The ability of climatic niche models to predict species extinction risks can be hampered if niches are incompletely quantified. This can occur when niches are estimated considering only currently available climatic conditions, disregarding the fact that climate change can open up portions of the fundamental niche that are currently inaccessible to species. Using a new metric, we estimate the prevalence of potential situations of fundamental niche truncation by measuring whether current ecological niche limits are contiguous to the boundaries of currently available climatic conditions for 24,944 species at the global scale in both terrestrial and marine realms and including animals and plants. We show that 12,172 (~49%) species are showing niche contiguity, particularly those inhabiting tropical ecosystems and the marine realm. Using niche expansion scenarios, we find that 86% of species showing niche contiguity could have a fundamental niche potentially expanding beyond current climatic limits, resulting in lower—yet still alarming—rates of predicted biodiversity loss, particularly within the tropics. Caution is therefore advised when forecasting future distributions of species presenting niche contiguity, particularly towards climatic limits that are predicted to expand in the future.

如果生态位未完全量化，气候生态位模型预测物种灭绝风险的能力可能会受到阻碍。当仅考虑当前可用的气候条件来估计生态位时，就会发生这种情况，而忽略了气候变化可能会开放物种目前无法进入的部分基本生态位的事实。使用新的指标，我们通过测量当前的生态位限制是否与全球范围内陆地和海洋领域（包括动物和海洋生物）24,944个物种的当前可用气候条件的边界相邻，来估计基本生态位截断潜在情况的普遍程度。植物。我们发现 12,172 个（约 49%）物种表现出生态位连续性，特别是那些栖息在热带生态系统和海洋领域的物种。利用生态位扩展情景，我们发现 86% 表现出生态位连续性的物种可能拥有一个基本生态位，可能会扩展到超出当前的气候限制，从而导致预测的生物多样性丧失速度较低（但仍然令人震惊），特别是在热带地区。因此，在预测具有生态位连续性的物种的未来分布时，特别是针对预计未来扩大的气候限制时，应谨慎行事。