Ambient climate determines the directional trend of community stability under warming and grazing

Abstract

Changes in ecological processes over time in ambient treatments are often larger than the responses to manipulative treatments in climate change experiments. However, the impacts of human-driven environmental changes on the stability of natural grasslands have been typically assessed by comparing differences between manipulative plots and reference plots. Little is known about whether or how ambient climate regulates the effects of manipulative treatments and their underlying mechanisms. We collected two datasets, one a 36-year long-term observational dataset from 1983 to 2018, and the other a 10-year manipulative asymmetric warming and grazing | 5199 LIU et aL.

Ambient precipitation determines the sensitivity of soil respiration to precipitation treatments in a marsh

“…Our results showed clear evidence that ambient precipitation determines the sensitivity of SR to precipitation treatments in the marsh, which might have strong implications for long-term field manipulation experiments under intensified ambient climate (Dangal et al, 2017;Korth et al, 2015). The importance of ambient climate in long-term field manipulation experiments highlighted by our study was consistent with the conclusions of previous studies that ambient climate plays a crucial role in regulating ecosystem functions (community stability and ecosystem carbon cycle; Chen et al, 2017;Jung et al, 2019;Liu et al, 2021). For instance, field warming experiments not only underpredict plant phenological responses to climate change (Wolkovich et al, 2012), but also shows similar but faster changes in vegetation community composition compared to that in ambient plots (Harte et al, 2015).…”

“…The impacts of climate changes on ecosystem carbon cycling have been extensively studied through field observations and manipulation experiments (Chen et al, 2019;Han et al, 2018;Li, Zhou, et al, 2020;Liu et al, 2021;Wang et al, 2021;Zou et al, 2018). Relative to observations, manipulative experiments are very powerful in enabling replication, controlling confounding factors, and studying multiple scenarios simultaneously (Beier et al, 2012;Langley et al, 2018).…”

“…However, the intensified climate changes amplify the intra and interannual variability in ambient climate, and the experiment's effects on ecosystem dynamics may be profoundly altered by ambient climate as the experimental duration increases (Langley et al, 2018;Montgomery et al, 2020;Wang et al, 2021). For instance, ambient climate determines the directional trend of alpine meadow aboveground net primary productivity under the 10-year warming and grazing treatments (Liu et al, 2021).…”

“…However, previous field precipitation manipulation experiments ignored the above-mentioned interannual variability in ambient precipitation, the sensitivity of SR to precipitation changes that registered only as a deviation from untreated controls (Du et al, 2020;Liu et al, 2016;. As a consequence, the findings based on the above process may potentially pose a challenge to providing accurate information for ecosystem models (Beier et al, 2012;Liu et al, 2021).…”

Increased frequency of extreme climatic events weakens the community stability of natural grassland under directional climate changes by reducing resilience

“…This limits its utility in tracking the independent and co‐occurring effects of chronic directional climate changes and the increased frequency of discrete ECEs on ANPP stability. We therefore resampled ANPP data using nested windows to create newly produced datasets consisting of a series of consecutive years from 3 years to the longest duration for each study (Liu et al., 2021). The frequencies of ECEs were derived from the counted years of ECEs (i.e.…”