Functional diversity of ground beetles improved aphid control but did not increase crop yields on European farms
Data files
Sep 04, 2024 version files 347.03 KB
Abstract
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.
README: Functional diversity of ground beetles improved aphid control but did not increase crop yields on European farms
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 |
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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).