Earthworms are a key faunal group in agricultural soils, but little is known on how farming systems affect their communities across wide climatic gradients and how farming system choice might mediate earthworms' exposure to climate conditions. Here, we studied arable soil earthworm communities on wheat fields across a European climatic gradient, covering nine pedo‐climatic zones, from Mediterranean to Boreal (S to N) and from Lusitanian to Pannonian (W to E). In each zone, 20–25 wheat fields under conventional or organic farming were sampled. Community metrics (total abundance, fresh mass, and species richness and composition) were combined with data on climate conditions, soil properties, and field management and analyzed with mixed models. There were no statistically discernible differences between organic and conventional farming for any of the community metrics. The effects of refined arable management factors were also not detected, except for an elevated proportion of subsurface‐feeding earthworms when crop residues were incorporated. Soil properties were not significantly associated with earthworm community variations, which in the case of soil texture was likely due to low variation in the data. Pedo‐climatic zone was an overridingly important factor in explaining the variation in community metrics. The Boreal zone had the highest mean total abundance (179 individuals m−2) and fresh mass (86 g m−2) of earthworms while the southernmost Mediterranean zones had the lowest metrics (<1 individual m−2 and <1 g m−2). Within each field, species richness was low across the zones, with the highest values being recorded at the Nemoral and North Atlantic zones (mean of 2–3 species per field) and declining from there toward north and south. No litter‐dwelling species were found in the southernmost, Mediterranean zones. These regional trends were discernibly related to climate, with the community metrics declining with the increasing mean annual temperature. The current continent‐wide warming of Europe and related increase of severe and rapid onsetting droughts will likely deteriorate the living conditions of earthworms, particularly in southern Europe. The lack of interaction between the pedo‐climatic zone and the farming system in our data for any of the earthworm community metrics may indicate limited opportunities for alleviating the negative effects of a warming climate in cereal field soils of Europe.

中文翻译：

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欧洲气候梯度不同农业系统下的麦田蚯蚓


蚯蚓是农业土壤中的关键动物群，但人们对农业系统如何在广泛的气候梯度上影响其社区以及农业系统的选择如何介导蚯蚓暴露于气候条件知之甚少。在这里，我们研究了欧洲气候梯度上麦田上的耕地土壤蚯蚓群落，涵盖从地中海到北方（南到北）和从卢西塔尼亚到潘诺尼亚（西到东）的九个土壤气候区。在每个区域，对 20-25 块传统或有机农业的麦田进行了采样。将群落指标（总丰度、新鲜质量、物种丰富度和组成）与气候条件、土壤特性和田间管理数据相结合，并使用混合模型进行分析。对于任何社区指标，有机农业和传统农业之间在统计上都没有明显的差异。精制耕作管理因素的影响也没有被检测到，除了当掺入作物残留物时，地下取食的蚯蚓的比例增加。土壤特性与蚯蚓群落变化没有显著相关性，在土壤质地的情况下，这可能是由于数据的低变化。土壤气候带是解释群落指标变化的压倒一切的重要因素。北方地区的蚯蚓平均总丰度（179 个个体 m-2）和新鲜质量 （86 g m-2），而最南端的地中海地区的指标最低（<1 个体 m-2 和 <1 g m-2）。在每个田地中，各区域的物种丰富度较低，最高值出现在 Nemoral 和 North Atlantic 地区（平均每块田地 2-3 种），并且从那里向北和向南下降。 在最南端的地中海地区没有发现垃圾栖息物种。这些区域趋势与气候明显相关，群落指标随着年平均气温的升高而下降。当前欧洲大陆范围的变暖以及相关的严重和快速干旱的增加可能会恶化蚯蚓的生活条件，尤其是在南欧。对于任何蚯蚓群落指标，我们的数据中土壤气候带和农业系统之间缺乏交互作用，这可能表明减轻气候变暖对欧洲谷物田土壤的负面影响的机会有限。