Climatic history can shape the functioning of soil microbial communities and thus rates of ecosystem processes such as organic matter decomposition. For example, broad spatial scale differences in climatic history, such as contrasting precipitation regimes, have been shown to generate unique microbial functional responses to contemporary moisture conditions. Yet it is an open question as to whether local differences in soil microclimate similarly influence the functional potential of decomposer communities. Here, we use a multi-scale approach within and among two temperate forest field sites to investigate this question. Soils from fifty-four microsites, that vary in their soil moisture climate-regimes, were used as inocula for a common leaf litter (Quercus rubra L.) in a controlled, laboratory microcosm study. Microcosms were placed under dry, mesic and wet lab-moisture conditions and the rate of carbon (C) mineralization of the litter was measured over 202 days. Our results reveal differences in decomposition rates under controlled conditions that highlight broad-scale functional differences between the soil communities at each site. Specifically, we found that C mineralization differed by as much as two-fold for soil communities when compared between the sites. Our results also show that functional differences of soil communities are observable within one site but not the other. In the site where local-scale functional legacies were apparent, the historical soil moisture microclimate-regimes generated as much as an 89% change in C mineralization rates of the leaf litter under the same contemporary, lab-imposed moisture conditions. A similar pattern was not observable in the other site; instead, laboratory moisture conditions explained almost all variation in C mineralization. Notably, for the site with pronounced local-scale functional legacies, there was much greater within-site variation in field-soil microsite moisture than at the site which did not exhibit functional legacies, suggesting that the extent of local-scale variation in microclimate may act as control on whether local-scale functional legacies are observed. Regardless of whether this mechanism does explain our findings, our observations do confirm those from prior studies where regional-scale moisture-regime differences shape microbial function, and extend this prior work by providing evidence that pronounced local-scale differences in soil moisture microclimate-regimes are associated with microbial functional legacies.

气候历史可以影响土壤微生物群落的功能，从而影响有机物质分解等生态系统过程的速率。例如，气候历史中广泛的空间尺度差异，例如对比降水制度，已被证明会产生对当代水分条件的独特微生物功能反应。然而，土壤微气候的局部差异是否同样影响分解者群落的功能潜力，这是一个悬而未决的问题。在这里，我们在两个温带森林场地内部和之间使用多尺度方法来研究这个问题。来自 54 个微型站点的土壤，它们的土壤水分气候状况各不相同，被用作普通落叶 ( Quercus rubra) 的接种物L.) 在一项受控的实验室微观研究中。微观世界被放置在干燥、中等和潮湿的实验室湿度条件下，并在 202 天内测量了垃圾的碳 (C) 矿化率。我们的结果揭示了在受控条件下分解率的差异，突出了每个地点土壤群落之间的广泛功能差异。具体而言，我们发现在不同地点之间进行比较时，土壤群落的 C 矿化差异高达两倍。我们的结果还表明，土壤群落的功能差异在一个地点内是可观察到的，而在另一个地点则不是。在局部规模功能遗产明显的地点，历史土壤水分小气候制度在同一当代情况下产生了高达 89% 的落叶落叶 C 矿化率变化，实验室施加的水分条件。在另一个站点没有观察到类似的模式；相反，实验室水分条件几乎解释了 C 矿化的所有变化。值得注意的是，对于具有明显局部尺度功能遗产的场地，场地土壤微场地水分的场地内变化比没有表现出功能遗产的场地大得多，这表明局部尺度小气候变化的程度可能作为对是否观察到局部规模的功能遗产的控制。不管这种机制是否确实解释了我们的发现，我们的观察确实证实了先前研究中区域尺度水分状况差异影响微生物功能的研究，