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Land-use change is massively reshaping terrestrial ecosystems worldwide, and is recognized as a key driver of biodiversity loss with negative consequences on ecosystem functioning. Understanding how species use resources across landscapes is essential for the design of effective management strategies. Despite recent advances in theoretical ecology, there is still a gap between theory and applied ecological science and we lack the tools to manage entire landscapes to maximize biodiversity conservation and ecosystem service delivery. Here, we propose a new approach that uses existing bipartite networks to create species-habitat networks. Networks enable powerful visualizations via a common language that defines most processes in terms of nodes and links. This approach explicitly links multiple species and habitat resources, provides tools to estimate the importance of particular species in a given landscape, and quantifies emerging properties of entire habitat networks. Most existing metrics used to study properties of bipartite ecological networks can easily be adapted to investigate species-habitat relationships. One key advantage of this approach is that the scale of the derived ecological information will match the scale of management interventions. The flexibility of the proposed approach is that it can be easily applied across a range of ecological fields such as species conservation, habitat restoration, ecosystem services management, or invasion ecology. Network emerging properties could also be used to test the effects of large scale drivers of global change upon ecosystem structure and stability.

Xylella fastidiosa subsp. pauca is a plant pathogen that causes the Olive Quick Decline Syndrome, the spread of which is linked to insect vectors. Since these vectors can use and move across multiple managed and natural habitats, understanding their occurrence in different habitat types at the landscape scale is particularly challenging. Here, we applied a bipartite network approach to explore the spatio-temporal distribution of confirmed and potential vectors of X. fastidiosa in olive groves. We sampled sharpshooters and spittlebugs in 10 heterogeneous landscapes in southern Italy during spring, summer, and autumn. In each landscape, we sampled insects in the main habitat types, i.e., arable land, grassland, olive grove, vineyard, and woodland. We then built and analyzed the resulting bipartite species–habitat networks. The abundance of vectors in different habitat types throughout the seasons varied from species to species, with Philaenus spumarius, the main vector of X. fastidiosa, being mostly collected in olive groves. However, the analysis of habitat specialization showed that P. spumarius acted as a super-generalist species, occupying all the habitats. Insect vectors in olive grove patches were strongly influenced by other olive grove patches in the landscape and also by grasslands, particularly in spring, therefore highlighting the focal role of non-crop habitats on potential pathogen spread. Landscapes dominated by olive orchards and grasslands seemed to provide the most suitable conditions to support large vector populations. Network analyses helped untangle the complex interactions between vectors of X. fastidiosa and the landscapes and habitats they use.

Reliable monitoring of arthropod diversity in a given agroecosystem is essential for the conservation of the related ecosystem services, such as biological control. The often daunting complexity of arthropod collection and identification, however, highlights the need for surrogate taxa that can be easily sampled and be representative of a number of other taxa in term of diversity, general community features and specific composition. In this study, we used pitfall traps to sample three ground-dwelling arthropod taxa important as biocontrol agents (ground beetles, rove beetles and spiders) in 9 conventionally managed maize agroecosystems of Northern Italy over the course of two years, with the goal of characterizing their assemblages and evaluating their reciprocal potential as indicators of activity density, species richness, community turnover and species co-occurrence. Although dominated by few generalist species, sampled arthropod communities were relatively species-rich, and included the first Italian record of the spider Zelotes metellus (Roewer) (Araneae: Gnaphosidae). Ground beetles as a group were confirmed as promising indicators for the species richness and community composition turnover of rove beetles and spiders. Additionally, several abundant arthropod species acted as indicators of the species richness of their respective groups, and the ground beetle Pterostichus macer (Marsham) also worked as an indicator of overall rove beetle activity density. While the co-occurrence of individual arthropod species was limited for the studied taxa, a few species such as the ground beetle Parophonus maculicornis (Duftschmid) did show promise as species-specific bioindicators. Our results could be useful in improving the monitoring and management of these important natural enemies in maize-growing regions.

