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The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.

Land‐use intensification is often associated with a decline in functional diversity, potentially undermining the provision of ecosystem services. However, how changes in traits affect ecosystem processes remains poorly understood. Variation in trait values among species in a community may drive ecosystem processes. Alternatively, the mass ratio hypothesis proposes that trait values of the dominant species in a local community are related to ecosystem processes. Using data from 159 farms in six European countries, we quantified the impact of local and landscape‐level land‐use intensity on ground beetles as pest control agents. We then assessed the extent to which functional diversity and community‐weighted mean trait values relate to pest control and cereal yield. In addition, we assessed how the responses to land use and the effects of different species on pest control and yield varied with their traits to compare the relative impact of the traits studied. Functional diversity of ground beetles improved aphid removal, but did not translate into higher crop yields. Pest control of aphids was enhanced by a higher proportion of smaller, mobile ground beetles with a preference for the vegetation layer. Smaller, predatory ground beetles in communities improved crop yield. The magnitude of responses to land‐use intensification and the effects on pest control and yield were more strongly influenced by body size than other traits. Our study provides evidence that reduced management intensity can improve pest control by supporting small‐sized, macropterous ground beetles. In contrast to the claims of ecological intensification, our joint analysis of the direct effects of land use on yield and indirect effects via functional diversity of ground beetles and pest control suggests that ecosystem services by ground beetles cannot compensate for the yield gap due to a reduction in land‐use intensity. [ABSTRACT FROM AUTHOR]

• Dwarf shrubs cooler and moister than the surrounding grassland. • Therefore, dwarf shrubs buffer microclimatic extremities. • Forests and edges had a higher spider richness than grasslands and dwarf shrubs. • We found a different community composition of spiders in the four microhabitats. Climate change negatively affects arthropod biodiversity worldwide. Mitigating the resulting arthropod decline is a great challenge. Dwarf shrubs in open areas might buffer microclimatic extremities by reducing the solar radiation reaching the ground and weakening air circulation near the soil surface. Forest steppes are mosaics of forests and grasslands covering a vast area in Eurasia. This heterogeneous ecosystem offers the opportunity to study the effect of small habitat features, i.e. dwarf shrubs, in dry grasslands and compare the fauna of rosemary-leaved willow (Salix rosmarinifolia) shrubs with forest patch interiors, open grasslands and their edges. We hypothesized that the dwarf shrub microhabitat has a wetter and cooler microclimate than open grassland and a different spider community composition than other forest-steppe microhabitats. We recorded microclimatic parameters with data loggers, measured soil moisture with TDR and collected ground-dwelling spiders with pitfall traps. We detected the highest soil moisture (6.26 ± 1.21%, mean ± 95% confidence interval) and air humidity (80.19 ± 3.19%) in forests and the lowest in grasslands (4.36 ± 0.65%; 66.59 ± 2.53%, respectively). The warmest microhabitats were grasslands (23.23 ± 0.51°C), whereas the coolest microhabitats were forests (18.92 ± 0.41°C). The distinct microclimate of dwarf shrubs was cooler (21.46 ± 0.41°C) and moister (5.43 ± 0.53%) than the surrounding semi-desert like grassland. Furthermore, we found a different spider community composition and trait state composition of spiders in forests, edges, grasslands and dwarf shrub microhabitats. Forests (9.90 ± 0.95) and edges (11.44 ± 1.27) hosted a higher species richness than grasslands (7.08 ± 4.27) and dwarf shrubs (5.09 ± 1.33). We collected larger spiders on the edges than in dwarf shrub microhabitats. The dwarf shrubs hosted a different microclimate and spider community composition from the grassland. Climate change in the forest-steppe region is assumed to be driven by a combination of warming and drying. In the coming decades, drought frequency and severity are predicted to increase. Woody vegetation, even dwarf shrubs, creates a thermal and moisture heterogeneity that might aid arthropods in buffering macroclimatic warming through behavioural thermoregulation. Therefore, their presence on grasslands can benefit the conservation of specialised grassland arthropods. [ABSTRACT FROM AUTHOR]

The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Nature Communications 6: Article number: 7414 (2015); Published: 16 June 2015; Updated: 18 February 2016. The authors inadvertently omitted Kimiora L. Ward, who managed and contributed data, from the author list. This has now been corrected in both the PDF and HTML versions of the Article.

