Neutral theory exposes the challenge of bending the curve of
biodiversity loss for the post-2020 Global Biodiversity Framework
Abstract
In May, nations of the world will meet to negotiate the post-2020 Global
Biodiversity Framework under the Convention on Biological Diversity. An
influential ambition is “bending the curve of biodiversity loss”,
which aims to reverse the decline of global biodiversity indicators. A
second relevant, yet less prominent, milestone is the 20th anniversary
of the publication of The Unified Neutral Theory of Biodiversity and
Biogeography. Here, I apply neutral theory to show how global
biodiversity indicators for population size (Living Planet Index) and
extinction threat (Red List Index) decline under neutral ecological
drift. This demonstrates that declining indicators alone do not
necessarily reflect deterministic species-specific or geographical
patterns of biodiversity loss. Thus, “bending the curve” could be
assessed relative to a counterfactual based on neutral theory, rather
than static baselines. If used correctly, the 20-year legacy of neutral
theory can be extended to make a valuable contribution to the post-2020
Global Biodiversity Framework