School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Ecol Lett. 2019 Apr;22(4):563-571. doi: 10.1111/ele.13212. Epub 2019 Jan 10.
While nitrogen (N) amendment is known to affect the stability of ecological communities, whether this effect is scale-dependent remains an open question. By conducting a field experiment in a temperate grassland, we found that both plant richness and temporal stability of community biomass increased with spatial scale, but N enrichment reduced richness and stability at the two scales considered. Reduced local-scale stability under N enrichment arose from N-induced reduction in population stability, which was partly attributable to the decline in local species richness, as well as reduction in asynchronous local population dynamics across species. Importantly, N enrichment did not alter spatial asynchrony among local communities, which provided similar spatial insurance effects at the larger scale, regardless of N enrichment levels. These results suggest that spatial variability among local communities, in addition to local diversity, may help stabilise ecosystems at larger spatial scales even in the face of anthropogenic environmental changes.
虽然氮（N）添加已知会影响生态群落的稳定性，但这种影响是否具有尺度依赖性仍是一个悬而未决的问题。通过在温带草原进行实地实验，我们发现植物丰富度和群落生物量的时间稳定性均随空间尺度的增加而增加，但 N 富集在考虑的两个尺度上均降低了丰富度和稳定性。N 富集下的局部稳定性降低源于 N 诱导的种群稳定性降低，这部分归因于局部物种丰富度下降，以及种间局部种群动态的不同步减少。重要的是，N 富集并未改变局部群落之间的空间不同步性，这在更大的尺度上提供了相似的空间保险效应，而与 N 富集水平无关。这些结果表明，即使面对人为的环境变化，局部群落之间的空间变异性（除了局部多样性之外）也可能有助于在更大的空间尺度上稳定生态系统。
