, providing empirical evidence of the importance of biodiversity for stable ecosystem functions across space. Within a continent-wide study, we assess the impact of agricultural intensity and landscape simplification on the functional redundancy of weed seed predation. We found that functional redundancy was reduced with high field management intensity and simplified crop rotations. Additionally, high functional redundancy increased the spatial stability of weed seed predation, underscoring the importance of biodiversity in maintaining stable ecosystem functions across space in intensively managed agroecosystems.image