Ecological communities typically contain more species when located within geologically older regions. This pattern is traditionally attributed to the long‐term accumulation of species in the regional species pool, with local species interactions playing a minor role. We provide evidence suggesting a more important role of local species interactions than generally assumed. We assembled 320 communities of root‐associated fungi under 80 species pools, varying species pool richness and the mean age of the sites from which the fungi were collected across a 4‐myr soil chronosequence. We found that local diversity increased more with increasing species pool richness when species were from older sites. We also found that older species pools had lower functional and phylogenetic diversity, indicating greater competitive equivalence among species. Our results suggest that older regions have higher local richness not simply because older pools are more speciose but also because species have evolved traits that allow them to locally co‐occur.

中文翻译：

---

竞争对等性的提高可能会导致较旧物种库下更大的本地多样性

当位于地质较旧的区域内时，生态群落通常包含更多物种。传统上，这种模式归因于区域物种库中物种的长期积累，而局部物种之间的相互作用起着较小的作用。我们提供的证据表明，本地物种相互作用的作用比一般假设的更为重要。我们在80种物种库中组装了320个与根相关的真菌群落，不同物种库的丰富度以及在4密尔土壤时间序列中收集真菌的位点的平均年龄。我们发现，当物种来自较旧的地点时，物种多样性随着物种库丰富度的增加而增加。我们还发现，较旧的物种库具有较低的功能和系统发育多样性，表明物种之间具有更大的竞争性。