Anthropogenic disruptions to longstanding patterns of trophic-size structure in vertebrates

• Diet and body mass are inextricably linked in vertebrates: while herbivores and carnivores have converged on much larger sizes, invertivores and omnivores are, on average, much smaller, leading to a roughly U-shaped relationship between body size and trophic guild. Although this U-shaped trophic-size structure is well documented in extant terrestrial mammals, whether this pattern manifests across diverse vertebrate clades and biomes is unknown. Moreover, emergence of the U-shape over geological time and future persistence are unknown. Here we compiled a comprehensive dataset of diet and body size spanning several vertebrate classes and show that the U-shaped pattern is taxonomically and biogeographically universal in modern vertebrate groups, except for marine mammals and seabirds. We further found that, for terrestrial mammals, this U-shape emerged by the Palaeocene and has thus persisted for at least 66 million years. Yet disruption of this fundamental trophic-size structure in mammals appears likely in the next century, based on projected extinctions. Actions to prevent declines in the largest animals will sustain the functioning of Earth's wild ecosystems and biomass energy distributions that have persisted through deep time. Analysis of diet and body size in terrestrial and aquatic vertebrates shows that a U-shaped relationship between body size and trophic guild prevails across extant vertebrates with the exception of marine mammals and seabirds. Analysis of fossil data shows that, for terrestrial mammals, this pattern has persisted for at least 66 million years, despite anthropogenic perturbance, which may have greater effects in the next centuries.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

Nyckelord

mammalian body-size

functional redundancy

ecosystem function

fossil

record

evolution

extinctions

diet

life

mass

constraints

Environmental Sciences & Ecology

Evolutionary Biology

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