Reduced predation pressure as a potential driver of prey diversity and abundance in complex habitats.

Habitat complexity is positively associated with biodiversity and abundance and is often a focus of habitat restoration programmes, however, the mechanisms underlying these relationships are not yet resolved. In this Perspective, we postulate that reduced predation pressure in complex habitats could contribute to increased prey diversity and abundance. Based on a systematic review and meta-analysis of experimental studies, reduced predation pressure in complex habitats is consistent across freshwater and marine ecosystems, field and laboratory experiments, different hunting modes of predators, and different numbers of prey species. However, the effects are less clear in terrestrial ecosystems. Easing predation pressure, in conjunction with increased resources for prey, could help explain the high biodiversity and abundance found in complex habitats. This knowledge can be used in restoration and ecological engineering projects to maximise species diversity and abundance gains.