- The characteristics of communities are determined by dispersal processes that are driven by landscape structure and species characteristics (traits). Understanding these processes requires a better assessment of the spatial scales that matter to species, based on their traits. This can be particularly addressed in an urban context where habitats are highly fragmented.
- We assessed the effects of urbanisation intensity on Orthoptera at different spatial scales and focused on two species traits: dispersal ability and habitat specialisation.
- We recorded Tettiigonidae sounds from running trains along 209 km of five railway lines. As an urbanisation measure, the percentage of impervious surfaces around the railway edges was calculated at 11 spatial scales around the railways. We then tested the effect of urbanisation on species richness, abundance, and traits and determined at which spatial scale the relationship was strongest.
- Urbanisation had a negative effect on total species richness, abundance and community specialisation. This pattern was stronger at larger spatial scales, and the results differed according to the species' functional traits: mobile species were more sensitive to urbanisation at larger scales than sedentary species, and no scale effect on specialisation was detected.
- We conclude that insects may respond to landscapes over a broad set of spatial scales and that considering their specific traits is essential in spatial scales studies. Finally, we argue that railway edges can play a role in insect conservation in urban landscapes.