Worldwide decline of specialist species
Frontiers in ecology and the environment 9(4)
Specialization is a concept based on a broad theoretical framework developed by evolutionary biologistsand ecologists. In the past 10 years, numerous studies have reported that – in many contexts – generalistspecies are "replacing" specialist species. We review recent research on the concept of the ecological nicheand species specialization, and conclude that the observed worldwide decline in specialist species is pre-dicted by niche theory, specialist declines cause "functional homogenization" of biodiversity, and such homogenization may be used to measure the impact of disturbance on communities. Homogenizationat the community level could alter ecosystem functioning and productivity, as well as result in the deterio-ration of ecosystem goods and services. We propose community-level specialization as an indicator of theimpact of global changes (habitat and climate disturbances) on biodiversity.