Dataset for: Asymmetric response of aboveground and belowground temporal stability to nitrogen and phosphorus addition in a Tibetan alpine grassland

Anthropogenic eutrophication is known to impair the stability of
aboveground net primary productivity (ANPP), but its effects on the
stability of belowground (BNPP) and total (TNPP) net primary productivity
remain poorly understood. Based on a nitrogen and phosphorus addition
experiment in a Tibetan alpine grassland, we show that nitrogen addition
had little impact on the temporal stability of ANPP, BNPP and TNPP,
whereas phosphorus addition reduced the temporal stability of BNPP and
TNPP, but not ANPP. Significant interactive effects of nitrogen and
phosphorus addition were observed on the stability of ANPP because of the
opposite phosphorus effects under ambient and enriched nitrogen
conditions. We found that the stability of TNPP was primarily driven by
that of BNPP rather than that of ANPP. The responses of BNPP stability
cannot be predicted by those of ANPP stability, as the variations in
responses of ANPP and BNPP to enriched nutrients, with ANPP increased
while BNPP remained unaffected, resulted in asymmetric responses in their
stability. The dynamics of grasses, the most abundant plant functional
group, instead of community species diversity, largely contributed to the
ANPP stability. Under the enriched nutrient condition, the
synchronization of grasses reduced the grass stability, while the latter
had a significant but weak negative impact on the BNPP stability. These
findings challenge the prevalent view that species diversity regulates the
responses of ecosystem stability to nutrient enrichment. Our findings also
suggest that the ecological consequences of nutrient enrichment on
ecosystem stability cannot be accurately predicted from the responses of
aboveground components, and highlight the need for a better understanding
of the belowground ecosystem dynamics.