Anthropocene Drivers of Biodiversity Decline

Abstract

Anthropocene biodiversity decline is driven by five primary threat categories -- habitat loss and degradation, overexploitation, invasive alien species, pollution, and climate change -- whose relative importance varies by taxonomic group, geographic region, and ecosystem type, and whose interactions create compound threat synergies that are more damaging than any single driver alone. The IPBES Global Assessment (2019) ranked these drivers by their contribution to biodiversity loss, with habitat change leading for terrestrial and freshwater systems and direct exploitation leading for marine systems -- but the quantitative basis for this ranking was acknowledged to be limited by data availability rather than confirmed by systematic analysis. This study provides the most rigorous quantitative multi-driver analysis yet conducted, using a novel threat attribution framework applied to 8,470 species population trend datasets from 247 monitoring programmes across 84 countries, partitioning population trend variance across the five IPBES threat categories with and without interaction terms. Habitat loss and degradation dominated overall (partial R2 = 0.38 of population decline variance) followed by overexploitation (R2 = 0.24) and invasive species (R2 = 0.18). Driver interactions -- particularly habitat loss + climate change and overexploitation + invasive species -- explained an additional 0.14 of variance as synergistic effects beyond the additive expectation. Climate change emerged as the fastest-growing driver (trend coefficient most steeply negative 2000-2022) despite currently the lowest absolute explained variance - projecting to become the dominant driver by 2050 under business-as-usual scenarios.