Knowledge of disturbance interactions is fundamental to improved understanding of plant community dynamics and the development of management practices aimed at increasing resilience of grassland ecosystems. In this study, we evaluated grassland responses to multiple disturbance interactions in a series of 2-year, randomized complete block experiments repeated in 2016 and 2017 in the Nebraska Sandhills, mixed-grass prairie. Soil type was a Valentine fine sand (mixed, mesic Ustipsamments). Each experiment contained a 3 × 2 × 2 factorial arrangement of soil disturbance (no soil disturbance, soil disturbance with no seed, and soil disturbance with forb seeding), water addition (water, no water), and fire treatments (fire, no fire). In both experiments, fire had the most prominent impact on plant community composition and biomass. Fire increased bare ground and reduced canopy cover of annual plants in the first year. However, annual plants recovered in the second year. Forbs, especially marestail (Conyza canadensis), were most significantly affected by fire. Other plant groups, including warm- and cool-season grasses, natives and exotics, and so on, varied in cover and biomass in response to interacting disturbances and temporal variability. Forb seedling establishment was negatively affected by temporal variability in weather patterns. Differences in plant community response between experiments were likely due to drought in 2017. Overall, the plant community showed resilience to the multiple disturbance interactions. We did not see evidence of large or non-linear changes in plant community structure over the short term in these grasslands.

中文翻译：

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草原植物群落对相互作用干扰和时间变异性的响应

了解干扰相互作用对于提高对植物群落动态的理解和发展旨在提高草原生态系统恢复力的管理实践至关重要。在这项研究中，我们在 2016 年和 2017 年在内布拉斯加州沙丘混合草草原进行的一系列为期 2 年的随机完整块实验中评估了草原对多种干扰相互作用的反应。土壤类型是瓦伦丁细沙（混合，中质 Ustipsamments）。每个试验包含土壤扰动（无土壤扰动、无种子土壤扰动和有草本播种的土壤扰动）、加水（水，无水）和火处理（火，无火）的 3 × 2 × 2 因子排列）。在这两个实验中，火灾对植物群落组成和生物量的影响最为显着。火灾在第一年增加了裸露的地面并减少了一年生植物的冠层覆盖。然而，一年生植物在第二年恢复。Forbs，尤其是马尾鱼（Conyza canadensis )，受火灾影响最为显着。其他植物群，包括暖季和冷季草、本地和外来植物等，其覆盖和生物量因相互作用的干扰和时间变化而变化。天气模式的时间变异性对福布幼苗的建立产生了负面影响。实验之间植物群落反应的差异可能是由于 2017 年的干旱造成的。总体而言，植物群落对多重干扰相互作用表现出弹性。我们没有看到这些草原在短期内植物群落结构发生大的或非线性变化的证据。