A plea for scale, and why it matters for invasive species management, biodiversity, and conservation

Invasive species are suspected to be major contributors to biodiversity declines worldwide. Counterintuitively, however, invasive species effects are likely scale-dependent, and are hypothesized to be positively related to biodiversity at large spatial scales. Past studies investigating the effect of invasion on biodiversity have been mostly conducted at small scales (<100 m2) that cannot represent large-dynamic landscapes by design. Therefore, replicated experimental evidence supporting a negative effect of invasive plants on biodiversity is lacking across many landscape types, including large grasslands. We collected data across eight large (333–809 ha) grassland landscapes managed with pyric herbivory—i.e., the recoupling of fire and grazing—to test how an invasive legume (Lespedeza cuneata) affected plant and bird communities at spatial grains ranging from 0.1 m2 to >3,000,000 m2. L. cuneata invasion effects on grassland plant diversity and composition changed with scale; be..., ,