Wildflower strip establishment supports beneficial ground-dwelling arthropods and pest control but has limited effects on weed seed control and spillover to adjacent fields

Recent arthropod declines in agricultural landscapes can threaten biodiversity and the provision of ecosystem services. Wildflower strips (WFS) represent popular measures to support biodiversity. Most studies investigated their effects on pollinators, whereas ground-dwelling arthropods are less studied. In addition, time after WFS establishment is a relevant factor, but most experiments are performed in a single season. Here, we evaluated the effects of WFS on ground-dwelling arthropods (carabids, spiders, and myriapods) and ecosystem services (pest and weed seed predation) across three years. Using a standardised experimental design with paired control and WFS margins in 12 fields, we sampled before and up to the first two years after WFS establishment while also assessing spillover into adjacent fields. Our analyses revealed that spiders, as well as total pest predation and predation by rodents, were enhanced in two-year-old WFS, whereas similar but weaker patterns were observed for c..., Study sites and experimental design
The study was performed between 2020 and 2022 in the northeast of Prague, Czech Republic (50°7′–50°10′N, 14°31′–14°34′W; mean altitude 252 m a.s.l), where we selected 12 conventionally managed arable fields (areas ranging from 3.5 to 33.9 ha; Table S1; Figure S1a). Fields were managed conventionally by the VIN AGRO company and sown with cereals, sugar beet, oilseed rape, and mustard. Following a BACI approach (i.e., before and after design), within each field, two margins separated by at least 75 m (mean 397 m) were chosen for sampling arthropod and ecosystem services before and after sowing flower strips. In addition to the field margins (12 m from the original boundary), we also sampled the interior of the fields adjacent to both margins, at 36 and 60 m (see Venturo et al., 2024 for details), making a total of six transects per field. In 2020 (hereafter, before WFS establishment), both field margins were part of the arable fields, whereas in 2021, o..., , # Data from: Wildflower strip establishment supports beneficial ground-dwelling arthropods and pest control but has limited effects on weed seed control and spillover to adjacent fields

Dataset DOI: [10.5061/dryad.zpc866thp](10.5061/dryad.zpc866thp)

## Description of the data and file structure

### Files and variables

#### File: Data\_sets\_WFS.xlsx

**Description:** The dataset includes multiple sheets with all the data used in the article. The metadata sheet includes detailed instructions for reading and interpreting the remaining tables. The field and transect locations sheet includes the latitude, longitude, and elevation of each transect within the study sites. Trap-level data of arthropod taxa are provided in the sheets Araneae, Carabidae, Diplopoda, and Chilopoda, and the values in each cell represent the abundance of each species (column) in a given trap (row), with empty cells representing no individuals. Pest predation and Weed seed predation include all ecosystem services...,