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

Despite extensive research, the mechanisms stabilizing ecosystems remain
uncertain. Taylor’s Power Law (TPL), which describes how variance scales
with mean abundance (σ² = aμᵇ), is a pervasive ecological pattern. While
TPL has been widely examined within populations, its role across species
within communities and its implications for stability remain largely
unexplored. A TPL scaling exponent (b) < 2 implies a stabilizing
influence of dominant species—hereafter referred to as the dominance
effect—where community stability emerges because dominant species are
relatively more stable than subordinate species. Using data from over
9,000 permanent vegetation plots worldwide, we quantified within-community
TPL, linked variation in the exponent b to dominance effects on temporal
stability, and identified the biotic and abiotic drivers shaping b. We
found a ubiquitous within-community TPL (mode R² = 0.92) with consistently
b < 2, indicating widespread dominance effects. Variation in b,
together with species evenness, strongly contributed to dominance-driven
stability. Lower b values were associated with resource-conservative
strategies and greater climatic seasonality, highlighting the role of
environmental filtering in shaping community stability. Overall, these
results demonstrate that dominance effects on temporal stability are
widespread, particularly in communities dominated by woody, large-seeded
species in cold and seasonal climates, and identify the TPL exponent b as
a powerful indicator of the stabilizing role of dominant species,
complementing the well-established effects of species diversity.