Climate warming in an alpine meadow: differential responses of soil faunal vs. microbial effects on litter decomposition

We investigated the effects of warming on litter decomposition and the contribution of soil organisms (microbes vs. fauna) to it across the cold and warm seasons in an alpine meadow of the Qinghai-Tibetan Plateau. Our results showed that (1) warming profoundly increased litter decomposition by ~ 35%, but this warming effect only occurred in coarse-meshed bags (i.e., in the presence of soil fauna) and in warm season; (2) litter decomposition significantly increased by ~ 2.3-fold from fine- to coarse-meshed bags. However, such a mesh effect was only detected in warm (but not cold) season; (3) litter decomposed ~ 6.7 times faster in warm season than in cold season, and this seasonal effect was consistent across ambient and warming climates. Collectively, warm season may greatly promote the role of both fauna and microbes in litter decomposition and determine the amount of annual decomposition. Nevertheless, climate warming may only profoundly stimulate faunal (but not microbial) decomposition, especially during warm season of the alpine meadow.