Chapter 02 · Nature, land & waterBiodiversity & Nature
Biotic homogenization
Definition
The process by which the species composition of different ecosystems or regions becomes more similar over time, as locally adapted specialist species are lost and generalist species with wide distributions spread. It can occur at local, regional or global scales, and at species, genetic or functional levels; the main drivers are extinction of native species and invasion by non-native species, under pressures such as habitat loss and climate change.
References
Definition (Clavel et al. 2010 lineage); specialist-to-generalist replacement; drivers (extinctions, invasions, habitat loss, climate); species/genetic/functional levels.
Overview
What it means
Homogenization is a dimension of the biodiversity crisis that species counts miss: a landscape can hold steady or even gain species while losing distinctiveness, as the same suite of cosmopolitan species replaces unique local assemblages everywhere. It is measured as declining beta diversity — the turnover component linking local (alpha) and regional (gamma) diversity.
Notably, it can also result from climate-driven range shifts, for example southern species replacing alpine specialists.
How it is used
Ecologists track homogenization through temporal beta-diversity trends; conservation planners use it to argue for protecting complementary, distinctive sites rather than simply the richest ones. It also frames concern about invasive species and urban biotas.
Why it matters
Homogenization degrades the resilience encoded in regional diversity: as ecosystems converge on the same generalist species, they lose functional variety and the capacity to respond to further change.