The extinction of species can destabilize ecological processes. A way to assess the ecological consequences of species loss is by examining changes in functional diversity. The preservation of functional diversity depends on the range of ecological roles performed by species, or functional richness, and the number of species per role, or functional redundancy. However, current knowledge is based on short timescales and an understanding of how functional diversity responds to long-term biodiversity dynamics has been limited by the availability of deep-time, trait-based data. Here, we compile an exceptional trait dataset of fossil molluscs from a 23-million-year interval in the Caribbean Sea (34 011 records, 4422 species) and develop a novel Bayesian model of multi-trait-dependent diversification to reconstruct mollusc (i) diversity dynamics, (ii) changes in functional diversity, and (iii) extinction selectivity over the last 23 Myr. Our results identify high diversification between 23–5 Mya, leading to increases in both functional richness and redundancy. Conversely, over the last three million years, a period of high extinction rates resulted in the loss of 49% of species but only 3% of functional richness. Extinction rates were significantly higher in small, functionally redundant species suggesting that competition mediated the response of species to environmental change. Taken together, our results identify long-term diversification and selective extinction against redundant species that allowed functional diversity to grow over time, ultimately buffering the ecological functions of biological communities against extinction.

中文翻译：

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针对冗余物种的选择性灭绝缓冲了功能多样性


物种灭绝会破坏生态过程的稳定。评估物种丧失的生态后果的一种方法是检查功能多样性的变化。功能多样性的保存取决于物种所发挥的生态作用的范围，或功能丰富度，以及每种作用的物种数量，或功能冗余。然而，当前的知识是基于较短的时间尺度，并且对功能多样性如何响应长期生物多样性动态的理解受到深度、基于性状的数据的可用性的限制。在这里，我们编制了加勒比海 2300 万年间隔的软体动物化石特征数据集（34 011 条记录，4422 个物种），并开发了一种新颖的多特征依赖多样化贝叶斯模型来重建软体动物 (i)多样性动态，(ii) 功能多样性的变化，以及 (iii) 过去 23 Myr 的灭绝选择性。我们的结果发现 23-5 Mya 之间存在高度多样化，从而导致功能丰富度和冗余度的增加。相反，在过去 300 万年里，一段高灭绝率时期导致 49% 的物种消失，但功能丰富度仅下降 3%。功能冗余的小型物种的灭绝率明显更高，这表明竞争介导了物种对环境变化的反应。总而言之，我们的结果确定了针对冗余物种的长期多样化和选择性灭绝，使得功能多样性随着时间的推移而增长，最终缓冲生物群落的生态功能免遭灭绝。