Measuring habitat specialisation is pivotal for predicting species extinctions and for understanding consequences on ecosystem functioning. Here, we sampled pollinator and natural enemy communities in all major habitat types occurring across multiple agricultural landscapes and used species-habitat networks to determine how habitat specialisation changed along gradients in landscape composition and configuration. Although it is well known that landscape simplification often causes the replacement of specialists with generalists, our study provided evidence for intraspecific variation in habitat specialisation, highlighting how a large number of arthropod species adapted their way of selecting habitat resources depending on the landscape structure. Groups with higher diet specialisation and limited foraging flexibility appeared to have a reduced ability to respond to landscape changes, indicating that some arthropod taxa are better able than others to adapt to an increasingly broad set of resources and persist in highly impacted landscapes.

Exotic plant invasions are considered one of the major threats to biodiversity causing important impacts at the population, community, and ecosystem levels. Understanding the drivers of plant invasions across multiple spatial and temporal scales often requires a landscape approach. The effect of landscape composition on biological invasion has been extensively studied, whereas landscape configuration effects were seldom considered or the analyses were limited to single species. Here, we aimed to analyze how the expansion of urban and agricultural areas can affect exotic species richness (both neophytes and archaeophytes) at three spatial scales, namely regional (scale: 37.5 km2), landscape (scale: 7.1 km2) and local (scale: 100 m2). We considered the possible contribution of urban and agricultural areas both in terms of composition (i.e. habitat cover) and configuration (i.e. shape complexity of patches). First, we found that increasing urbanization coupled with high shape complexity of urban elements were major drivers of both neophyte and archaeophyte invasions across heterogeneous landscapes. In particular, shape complexity seemed to be a key driver of plant invasions at large spatial scale, whereas the type of recipient habitat and urban cover determined the exotic success at the patch level. Second, archaeophytes were also affected by agriculture land use, i.e. agricultural patches shape complexity increased their spread at both regional and landscape scales. High shape complexity of highly disturbed habitats is expected to increase the exchange surface that exotic plant use to spread their propagules across the landscape mosaics. Our findings suggest that urban planning aimed at curbing urban fragmentation by both reducing shape complexity and diffuse urban sprawl might greatly improve the resistance of landscapes to biological invasions.

1. Land-use change is reshaping terrestrial ecosystems world-wide and is recognized as a key driver of biodiversity loss with negative consequences on ecosystem functioning. Understanding how species use resources across landscapes is essential for the design of effective management strategies. 2. Despite recent advances in network ecology, there is still a gap between theory and applied ecological science, and we lack the information to manage entire landscapes to maximize biodiversity conservation and ecosystem service delivery. While several pioneering approaches have tried to link ecological networks and conservation science, applied ecologists still struggle to incorporate these models into research due to their inherent complexity. 3. We propose the application of bipartite networks principles to create species–habitat networks. This approach explicitly links multiple species and habitat resources, provides tools to estimate the importance of particular species or specific habitat in a given landscape, and quantifies emerging properties of entire habitat networks. Most existing metrics used to study properties of bipartite ecological networks can easily be adapted to investigate species–habitat relationships. The tool use is relatively simple and does not require advanced computational expertise. 4. Synthesis and applications. One of the biggest challenges in applied ecology is managing multiple habitats for the effective conservation of multiple species. One key advantage of this proposed approach is that the scale of the derived ecological information could match the scale of landscape management interventions. The versatility, visualization power and ease of interpretation of these networks will enable application of the species–habitat network concept to a wide array of real-world problems, such as multispecies conservation, habitat restoration, ecosystem services management or invasion ecology. In particular, species–habitat networks could be applied to identify optimal landscape compositions and configurations to design effective interventions at the landscape scale. This approach also enables the detection of emerging network properties that could also be used to test the effects of large-scale drivers of global change upon ecosystem structure and stability.

Seed predation by arthropods can contribute in regulating population and community dynamics of weeds. While the role of insects, and especially ground beetles (Coleoptera: Carabidae) as seed predators in crop fields is well studied, the drivers of predation stability and the relationships between species diversity and predation are less understood. The aims of the study were: 1) to unveil the direct relationships between predator community diversity and seed predation intensity and stability, and 2) to test the effects of soil disturbance (conventional vs. conservation tillage) and distance from field margin on seed predator communities and predation. Seed predation was measured using seed cards, and predator communities were sampled using pitfall traps over two years. Granivorous ground beetles, ants and crickets were the most abundant seed predators in both conventional and conservation tillage fields. Abundant and diverse predator communities were beneficial to predation intensity and stability. However, in communities dominated by large predators, an increase in number of species was related to a partial suppression of seed predation. Soil disturbance per se did not influence the overall predator community composition and predation, but it modified their spatial patterns within the fields. At the margins of conventional tillage fields, predation was lower and patchier than at the margins of conservation tillage fields. However, predation increased more steeply towards the center of conventional tillage field. Our results could find applications in sustainable weed management through biological control, as well as in better understanding the role of functional diversity in regulating ecosystem services.