There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.

As a consequence of agricultural intensification and habitat fragmentation since the mid-20th century, biological diversity has declined considerably throughout the world, particularly in Europe. We assessed how habitat and landscape-scale heterogeneity, such as variation in fragment size (small vs. large) and landscape configuration (measured as connectivity index), affect plant and arthropod diversity. We focused on arthropods with different feeding behaviour and mobility, spiders (predators, moderate dispersal), true bugs (mainly herbivores and omnivores with moderate dispersal), wild bees (pollinators with good dispersal abilities), and wasps (pollinators, omnivores with good dispersal abilities). We studied 60 dry grassland fragments in the same region (Hungarian Great Plain); 30 fragments were represented by the grassland component of forest-steppe stands, and 30 were situated on burial mounds (kurgans). Forest-steppes are mosaics of dry grasslands with small forests in a matrix of plantation forests. Kurgans are ancient burial mounds with moderately disturbed grasslands surrounded by agricultural fields. The size of fragments ranged between 0.16–6.88 ha (small: 0.16–0.48 ha, large: 0.93–6.88 ha) for forest-steppes and 0.01–0.44 ha (small: 0.01–0.10 ha and large: 0.20–0.44 ha) for kurgans. Fragments also represented an isolation gradient from almost cleared and homogenous landscapes, to landscapes with relatively high compositional heterogeneity. Fragment size, connectivity, and their interaction affected specialist and generalist species abundances of forest-steppes and kurgans. Large fragments had higher species richness of ground-dwelling spiders, and the effect of connectivity was more strongly positive for specialist arthropods and more strongly negative for generalists in large than in small fragments. However, we also found a strong positive impact of connectivity for generalist plants in small kurgans in contrast to larger ones. We conclude that besides the well-known effect of enhancing habitat quality, increasing connectivity between fragments by restoring natural and semi-natural habitat patches would help to maintain grassland biodiversity. [ABSTRACT FROM AUTHOR]

• Flower fields can have similarly positive effects on bat activity as hedgerows. • AES can promote bats in agricultural landscapes and may provide suitable foraging habitats for bats in homogenous landscapes. • Critically endangered bat species were found flying above all our AES. Agri-environment schemes (AES) have become important tools for farmland biodiversity conservation, providing suitable habitats, resources, and connectivity within the agricultural landscapes. Bats are rarely studied in relation to AES effectiveness in contrast to birds, even though their presence and activity as biological control agents on insects, especially pest species, can be important for agricultural crops. While the role of hedgerows for bat occurrence and activity, as well as for their prey's diversity and abundance has been widely studied, the role of other AESs such as flower fields remains unclear. We monitored the activity of the main functional groups (edge, narrow and open space foragers) using ultrasound recorders, as well as potential prey abundances using light traps, across 35 study sites representing different AES in Central Germany from late July to September 2018. The sampled AES consisted of annual flower fields, mixed flower fields (with annual and biennial vegetation), perennial flower fields (sown every 5 years), hedgerows (surrounded by meadows and agricultural fields), and were compared to winter wheat (control) in a balanced design. Bat activity over hedgerows increased threefold for edge space foragers and sevenfold for narrow space foragers compared to wheat fields. Compared to wheat fields, narrow space forager activity increased fourfold over perennial flower fields, threefold over annual and twofold over mixed flower fields. This group's activity over hedgerows also increased almost threefold compared to mixed flower fields. However, the number of feeding buzzes and prey abundance did not differ significantly between AES. We detected foraging group-specific differences in bat activity between the studied AES. Thus, to promote bats in agricultural landscapes and to ensure their biological control services, it is important to establish more AES, such as hedgerows and flower fields, to increase their diversity and connectivity in intensively used agricultural landscapes. [ABSTRACT FROM AUTHOR]

