Data from: Prolonged impacts of past agriculture and ungulate overabundance on soil fungal communities in restored forests

Soil fungi can help improve ecosystem restoration, yet our understanding of how they reassemble in degraded land is limited. Here, using DNA metabarcoding, we studied the fungal community structure in reforested sites following agricultural abandonment and ungulate overabundance. Two treatments, namely 'reforestation using different numbers of tree species' and 'deer exclusion,' have been applied for multiple decades in the study sites. We found that local fungal richness (alpha diversity) and total fungal richness (gamma diversity) were 1.9–2.9 and 1.3–1.9 times greater, respectively, in reforested stands than in natural forests. These results were regardless of the number of tree species planted in the reforested stands. Conversely, reforested stands had a spatially homogenized community structure with relatively lower degrees of compositional dissimilarity among sites within each stand (beta diversity). These findings were attributable to lower environmental heterogeneity, stronger dispersal limitation, and a comparatively shorter time since the onset of community assembly in reforested stands. Deer exclosures had no detectable effect on fungal community structure. Overall, the agricultural legacy in fungal community structure appears to have persisted for decades, even under proactive restoration of aboveground vegetation. Direct human intervention belowground may therefore be necessary for the recovery of soil biota once altered.

土壤真菌可助力生态系统修复，但目前学界对其在退化土地中的群落重新组装机制仍认知有限。本研究借助DNA元条形码测序（DNA metabarcoding）技术，针对农业弃耕与大型有蹄类动物过度繁衍后的造林修复样地，开展真菌群落结构分析。研究样地已开展长达数十年的两组干预处理：分别为「不同树种数量的造林修复」与「鹿类禁入」。研究发现，造林修复林分的局部真菌丰富度（α多样性，alpha diversity）与总真菌丰富度（γ多样性，gamma diversity）分别较天然林高出1.9至2.9倍、1.3至1.9倍，且该结果不受造林修复林分所种植树种数量的影响。与之相反，造林修复林分的群落结构呈现空间均质化特征，单林分内各样地间的群落组成差异度（β多样性，beta diversity）相对更低。上述现象可归因于造林修复林分的环境异质性更低、扩散限制更强，且群落组装起始时间相对较短。鹿类禁入处理对真菌群落结构未产生可检测到的影响。总体而言，即便对地上植被开展了主动修复，农业活动遗留的真菌群落结构印记仍可留存数十年。由此可见，一旦地下生态系统遭到扰动，需通过直接的地下人为干预，方能实现土壤生物群落的恢复。