The niche dimension hypothesis predicts that more species can coexist given a greater number of niche axes along which they partition the environment. Although this hypothesis has been broadly supported by nutrient enrichment experiments, its applicability to other ecological factors, such as natural enemies and abiotic stresses, has not been vigorously tested. Here, we examined the generality of the niche dimension hypothesis by experimentally manipulating both resource and non-resource niche dimensions—nitrogen limitation, pathogens and low-temperature stress—in a Tibetan alpine meadow. We found that decreases in niche dimensions led to a significant reduction in species richness, consistent with results from nutrient addition studies. However, different niche variables uniquely affected the plant communities. While nitrogen had largest effects on both community biomass and species richness, pathogens and low-temperature stress, in combination with nitrogen, had synergistic effects on them. Our results provide direct evidence demonstrating that both resource and non-resource niche dimensions can influence species coexistence. These findings suggest that other non-resource factors need to be taken into consideration to better predict the community assembly and control over biodiversity, particularly under the future multifaceted global change scenarios.

生态位维假说预测，在分配更多生态位轴的环境中，更多物种可以共存。尽管这一假设已得到营养富集实验的广泛支持，但尚未严格测试其对其他生态因素（如天敌和非生物胁迫）的适用性。在这里，我们通过实验性地操纵藏高寒草甸的资源和非资源生态位维度（氮限制，病原体和低温胁迫），研究了生态位维度假设的一般性。我们发现，生态位尺寸的减小导致物种丰富度的显着降低，这与营养添加研究的结果一致。但是，不同的利基变量独特地影响植物群落。氮对群落生物量和物种丰富度的影响最大，而病原体和低温胁迫与氮结合对它们具有协同作用。我们的结果提供了直接的证据，表明资源和非资源生态位都可以影响物种共存。这些发现表明，还需要考虑其他非资源因素，以更好地预测社区对生物多样性的聚集和控制，尤其是在未来多方面的全球变化情况下。