Based loosely on work from @Thompson2017Dispersal.
Empirical networks were constructed from the interactions recorded by @Kopelke2017Foodweb. This dataset consists of replicate samples of Salix (willow species) -- willow-galling sawfly -- predator interactions across Europe. Data collection spanned 29 years across 641 sites (some with repeat visits) revealing 1 173 links across sites and trophic levels. Sites spanned a large latitudinal (in the context of continental Europe) from Italy (39.00$/deg$ N) to Norway (70.78$/deg$ N). Making this a good dataset to interrogate regarding the aim of this paper owing to the large environmental gradient.