A globally consistent scaling relationship reveals stabilizing effects of dominant species in plant communities

Despite extensive research, stabilizing mechanisms in ecosystems remain uncertain. Taylor's power law (TPL) is a pervasive ecological pattern that describes how variance scales with mean abundance (σ2 = aμᵇ). While TPL has been widely studied within populations, its role across species within communities and its implications for stability remain largely unexplored. A TPL scaling factor (b) < 2 implies an unexplored stabilizing effect of dominant species (hereafter the ‘dominance effect'), where community stability arises from dominant species being relatively more stable than subordinates. This study aims to explore the influence of TPL exponent b on the dominance effect on stability and identify the biotic and abiotic community factors shaping it. Using data from over 9000 permanent vegetation plots globally, we investigated within-community TPL, linked it to the dominance effect, and examined drivers of b values. Results reveal a strong contribution of b, together with species evenness, to dominance effects on stability. A ubiquitous TPL (mode R2 = 0.92) with a consistent b < 2 highlights widespread dominance effects. Lower b values were linked to resource-conservative strategies and climatic seasonality, reinforcing the role of environmental filtering in stability. These findings highlight the widespread dominance effect on community temporal stability, particularly driven by woody, large-seeded species in cold, seasonal climates. Moreover, results identify the TPL exponent b as a powerful indicator of dominant species' stabilizing effects, complementing the well-known role of species diversity.