Since the mid-2000s, the exotic coccinellid species Harmonia axyridis (Pallas) has established itself in Northern Italy, raising serious concerns about possible repercussions on native ladybirds. In this study we compared the ladybird assemblages in 2015–2016 with those sampled in 1995–1996, before the arrival of H. axyridis. Surveys were carried out in the same sites and with the same methods for both periods. Aphidophagous ladybirds were sampled in hedgerows and herbaceous habitats at field margins by mechanical knockdown and sweeping net, respectively. The changes in the structure of ladybird communities after the arrival of H. axyridis were significantly different between arboreal and herbaceous habitats. Harmonia axyridis is currently the dominant species in shrubs and trees, and all the native ladybird species taken together account for only approximately one third of the total individuals sampled in 2015–2016. On the other hand, the relative abundance of the exotic species in herbaceous habitats was low, and it has had a negligible relevance on the structure of ladybird communities on grasslands. Among native species, Adalia bipunctata (L.), whose ecological niche largely overlaps with that of H. axyridis, suffered the largest decline between 1995–1996 and 2015–2016. The co-occurrence of H. axyridis invasion and the regression of A. bipunctata suggest a direct impact of the exotic species, because no other major modifications occurred in the studied areas between sampling periods.

Yield production in flowering crops depends on both nutrient availability and pollination, but their relative roles and potential interactions are poorly understood. We measured pollination benefits to yield in sunflower, combining a gradient in insect pollination (0, 25, 50, 100%) with a continuous gradient in nitrogen (N) fertilization (from 0 to 150 kg N ha −1 ) in an experiment under realistic soil field conditions. We found that pollination benefits to yield were maximized at intermediate levels of N availability, bolstering yield by approximately 25% compared with complete pollinator exclusion. Interestingly, we found little decrease in yield when insect visits were reduced by 50%, indicating that the incremental contribution of pollination by insects to yield is greater when the baseline pollination service provision is very low. Our findings provide strong evidence for interactive, nonlinear effects of pollination and resource availability on seed production. Our results support ecological intensification as a promising strategy for sustainable management of agroecosystems. In particular, we found optimal level of pollination to potentially compensate for lower N applications.

Ladybird beetles (Coleoptera Coccinellidae) are important predators of aphids and other crop pests, and there is great interest in their conservation in agroecosystems. Bt-maize, genetically engineered to express insecticidal Cry proteins, is regarded as a taxon-specific way of controlling pests, but some concerns have been raised about the possibility of unintended negative effects on non-target organisms, including coccinellids. One of the possible routes of exposure of ladybird beetles to Cry toxins is by feeding on maize pollen, as for many species pollen is an important integrative food source. In this study, coccinellid adults were sampled by sweep netting in Ecological Compensation Areas (ECAs) in three sites of Northern and Central Italy, where conventional maize cultivars are grown (Bt-maize is currently forbidden for commercial cultivation in Italy). The coccinellid communities were sampled during and around the typical flowering periods of maize in order to check their diversity and their overlap with pollen shedding. A total of 11 species were recorded. Hippodamia variegata (Goeze), Coccinella septempunctata L. and the exotic Harmonia axyridis (Pallas) were the most abundant species in Northern Italy, whereas Tytthaspis sedecimpunctata (L.) and Coccinula quatuordecimpustulata (L.) were dominant in Central Italy. The potential exposure to maize pollen was different in the two areas, since in Northern Italy the maize flowering coincided with a period of high coccinellid activity in the field, whereas in Central Italy the ladybird population peaks occurred roughly one month earlier than the anthesis. The collected data might be useful for exposure characterization of ladybird beetles in a possible future scenario of Bt-maize cropping in the studied areas.