Bee-plant interactions and network structure across land cover types in New Zealand

Land cover change and biological invasions alter pollinator communities and the distribution of floral resources, but how these changes influence specific bee–plant interactions across different landscapes and time often remains unclear. We reconstructed bee–plant interaction networks from New Zealand using 2,266 interactions extracted from digitised natural history collections and compared interaction patterns between land cover dominated by native or exotic vegetation. Native bees accounted for most recorded interactions across all land cover types. Bee and plant biostatus showed strong non-random associations, with native bees interacting mainly with native plants and exotic bees interacting more frequently with exotic plants. Network-level specialisation was moderate and varied little among land cover types (H2′ = 0.63–0.68), although species-level specialisation differed substantially among bee species. Preference indices showed that most native bee species exhibited neutral or negative preferences for exotic plants, whereas several exotic bee species preferentially visited exotic plants. Temporal analyses further showed that native bees increasingly incorporated exotic plants into their interactions through time, while exotic bees showed increased use of native plants. Our results suggest that changes to land cover influences bee–plant interaction patterns while native and exotic bees differ in their use of floral resources.