Data from: Local habitat, not landscape diversity, drives richness and reproduction of cavity-nesting bees and wasps in agricultural landscapes

Studying insect decline in human-dominated landscapes, especially in intensively managed agricultural areas, requires understanding its drivers. Studies of cavity-nesting bees and wasps with trap nests provide information on the number of locally reproducing species and their potential offspring, and how this relates to local resources and landscape diversity. We investigated insect communities across all major habitat types in agricultural landscapes using a grid-based design to evenly and proportionally cover the major habitats of the landscape plots. The landscape plots covered a gradient from complex landscapes with a variety of habitats to simple landscapes dominated by arable land. At the local scale, we found that bee species richness was highest in grasslands and orchard meadows and lowest in forests, mirroring the pattern of local floral resources. However, it was unaffected by local hedgerow cover. Wasp species richness was highest in forests, followed by orchards, and lowest in grasslands and arable land, and it also responded positively to hedgerows. Bee brood cell abundance was highest in orchards and lowest in forests, whereas wasp brood cell abundance showed the opposite pattern. Neither group was affected by hedgerows. At the landscape scale, landscape diversity neither affected species richness nor the number of brood cells of bees and wasps. Our results highlight the importance of local habitat diversity in agricultural landscapes for supporting diverse cavity-nesting bee and wasp communities, as bees benefit from flower-rich grasslands and orchards, while wasps rely on forest resources. To counteract insect decline, conservation efforts should target both seminatural and cultivated habitats. # Data from: Local habitat, not landscape diversity, drives richness and reproduction of cavity-nesting bees and wasps in agricultural landscapes Dataset DOI: [10.5061/dryad.2fqz61348](https://doi.org/10.5061/dryad.2fqz61348) ## Description of the data and file structure * Data_cavity_nesting_bees_and_wasps.xlsx This dataset contains data on species richness and reproductive output (brood cell numbers) of cavity-nesting bees and wasps sampled using trap nests across agricultural landscapes in south-western Germany. The study was conducted in 2022 across twelve 1-km² landscape plots selected along a gradient of landscape diversity (Shannon diversity index). Data are provided at two spatial scales: 1. **Landscape scale** (aggregated across all trap nests within each 1-km² landscape plot), and 2. **Trap-nest (local) scale** (individual trap nests). Additionally, a species-level table reports brood cell counts of each collected species across local habitat types. The dataset accompanies a manuscript investigating the relative importance of local habitat type, hedgerow cover, floral resources, and landscape diversity for bee and wasp diversity and reproduction. --- #### File structure The dataset is provided in one main Excel file and two backup CSV files: 1. **Data_cavity_nesting_bees_and_wasps.xlsx**\ Contains two worksheets: * *Table_A1* (landscape-scale data) * *Table_A2* (trap-nest-scale data) 2. **Backup_data_cavity_nesting_bees_and_wasps_table_A1.csv**\ CSV version of *Table_A1* (landscape-scale data). 3. **Backup_data_cavity_nesting_bees_and_wasps_table_A2.csv**\ CSV version of *Table_A2* (trap-nest/local-scale data). The CSV files are included as plain-text backups to facilitate data access and reproducibility. They contain the same information as the corresponding Excel worksheets, with the same variable names and order. --- #### Sheet descriptions **Table A1 – Landscape-scale data (in Excel and** **`Backup_data_cavity_nesting_bees_and_wasps_table_A1.csv`)** **Description:**\ Aggregated data for each of the twelve 1-km² landscape plots. Each row represents one landscape plot. **Number of rows:** 12 (one per landscape plot) **Variables:** * `landscape` – Landscape plot identifier * `arable` – Proportion of arable land per landscape plot * `forest` – Proportion of forest per landscape plot * `grassland` – Proportion of grassland per landscape plot * `hedge` – Proportion of hedgerows per landscape plot * `orchard` – Proportion of orchards per landscape plot * `road` – Proportion of roads per landscape plot * `settlement` – Proportion of settlements per landscape plot * `land_div` – Landscape diversity (Shannon diversity index) **Community metrics:** * `total_rich` – Total bee and wasp species richness * `bee_rich` – Bee species richness * `wasp_rich` – Wasp species richness --- **Table A2 – Trap-nest (local) scale data (in Excel and** **`Backup_data_cavity_nesting_bees_and_wasps_table_A2.csv`)** **Description:**\ Data aggregated per individual trap nest. Each row represents one trap nest. **Number of rows:** 192 (16 trap nests × 12 landscapes) **Variables:** **Identifiers and land cover:** * `trap_nest` – Trap nest identifier * `landscape` – Landscape plot identifier * `arable`, `forest`, `grassland`, `hedge`, `orchard`, `settlement`, `road` – Proportional land cover (%) within a 100-m radius around the trap nest * `sum` – Sum of proportional land-cover values * `trap_main_habitat` – Dominant land-cover category within 100 m (arable, forest, grassland, orchard) * `land_div` – Landscape diversity (Shannon index within 1-km² landscape) **Community metrics:** * `trap_rich` – Total bee and wasp species richness * `rich_bees` – Bee species richness * `rich_wasps` – Wasp species richness **Reproductive output:** * `trap_brood_all` – Total number of hatched brood cells * `trap_brood_bee` – Number of hatched bee brood cells * `trap_brood_wasp` – Number of hatched wasp brood cells **Floral resources (local scale):** * `trap_flower_abundance` – Flower abundance (combined herbaceous and woody plants, April–October 2022) * `trap_flower_richness` – Flower species richness **Brood cell counts of predominant and less-dominant taxa:** * `Osmia.bicornis` * `Osmia.cornuta` * `all_other_bees` * `Ancistrocerus.nigricornis` * `Trypoxylon.figulus` * `all_other_wasps` --- #### Data aggregation and processing Trap nests were checked monthly from March to October 2022. Brood cell counts and floral resource data were aggregated across all sampling months prior to analysis. Data provided in this dataset represent final aggregated values used for statistical analyses. Brood cells were counted after adult emergence; only **hatched individuals** were considered in the analyses. Empty cells and cells with dead or parasitized individuals were excluded.