Interactions outside local patches contribute to the compound topology of plant-pollinator networks in fragmented dune slacks

Plants and pollinators engage in ephemeral interactions that are essential for both plant reproduction and pollinator fitness. Most plant species interact with multiple pollinator species and, similarly, most pollinators visit multiple plant species, leading to complex networks of interactions. A better understanding of the factors that affect the structure of these networks is crucial for effective biodiversity conservation. While previous research has shown significant negative impacts of habitat fragmentation on plant and pollinator diversity, far less is known about how habitat fragmentation contributes to the overall network structure. In this study, we used DNA metabarcoding to construct pollen transport networks across nineteen dune slacks along a fragmentation gradient at the Belgian coast. For each network, we investigated the impact of patch area, connectivity, and floral diversity on network size, connectance, nestedness and modularity. We found a total of 3222 unique pairwis..., Data collection
Pollinators were collected during the summer of 2021 in two sampling periods: 24 June – 9 July and 2 – 13 August. These periods were chosen to coincide with the two main flowering peaks in the study area. Each of the nineteen dune slacks (Fig. S1) was sampled once during each period. Sampling took place between 10:00 and 17:00 under sunny weather conditions, with air temperature above 16°C, wind speeds below 3 Bft, and cloud cover below 90%, using manual netting, with two persons actively walking through the entire dune slacks for two hours. Every insect species that was observed foraging on flowers was considered a pollinator. In total 3307 pollinators were collected. After capturing, pollinators were immediately placed in individual tubes, filled with 100% ethanol to kill and preserve them. Whenever possible, pollinators were identified to species level using sequential identification keys. If species identification was not possible, individuals were assigned to the hi..., , # Interactions outside local patches contribute to the compound topology of plant-pollinator networks in fragmented dune slacks

[https://doi.org/10.5061/dryad.sj3tx96dp](https://doi.org/10.5061/dryad.sj3tx96dp)

## Description of the data and file structure

**Interactions outside local patches preserve compound topology of plant-pollinator networks in fragmented dune slacks**

In this study, we used DNA metabarcoding to construct pollen transport networks across nineteen dune slacks along a fragmentation gradient at the Belgian coast and  investigated the impact of patch area, connectivity, and floral diversity on network size, connectance, specialization, nestedness and modularity. Networks showed a low degree of specialization and none of them were significantly nested, while most were significantly modular with a hierarchical compound structure. Importantly, no significant relationships were found between network measures and patch area or connectivity, indicating that local patch ...,