Ants play multiple roles in ecosystems, but their ability to affect decomposition processes in temperate grasslands is relatively unknown. We investigated whether the suppression of ant populations influenced litter decomposition in grasslands via predation of some decomposers (e.g., mites and springtails) and/or microbial activity and composition. We performed two successful ant suppression treatments (seven weeks, 37% suppression, year 1, 10 weeks, 70% suppression, year 2) over the course of a 59-week experiment. We then assayed the effects of ant suppression using coarse- and fine-mesh litterbags and evaluated litter chemistry, microbial and arthropod communities, and microbial enzyme activity. Ant suppression efforts reduced ant abundance and altered ant, arthropod decomposer, and non-ant predator community composition. However, ant suppression did not affect decomposer arthropod abundance, litter mass loss, microbial composition, or enzyme activity in litterbags. Litterbag mesh size did not alter microbial composition, perhaps due to a failure to exclude decomposers, as mites and springtails were more or equally abundant in fine-mesh bags. Nevertheless, mesh size did change litter chemistry, suggesting that mesh size-mediated microenvironments affect decomposition environment regardless of invertebrate exclusion. Coarse-mesh litterbags had higher concentrations of microbial sugars, lignin, and N and lower concentrations of litter C and crystalline cellulose than fine-mesh litterbags. Litterbag mesh size may alter decomposition processes irrespective of invertebrate abundance. We found no evidence that ant predation was an important driver of decomposer populations or decomposition in these systems, and we suspect redundancy at the top of the detrital food web dilutes the role of ants.

中文翻译：

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没有证据表明蚂蚁对温带草原凋落物分解产生自上而下的影响

蚂蚁在生态系统中扮演着多重角色，但它们影响温带草原分解过程的能力相对未知。我们调查了蚂蚁种群的抑制是否通过捕食某些分解者（例如螨虫和跳虫）和/或微生物活动和组成来影响草地的凋落物分解。在为期 59 周的实验过程中，我们进行了两次成功的蚂蚁抑制治疗（7 周，37% 抑制，第 1、10 周，70% 抑制，第 2 年）。然后，我们使用粗网和细网垃圾袋分析了蚂蚁抑制的效果，并评估了垃圾化学、微生物和节肢动物群落以及微生物酶活性。蚂蚁抑制工作减少了蚂蚁丰度并改变了蚂蚁、节肢动物分解者和非蚂蚁捕食者群落组成。然而，蚂蚁抑制不影响分解节肢动物的丰度、垃圾质量损失、微生物组成或垃圾袋中的酶活性。垃圾袋网眼尺寸没有改变微生物组成，这可能是由于未能排除分解者，因为螨虫和跳虫在细网眼袋中更多或同样丰富。然而，网格大小确实改变了垫料化学，这表明网格大小介导的微环境会影响分解环境，而不管无脊椎动物是否被排除在外。与细网眼垃圾袋相比，粗网眼垃圾袋具有更高浓度的微生物糖、木质素和 N 以及更低浓度的垃圾 C 和结晶纤维素。垃圾袋网眼大小可能会改变分解过程，而与无脊椎动物的丰度无关。