Grasslands provide a number of ecosystem services for human society. Degradation of grasslands results in the loss of biodiversity and leads to the deterioration of ecosystem functions. In order to accurately assess the influence of grassland degradation on belowground ecosystems, we conducted experiments on a temperate steppe with different levels of degradation and investigated the influence of degradation on soil quality and soil biotic communities. Our results showed that grassland degradation significantly decreased soil quality, with lower values of soil quality index (SQI) observed in the degraded grassland than the meadow steppe and the grassland from the forest-steppe ecotone. Changes in the SQI along the grassland degradation gradient were positively correlated with soil carbon stock and the aboveground biomass, and negatively correlated with the root shoot ratio. Nematode trophic diversity and the ratio of fungal to bacterial PLFA were lower in the degraded grassland than the grassland from the forest-steppe ecotone. The dissimilarities in soil microbial and nematode community composition increased with the changes in soil quality index. Our results indicate that soil quality index based on the minimum data sets could effectively assess the influence of grassland degradation on soil biodiversity and ecosystem function. In order to effectively restore degraded grasslands, the key contributors to the soil quality, such as soil carbon, should be taken on priority basis for revitalizing the soil biodiversity and ecosystem function.

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半干旱温带草原草地退化对土壤质量和土壤生物群落的影响

草原为人类社会提供了许多生态系统服务。草原的退化导致生物多样性的丧失并导致生态系统功能的恶化。为了准确评估草地退化对地下生态系统的影响，我们在具有不同退化程度的温带草原上进行了实验，并研究了退化对土壤质量和土壤生物群落的影响。我们的研究结果表明，草地退化显着降低了土壤质量，退化草地中的土壤质量指数（SQI）值比草甸草原和森林草原过渡带的草地要低。沿着草地退化梯度的SQI变化与土壤碳储量和地上生物量呈正相关，与根冠比率负相关。退化草地的线虫营养多样性和真菌与细菌PLFA的比率低于森林草原过渡带的草地。土壤微生物和线虫群落组成的差异随着土壤质量指数的变化而增加。我们的结果表明，基于最小数据集的土壤质量指数可以有效评估草地退化对土壤生物多样性和生态系统功能的影响。为了有效恢复退化的草原，应优先考虑土壤质量的关键因素，例如土壤碳，以活化土壤生物多样性和生态系统功能。退化草地的线虫营养多样性和真菌与细菌PLFA的比率低于森林草原过渡带的草地。土壤微生物和线虫群落组成的差异随着土壤质量指数的变化而增加。我们的结果表明，基于最小数据集的土壤质量指数可以有效评估草地退化对土壤生物多样性和生态系统功能的影响。为了有效恢复退化的草原，应优先考虑土壤质量的关键因素，例如土壤碳，以活化土壤生物多样性和生态系统功能。退化草地的线虫营养多样性和真菌与细菌PLFA的比率低于森林草原过渡带的草地。土壤微生物和线虫群落组成的差异随着土壤质量指数的变化而增加。我们的结果表明，基于最小数据集的土壤质量指数可以有效评估草地退化对土壤生物多样性和生态系统功能的影响。为了有效恢复退化的草原，应优先考虑土壤质量的关键因素，例如土壤碳，以活化土壤生物多样性和生态系统功能。我们的结果表明，基于最小数据集的土壤质量指数可以有效评估草地退化对土壤生物多样性和生态系统功能的影响。为了有效恢复退化的草原，应优先考虑土壤质量的关键因素，例如土壤碳，以活化土壤生物多样性和生态系统功能。我们的结果表明，基于最小数据集的土壤质量指数可以有效评估草地退化对土壤生物多样性和生态系统功能的影响。为了有效恢复退化的草原，应优先考虑土壤质量的关键因素，例如土壤碳，以活化土壤生物多样性和生态系统功能。