The effectiveness of agri-environment schemes depends on scheme type, taxon and landscape. Here, we show how spatial scale, i.e. studied transect, field or farm level, and controlling for yield loss, can drastically change the evaluation of biodiversity benefits of on-field (organic farming) vs. off-field (flower strips) schemes. We selected ten agricultural landscapes in Central Germany, each with a triplet of winter wheat fields: one organic, one conventional with flower strip, and one conventional without flower strip as a control. We surveyed the abundance of wild bees at field edges for two years. We found that comparing data at the transect level may lead to misleading conclusions, because flower strips, covering only 5% of conventional fields, support fewer bees than large organic fields. However, a 50% cereal yield loss of organic farming can be considered as equivalent to yield levels of 50 ha conventional plus 50 ha flower strip. This would promote 3.5-times more bees than 100 ha organic farming. In conclusion, considering various scales in the evaluation of agri-environment scheme measures is necessary to reach a balanced understanding of their ecological and economic effects and their effectiveness. [ABSTRACT FROM AUTHOR]

Wood mouse Apodemus sylvaticus and striped field mouse A. agrarius are the most abundant mouse species in Central Europe coexisting in several habitats not only such as in forests but also in rural and urban areas. Their basic colours are similar, but the striped field mouse has a pronounced black stripe on its back. The biological function of this phenotypic difference is unexplored; therefore, our goal was to study the impact of fur pattern as well as the scent on the survival of these species. In our study, we used plasticine models mimicking wood mouse and striped field mouse. For imitating mouse scent, cotton pads saturated with mouse urine were placed under the models. In spring 2016, 200 plasticine mice divided into four types (non‐striped with scent, non‐striped without scent, striped with scent, striped without scent) were placed randomly in four sampling sites in the mid‐sized city, Pécs, Hungary. During 4 weeks of exposure, we recorded predation on 71 plasticine models. Birds (51%) and large mammals (25%) were the most common predators, and in 24% of the cases, the models disappeared. Considering predation only by large mammals, we found that the daily survival rate of both striped and non‐striped models with scent decreased in comparison to models without scent. Thus, large mammalian predators could discover plasticine models sooner than avian predators, which suggests a strong impact of scent. Despite the high rate of bird predation, we did not detect an effect of fur pattern suggesting that it may not be related to survival but might have other functional roles. With the dummy mouse experiment, we showed that fur pattern may play a minor role in mice detection by predators, thus further studies are needed to discover its ecological function. [ABSTRACT FROM AUTHOR]

• Food webs are less diverse in homogeneous compared to heterogeneous landscapes. • Environmentally-friendly and organic management supported food web diversity. • Food web interactions with agri-environment schemes are seasonal. • Seed mixtures should include Trifolium spp. to support bumblebee diversity. • Seed mixtures should consist of species that provide flowers throughout the growing season. Plant and pollinator diversity have declined concurrently in Europe in the last half century. We studied plant–bumblebee food webs to understand the effects of two agri-environmental schemes (AES, organic farming and environmentally-friendly management practice) vs. conventional farming as control group, landscape structure (heterogeneous vs. homogeneous landscapes) and seasonality (June, July, and August) interactions using Estonian AES monitoring data. In the summer of 2014, we observed foraging bumblebees (20 species) on 64 farms that varied in agricultural management and landscape structure, yielding a total of 2303 flower visits on 76 plant species. We found that both management practice and landscape structure influenced the generality (redundancy in the use of flower resources) of food webs. In homogeneous landscapes, environmentally-friendly management practices, including restrictions on the application of glyphosates, enhancement of bumblebee habitats, such as permanent grassland field margins, the allocation of a minimum of 15% of arable land (including rotational grasslands) to legumes, contributed to a higher number of visited plant species (generality) in July, whereas organic farming did so in August. Therefore, both environmentally-friendly and organic management practices are needed to support plant–bumblebee food webs in agricultural landscapes. Food web generality and diversity (Shannon index) are affected by a significant interaction between landscape structure and seasonality: food web diversity varied in homogeneous landscapes between the three different survey months, whereas food webs were more diverse in heterogeneous landscapes. We did not find any significant interaction effect of management, landscape structure and seasonality on linkage density and vulnerability. A full list of the most visited plant species by bumblebees based on species-specific flower visitation was also assembled. In homogeneous landscapes, resource limitation is an issue for bumblebees in certain time periods. For supporting bumblebees in the agricultural landscapes, avoiding resource limitation is important and this can be secured with a combination of AES management practices. [ABSTRACT FROM AUTHOR]

