A pan-European model of landscape potential to support natural pest control services

Pest control by natural enemies (natural pest control) is an important regulating ecosystem service with significant implications for the sustainability of agro-ecosystems. The presence of semi-natural habitats and landscape heterogeneity are key determinants of the delivery of this service. However, to date, synthetic and consistent indicators at large scales are lacking. We developed a pan-European, spatially-explicit model to map and assess the landscape potential to sustain natural pest control. The model considers landscape composition in terms of semi-natural habitats types, abundance, spatial configuration and distance from the focal field. It combines recent high-resolution geospatial layers with empirical results from extensive field surveys measuring the specific contribution of different semi-natural habitats to support insects flying enemies providing natural pest control. The resulting maps facilitate a comparison of the relative biological control potential of different areas and show that currently a large proportion of high-productive agricultural areas in Europe has low potential. The obtained indicator can inform the formulation of policies and planning strategies aimed at increasing biodiversity and ecosystem services and can be used to assess trade-offs between different services. Potential fields of application include the Common Agricultural Policy and the EU Biodiversity Strategy, in particular the implementation of Green Infrastructure

Data from: Enhancing plant diversity in agricultural landscapes promotes both rare bees and dominant crop-pollinating bees through complementary increase in key floral resources

1. Enhancing key floral resources is essential to effectively mitigate the loss of pollinator diversity and associated provisioning of pollination functions in agro-ecosystems. However, effective floral provisioning measures may diverge among different pollinator conservation targets, such as the conservation of rare species or the promotion of economically important crop pollinators. We examined to what extent such diverging conservation goals could be reconciled. 2. We analysed plant–bee visitation networks of 64 herbaceous semi-natural habitats representing a gradient of plant species richness to identify key resource plants of the three distinct conservation target groups rare bees (of conservation concern), dominant wild crop-pollinating bees, and managed crop-pollinating bees (i.e. honey bees). 3. Considering overall flower visitation, rare bees tended to visit nested subsets of plant species which were also visited by crop pollinators (46% and 77% nestedness in the dissimilarity between rare bees and wild crop pollinators or managed honey bees, respectively). However, the set of preferred plant species, henceforth ‘key plant species’ (i.e. those species disproportionately more visited than expected according to their floral abundance) was considerably more distinct and less nested among bee target groups. 4. Flower visits of all bee target groups increased with plant species richness at a similar rate. Importantly, our analyses revealed that an exponential increase in the flower abundance of the identified key plant species and complementarity in the bee visitation pattern across plant species ─ rather than total flower abundance ─ were the major drivers of these relationships. 5. Synthesis and applications. We conclude that the multiple goals of preserving high bee diversity, conserving rare species and sustaining crop pollinators can be reconciled if key plant species of different target groups are simultaneously available, which is facilitated by a high floral resource complementarity in the plant community. The list of identified key resource plant species we provide here can help practitioners such as land managers and conservationists to better design and evaluate pollinator conservation and restoration measures according to their goals. Our findings highlight the importance of identifying and promoting such plant species for pollinator conservation in agricultural landscapes.10-Mar-201

model data and nestedness

mod.dat.csv: all variables for all sites used for the models that were extracted from individual networks header of mod.dat.csv: regionsite functionalgrouptarget group of pollinators (icp, hb, rare) visitspertargetgroupnumber of visits functionalcomplementarityfunctional complementarity of plant community numberofkeyplantspresentkey plant species richness flowerabundancekeyplantsflower abundance of key plant species richness totalnumberofspeciestotal plant species richness totalflowerabundancetotal flower abundance prop.nestedness.csv. gives the proportional visits for each group to all visited plant species, data used to calculate dissimilarity and nestendess

The potential of different semi-natural habitats to sustain pollinators and natural enemies in European agricultural landscapes

Semi-natural habitats (SNH) are vital to sustain pollinators and natural enemies, and the ecosystem services they provide in agroecosystems. However, little is known about the relative importance of different SNH types and their vegetation traits for pollinators and natural enemies. Yet, such knowledge is essential for effective habitat management to promote both functional arthropod groups and associated multiple ecosystem services. We quantified vegetation traits and abundances of pollinators (bees) and natural enemies (predatory flies and parasitic wasps) in 217 SNH differing in type (woody or herbaceous) and shape (linear or areal habitats), for edge and interior locations within each SNH patch with respect to adjacent crops, across 62 agricultural landscapes in four European countries. Pollinators and natural enemies responded distinctively to major SNH types and within-habitat location of SNH: abundance of natural enemies (predatory flies and parasitic wasps) was higher along woody habitat edges than herbaceous SNH or the interior of woody habitats. In contrast, bee abundances, especially of honey bees, were generally higher in areal herbaceous compared to woody SNH. Abundances of both wild bees and managed honey bees were lowest for the interior sampling location in areal woody habitats. These findings reflected divergent key vegetation traits driving pollinator and natural enemy abundances across SNH: bee pollinators increased with herbaceous plant cover and were well predicted by SNH type and the floral abundance of identified key plant trait groups. In contrast, floral abundances of these plant groups were poor predictors of the studied natural enemies, which were better predicted by SNH type and sampling location within SNH. Our findings stress the need to move beyond the simplistic pooling of SNH types and highlight the importance of considering their vegetation traits to more reliably predict pollinators and natural enemies in agroecosystems. They suggest that the floral abundance of key groups of flowering plants is crucial for habitat management to promote bee pollinators, while vegetation-structural traits appear more important for predatory flies and parasitoids. The distinct importance of different SNH types and associated vegetation traits for pollinators and natural enemies calls for agroecosystem management ensuring diverse SNH with complementary vegetation traits to concomitantly foster pollination and pest control services.</p