DOI: 10.5061/dryad.pc866t1zs
title: Functional diversity of ground beetles improved aphid control but did not increase crop yields on European farms

description: 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.
description: # Functional diversity of ground beetles improved aphid control but did
 not increase crop yields on European farms
 [https://doi.org/10.5061/dryad.pc866t1zs](https://doi.org/10.5061/dryad.pc866t1zs) The data set contains ground beetle community and trait information, local and landscape-level land use data, data on aphid removal, and crop yield. The data has been collected in the framework of the EuroDiversity programm-AGRIPOPES originating from six countries (France, Germany, Ireland, Netherlands, Poland, and Sweden; This is a sub-set of the full data limited by the availability of aphid removal data). Trait information has been gathered in the framework of the Biodiversa-FunProd project. The empirical data has been collected in 2007 from spring to summer on 159 farms (mainly winter wheat, rarely winter barley). Ground beetle community data and aphid removal trials were done twice, samples are pooled. ## Description of the data and file structure 1\) Table with following tabs: a) sites x species: ground beetle community data from pitfall traps b) species x traits: species traits from the literature (see Table 1 and references in the article) c) functional indices: functional diversity (FD) and community weighted means (CWM) based on a) sites x species and b) species x traits matrices (see R-code) d) variables: aphid removal (three lables with three aphids glued that were placed on the ground); Farm-level land use and yield data were obtained through questionnaires conducted by personal interviews with all farmers; Landscape cover measures based on CORINE 2\) Text file containing the used R-code to calculate community weighted means (CWM) and functional diversity (FD) based on a) and b) as well as the code to calculate piecewise structural equation models based on c) and d) and fourth-corner models based on a), b), and d). ## Sharing/Access information Permission to re-analyze and publish AGRIPOPES data in this form kindly granted by J. Bengtsson.  For more information about the AGRIPOPES project see: | Emmerson, M., Morales, M. B., Oñate, J. J., Batary, P., Berendse, F., Liira, J., ... & Bengtsson, J. (2016). How agricultural intensification affects biodiversity and ecosystem services. In Advances in ecological research (Vol. 55, pp. 43-97). Academic Press. [https://doi.org/10.1016/bs.aecr.2016.08.005](https://doi.org/10.1016/bs.aecr.2016.08.005) | | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ## R-code All analyses have been done in R version 4.2.0. The R-package 'FD' was used to calculate community weighted means (CWM) and the R-function 'gawdis' was used to calculate functional dissimilarity between the species combining a) sites x species and b) species x traits matrices. The 'piecewiseSEM' R-package was used to calculate structural equation models (SEM). The SEM's include functional indices (FD, CWM_'trait') from c) and local (LUI) and landscape-level (Arab1000_stand) land use data, the proportion of removed aphids (PerPred), and standardized (i.e., divided by the mean across all regions) yield data from d). Country identity entered the models as random effect. The R-packages 'mvabund', 'lattice', and 'gllvm' were used to calculate and visualize 4th corner models for each country seperately (standardized within country therefore variable endings with 'stand_per'). This was done by drawing respective subsets from the sites x species matrix a), the species x traits matrix b) and selected variables (local [LUI] and landscape-level [Arab1000] land use, aphid removal [Pred], and crop yield) from d). [Learn about README files(opens in new window)](https://datadryad.org/stash/best_practices#describe-your-dataset-in-a-readme-file)