Ants are undisputed masters at transforming the local environments they inhabit, with subsequent vast effects on soil chemical and hydrological processes. Yet, it remains unclear how deep into the subsoil these effects range, as most ant-soil studies focus on the topsoil. Furthermore, studies quantifying these effects on podzolized, and nutrient-poor heathland soils remain scarce. We excavated 15 ant mounds on a long-term, unmanaged heathland in Denmark. We sampled soil moisture, soil penetration resistance (SPR), pH, total phosphorous content, and the thickness of each soil horizon at three positions at each mound: directly below the mound, at the edge of the mound, and an adjacent undisturbed reference soil. Results revealed that ant activity reduced soil moisture, loosened the soil, and increased the flow of total phosphorus to the deeper layers. Importantly, the cemented spodic horizons (hardpans) with waterlogging properties were penetrated by ant digging, resulting in potentially higher water infiltration into the subsoil. The ant activity within the otherwise undisturbed sandy subsoil below the hard pan caused a slight alteration in the thickness of each soil horizon and chemistry. These patchy, small-scale disturbances (mounds covered 0.06 % of the site) increase heathland soil heterogeneity and affect subsoil properties in time. We conclude that ant mounds may play a previously overlooked role in heathland soil dynamics by penetrating the heathland hardpans and manipulating soil chemistry and soil moisture. We argue that a viable mound-forming ant community is valuable for the soil heterogeneity of dry heathland ecosystems.

中文翻译：

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荒地中蚂蚁坐骑（Formica exsecta）对底土特性的影响

蚂蚁是无可争议的改变它们所栖息的当地环境的大师，随后对土壤化学和水文过程产生巨大影响。然而，目前尚不清楚这些影响范围有多深，因为大多数蚂蚁土壤研究都集中在表土上。此外，量化这些对灰化土和营养贫乏的荒地土壤的影响的研究仍然很少。我们在丹麦一片长期无人管理的荒地上挖掘了 15 个蚁丘。我们在每个土丘的三个位置对土壤湿度、土壤渗透阻力 (SPR)、pH、总磷含量和每个土层厚度进行了采样：土丘正下方、土丘边缘和相邻的未受干扰的参考土壤。结果显示，蚂蚁活动降低了土壤湿度，疏松了土壤，并增加了总磷向深层的流动。重要的是，具有防涝特性的胶结地层（硬地层）被蚂蚁挖掘所渗透，导致潜在更高的水渗入底土。硬盘下方未受干扰的沙质底土中的蚂蚁活动导致每个土壤层的厚度和化学成分发生轻微变化。这些零散的小规模扰动（土丘覆盖了场地的 0.06%）增加了石南地土壤的异质性并及时影响底土特性。我们得出的结论是，蚁丘可能通过穿透石南地硬土并操纵土壤化学和土壤湿度，在石南地土壤动力学中发挥着以前被忽视的作用。我们认为，一个可行的蚁丘形成蚂蚁群落对于干旱石南生态系统的土壤异质性很有价值。