Context The effects of landscape structure on biodiversity may change with the spatial and temporal scale at which landscape structure is measured. Identifying the spatial extent and temporal scale at which the biodiversity-landscape relationship is strongest (i.e., the scale of effect) is important to better understand the effect of landscape structure.
Objectives The spatial and temporal scale of effect is analyzed to identify whether it differs in ecologically distinct species groups. How species richness-landscape relationship changes with spatial and temporal scales is tested.
Methods Based on 98 survey plots (1 km²) of vascular plants on the Swiss Plateau, we analyzed the relationships between species richness of different species groups and landscape predictors at different spatial extents (1 km², 4 km², 16 km², 36 km²) and time periods (past landscapes - 1985, 1997, 2009 and the current landscape 2018).
Results The spatial scale of effect was 1 km for most species groups, while the temporal scale of effect differed among species groups. The strength of the species richness-landscape relationship generally decreased with increased spatial extents, while it changed little across temporal scales.
Conclusions Although our study only considered changes in landscape structure over the last c. 30 years, ecologically distinct species groups revealed differences in the temporal scale of effect including a rapid response of neophytes linked to ongoing biological invasions. However, the variation in the species richness-landscape relationship was greater when changing spatial extent than time. We highlight that studying the relationship between landscape structure and biodiversity should consider not only space but also time, and different responses of ecologically distinct species groups.