Agri-environment schemes, like flower fields, have been implemented in the EU to counteract the dramatic decline of farmland biodiversity. Farmers in Lower Saxony, Germany, may receive payments for three flower field types: annual, perennial (five years old), and mixed flower fields composed of yearly alternating annual and biannual parts. We assessed the effectiveness of these flower field types in providing bumblebee foraging habitat compared to control cereal fields. We sampled bumblebees with transect walks and assessed the richness of exploited pollen plants using DNA meta-barcoding and direct observations. All flower field types enhanced bumblebee abundance and species richness compared to control fields but attracted mostly three generalist species. Although we expected highest benefits from the more heterogeneous mixed flower fields, abundance was highest in annual, only intermediate in mixed, and lowest in perennial flower fields. Bumblebee species richness did not differ between flower field types. Overall, the proportion of sown plants in pollen loads was surprisingly low (< 50%). Bombus pascuorum, but not B. terrestris agg. , exploited 10% of the sown plant species in perennial, 36% in annual and 45% in mixed flower fields, respectively. Compared to direct observations, pollen samples revealed 4.5 times more visited plant species and thus assessed floral resource use more reliably. Plant species richness in pollen loads decreased with local flowering plant species richness and increased with proportion of annual crops in the landscape, potentially due to the exploitation of more diverse and scattered resources, including flowering crops, in homogenized landscapes to fulfil dietary requirements. Our results indicate that under the current management, both annual and mixed flower fields provide the most attractive food resources, while perennial flower fields offered the poorest foraging habitats. Conclusively, flower fields seem important but resources from the surrounding landscape are still needed to sustain bumblebees in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Agri-environment scheme (AES) approaches can be classified according to whether they prescribe management in non-productive areas, such as field boundaries and wildflower strips, or in productive areas, such as arable crops. Here we tested the ecological effectiveness of two popular AESs in Germany: wildflower strips next to winter wheat fields as off-field management and organic farming on winter wheat fields as on-field management. We selected ten landscapes along a field size gradient with three focal wheat fields, one conventional field with flower strip, one organic field and one conventional field without flower strip as a control. We sampled arthropods with pitfall traps at field edges and field interiors. We selected three ecological traits for spiders and carabids (body size, feeding trait, dispersal ability). We calculated community weighted mean values (CWM), and we used linear mixed effects models to test the effect of management type and transect position on CWM values. We found pronounced edge effects on most traits, and weaker effects of field size and AES in shaping functional traits. Smaller spiders, spiders with higher ballooning propensity and more web-builders were in the field interior than at the field edge, whereas carnivore carabids preferred field interiors. We also found a strong effect of landscape configuration, i.e. mean field size, as larger field size was positively related to more web-building spiders and more carnivore beetles. Flower strips enhanced populations of web-building spiders. Our results suggest that small-scale agriculture leading to high landscape-scale edge density has a major effect in shaping functional traits and potential ecosystems services in agricultural landscapes. Spider and carabid communities exhibit very different responses to edge vs. interior sites, and, based on the landscape-scale field size gradient emphasize the importance of landscape configuration in shaping the heterogeneity of the arthropods' traits and presumably ecosystem services in agricultural landscapes. [ABSTRACT FROM AUTHOR]