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<p>Clade extinction is a crucial process that contributes to the loss of evolutionary history. The extinction of abundant and diverse clades has been linked to a range of abiotic and biotic factors, but their relative contributions and importance remain debated. Here, by analysing the fossil record of 12 major extinct marine clades, we show a consistent extinction trajectory comprising two phases: a slow, age-dependent decline followed by a fast, environment-triggered wipe-out. In the first phase, the clade proportional diversity (the diversity of a clade relative to the combined diversity of its ecologically similar taxa) steadily declined, largely independent of environmental factors such as temperature, dissolved oxygen, sea level and carbon-cycle variations, and instead reflecting biotic drivers such as competition and niche contraction. Once proportional diversity fell below a critical threshold (mean of approximately 0.13), major abiotic perturbations acted as the ‘last straw’, causing the clade extinction. Simulation and analytical models corroborate this pattern, showing near-zero extinction risk at high proportional diversity, but a steep risk rise once thresholds are crossed owing to reduced ecological dominance and narrowed functional roles. These findings reveal additive effects of biotic–abiotic factors in driving clade extinction, providing a predictive hypothesis for assessing future extinction risk among modern clades.</p>

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Identifying biotic and abiotic roles in marine clade extinction

  • 期刊论文

  • 发表日期：

    2026年7月27日

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  • Haijun Song,
  • Xiaokang Liu,
  • Jacopo Dal Corso,
  • Daoliang Chu,
  • Xu Dai,
  • Li Tian,
  • Huyue Song,
  • Yuyang Wu,
  • Fengyu Wang,
  • Daniele Silvestro

摘要

Clade extinction is a crucial process that contributes to the loss of evolutionary history. The extinction of abundant and diverse clades has been linked to a range of abiotic and biotic factors, but their relative contributions and importance remain debated. Here, by analysing the fossil record of 12 major extinct marine clades, we show a consistent extinction trajectory comprising two phases: a slow, age-dependent decline followed by a fast, environment-triggered wipe-out. In the first phase, the clade proportional diversity (the diversity of a clade relative to the combined diversity of its ecologically similar taxa) steadily declined, largely independent of environmental factors such as temperature, dissolved oxygen, sea level and carbon-cycle variations, and instead reflecting biotic drivers such as competition and niche contraction. Once proportional diversity fell below a critical threshold (mean of approximately 0.13), major abiotic perturbations acted as the ‘last straw’, causing the clade extinction. Simulation and analytical models corroborate this pattern, showing near-zero extinction risk at high proportional diversity, but a steep risk rise once thresholds are crossed owing to reduced ecological dominance and narrowed functional roles. These findings reveal additive effects of biotic–abiotic factors in driving clade extinction, providing a predictive hypothesis for assessing future extinction risk among modern clades.