Data from: Foliar fungal pathogen inhibition increases ecosystem carbon sequestration independently of nitrogen enrichment in a Tibetan alpine meadow

Anthropogenically caused nitrogen (N) enrichment may stimulate both
photosynthetic carbon (C) fixation and infection of foliar pathogens.
However, the interactive effects of N input and foliar fungal pathogens on
the ecosystem C cycling are poorly understood. Using a 6-year field
experiment with N input and fungicide application in a Tibetan alpine
meadow, we examined how N enrichment and foliar fungal pathogens influence
ecosystem C sequestration independently and in combination, possibly
resulting in interactions between N enrichment and fungal pathogens.
Nitrogen input increased the gross ecosystem productivity (GEP) and
ecosystem respiration (ER) through increasing plant biomass and foliar N
content, but did not affect net ecosystem productivity (NEP). Fungicide
application increased GEP and NEP by relieving foliar pathogen infection
but did not affect ER, resulting in net increased ecosystem C
sequestration. However, no significant interactive effects between N input
and fungicide application were detected. Synthesis. These results indicate
that foliar fungal pathogens are critical biotic factors influencing
ecosystem C sequestration in alpine ecosystems, independent of N input.
This study emphasizes the important role of biotic factors in regulating
ecosystem functions.

人为氮（N）富集可同时促进光合碳（C）固定与叶部病原菌侵染。然而，氮输入与叶部真菌病原菌（foliar fungal pathogens）对生态系统碳循环的交互效应尚未得到充分阐明。本研究于青藏高原高寒草甸开展了为期6年的野外控制实验，设置氮输入与杀菌剂施用处理，以此探究氮富集与叶部真菌病原菌单独及联合作用对生态系统碳固存的影响，并验证二者间是否存在交互效应。
氮输入通过提升植物生物量与叶部氮含量，提高了总生态系统生产力（gross ecosystem productivity, GEP）与生态系统呼吸（ecosystem respiration, ER），但未显著改变净生态系统生产力（net ecosystem productivity, NEP）。杀菌剂施用通过缓解叶部病原菌侵染，提升了总生态系统生产力（GEP）与净生态系统生产力（NEP），但未对生态系统呼吸（ER）产生影响，最终使生态系统碳固存水平显著提升。然而，本研究未检测到氮输入与杀菌剂施用间存在显著交互效应。
综合分析结果表明，叶部真菌病原菌是高寒生态系统中调控生态系统碳固存的关键生物因子，且该效应不受氮输入水平的影响。本研究强调了生物因子在生态系统功能调控中的重要作用。