Landscape simplification leads to loss of plant-pollinator interaction diversity and flower visitation frequency despite buffering by abundant generalist pollinators

Global change, especially landscape simplification, is a main driver of species loss that can alter ecological interaction networks, with potentially severe consequences to ecosystem functions. Therefore, understanding how landscape simplification affects the rate of loss of plant-pollinator interaction diversity (i.e., number of unique interactions) compared to species diversity alone, and the role of persisting abundant pollinators, is key to assess the consequences of landscape simplification on network stability and pollination services. We analysed 24 landscape-scale plant-pollinator networks from standardised transect walks along landscape simplification gradients in three countries. We compared the rates of species and interaction diversity loss along the landscape simplification gradient and then stepwise excluded the top 1-20% most abundant pollinators from the data set to evaluate their effect on interaction diversity, network robustness to secondary loss of species, and flowe..., Plant-pollinator interactions (bees: Hymenoptera: Anthophila; and hoverflies: Diptera: Syrphidae) were sampled along transects (1 km x 2 m) in different flowering habitat types (e.g., meadows, forest edges, hedgerows, flowering crops) in each surveyed agricultural landscape (24 landscapes in total, n=8 landscapes in Switzerland, Germany, and France). The transects were located within 500 m of the center of the landscapes, and 3 min were invested for sampling 25 m of the transect (stopping the clock when handling the pollinator or flower). Flowering plants were surveyed in quadrats of 1 m^2 along the same transects. Three sampling rounds were conducted in 2020 (the first in April, the second in May/June, and the third in July). Please see the methods section in the published manuscript for details about the sampling procedure., , # Landscape simplification leads to loss of plant-pollinator interaction diversity and flower visitation frequency despite buffering by abundant generalist pollinators

[https://doi.org/10.5061/dryad.1zcrjdg0b](https://doi.org/10.5061/dryad.1zcrjdg0b)

## Description of the data and file structure

The Data.zip folder contains three CSV files:

### LandscapeData.csv

Data on landscape-scale arable crop cover per landscape was calculated using the R package *landscapemetrics* (Hesselbarth, 2019).

* \[Site] = ID of the study landscape
* \[arable_PLAND_1000] = Arable crop cover (%) was measured in a 1000 m radius around the center of the study landscapes
* \[arable_PLAND_500] = Arable crop cover (%) was measured in a 500 m radius around the center of the study landscapes
* \[Country] = Country where the landscapes were located (CH = Switzerland; FR = France; GE = Germany)

### InteractionData.csv

Plant-pollinator interactions from transect data of the 24 landscapes (n=8 per coun...