Data for: Functional redundancy of weed seed predation is reduced by intensified agriculture

Intensive agriculture, a driver of biodiversity loss, can diminish ecosystem functions and their stability. Biodiversity can increase functional redundancy and is expected to stabilize ecosystem functions. Few studies however have explored how agricultural intensity affects functional redundancy and its link with ecosystem function stability. Here, within a continent-wide study, we assess how the functional redundancy of seed predation is affected by agricultural intensity and landscape simplification. By combining carabid abundances with molecular gut content data, functional redundancy of seed predation was quantified for 65 weed genera across 60 fields in four European countries. Across weed genera, functional redundancy was reduced with high field management intensity and simplified crop rotations. Moreover, functional redundancy increased the spatial stability of weed seed predation within fields. We found that ecosystem functions are vulnerable to disturbance in intensively managed agroecosystems, providing empirical evidence of the importance of biodiversity for stable ecosystem functions across space.

Methods
This dataset contains information on the functional redundancy of seed predation for 65 weed genera and field estimates of weed seed predation. It also contains data on two aspects of agricultural intensity (field management intensity, measured as the number of field visits by the farmer to conduct operations, and crop rotation diversity) and two aspects of landscape simplification (the proportion of semi-natural habitat surrounding each field, and the length of the interface between crops and semi-natural habitat). The data were collected in 2018 from 60 cereal fields located in four European countries. Data organisation and analysis were conducted in Microsoft Excel and R. The primary objective of the data was to investigate the impact of agricultural intensity and landscape simplification on the functional redundancy of seed predation and to explore the link between functional redundancy and spatial stability (degree of within-field spatial variability) of field estimates of seed predation. Functional redundancy is the exponential Shannon diversity of carabid species-specific predation pressure on each weed genus. Data on each carabid species' weed-specific pressure were collected using pitfall traps and molecular gut content analysis. Data on weed seed predation were collected by using seed cards with 50 seeds of the weed Poa annua.  Landscape data were extracted through landscape analysis, using the software CHLOE 4.0. These landscape data were based on the Corine Land Cover (CLC) classification, available national databases, and additional field surveys. Field management intensity data were estimated after communicating with farmers.