Earthworms play a key role as soil bioengineers, but livestock farming and croplands can impact on the composition, structure, and functioning of earthworm communities. This study aimed to quantify the effects of replacing natural grasslands with crop rotations on the seasonal dynamics of key attributes of earthworm communities and explore soil physicochemical properties as mechanisms behind these effects. We conducted paired samplings on seven sites across Uruguay, comparing earthworm communities in soils under grazed natural grasslands and adjacent croplands, considering earthworm species composition, richness, diversity, and evenness, biomass, density, and mean body weight, over five consecutive seasons. Results revealed a clear negative impact of croplands on earthworm communities, showing substantial reductions in all considered attributes. Observed changes were attributed to environmental filters limiting the occurrence of larger exotic earthworm species in croplands, and variations in soil physicochemical properties were identified as potentially mediating some of these effects, including soil water regime (particularly affecting juvenile individuals) and soil organic matter content. These impacts resulted in a shift to dominance of r strategists (smaller, surface-feeding species such as spp. in croplands compared to larger deeper-burrowing species in grasslands) and reduced functional composition of earthworm communities. Furthermore, seasonal dynamics revealed that differences between land uses were more pronounced during wetter periods, underscoring the relevance of seasonal variations when evaluating land use impacts on earthworm communities. Earthworms mean body weight resulted a useful attribute to be included in earthworm's assessments, allowing to identify impacts in community functional composition and suggesting size dependent mechanisms. Additional research is required to comprehensively understand the mechanisms behind these patterns and to develop more sustainable agricultural practices by considering soil fauna.

中文翻译：

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农业土地利用的季节性动态对蚯蚓群落的影响：深入了解多样性、丰度和功能组成

蚯蚓作为土壤生物工程师发挥着关键作用，但畜牧业和农田可以影响蚯蚓群落的组成、结构和功能。本研究旨在量化轮作取代天然草地对蚯蚓群落关键属性季节性动态的影响，并探索土壤理化特性作为这些影响背后的机制。我们在乌拉圭各地的七个地点进行了配对采样，比较了放牧的天然草地和邻近农田下土壤中的蚯蚓群落，考虑了连续五个季节的蚯蚓物种组成、丰富度、多样性和均匀度、生物量、密度和平均体重。结果显示，农田对蚯蚓群落产生了明显的负面影响，所有考虑的属性均大幅减少。观察到的变化归因于环境过滤器限制了农田中较大的外来蚯蚓物种的出现，土壤理化性质的变化被认为可能介导其中一些影响，包括土壤水状况（特别是影响幼体）和土壤有机质含量。这些影响导致蚯蚓群落的主导地位发生转变（农田中较小的地表食性物种，如农田中的物种，与草原中较大的深层穴居物种相比），并减少了蚯蚓群落的功能组成。此外，季节动态表明，在湿润时期，土地利用之间的差异更为明显，这强调了在评估土地利用对蚯蚓群落影响时季节性变化的相关性。蚯蚓的平均体重是一个有用的属性，可以纳入蚯蚓的评估中，从而可以确定对群落功能组成的影响并提出大小依赖机制。需要进行更多的研究来全面了解这些模式背后的机制，并通过考虑土壤动物来开发更可持续的农业实践。