Understanding the relationship of soil carbon storage and species diversity in grasslands can provide insights into managing these ecosystems. We studied relationships among soil C and plant species richness within ~ 9700 ha of grasslands in Colorado, US. Using 141 grassland transects, we tested how soil C was related to plant species richness, grassland type, soil texture, and prairie dog presence. Soil C was significantly, positively related to plant species richness, while native perennial graminoid species richness exhibited an even stronger positive relationship. However, the relationship of soil C and plant richness was not found in all three grassland types studied, but instead was unique to the most common grassland type, mixed grass prairie, and absent from both xeric tallgrass and mesic tallgrass prairie. The presence of a single indicator species, Andropogon gerardii, showed a significant, positive relationship with soil carbon. Our best possible model explained 45% of the variance in soil C using species richness, grassland type, and their interaction. Surprisingly, soil C was negatively related to soil clay, suggesting that surface clays amplify evaporation and water runoff rather than protecting soil organic matter from decomposition. Soil C was negatively related to prairie dog presence, suggesting that prairie dogs do not enhance soil carbon sequestration; in fact, prairie dog occupied sites had significantly lower soil C, likely related to loss of topsoil from prairie dog colonies. Our results suggest that management for species richness provides the co-benefit of soil C storage, and high clay and prairie dog disturbance compromises both.

了解草原土壤碳储量和物种多样性的关系可以为管理这些生态系统提供见解。我们研究了美国科罗拉多州约 9700 公顷草原内土壤碳与植物物种丰富度之间的关系。我们使用 141 个草原样带，测试了土壤 C 与植物物种丰富度、草原类型、土壤质地和草原土拨鼠存在的关系。土壤 C 与植物物种丰富度呈显着正相关，而原生多年生禾本科植物物种丰富度表现出更强的正相关关系。然而，在所研究的所有三种草地类型中都没有发现土壤 C 和植物丰富度的关系，而是最常见的草地类型，混合草草原，并且在干旱高草和中生高草草原中都没有发现。Andropogon gerardii与土壤碳呈显着正相关。我们最好的模型使用物种丰富度、草地类型及其相互作用来解释土壤 C 的 45% 的变化。令人惊讶的是，土壤 C 与土壤粘土呈负相关，这表明表面粘土会放大蒸发和水径流，而不是保护土壤有机质免于分解。土壤 C 与土拨鼠的存在呈负相关，表明土拨鼠不会增强土壤碳固存；事实上，土拨鼠占据的地点的土壤 C 显着降低，这可能与土拨鼠群落表土流失有关。我们的研究结果表明，物种丰富度管理提供了土壤碳储存的共同利益，而高粘土和草原土拨鼠干扰会损害两者。