Pteridium aquilinum
Vacant niches can best be demonstrated by considering the spatial component of niches in simple habitats. For example, Lawton and collaborators compared the insect fauna of the bracken "Pteridium aquilinum", a widely distributed species, in different habitats and geographical regions and found vastly differing numbers of insect species. They concluded that many niches remain vacant (e.g., Lawton 1984).